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Showing 1201 - 1400 of 3562 Journals sorted alphabetically
Journal of Health Economics and Outcomes Research     Open Access   (Followers: 1)
Journal of Health Promotion and Behavior     Open Access  
Journal of Health Research and Reviews     Open Access  
Journal of Health Science and Medical Research     Open Access  
Journal of Health Science Research     Open Access  
Journal of Health Sciences     Open Access   (Followers: 1)
Journal of health sciences     Open Access  
Journal of Health Sciences / Sağlık Bilimleri Dergisi     Open Access  
Journal of Health Sciences and Medicine     Open Access  
Journal of Health Sciences and Surveillance System     Open Access  
Journal of Health Sciences Scholarship     Open Access  
Journal of Health Specialties     Open Access  
Journal of Health Studies     Open Access  
Journal of Healthcare Informatics Research     Hybrid Journal   (Followers: 1)
Journal of Heavy Metal Toxicity and Diseases     Open Access  
Journal of Helminthology     Hybrid Journal   (Followers: 2)
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Journal of HIV for Clinical and Scientific Research     Open Access   (Followers: 1)
Journal of Hospital Medicine     Hybrid Journal   (Followers: 10)
Journal of Huazhong University of Science and Technology [Medical Sciences]     Hybrid Journal  
Journal of Human Hypertension     Hybrid Journal   (Followers: 3)
Journal of Human Rhythm     Open Access  
Journal of Human Transcriptome     Open Access  
Journal of Ideas in Health     Open Access  
Journal of Inflammation     Open Access   (Followers: 2)
Journal of Inflammation Research     Open Access  
Journal of Injury and Violence Research     Open Access   (Followers: 7)
Journal of Innovation in Health Informatics     Open Access   (Followers: 17)
Journal of Institute of Medicine     Open Access  
Journal of Insulin Resistance     Open Access   (Followers: 1)
Journal of Interactional Research in Communication Disorders     Hybrid Journal   (Followers: 5)
Journal of Interferon & Cytokine Research     Hybrid Journal   (Followers: 3)
Journal of International Medical Research     Open Access   (Followers: 4)
Journal of Interventional Medicine     Open Access   (Followers: 1)
Journal of Investigative Medicine     Hybrid Journal   (Followers: 3)
Journal of Islamabad Medical & Dental College     Open Access  
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Journal of Karnali Academy of Health Sciences     Open Access   (Followers: 1)
Journal of Kathmandu Medical College     Open Access   (Followers: 1)
Journal of King Abdulaziz University : Medical Sciences     Open Access   (Followers: 2)
Journal of Laboratory Medicine     Hybrid Journal   (Followers: 27)
Journal of Laryngology and Voice     Open Access   (Followers: 11)
Journal of Lasers in Medical Sciences     Open Access  
Journal of Law, Medicine & Ethics     Hybrid Journal   (Followers: 24)
Journal of Legal Medicine     Hybrid Journal   (Followers: 7)
Journal of Limb Lengthening & Reconstruction     Open Access  
Journal of Lumbini Medical College     Open Access   (Followers: 1)
Journal of Mahatma Gandhi Institute of Medical Sciences     Open Access  
Journal of Manipulative and Physiological Therapeutics     Hybrid Journal   (Followers: 6)
Journal of Manmohan Memorial Institute of Health Sciences     Open Access   (Followers: 1)
Journal of Marine Medical Society     Open Access  
Journal of Materials Science : Materials in Medicine     Hybrid Journal   (Followers: 4)
Journal of Maternal and Child Health     Open Access  
Journal of Mechanics in Medicine and Biology     Hybrid Journal  
Journal of Medical and Biological Engineering     Hybrid Journal   (Followers: 4)
Journal of Medical and Biomedical Sciences     Open Access   (Followers: 2)
Journal of Medical Case Reports     Open Access   (Followers: 1)
Journal of Medical Cases     Open Access   (Followers: 6)
Journal of Medical Colleges of PLA     Full-text available via subscription  
Journal of Medical Disorders     Open Access  
Journal of Medical Economics     Hybrid Journal   (Followers: 8)
Journal of Medical Education and Curricular Development     Open Access   (Followers: 6)
Journal of Medical Ethics     Partially Free   (Followers: 25)
Journal of Medical Ethics and History of Medicine     Open Access   (Followers: 15)
Journal of Medical Humanities     Hybrid Journal   (Followers: 21)
Journal of Medical Hypotheses and Ideas     Open Access  
Journal of Medical Imaging and Health Informatics     Full-text available via subscription   (Followers: 1)
Journal of Medical Investigation and Practice     Open Access  
Journal of Medical Laboratory and Diagnosis     Open Access  
Journal of Medical Law and Ethics     Full-text available via subscription   (Followers: 15)
Journal of Medical Microbiology     Full-text available via subscription   (Followers: 6)
Journal of Medical Sciences     Open Access  
Journal of Medical Sciences     Open Access  
Journal of Medical Screening     Hybrid Journal   (Followers: 6)
Journal of Medical Signals and Sensors     Open Access   (Followers: 3)
Journal of Medical Society     Open Access  
Journal of Medical Systems     Hybrid Journal  
Journal of Medical Toxicology     Hybrid Journal   (Followers: 6)
Journal of Medical Ultrasound     Open Access   (Followers: 2)
Journal of Medicinal Botany     Open Access  
Journal of Medicinal Chemistry     Hybrid Journal   (Followers: 197)
Journal of Medicine     Open Access   (Followers: 1)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Medicine and Philosophy     Hybrid Journal   (Followers: 8)
Journal of Medicine and the Person     Hybrid Journal  
Journal of Medicine in Scientific Research     Open Access  
Journal of Medicine in the Tropics     Open Access  
Journal of Medicine Research and Development     Open Access   (Followers: 3)
Journal of Medicine, Physiology and Biophysics     Open Access   (Followers: 5)
Journal of Medicines Development Sciences     Open Access   (Followers: 1)
Journal of Metabolomics & Systems Biology     Open Access  
Journal of Mind and Medical Sciences     Open Access   (Followers: 1)
Journal of Molecular Medicine     Hybrid Journal   (Followers: 11)
Journal of Movement Disorders     Open Access   (Followers: 2)
Journal of Muscle Research and Cell Motility     Hybrid Journal   (Followers: 1)
Journal of Nanotechnology in Engineering and Medicine     Full-text available via subscription   (Followers: 6)
Journal of Natural Medicines     Hybrid Journal  
Journal of Natural Science, Biology and Medicine     Open Access   (Followers: 3)
Journal of Nature and Science of Medicine     Open Access   (Followers: 4)
Journal of Negative and No Positive Results     Open Access  
Journal of Nepalgunj Medical College     Open Access  
Journal of Neurocritical Care     Open Access  
Journal of Neurodegenerative Diseases     Open Access   (Followers: 2)
Journal of Neurorestoratology     Open Access  
Journal of Neuroscience and Neurological Disorders     Open Access  
Journal of Nobel Medical College     Open Access  
Journal of Obesity and Bariatrics     Open Access  
Journal of Occupational Health     Open Access  
Journal of Occupational Therapy Education     Open Access   (Followers: 9)
Journal of Ocular Biology, Diseases, and Informatics     Hybrid Journal  
Journal of Oral Biology and Craniofacial Research     Full-text available via subscription  
Journal of Oral Health and Craniofacial Science     Open Access  
Journal of Orofacial Sciences     Open Access  
Journal of Otorhinolaryngology, Hearing and Balance Medicine     Open Access   (Followers: 1)
Journal of Ovarian Research     Open Access  
Journal of Ozone Therapy     Open Access  
Journal of Palliative Medicine     Hybrid Journal   (Followers: 47)
Journal of Paramedical Sciences & Rehabilitation     Open Access  
Journal of Parkinsonism and Restless Legs Syndrome     Open Access   (Followers: 2)
Journal of Parkinson’s Disease and Alzheimer’s Disease     Open Access  
Journal of Participatory Medicine     Open Access  
Journal of Patan Academy of Health Sciences     Open Access  
Journal of Pathogens     Open Access   (Followers: 1)
Journal of Patient Experience     Open Access  
Journal of Patient Safety and Risk Management     Hybrid Journal   (Followers: 1)
Journal of Patient-Centered Research and Reviews     Open Access  
Journal of Patient-Reported Outcomes     Open Access  
Journal of Periodontal Research     Hybrid Journal  
Journal of Personalized Medicine     Open Access   (Followers: 3)
Journal of Pest Science     Hybrid Journal   (Followers: 1)
Journal of Pharmaceutical Policy and Practice     Open Access   (Followers: 4)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 2)
Journal of Physiology-Paris     Hybrid Journal   (Followers: 2)
Journal of Pioneering Medical Sciences     Open Access  
Journal of Postgraduate Medicine     Open Access  
Journal of Pregnancy     Open Access   (Followers: 4)
Journal of Prevention & Intervention Community     Hybrid Journal   (Followers: 6)
Journal of Preventive Medicine and Public Health     Open Access  
Journal of Primary Prevention     Hybrid Journal   (Followers: 7)
Journal of Prosthodontic Research     Full-text available via subscription   (Followers: 1)
Journal of Prosthodontics     Hybrid Journal   (Followers: 2)
Journal of Receptor, Ligand and Channel Research     Open Access  
Journal of Regenerative Medicine     Partially Free   (Followers: 3)
Journal of Research in Medical Sciences     Open Access   (Followers: 2)
Journal of Science and Applications : Biomedicine     Open Access   (Followers: 1)
Journal of Science and Technology (Ghana)     Open Access   (Followers: 3)
Journal of Scientific Innovation in Medicine     Open Access  
Journal of Scientific Perspectives     Open Access   (Followers: 1)
Journal of Sensory Studies     Hybrid Journal   (Followers: 4)
Journal of Shaheed Suhrawardy Medical College     Open Access  
Journal of Shoulder and Elbow Arthroplasty     Open Access  
Journal of Sleep Disorders : Treatment & Care     Hybrid Journal   (Followers: 10)
Journal of South American Earth Sciences     Hybrid Journal   (Followers: 5)
Journal of Spinal Cord Medicine     Hybrid Journal   (Followers: 4)
Journal of Spinal Disorders & Techniques     Hybrid Journal   (Followers: 2)
Journal of Sports Medicine and Allied Health Sciences : Official Journal of the Ohio Athletic Trainers Association     Open Access   (Followers: 1)
Journal of Stem Cell Therapy and Transplantation     Open Access   (Followers: 1)
Journal of Stomal Therapy Australia     Full-text available via subscription  
Journal of Strength and Conditioning Research     Hybrid Journal   (Followers: 73)
Journal of Substance Use     Hybrid Journal   (Followers: 14)
Journal of Surgical Academia     Open Access   (Followers: 1)
Journal of Surgical and Clinical Research     Open Access  
Journal of Surgical Case Reports     Open Access  
Journal of Surgical Education     Full-text available via subscription   (Followers: 3)
Journal of Surgical Technique and Case Report     Open Access  
Journal of Systemic Therapies     Full-text available via subscription   (Followers: 3)
Journal of Taibah University Medical Sciences     Open Access  
Journal of Telemedicine and Telecare     Hybrid Journal   (Followers: 12)
Journal of The Academy of Clinical Microbiologists     Open Access  
Journal of the American Association for Laboratory Animal Science     Full-text available via subscription   (Followers: 7)
Journal of the American College of Certified Wound Specialists     Hybrid Journal   (Followers: 2)
Journal of the American College of Clinical Wound Specialists     Hybrid Journal   (Followers: 2)
Journal of the American Medical Directors Association     Hybrid Journal   (Followers: 6)
Journal of the American Medical Informatics Association : JAMIA     Hybrid Journal   (Followers: 35)
Journal of the American Podiatric Medical Association     Full-text available via subscription   (Followers: 7)
Journal of the Anatomical Society of India     Full-text available via subscription  
Journal of the Anus, Rectum and Colon     Open Access  
Journal of The Arab Society for Medical Research     Open Access  
Journal of the Australasian College of Nutritional and Environmental Medicine     Full-text available via subscription  
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 1)
Journal of the Ceylon College of Physicians     Open Access  
Journal of the Chinese Medical Association     Open Access   (Followers: 2)
Journal of the College of Community Physicians of Sri Lanka     Open Access  
Journal of The Egyptian Public Health Association     Open Access   (Followers: 1)
Journal of the Formosan Medical Association     Open Access   (Followers: 2)
Journal of the Ghana Science Association     Full-text available via subscription   (Followers: 3)
Journal of the Grodno State Medical University     Open Access   (Followers: 1)
Journal of the History of Medicine and Allied Sciences     Hybrid Journal   (Followers: 17)
Journal of the International Society for Telemedicine and eHealth     Open Access   (Followers: 3)
Journal of the Learning Sciences     Hybrid Journal   (Followers: 17)
Journal of the Medical Library Association     Open Access   (Followers: 284)
Journal of the Medical Sciences (Berkala ilmu Kedokteran)     Open Access   (Followers: 1)
Journal of the National Medical Association     Full-text available via subscription  
Journal of the Peripheral Nervous System     Hybrid Journal   (Followers: 3)
Journal of the Postgraduate Institute of Medicine     Open Access  
Journal of the Renin-Angiotensin-Aldosterone System     Open Access   (Followers: 1)
Journal of the Royal Society of Medicine     Hybrid Journal   (Followers: 2)
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Journal of the Scientific Society     Open Access   (Followers: 1)
Journal of the Siena Academy of Sciences     Open Access   (Followers: 1)

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Similar Journals
Journal Cover
Journal of Prosthodontic Research
Journal Prestige (SJR): 1.203
Citation Impact (citeScore): 3
Number of Followers: 1  
 
  Full-text available via subscription Subscription journal
ISSN (Print) 1883-1958
Published by Elsevier Homepage  [3203 journals]
  • Masticatory function and bite force of mandibular single-implant
           overdentures and complete dentures: a randomized crossover control study
    • Abstract: Publication date: Available online 5 April 2019Source: Journal of Prosthodontic ResearchAuthor(s): Thuy Lam Vo, Manabu Kanazawa, Khaing Myat Thu, Mari Asami, Daisuke Sato, Shunsuke Minakuchi PurposeThe study aimed to compare the mixing ability (MA), comminuting ability (CA), and maximum bite force (MBF) of single-implant overdentures (IODs) and clinically acceptable complete dentures (CDs) through a randomized crossover control trial.MethodsNew CDs were fabricated for 22 patients. One implant was inserted in the middle of the symphyseal region for each patient. The patients were randomly allocated into two groups: group IC received an IOD, whereas group CI received a CD, for 2 months; the treatments were interchanged for the next 2 months. The MA, CA, and MBF were evaluated with the old CDs, new CDs (at the end of CD treatment period), and IODs (at the end of IOD treatment period).ResultsThe MA, CA, and MBF of the IODs were significantly higher than those of the old and new CDs (p 
       
  • Erratum to “Complete assessment of occlusal dynamics and establishment
           of a digital workflow by using target tracking with a three-dimensional
           facial scanner” [J Prosthodont Res (2019) 120–124]
    • Abstract: Publication date: Available online 5 April 2019Source: Journal of Prosthodontic ResearchAuthor(s): Jong-Eun Kim, Ji-Hyun Park, Hong-Seok Moon, June-Sung Shim
       
  • Evaluation of the trueness and precision of eight extraoral laboratory
           scanners with a complete-arch model: a three-dimensional analysis
    • Abstract: Publication date: Available online 4 April 2019Source: Journal of Prosthodontic ResearchAuthor(s): Faruk Emir, Simel Ayyıldız PurposeThe purpose of this study was to evaluate the trueness and precision of eight different extraoral laboratory scanners using three-dimensional (3D) analysis method.MethodAn arch-shaped master model was designed with a computer software (Rapidform XOR2) and manufactured with a 3D printer (Projet 3510 MP). Then the master model was digitized with an industrial 3D scanner (ATOS Core 200). With each scanner master model was scanned ten times and stereolithography (.stl) data were imported into 3D analysis software (Geomagic Control). Accuracy was determined with evaluating trueness and precision.ResultsTrueness of the scanners were 27.5 μm for 7 series; 30.9 μm for D640; 26.8 μm for D710; 33.3 μm for Activity 102; 32.4 μm for Tizian Smart-Scan; 21.6 μm for NeWay; 26.1 μm for inEOS X5 and 17,47 μm for D2000. 28.2 μm for laser; 32.9 μm for white light and 21.7 μm for blue light scanners. Significant differences were found between scanners (p 
       
  • Complete rehabilitation of patients with bruxism by veneered and
           non-veneered zirconia restorations with an increased vertical dimension of
           occlusion: an observational case-series study
    • Abstract: Publication date: Available online 21 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): S. Levartovsky, R. Pilo, A. Shadur, S. Matalon, E. Winocur PurposeTo assess the clinical performance of the complete rehabilitation of a series of patients with bruxism treated by teeth- and implant-supported veneered and non-veneered zirconia restorations with an increased vertical dimension of occlusion (VDO).MethodsTen patients with bruxism, aged 62–70 years, were treated with 108 veneered and 142 non-veneered zirconia restorations and attended the recall appointment. The mean observation period was 28.2 (±16.8) months. The patients were identified from records, and clinical details were retrieved from their files. In the recall appointment, the restorations were evaluated using modified California Dental Association (CDA) criteria. The periodontal probing depth, bleeding index, presence of caries and implant survival and success rate were recorded.ResultsNo biological complications were recorded for any restorations. The success and survival rate of all implants was 100%. The overall mean survival and success rate of all restorations was 99.6%. In the veneered group, the predominant complication was minor veneer chipping (13.9%) on the incisal edge, which required only polishing (grade 1); in the non-veneered group, the predominant failure was open proximal contacts between the implant restoration and adjacent teeth (9%); only one implant restoration needed repair. One restoration was replaced due to a horizontal tooth fracture.ConclusionsWithin the limitations of this study, we conclude that the survival and success rate of monolithic zirconia restorations installed in patients with bruxism was excellent, although the veneered zirconia restorations showed a high rate of minor veneer chipping, which required only polishing.
       
  • Change in the retentive force of Akers clasp for zirconia crown by
           repetitive insertion and removal test
    • Abstract: Publication date: Available online 20 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Akihiro Tanaka, Nahoko Miyake, Hiromi Hotta, Shinji Takemoto, Masao Yoshinari, Shuichiro Yamashita PurposeThe objective of this study was to evaluate the suitability of monolithic zirconia crowns (MZC) as abutment teeth of Akers clasps on removable partial dentures (RPD) by determining the change in retentive force after repetitive insertion/removal test.MethodsMZC and silver palladium copper alloy (Ag–Pd) full-metal crowns (FMC) for the mandibular second premolar were fabricated. Resin patterns of Akers clasps made with a 3D printer were casted with Ag–Pd or cobalt chromium alloy (Co–Cr). Clasp retentive force was measured with combinations of the crown and clasp materials. After measuring the initial retentive force of the clasp, repetitive insertion/removal test was carried out. The surface of the crown before and after the test was observed with an optical microscope and a scanning electron microscope; some specimens were subjected to element analysis by an electron probe microanalyzer.ResultsThe initial retentive force of the Co–Cr clasp was greater than the Ag–Pd clasp for both MZC and FMC. Clasp retentive force decreased with increasing number of insertion/removal cycles, and least reduction in force was observed for the Ag–Pd clasp on MZC. Wear marks were detected where FMC contacted the clasp. Discoloration of MZC due to wear of the Co–Cr clasp was observed.ConclusionsWhen repetitive insertion/removal of the clasp was performed on MZC, retentive force decreased depending on clasp materials. However, the amount of decrease in retentive force was comparable or small compared to conventional FMC. As a result, it was suggested that MZC could be used on abutment tooth for RPD.
       
  • Fifteen-year survival of resin-bonded vs full-coverage fixed dental
           prostheses
    • Abstract: Publication date: Available online 14 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): T. Yoshida, Y. Kurosaki, A. Mine, A. Kimura-Ono, T. Mino, S. Osaka, S. Nakagawa, K. Maekawa, T. Kuboki, H. Yatani, A. Yamashita PurposeWe clarified cumulative survival and event-free rates of resin-bonded fixed dental prostheses (RBFDPs) and compared them to those of fixed dental prostheses (FDPs) to refine risk factors for non-survival/event and use of tooth extraction after the period of non-survival/event.MethodsStudy subjects were selected among all patients who consecutively attended the Fixed Prosthodontic Clinic of Okayama University Hospital. Eligible patients were those who received 3-unit metal-framed 2-retainer (wing–wing) RBFDPs or conventional full-coverage FDPs (RBFDPs/FDPs: 129/177 prostheses). Data were analyzed by Kaplan–Meier analysis with the log-rank test, Mann–Whitney test, chi-square test, and Cox proportional hazards analysis.ResultsThe 15-year cumulative survival rates were 66.5% for the RBFDP group and 61.6% for the FDP group, which were not significantly different (p = 0.59). The 15-year cumulative event-free rates were 53.4% for the RBFDP group and 59.2% for the FDP group, which were not significantly different (p = 0.52). No significant risk factors related to non-survival and event-free of RBFDPs/FDPs were identified in the analysis model using treatment method, sex, age, number of remaining teeth, and treatment site as explanatory variables. The number of cases in which RBFDPs/FDPs resulted in non-survival due to abutment tooth extraction was significantly lower in RBFDPs (p 
       
  • Influence of different preparation forms on the loading-bearing capacity
           of zirconia cantilever FDPs. A laboratory study
    • Abstract: Publication date: Available online 14 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Shaza Bishti, Carsten Jäkel, Matthias Kern, Stefan Wolfart PurposeTo investigate the impact of inlay design and number of retainer wings on the failure load of all-ceramic resin-bonded inlay-retained cantilever fixed dental prostheses (IRCFDPs) made from a computer-aided design/computer-aided manufacturing (CAD/CAM) yttrium-oxide partially-stabilized zirconia framework(Y-TZP).MethodsSixty-four extracted human first molars were divided according to preparation design into four groups. Teeth were provided with IRCFDPs representing a premolar pontic and a retainer of variable design: (R1S) shallow inlay/one lingual retainer wing, (R2S) shallow inlay/two retainer wings (lingual/buccal), (R1D) deep inlay/one lingual retainer wing and (R2D) deep inlay/two retainer wings (lingual/buccal). All IRCFDPs were cemented using adhesive resin. Quasi-static fracture strength (QSFS) was tested for 32 specimens after 3 days in a universal testing machine (UTM). The other specimens were stored in a water bath (150 days/37 °C) and thermocycled (37,500 times, 5–55 °C); then exposed to dynamic loading in a chewing simulator (50 N/1,200,000 cycles).ResultsThe median QSFS (N) for the different designs were: R1S:105.1, R1D:167.5, R2S:147.9, R2D:232.3. The number of retainer wings had a statistically significant influence on the fracture load of both groups, whereas the inlay design had an impact only in the double-retainer wing group. Under dynamic loading, lower failure loads within all groups were reported except for the group R2S. The number of retainer wings continued to significantly influence the failure loads of both groups, whereas no influence of inlay design could be revealed.ConclusionsDouble-retainer IRCFDPs showed promising results for replacing single premolars. The inlay design seems to have no significant influence on the fracture strength of these restorations.
       
  • Fatigue damage of monolithic posterior computer aided designed/computer
           aided manufactured crowns
    • Abstract: Publication date: Available online 13 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Maximiliane Amelie Schlenz, Alexander Schmidt, Peter Rehmann, Bernd Wöstmann PurposeTo analyse fatigue damage of monolithic computer-aided-designed/computer-aided-manufactured (CAD/CAM)-materials after loading with high masticatory forces in standardized posterior crowns in a mouth-motion-simulator.MethodsFor manufacturing of test specimens (5 groups, 16 specimens each), two corresponding Standard-Tessellation-Language-(STL)-data-sets (one for the teeth and one for the crowns) were designed. The teeth were CAD/CAM-milled of human third molars and the crowns of three different CAD/CAM composite blocks (Lava Ultimate,‘LU’; Brilliant Crios‘BC’; Cerasmart,‘CS’), one polymer-infiltrated-ceramic network (Vita Enamic,‘VE’) and a control group of lithium disilicate ceramics (IPS e.max CAD,‘EM’). Crowns were adhesively cemented with their corresponding luting system on the human teeth. Half of the specimens were light-cured (‘LC’) and the others were chemical-cured (‘CC’). A mouth-motion-simulator (WL-tec, 2 Hz, 37 °C) applied dynamic cyclic loading between 50–500 N for a period of 1 million cycles. Afterwards, a dye penetration test (aqueous basic-fuchsine) revealed damage of test specimens. Each specimen was sectioned into four equidistant slices and the area without damage was measured with a digital microscope (Zeiss) and radial cracks at the cementation surface were assessed. Data were subjected to Tukey’s test.ResultsAll specimens showed fatigue damage in the occlusal contact area. LU, BC and CS exhibited a significant greater area without damage compared to VE and EM (p 
       
  • The influence of prosthetic material on implant and prosthetic survival of
           implant-supported fixed complete dentures: a systematic review and
           meta-analysis
    • Abstract: Publication date: Available online 11 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Aimen Bagegni, Samir Abou-Ayash, Gerta Rücker, Ahmad Algarny, Wael Att PurposeEvaluating the impact of the prosthetic material on implant- and prosthetic survival of implant-supported fixed complete dentures.Study selectionElectronic and hand searches were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify clinical studies including at least 10 patients restored with implant-supported dentures. The primary outcome was to evaluate the implant survival rate according to the applied restorative materials. The prosthetic survival rate was evaluated as secondary outcomes.ResultsForty-one of 2254 studies were finally selected. A statistically significant difference (p = 0.0337) was found between implant survival rates in the main restorative groups (metal-ceramic:97%(95%CI [0.96;0.98]), all-ceramic:99%(95%CI [0.98;1.00]), metal-resin:97%(95%CI [0.96;0.98])). Prosthetic survival rates were: (metal-ceramic:95%(95%CI [0.89;0.97]), all-ceramic:97%(95%CI [0.92;0.99]), metal-resin:97%(95%CI [0.95;0.98]), with no statistically significant difference (p = 0.3796) between the groups. Chipping incidence rates were as follows: metal-ceramic:8%(95%CI[0.03;0.20]), all-ceramic:15%(95%CI [0.06;0.32]), and metal-resin:22%(95%CI [0.13;0.33]).Five types of exact restorative materials were identified (porcelain-fused-to-non-precious alloy, porcelain-fused-to-zirconia, precious-metal-acrylic-resin, non-precious-metal-acrylic resin, and PMMA). Again, implant survival rates were statistically significantly influenced by the applied restorative materials (p = 0.0126), whereas, no significant differences were reported regarding prosthetic survival rate.ConclusionsProsthetic material selection seems to have no clinically relevant influence on implant- and prosthetic survival rate in implant-supported fixed complete dentures. Due to the high chipping rate, quantifying prosthetic survival alone does not seem to be a reliable tool for evaluating the outcome of the restorations and providing recommendations. These results, along with the obvious lack of evidence, suggest that clinicians must exercise caution whenever porcelain-fused-to-zirconia or metal-resin restorations are considered.
       
  • Chewing simulation of zirconia implant supported restorations
    • Abstract: Publication date: Available online 8 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Nadja Rohr, Marc Balmer, Johannes A. Müller, Sabrina Märtin, Jens Fischer PurposeTo test three potential prosthetic material options for zirconia implants in regard to their mechanical properties, loading and retention capacity as well as to record abrasion after chewing simulation followed by thermocyclic aging.MethodsMolar crowns (n = 96) of three different computer-aided design/computer-aided manufacturing (CAD/CAM) materials were produced and cemented on zirconia implants (ceramic.implant, Vita) with a diameter of 4.5 mm. Monolithic zirconia (Vita YZ [YZ] with RelyX Unicem 2 Automix [RUN], polymer-infiltrated ceramic (Vita Enamic [VE]) with Vita Adiva F-Cem [VAF] and acrylate polymer (CAD Temp [CT]) with RelyX Ultimate [RUL]. Fracture load and retentive force of the crowns were measured after 24 h water storage at 37 °C and after a chewing simulation followed by thermocyclic aging. Abrasion was recorded by matching stereolithography-data of the crowns obtained before and after chewing simulation. Additionally, the mechanical properties and bonding capabilities of the crown and cement materials were assessed.ResultsFracture load values were significantly highest for YZ > VE = CT. Retention force values did not differ significantly between the materials. The aging procedure did not affect the fracture load values nor the retention force significantly. Abrasion depth of the crowns was lowest for YZ followed by VE and CT. On unpolished crowns, abrasion of YZ and VE tended to be higher than on polished specimens.ConclusionsBased on the obtained in-vitro results, all tested materials can be recommended for the use on zirconia implants, although CT is only approved for temporary crowns. The loading and retention capacity of the materials were not significantly affected by aging.
       
  • Structural equation modeling of the impact of mandibular ridge form and
           denture quality on oral health-related quality of life in complete denture
           wearers
    • Abstract: Publication date: Available online 7 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Eijiro Yamaga, Yusuke Sato, Hitomi Soeda, Shunsuke Minakuchi PurposeTo examine the effect of mandibular ridge form and denture quality on oral health-related quality of life (OHRQoL) in complete denture wearers by using structural equation modeling (SEM) analysis of data before and after new complete denture insertion.MethodsFour hundred thirty-two edentulous patients who visited the Dental Hospital of Tokyo Medical and Dental University for new complete dentures were recruited. An intervention study design was conducted, including complete denture fabrication with SEM analysis. Mandibular ridge form, mandibular denture stability, accuracy of jaw relation record, and the Oral Health Impact Profile for edentulous subjects (OHIP-EDENT-J) total score before and after new complete denture insertion were used in the hypothesized model.ResultsTwo hundred and thirty-seven participants completed the research. SEM analysis demonstrated adequate model fit. Path coefficients of mandibular ridge form to OHIP-EDENT-J before and after insertion, and mandibular denture stability to OHIP-EDENT-J before insertion, were significant.ConclusionsThis study demonstrated that mandibular denture stability and mandibular ridge form are important to ensure successful complete denture therapy.
       
  • Vibratory stimulus to the masseter muscle impairs the oral fine motor
           control during biting tasks
    • Abstract: Publication date: Available online 2 March 2019Source: Journal of Prosthodontic ResearchAuthor(s): Abhishek Kumar, Yuto Tanaka, Kazutaka Takahashi, Anastasios Grigoriadis, Birgitta Wiesinger, Peter Svensson, Mats Trulsson PurposeTo investigated the effect of vibratory stimulus on masseter muscles during oral fine motor biting tasks.MethodsSixteen healthy individuals (age: 24.5 ± 2.4 years) participated in experiment I during which the participants were asked to “hold and split” half a roasted peanut placed on a force transducer with their front teeth. The participant performed ten series with ten trials of the “hold and split” behavioral task while vibratory stimulus was applied on the masseter muscle every alternate series. Further, fourteen participants participated (age: 25.2 ± 4.8 years) in experiment II during which they performed a series each of the behavioral task at baseline, an adjusted baseline without and with vibration as well as with and without visual feedback. Hold and split forces along with the variability of hold force and duration and force rate during the split were measured.ResultsThe results of the study showed an increase in the magnitude of the hold force (P = 0.002), force rate during the split (P 
       
  • Modal analysis of two different types of fixed implant-supported
           prostheses embedded in edentulous maxillae
    • Abstract: Publication date: Available online 28 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Akihiro Suzuki, Taiji Hoshiai, Hidemi Nakata, Takafumi Otomaru, Meiko Oki, Hisashi Taniguchi, Shohei Kasugai, Shinji Kuroda PurposeModal analysis has been used to monitor and quantify the vibration of each component of a prosthesis at its natural frequency. An understanding of the vibrational characteristics of a prosthesis can guide selection of the appropriate prosthesis configuration to prevent excessive stress. In this study, modal analysis of fixed implant-supported prostheses with 4 or 6 abutments in edentulous maxillae was performed.MethodsSixteen patients underwent maxillary dental implant treatment and received screw-fixed implant-supported prostheses (9 patients received 4-abutment prostheses and 7 patients received 6-abutment prostheses) in edentulous maxillae. An impact hammer was used for excitation of the prostheses, and vibration was detected on every crown of the prostheses. The modal parameters were determined in each subject. Furthermore, the modal shapes were compared at each natural frequency.ResultsThe median natural frequencies of subjects with 4- and 6-abutment prostheses were 697 and 781 Hz, respectively. The mean damping ratios did not differ significantly between 4- (8.2 ± 1.7%) and 6-abutment (6.6 ± 1.7%) prostheses (p = 0.125). The mean maximum displacements of fixed prostheses were significantly lower for 6-abutment (10.3 ± 3.3 μm) than for 4- (20.3 ± 9.1 μm) prostheses (p = 0.004). The median number of vectors in antiphase was significantly lower for 6- (4) than for 4-abutment prostheses (14) (p = 0.001).ConclusionsThe current study demonstrated less adverse vibration in the 6-abutment prostheses than in the 4-abutment prostheses, suggesting that modal analysis can contribute to novel future developments in the designs of dental implant prostheses.
       
  • Clinical performance of zirconia–ceramic cantilever fixed partial
           dentures—Longitudinal nine-year results from a prospective, randomized,
           controlled pilot study
    • Abstract: Publication date: Available online 22 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Wolfgang Bömicke, Peter Rammelsberg, Andreas Zenthöfer, Brigitte Ohlmann PurposeThe aim of this study was to prospectively compare the clinical performance of veneered zirconia cantilever fixed partial dentures (Z-CFPDs) and metal–ceramic CFPDs (MC-CFPDs) over 9 years of follow-up in terms of survival.MethodsTwenty-one participants were assigned by simple randomization to receive either 1 Z-CFPD (n = 11) or 1 MC-CFPD (n = 10). CFPDs were retained by 2 full crowns and replaced a missing premolar or a central or lateral incisor. Modified USPHS (United States Public Health Service) criteria were used to classify material chipping, retention, marginal integrity, secondary caries, and color of the restorations. The satisfaction of the study participants with the esthetics of their restorations was surveyed; pocket probing depths (PPD), plaque index (PI), and gingival index (GI) were also measured. Study groups were compared by use of U tests (continuous variables), or by use of Fisher exact probability tests (categorical variables) with α = 0.05.ResultsSixteen participants (n = 8 with a Z-CFPD and n = 8 with an MC-CFPD) attended the 9-year follow-up examination (response rate: 76.2%). Over the 9-year study period, survival of 50% for Z-CFPDs and 75% for MC-CFPDs was recorded (p = 0.608). No framework fractures occurred, and no statistically significant differences were observed between the groups regarding changes in PPD, PI, GI, or participant satisfaction (p > 0.05). USPHS criteria revealed statistically significantly poorer marginal quality for Z-CFPDs than for MC-CFPDs (p = 0.009).ConclusionWithin the limitations of this study, Z and MC-CFPDs demonstrated no statistically significant difference in terms of survival.
       
  • Bonding of different self-adhesive resins to high-strength composite resin
           block treated with surface conditioning
    • Abstract: Publication date: Available online 19 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Hao Yu, Keiichi Yoshida, Hui Cheng, Takashi Sawase PurposeThis study aimed to evaluate the effects of chemical conditioning and self-adhesive resins (SARs) on the bonding of mechanically conditioned high-strength composite resin block (HSCRB).MethodsEighteen sections of HSCRB (KZR-CAD HR 3 Gammatheta, Yamakin) were treated with alumina air abrasion and randomly divided into 3 groups according to the SARs for bonding: RelyX Unicem 2 (RXU), SA Luting Plus (SAL), and G-Cem ONE (GCO). The sections were further divided into 3 subgroups according to the chemical conditioning of the adherend surfaces: no conditioning (C), universal adhesive (UA), and a mixture of γ-MPTS and 10-MDP (MM). After the surface conditioning, the sections were cemented with the SARs. Each cemented section was cut into 40 beams. Half of the beams were thermocycled (4 °C/60 °C, 10,000 cycles). The micro-tensile bond strength (μTBS) values were measured using a universal testing machine. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), contact angles, and surface roughness measurements were performed on the adherend surfaces of each subgroup.ResultsRXU showed the highest μTBS values among the 3 SARs tested, while MM application exhibited the highest μTBS values among the 3 chemical conditioning methods tested. After thermocycling, the samples in the RXU/MM, RXU/UA, and GCO/MM groups showed no significant changes in the μTBS values, whereas the others showed a significant reduction.ConclusionsThe bond strength of HSCRB was influenced by the chemical conditioning, SARs, and aging. γ-MPTS and 10-MDP application yielded higher μTBS values of mechanically treated HSCRB than the UA.
       
  • Simplifying the digital workflow of facial prostheses manufacturing using
           a three-dimensional (3D) database: setup, development, and aspects of
           virtual data validation for reproduction
    • Abstract: Publication date: Available online 18 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Alexey Unkovskiy, Ariadne Roehler, Fabian Huettig, Juergen Geis-Gerstorfer, Joern Brom, Constanze Keutel, Sebastian Spintzyk PurposeTo set up the digital database (DDB) of various anatomical parts, skin details and retention elements in order to simplify the digital workflow of facial prostheses manufacturing; and to quantify the reproduction of skin wrinkles on the prostheses prototypes with stereolithography (SLA) and direct light processing (DLP) methods.MethodsTwo structured light scanners were used to obtain the nasal and auricle forms of 50 probands. Furthermore, the ala nasi and scapha areas were captured with the digital single lens reflex camera and saved in jpeg format. The four magnetic retention elements were remodeled in computer aided design (CAD) software. The 14 test blocks with embossed wrinkles of 0.05–0.8 mm were printed with SLA and DLP methods and afterwards analyzed by means of profilometry and confocal microscopy.ResultsThe introduced DDB allows for production of customized facial prosthesis and makes it possible to consider the integration of concrete retention elements on the CAD stage, which makes the prosthesis modelling more predictable and efficient. The obtained skin structures can be applied onto the prosthesis surface for customization. The reproduction of wrinkles from 0.1 to 0.8 mm in depth may be associated with the loss of 4.5%–11% of its profile with SLA or DLP respectively. Besides, the reproduction of 0.05 mm wrinkles may be met with up to 40% profile increasement.ConclusionsThe utilization of DDB may simplify the digital workflow of facial prostheses manufacturing. The transfer of digitally applied skin wrinkles till the prostheses’ prototypes may be associated with deviations from 11 to 40%.
       
  • Receptivity of the mandible versus the maxilla to external stimuli in
           patients with complete dentures
    • Abstract: Publication date: Available online 10 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Suguru Kimoto, Nobuhiko Furuse, Takahiro Ogawa, Yoshio Nakashima, So Furokawa, Masakazu Okubo, Hidenori Yamaguchi, Yasuhiko Kawai PurposeThis study aimed to investigate whether the mandible is more receptive to external stimuli than the maxilla in patients with complete dentures by comparing regional current perception thresholds (CPTs) and pain threshold (PTs).MethodsA single operator obtained measurements from maxillae at the incisor foramen and the left side of the greater palatine foramen region and the mandible at the left side of the mental foramen region, using the Neurometer CPT/C device, CPT and PT values from the oral mucosa of 20 edentulous individuals wearing complete dentures were analyzed. Participant characteristics such as mucosal thickness, occlusal force, age, and sex. Mucosal thickness over target regions and occlusal force were measured by the same operator using Krupp SDM and Occlusal Force-Meter GM10s devices. Differences in CPT and PT among the three measurement regions were tested with an analysis of covariance, and post hoc t-tests with the Bonferroni correction.ResultsThere were no significant differences between the mental foramen, incisor papilla, and greater palatine regions CPT values. PTs obtained at all current frequencies (2000 Hz, 250 Hz, and 5 Hz) were lowest in the mental foramen region and highest in the greater palatine region. Covariates including sex, mucosal thickness, and occlusal force had no significant influence on CPT or PT values at all frequencies.ConclusionsThe mandible exhibits higher receptivity to external pain stimuli than the maxilla.
       
  • Substrate masking ability of bilayer and monolithic ceramics used for
           complete crowns and the effect of association with an opaque resin-based
           luting agent
    • Abstract: Publication date: Available online 10 February 2019Source: Journal of Prosthodontic ResearchAuthor(s): Atais Bacchi, Samara Boccardi, Rodrigo Alessandretti, Gabriel Kalil Rocha Pereira PurposeTo evaluate the substrate masking ability of different ceramic systems used for complete crowns and assess the influence of their association with an opaque resin-based luting agent (OLA).MethodsEleven ceramic groups were tested (n = 10). Bilayer groups were: ZrPc — zirconia + porcelain; CAD-onHT — zirconia + high translucent lithium disilitace; CAD-onLT — zirconia + low translucent lithium disilicate; LDPc — high opaque lithium disilicate + porcelain. Monolithic groups were: TZ — high translucent zirconia; TLS — translucent, zirconia-reinforced lithium silicate; HTLS — high translucent, zirconia-reinforced lithium silicate; LTLD — low translucent lithium disilicate; HTLD — high translucent lithium disilitace; LGC — leucite-reinforced glass ceramic; FC — feldsphatic ceramic. The substrates adopted were resin composites shaded A1 (control), A3.5 and C4; coppery and silvery metals. Color differences (ΔE00) and translucency parameter (TP00) were assessed with the CIEDE2000 formula. ΔE00 was obtained assessing the ceramic influence only and in association with OLA.ResultsZirconia groups presented lower ΔE00 and TP00. CAD-on structures associated to OLA led to the lower ΔE00 when tested over metals. ΔE00 for LDPc were similar to zirconia when associated to OLA. Monolithic groups presented significant higher ΔE00 and TP00 compared to bilayers, with ΔE00 below the acceptability threshold only when associated to OLA over substrate shade A3.5.ConclusionsCeramic type and the white-opaque resin-based luting agent presented a significant effect on the substrate masking ability. All the discolored substrates tested are adequately masked with veneered zirconia or with LDPc (preferably associated to OLA). The CAD-on technique associated with OLA improved the masking ability over metallic substrates.
       
  • Impact of sleep bruxism on training-induced cortical plasticity
    • Abstract: Publication date: Available online 28 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Mai Ikuta, Takashi Iida, Mohit Kothari, Akiko Shimada, Osamu Komiyama, Peter Svensson PurposeTo investigate if sleep bruxism (SB) influences training-induced cortical plasticity and performance in terms of accuracy and precision of a tooth-clenching task (TCT).MethodsThirty-eight participants were allocated into SB group (N = 19) and control group (N = 19) according to presence of SB based on a 2-week screening. The participants were instructed to perform a standardized TCT for 58 min at three different force levels (10%, 20% and 40% of maximum voluntary contraction; MVC) in three series (first and third without visual-feedback and second with visual-feedback). Accuracy and precision of the TCT were calculated from actual bite force values. Transcranial magnetic stimulation was applied to elicit motor evoked potentials (MEPs) from the masseter and first dorsal interosseous muscle (FDI) before the TCT (pre-TCT-session) and 5-min after the TCT (post-TCT-session).ResultsAccuracy was significantly dependent on the series and target force level (P 
       
  • Influence of block-out on retentive force of thermoplastic resin clasps:
           an in vitro experimental and finite element analysis
    • Abstract: Publication date: Available online 28 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Toshiki Yamazaki, Natsuko Murakami, Shizuka Suzuki, Kazuyuki Handa, Masaru Yatabe, Hidekazu Takahashi, Noriyuki Wakabayashi PurposeThe purpose of this study was to determine the effect of block-out preparation, used to eliminate the undercut area, on the retentive force and stress distribution of resin clasps.MethodsA total of 72 polyester and polyamide resin clasps were fabricated on a premolar abutment crown following six block-out preparations. A combination of two types of vertical block-outs and three types of horizontal block-outs (on the missing side) was used on the abutment tooth. Each clasp was subjected to an in vitro removal test using a universal testing machine. The retentive force and traces of the clasp on the abutment tooth were recorded and analyzed with one-way analysis of variance and post hoc comparisons (α = 0.05). Non-linear finite element analysis was performed to assess the stress distributions of the resin clasps.ResultsResin clasps with a vertical block-out of 0.75 mm undercut showed significantly higher retentive force than those with the 0.5 mm undercut. Resin clasps with horizontal block-out showed significantly lower retentive force than those without horizontal block-out. There was no significant difference between the two thermoplastic resins. The maximum first principal stress of the resin clasp was concentrated under the shoulder of the clasp and strongly influenced by the width of horizontal block-out in the finite element analysis.ConclusionsThis in vitro experiment suggested that a horizontal block-out is necessary even for a 0.5-mm undercut. The design of the resin clasp should be considered from two aspects: retentive force and deformation risk.
       
  • Effect of different cleansing agents and adhesive resins on bond strength
           of contaminated zirconia
    • Abstract: Publication date: Available online 28 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Kamolporn Wattanasirmkit, Taksid Charasseangpaisarn PurposeThis study was observed the effect of cleansing agents and adhesive resins on shear bond strength (SBS), surface morphology and phase transformation of saliva and silicone disclosing medium contaminated zirconia.MethodsThe 110 zirconia specimens size 5 × 5 × 1 mm were fabricated and randomly divided into 5 surface treated groups: Non-contaminated (PC) Saliva and silicone disclosing medium contaminated without cleansing (NC) Surface contaminated and cleansing with Phosphoric acid (PO) Ivoclean (IC) or Hydrofluoric acid (HF). The twenty of each surface treated specimens were selected and bonded with Panavia F2.0 (P) and Superbond C&B (S) for SBS test (n = 10). The data was analyzed by Kruskal–Wallis H and Mann–Whitney U test. The remaining specimens of each surface treated groups were examined by SEM and XRD.ResultsThe saliva and silicone disclosing medium contaminated zirconia without cleansing group (PNC) had the lowest SBS when Panavia F2.0 was used for cementation (p  0.05). However, there were no difference in SBS among groups when cementation with Superbond C&B (SPC, SNC, SPO, SIC and SHF) (p > 0.05). There was no morphologic changing that could be observed by SEM. The XRD showed little phase transformation when surfaces were contaminated and cleaned.ConclusionsThe saliva and silicone disclosing medium contaminated zirconia should be cleaned with Phosphoric acid, Ivoclean or Hydrofluoric acid for 20 s prior to cementation with Panavia F2.0. However, the surface cleansing was not necessary when cementation with Superbond C&B.
       
  • Effect of denture treatment on masticatory movement in patients with
           complete dentures
    • Abstract: Publication date: Available online 26 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Atsuko Kuramochi, Hiroshi Shiga PurposeTo clarify the effect of denture treatment on masticatory movement in patients with complete dentures.MethodsForty eight patients who required new complete dentures and 20 patients who were satisfied with their original complete dentures (control: C group) participated in this study. Subjects were asked to chew a gummy jelly on their habitual chewing side. The movement of mandibular incisal point was recorded using a mandibular kinesiograph. First, average path and overlap of the movement path were displayed for the ten cycles between the fifth cycle and the fourteenth cycle. The movement path was classified into one of seven patterns and the frequency of each pattern was calculated and investigated the relationship between treatment and masticatory path pattern. Next, opening distance and masticatory width (spatial parameter) and cycle time (temporal parameter) were calculated and compared between the before treatment group (BT group) and after treatment group (AT group), and between the AT and C groups.ResultsThe BT group showed various patterns of masticatory path, whereas the majority of subjects in the AT and C groups showed path patterns that were representative of healthy dentate subjects. The opening distance and masticatory width increased, and the cycle time was shortened after wearing new complete denture, and there were no statistically significant differences between AT group and C group.ConclusionsFrom these results it was suggested that the masticatory movement of patients with complete dentures improved greatly after wearing new denture.
       
  • Relationship between preference and gaze in modified food using eye
           tracker
    • Abstract: Publication date: Available online 26 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Yuka Yasui, Junko Tanaka, Masaki Kakudo, Masahiro Tanaka PurposeThe relation between preference and the gaze for the test foods under unconsciousness using the eye-tracking system was investigated.MethodsParticipants consisted of 37 healthy volunteers. Test foods were steamed rice 150 g, grilled salmon approximately 45 g and slice cooked squash 60 g, all of which were served on a tray. Foods forms were regular food, chopped food, and blended food. After attached to the eye tracker, participants watched the each dish arranged in front of them freely for 10 s. And they ate test foods freely within 10 min. The gazing point was measured for 10 s from the time when the food was ordered and just before the eating. Preference levels were interviewed. The number of gaze point fixations and the total gaze point fixation time of the viewpoint during 10 s just before eating were analyzed. The analysis items were (1) the total number of gaze point fixations (2) the total gaze point fixation time (3) the amount of food intake and (4) the preference level details.ResultsFor foods with higher preference levels, the number of gaze point fixations increased significantly and the total gaze point fixation time significantly increased. In both groups, maximum food intake was observed for food forms with a high preference level. Most of the participants’ selected regular foods as their most preferred food form among the food forms.ConclusionsThe results suggested that subjects gazed at regular food which had high preference level.
       
  • Effects of the loss and reconstruction of molar occlusal support on memory
           retrieval and hippocampal neuron density in rats
    • Abstract: Publication date: Available online 25 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Akimasa Kurozumi, Tetsuya Hara, Shunichi Sakamoto, Daisuke Araki, Sachiyo Iida-Tamada, Chisa Kuroda-Ishimine, Shogo Minagi PurposeAnimal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells.MethodsThe experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase).ResultsThe denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group.ConclusionsOur results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.
       
  • Leaching behaviors of computer-aided design/computer-aided manufacturing
           composite resin component elements immersed in water
    • Abstract: Publication date: Available online 22 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Junji Iwata, Masaki Asakura, Tatsuhide Hayashi, Shozo Tsuruta, Miki Hori, Yoshinori Nagase, Akimichi Mieki, Seiji Ban, Tatsushi Kawai PurposeImmersion tests in purified water were conducted to evaluate the leaching behaviors of filler elements contained in computer-aided design/computer-aided manufacturing (CAD/CAM) composite resin.MethodsFour commercial CAD/CAM resin composite blanks were tested: Shofu block HC 2 layer, Cerasmart, Katana Avencia block, and KZR-CAD HR Block 2. The specimens in the size of 10.0 × 12.0 × 2.0 mm were immersed in a 50-mL conical tube containing 40 mL of purified water, and then placed in a constant-temperature oven set at a temperature of 37, 60, 70, or 80° C and stored statically for 30 days. After storage, the concentrations of leached elements in the immersion solution were measured with an inductively coupled plasma atomic emission spectrometer. To characterize the surface of the specimen after the immersion test, secondary electron images were obtained.ResultsThe immersion test resulted in the leaching of Si, the main component, from all materials tested. Some materials were found to have leached high amount of Ba or Sr in addition to Si, and remarkable surface degradation was observed. The amount of leached elements increased with increased immersion temperatures.ConclusionsFiller elements in CAD/CAM composite resins used in this study leached into purified water. The leached elements and its quantities greatly differed among materials and depend on the types of the oxides composing the filler. The amounts of leached elements varied in a temperature-dependent manner.
       
  • Changes in the nutritional statuses of edentulous elderly patients after
           new denture fabrication with and without providing simple dietary advice
    • Abstract: Publication date: Available online 16 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Hiroyuki Suzuki, Manabu Kanazawa, Yuriko Komagamine, Maiko Iwaki, Noriko Amagai, Shunsuke Minakuchi PurposeProviding appropriate dental prostheses and dietary interventions may improve food and nutrient intake in elderly edentulous patients, but evidence to support their use is scarce. In this trial, we aimed to clarify the combined effect, on the nutritional statuses of edentulous elderly patients, of dentists providing complete dentures with dietary advice.MethodsA randomized-controlled trial was performed on a healthy elderly population who required new complete dentures. All participants had new complete dentures fabricated and were randomly divided into an intervention or a control group. The intervention group received simple dietary advice through standardized patient information leaflets and the control group received advice on denture care only. Nutritional status was assessed using the Mini Nutritional Assessment short-form (MNA-SF) before and at 3 and 6 months after treatment. At each assessment point, the MNA-SF scores were compared using the Mann–Whitney U test. The within-group differences in the MNA-SF scores were analyzed using the Wilcoxon signed-rank test with Bonferroni correction.ResultsIn total, 59 participants completed all trial steps. At 6 months after treatment, the MNA-SF score in the intervention group was significantly higher than that in the control group (p = 0.01). Comparing the within-group changes in the MNA-SF score revealed that the score increased significantly from 3 to 6 months in the intervention group (p = 0.001, Bonferroni correction).ConclusionsNutritional statuses of healthy edentulous elderly population might be improved by fabricating new complete dentures and providing simple dietary advice.
       
  • Effects of number of metal restorations and mandibular position during
           computed tomography imaging on accuracy of maxillofacial models
    • Abstract: Publication date: Available online 15 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Yumi Tsuchida, Hidekazu Takahashi, Hiroshi Watanabe, Meiko Oki, Maho Shiozawa, Tohru Kurabayashi, Tetsuya SuzukiPurposeComputed tomography (CT) imaging for three-dimensional (3D) printed models may improve the quality of surgical preoperative plans. Although metal objects can cause artifacts in CT images, integration of CT and digital dental arch imaging may solve this problem. The present study aimed to evaluate effects of the number of metal restorations and mandibular position during CT imaging on accuracy of reproduced models.MethodsStereolithography datasets from three sets of dental models having different numbers of metal restorations were obtained using a laboratory digitizing device (control) and CT equipment (nonintegrated data). CT scanning was performed under two conditions: intercuspal position (closed) and separated using paraffin wax (open). Nonintegrated data after metal artifact removal were separated into maxillary and mandibular dentition groups. The occlusal part of the control dentition and nonintegrated data were superimposed and integrated (integrated data). The root mean square (RMS) between the control and stereolithography data was calculated and analyzed with three-way analysis of variance and t-test with Bonferroni correction.ResultsIncreasing numbers of metal restorations resulted in increase in metal artifacts and RMS values. Moreover, the RMS of the closed dataset was significantly greater than that of the open dataset because of the creation of artificial occlusal surfaces. The RMSs of the integrated datasets were significantly smaller than those of the nonintegrated datasets, except for the open model without metal restorations. Conclusions: Accuracies of reproduced maxillary and mandibular models decreased with increasing numbers of metal restorations and in the closed mandibular position during CT scanning.
       
  • Influence of elastic modulus mismatch between dentin and post-and-core on
           sequential bonding failure
    • Abstract: Publication date: Available online 14 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Daisuke Teshigawara, Teruo Ino, Hidetoshi Otsuka, Tomonori Isogai, Masanori Fujisawa PurposeClinical failures of teeth restored with post-and-core are critical issues for the survival of teeth and maintenance of oral functions. A tooth with post-and-core restoration is a complex structure. Cement adhesion is believed to be the weakest component, and breakage in this component leads to changes in stress distribution in the complex structure. The tested hypothesis was that cement breaking processes of prosthetic treated teeth were affected by elastic properties of post-and-cores.MethodsFinite element analysis focused on sequential adhesion failure between the dentin and cement; the penalty function method was used to analyze stress during each stage of bonding conditions. Failure patterns of adhesion and stress distribution within dentin under load of different materials of post-and-core was observed.ResultsAlthough, an initial failure of cement was observed at the palatal crown margin regardless of the material. Different patterns of adhesion failure between dentin and post-and-cores were observed by different elastic properties of post-and-cores. Stress concentration was observed at the corresponding areas of interface between adhesion failure and continued elements using both post-and-cores.ConclusionsUsing failure criteria for cement adhesion, sequential changes of adhesion failure between dentin and post-and-cores were observed. Local stress concentrations leading to severe destruction of dentin were caused by not only materials of post-and-cores but their adhesive conditions to dentin. Nonlinear finite element analysis (FEA) using complex structure model which deals with alterations of interfacial condition between components could provide the simulation for the clinical failure of teeth restored with post-and-cores.
       
  • Influence of decrease in the muscle activity during mastication on
           occurrence of the Stage II transport
    • Abstract: Publication date: Available online 12 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Akiko Komine, Ryo Ishida, Shuichiro Yamashita PurposeThe purpose of this study was to examine the hypothesis that in the process from food ingestion to swallowing, intentional decrease in the muscle activity during mastication would affect the number of chewing strokes, and thus the occurrence of Stage II transport (St2Tr) or the number of swallowing.MethodsTwenty adults with healthy dentition were instructed to make (1) normal mastication and (2) mastication with 50% muscle activity (50% mastication), controlled by visual feedback with electromyogram. Gummy jelly was selected as a test food. The oropharynx was observed during the sequence of events from the start of mastication until swallowing using a nasal endoscope. The number of chewing strokes was calculated by rhythmical masseter muscle activity on electromyogram.ResultsThe number of chewing strokes increased with 50% mastication. There was a particularly noticeable increase in the number of pre-St2Tr strokes. No effect on the number of additional swallows was seen as a result of 50% mastication.ConclusionsThe present study supported the hypothesis that intentional decrease in the muscle activity during mastication affected the number of chewing strokes and the occurrence of St2Tr. Particularly, this tendency was noticeable during the mastication before the start of St2Tr. However, our results did not support a question as to the number of swallowing.
       
  • Microstructural, mechanical, ionic release and tarnish resistance
           characterization of porcelain fused to metal Co–Cr alloys manufactured
           via casting and three different CAD/CAM techniques
    • Abstract: Publication date: Available online 12 January 2019Source: Journal of Prosthodontic ResearchAuthor(s): Youssef S. Al Jabbari, Xanthippi Barmpagadaki, Ilias Psarris, Spiros Zinelis PurposeTo perform a comparative analysis of the microstructure, porosity, mechanical properties, corrosion, and tarnish resistance of Co–Cr alloys prepared by casting and three different computer aided designed/computer aided manufacturing (CAD/CAM) techniques.MethodsFour groups of metallic specimens were prepared, one each by conventional casting (CST), milling (MIL), selective laser melting (SLM), and milling soft metal (MSM). Ten samples were tested by X-rays, after which their microstructure and elemental composition were tested by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) analysis. Martens hardness (HM) and elastic index (ηIT) were determined by instrumented indentation testing (IIT), while modulus of elasticity (E) was determined by three-point bending. Corrosion measurements were tested according to International Organization for Standardization (ISO) 10271. The electrolytes were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results were analyzed by one-way ANOVA and Holm–Sidak’s multiple-comparison test (α = 0.05).ResultsThe CST group illustrated internal flaws while all CAD/CAM group samples were found to be free of them. No statistically significant differences were identified among groups in their elemental composition. SLM showed the highest HM, followed by the MIL, CST, and MSM. Elastic index showed significant differences among all groups, with CST showing the lowest and SLM the highest values. SLM showed the highest elastic modulus values, followed by MSM, MIL, and CST. No significant differences were found in ionic release among groups. No surface deterioration after static and cyclic tarnish testing was determined.ConclusionsThe manufacturing procedure significantly affects the microstructure, porosity, and mechanical properties of Co–Cr alloys. In contrast, ionic release and tarnish resistance are independent of the manufacturing technique used.
       
  • Evaluation of salivary cortisol levels in relation to dento-maxillary
           prosthesis adjustment
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Moe Kosaka, Yuka I. Sumita, Hisashi Taniguchi, Toshihiko Suzuki, Keiichi Sasaki PurposeThe purpose of this study was to investigate the influence of dento-maxillary prosthesis adjustment procedure on levels of salivary cortisol.MethodsNine participants (six men, three women, mean age 65.9 years) took part in this study. Saliva samples were collected before and after dento-maxillary prosthesis adjustment during the four different visits. Free cortisol levels were determined using a salivary cortisol immunoassay kit (expanded-range high-sensitivity salivary cortisol enzyme immunoassay kit, Salimetrics). Besides, original self-report sheets, a 35-item food intake questionnaire, the University of Washington Quality of Life (UW-QOL) questionnaire version 4, and the Geriatric Oral Health Assessment Index (GOHAI) questionnaire were also administered. The changes of salivary cortisol levels were analyzed using 2-level multilevel linear regression, with adjustment for age, sex, and time. Wilcoxon signed-rank test was used to compare scores of the food intake questionnaire, UW-QOL questionnaire, and GOHAI questionnaire.ResultsSalivary cortisol levels decreased significantly after carrying out the dento-maxillary prosthesis adjustment procedure. During the third adjustment, the salivary cortisol levels were significantly low. In addition, salivary cortisol levels of participants aged 70 years and over were significantly higher than other aged groups. The total scores for grade III–V of the food intake questionnaire increased significantly. Other questionnaires had a trend toward increasing scores, yet the differences were not significant.ConclusionsWithin the limitations of this study, the results suggest that a reduction in symptoms of discomfort may have an influence on the decrease of salivary cortisol levels in dento-maxillary prosthesis wearers.
       
  • Development of three-dimensional facial expression models using morphing
           methods for fabricating facial prostheses
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Ayumi Matsuoka, Fumi Yoshioka, Shogo Ozawa, Jun Takebe PurposeIt is essential to fabricate a best-fit three-dimensional (3D) facial prosthesis model capable of facial expressions. In order for the facial prosthesis to remain in position, especially around marginal areas subject to movement, a new method of making 3D facial expression models using time-series data allowing changes in facial expression by morphing technique was developed.MethodsSeven normal subjects and seven patients with nasal defects or nasal deformities participated in this study. Three distinct facial expressions (i.e., a neutral expression, smiled, and open mouthed) were digitally acquired with a facial scanner. Prepared template models were transformed to homologous models, which can represent the form as shape data with the same number of point cloud data of the same topology referring to the scanning data. Finally, 3D facial expression models were completed by generating a morphing image based on two sets of homologous models, and the accuracy of the homologous models of all subjects was evaluated.Results3D facial expression models of both normal subjects and patients with nasal defects were successfully generated. No significant differences in shape between the scanned models and homologous models were shown.ConclusionsThe high accuracy of this 3D facial expression model in both normal subjects and patients suggests its use for fabricating facial prostheses.
       
  • A digital approach to dynamic jaw tracking using a target tracking system
           and a structured-light three-dimensional scanner
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Joo Hyun Kwon, Sungbin Im, Minho Chang, Jong-Eun Kim, June-Sung Shim PurposeThis technical procedure describes a method for tracking mandibular movement using a three-dimensional (3D) optical scanner and target tracking system to digitally portray the motion of the mandible and temporomandibular joints by merging cone beam computed tomography (CBCT) data.MethodsFour nonreflective targets were attached to the labial surface of the incisors in a noncolinear arrangement. Mandibular movement was tracked directly using a 3D facial scanner and target tracking software after merging facial scanning data, digital data obtained from a diagnostic cast, and CBCT scan data based on several landmarks of the anterior teeth. The moving path of the subjects’ mandible was converted to CBCT-based data to confirm the actual movement of the mandible and temporomandibular joints.ConclusionsThe digital implementation of mandibular movement using a 3D optical scanner and target tracking system is not prone to the same restrictions and limitations inherent in mechanical equipment; therefore, it is possible to reconstruct more realistic movement(s). This technique can be used in a wide variety of dental applications involving movement of the mandibular jaw, such as fabrication of dental prostheses, or for the diagnosis and treatment of temporomandibular joint disease.
       
  • Titanium clasp fabricated by selective laser melting, CNC milling, and
           conventional casting: a comparative in vitro study
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Fa-Bing Tan, Jin-Lin Song, Chao Wang, Yu-Bo Fan, Hong-Wei Dai PurposeThis study aimed to investigate the effects of selective laser melting (SLM), milling methods, and casting on the behavior of titanium clasp.MethodsThe clasp and its die simulating the molar were designed using 3D software. Clasp specimens were fabricated using SLM approaches (SLM Ti) and computerized numerical control (CNC) milling technology (Milling CPTi). Cast clasps of the same forms were also prepared as controls using titanium alloy powder (Cast Ti) and commercial pure titanium (Cast CPTi), following the conventional casting methods. The surface roughness and accuracy of clasps were analyzed. The changes in retentive force and permanent deformation were measured up to 10,000 insertion/removal cycles. One-way analysis of variance and Tukey’s test or Kruskal–Wallis H test were performed for data analysis and comparisons.ResultsThe Milling CPTi clasps had a smoother inner surface than the other groups (p 
       
  • Effect of laser groove treatment on shear bond strength of resin-based
           luting agent to polyetheretherketone (PEEK)
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Hiroki Tsuka, Koji Morita, Kan Kato, Hitomi Kimura, Hitoshi Abekura, Isao Hirata, Koichi Kato, Kazuhiro Tsuga PurposeThe mechanical properties of polyetheretherketone (PEEK) are ideally suited for fixed dental prostheses. However, PEEK typically has low adhesion strength to resin-based luting agent. This study assessed the shear bond strength between laser groove treated PEEK and resin-based luting agent.MethodsA total of 230 specimens were randomly divided into five groups (n = 46): no-treatment, air abrasion treatment, 100 μm-deep, 150 μm-deep, and 200 μm-deep laser groove treatments. The surface roughness was measured, scanning electron microscopy was used to observe the specimen surfaces, and X-ray photoelectron spectroscopy (XPS) was used to analyze the surfaces. Each group was divided into four resin-based luting agent subgroups: Panavia V5, RelyX Ultimate Resin Cement, G-CEM Link Force, and Super-Bond C&B. After the resin-based luting agent was bonded to the specimens, the bond strength was measured using shear tests and the failure modes were assessed by stereomicroscopy. The surfaces were also observed by scanning electron microscopy (SEM) after the shear bond strength measurements. The data were statistically analyzed using a two-way analysis of variance and Tukey’s honest significant difference test (α = 0.05).ResultsThe PEEK surface after laser groove treatment groups exhibited the highest mean Ra values. In the XPS analysis, the laser treated PEEK surface exhibited an effective surface composition for bonding with resin-based luting agent. The shear bond strengths for the laser groove treated samples were significantly higher (p 
       
  • Does the retention system influence the stability of implant-supported
           maxillary overdentures' A comparison with fixed and conventional
           dentures
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): M.M.M. Michelon, A.T. Posch, H.R. Sampaio-Filho, E.J.V. Lourenco, D.M. Telles PurposeThe purpose of this in vitro study was to compare the stability of removable implant-supported maxillary overdentures with fixed complete dentures and conventional dentures.MethodsFour types of complete dentures were tested: conventional complete dentures; overdentures retained by a male resilient attachment system; overdentures retained by a combination of clip bar and attachment system; and fixed complete dentures. Each group was placed in the posterior and anterior region and the stability was recorded by measuring the vertical displacement of the prosthesis.ResultsThere was a difference in the vertical movement of the prosthesis according to the type of system. The results showed that the behavior of the overdenture retained by a combination of a clip bar and attachment system is comparable with the stabilization of an implant-retained fixed complete denture.ConclusionsOverdentures retained by a combination of a clip bar and attachment presented better stability and retention capacity under our experimental conditions, close to that of the positive control (fixed complete denture), with the advantages of removable overdentures.
       
  • Micro-CT evaluation of marginal and internal fit of cemented polymer
           infiltrated ceramic network material crowns manufactured after
           conventional and digital impressions
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Rinet Dauti, Barbara Cvikl, Bledar Lilaj, Patrick Heimel, Andreas Moritz, Andreas Schedle PurposePurpose of this study was to evaluate the accuracy of fit of cemented polymer infiltrated ceramic network (PICN) material crowns manufactured after digital and conventional impression techniques using micro computed tomography (CT). Furthermore to determine the cement space volume and porosities in the cement layer.MethodsA molar typodont tooth was prepared for PICN material crowns and replicated thirty times. The dies were randomly divided into three groups of 10 specimens each according to the impression technique: 3M True Definition Scanner (TDS), cara TRIOS (Trios) and Impregum Penta Soft (Impregum). PICN material crowns were milled for each specimen from Vita Enamic blocks and cemented on their respective dies. The absolute marginal discrepancy (AMD), internal fit (IG), total cement space volume (TVC) and marginal porosities (VP) were measured using Micro-CT.ResultsMean and standard deviations values in μm for the AMD were: TDS 140.1 (28.4); Trios 253.7 (56.8); Impregum 220.2 (101.1). IG values in μm: TDS 173.1 (27.7); Trios 222.2 (22.4); Impregum 211.6 (55.9). TVC in mm3: TDS 19.82 (2.9); Trios 23.67 (2.01); Impregum 23.77 (5.09). VP in mm3: TDS 0.38 (0.09); Trios 0.36 (0.10); Impregum 0.51 (0.31).ConclusionsTDS group showed significantly better marginal and internal fit than the Trios group. No difference of the parameters was detected between the Impregum and both digital groups which implies that the digital impression technique is suitable in the manufacturing process of PICN material crowns.
       
  • Ten-year survival of immediate-loading implants in fully edentulous
           mandibles in the Japanese population: a multilevel analysis
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Kazuhiko Kaneda, Yusuke Kondo, Chihiro Masaki, Taro Mukaibo, Shintaro Tsuka, Akiko Tamura, Fumiko Aonuma, Kouhei Shinmyouzu, Masanori Iwasaki, Toshihiro Ansai, Ryuji Hosokawa PurposeTo evaluate the long-term clinical results of and risk factors for immediate-loading implant treatment of completely edentulous mandibles.MethodsWe retrospectively studied 220 implants in 52 patients who received immediate-loading implants in fully edentulous mandibles. Kaplan–Meier survival analyses, log-rank tests, and multilevel mixed-effects parametric survival analysis was used for statistical analyses.ResultsThirteen of implants in seven patients failed, and the 10-year cumulative implant survival rate was 93.9 % and significantly (p = 0.049) higher in women than in men. None of the predictor variables were significantly associated with implant survival, although sex tended to be associated with implant survival.ConclusionsImmediate-loading implant treatment for completely edentulous mandibles had acceptable clinical results in the long term. Although we could not identify significant risk factors, we established a multilevel mixed-effects parametric survival analysis with the immediate-loading implant survival data.
       
  • Tongue function is important for masticatory performance in the healthy
           elderly: a cross-sectional survey of community-dwelling elderly
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Keiichiro Sagawa, Hiroyasu Furuya, Yuki Ohara, Mitsuyoshi Yoshida, Hirohiko Hirano, Katsuya Iijima, Takeshi Kikutani PurposeThe aim of this study was to determine the influences of oral motor function such as tongue function and bite force on masticatory performance in the elderly.MethodsWe randomly selected 245 subjects who has 28 natural teeth among community-dwelling elderly. We evaluated masticatory performance using a gummy jelly, and also measured bite force, tongue muscle force, and the speed of tongue movement.ResultsWe found that reduced masticatory performance to be associated with decreased the speed of tongue movement and/or tongue muscle force, indicating that reduced oral motor function also influences masticatory performance.ConclusionsThese results suggest that keeping oral motor function, as well as maintenance of occlusal support, to be important for maintaining masticatory function in the elderly.
       
  • Comparing the accuracy (trueness and precision) of models of fixed dental
           prostheses fabricated by digital and conventional workflows
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Ji-Young Sim, Yeon Jang, Woong-Chul Kim, Hae-Young Kim, Dong-Hwan Lee, Ji-Hwan Kim PurposeThis study aimed to evaluate and compare the accuracy.MethodsA reference model was prepared with three prepared teeth for three types of restorations: single crown, 3-unit bridge, and inlay. Stone models were fabricated from conventional impressions. Digital impressions of the reference model were created using an intraoral scanner (digital models). Physical models were fabricated using a three-dimensional (3D) printer. Reference, stone, and 3D printed models were subsequently scanned using an industrial optical scanner; files were exported in a stereolithography file format. All datasets were superimposed using 3D analysis software to evaluate the accuracy of the complete arch and trueness of the preparations. One-way and two-way analyses of variance (ANOVA) were performed to compare the accuracy among the three model groups and evaluate the trueness among the three types of preparation.ResultsFor the complete arch, significant intergroup differences in precision were observed for the three groups (p  .05). 3D printed models had the poorest accuracy.A two-way ANOVA revealed significant differences in trueness among the model groups (p 
       
  • Complete assessment of occlusal dynamics and establishment of a digital
           
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Jong-Eun Kim, Ji-Hyun Park, Hong-Seok Moon, June-Sung Shim PurposeTo introduce a new and simple digital workflow to record dynamic occlusion, and apply it to occlusal analysis and prosthetic treatment in a virtual environment.MethodsA table-top scanner (Identica hybrid) was used to transfer fabricated casts into a virtual environment. A facial scanner (Rexcan CS2) was used for facial scanning and target tracking. Four targets were attached to each of the four incisors in the maxilla and mandible to track jaw movement. Target position data were recorded in real time during eccentric movement. The targets were replaced with maxilla and mandible cast scan data, and mandibular movement relative to the maxilla was reconstructed. Four types of antagonist meshes were reconstructed in computer-aided design (CAD) software (EzScan8). The CAD software (Exocad) enabled checking of occlusal contacts in the maximal intercuspation position during eccentric movement.ConclusionsTarget tracking data were transformed into video clips of dental cast scan data, which showed jaw movements in real time. Occlusal contact information was produced by the CAD software. Both dynamic and static occlusion analyses were performed with reconstructed eccentric movement antagonist meshes. Our new method for reconstructing eccentric movements of the mandible can reveal the occlusal dynamics of a patient within a virtual environment.
       
  • Digital transfer of the subgingival contour and emergence profile of the
           provisional restoration to the final bone-anchored fixed restoration
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Yoko Kurosaki, Takuya Mino, Kenji Maekawa, Koji Izumi, Takuo Kuboki PurposeThis report was written to introduce an attempt at clinical application of our newly developed digital workflow to reproduce the morphology of the subgingival contour and the emergence profile of the provisional restoration within the final bone-anchored fixed restoration, using a bounded unilateral edentulous case.MethodsThis digital workflow involves superimposition of the composite images of two specific types of working casts onto the working cast for the provisional restoration namely, a split cast screwed with a titanium base and a split cast screwed with a provisional restoration and integrating these with the whole intraoral surface image, in which the provisional restoration was present. The final restoration fabricated using this technique could be installed without any clinical problems. The results of in silico analysis revealed that the cubic volume ratio of the total discrepancy between the provisional and the final restorations was only 2.4%. Further, sufficient oral hygiene was maintained and the patient was satisfied with the outcome of the treatment.ConclusionsThis technical report suggests that our newly developed digital workflow provided clinical applicability and may enable accurate transfer of the morphology of the subgingival contour and emergence profile of the provisional to the final bone-anchored fixed restoration.
       
  • Comparing the precision of reproducibility of computer-aided occlusal
           design to conventional methods
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Almina Muric, Bilge Gokcen Röhlig, Deger Ongul, Gulumser Evlioglu PurposeReconstruction of patients’ dental occlusion should be performed to fulfill esthetic and functional demands. These applied restorations should be in harmony with the existing occlusion and should not have any negative effects on intraoral dynamics. The aim of this clinical study is to compare the accuracy of the occlusal design shaped by conventional Wax Up methods and computer-aided design (CAD) regarding their similarity to the natural tooth morphology.MethodsImpressions of 10 caries-free jaws were taken, and the resulting gypsum casts were scanned with a laboratory scanner. Preparations for all-ceramic full crowns were performed on second premolars and second molars. Occlusal design of 40, 3-member fixed partial dentures (FPD) were obtained with two different methods 10 FPD was designed with conventional wax up technique (Wax Up), 30 design was performed with CAD Dental wings open system (DWOS) software using three different anatomy libraries (Dental Wings (DW), Merz, Vita). The data of the bridges in the STereo-Lithography Interface Format (STL) was compared with the pre-cut data, which was regarded as a reference in terms of accuracy in the Atos so high end 3D digitizer.ResultsAccording to the results of Kruskal–Wallis test, there was no statistical difference between the Wax Up, Vita, Merz and Dental Wings groups (p > 0.05) when compared to the natural teeth. The main difference between all four groups and natural surface was 550 ± 130 μm.ConclusionsOcclusal design produced by conventional techniques and CAM DWOS system compared to natural tooth morphology showed no statistically significant difference.
       
  • Relationship between oral stereognostic ability and dietary intake in
           older Japanese adults with complete dentures
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Motoyoshi Fukutake, Kazunori Ikebe, Hitomi Okubo, Ken-ichi Matsuda, Kaori Enoki, Chisato Inomata, Hajime Takeshita, Yusuke Mihara, Kodai Hatta, Yasuyuki Gondo, Kei Kamide, Yukie Masui, Tatsuro Ishizaki, Yasumichi Arai, Yoshinobu Maeda PurposeOral stereognostic ability (OSA) is a useful indicator of oral perception to recognize food characteristics during mastication. Previous studies have shown associations between dietary intake and oral health status, such as taste perception. However, the effect of oral sensory ability on dietary intake is unclear. The purpose of this study was to investigate the association between oral sensory ability and dietary intake in older Japanese complete denture wearers.MethodsThis cross-sectional study included 164 participants aged 69–71 or 79–81 years old, wearing both maxillary and mandibular complete dentures. OSA test was used to evaluate oral tactile perception. Diet during the preceding month was assessed using a self-administered diet history questionnaire. Multivariable linear regression analysis was conducted to assess the association between OSA score and food and nutrient intake after adjusting for age, sex, socioeconomic factors, and occlusal force.ResultsThe bivariate analysis showed that OSA score was significantly and positively correlated with intake of green and yellow vegetables and negatively correlated with intake of cereals among examined foods. OSA score was also positively correlated with intake of vitamins A, B2, and C and α-tocopherol (as a substitute for vitamin E) among examined nutrients. After adjusting for age, sex, socioeconomic factors, and occlusal force, OSA score remained significantly associated with intake of green and yellow vegetables and α-tocopherol.ConclusionsOSA was significantly associated with intake of green and yellow vegetables in older complete denture wearers.
       
  • Influence of preparation design and spacing parameters on the risk of
           chipping of crowns made with Cerec Bluecam before cementation
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): A. Arena, P. Baldissara, L. Ciocca, R. Scotti, C. Monaco PurposeTo evaluate the influence of the preparation design and spacing parameters on the risk of chipping of crowns made by CEREC Bluecam before cementation.MethodsA knife-edge preparation and a chamfer preparation were made on upper premolars. The teeth were scanned and two Co–Cr alloy replicas were made. Fifteen full crowns were manufactured for four groups using CEREC. The groups differed in type of preparation (knife-edge (KE) or chamfer (CHA)) and spacing parameters: spacer (0 or 150 μm), marginal adhesive gap (10 or 50 or 150 μm) and margin thickness (0 or 300 μm). The four groups were: CHA 150 (spacer)- 50 (marginal adhesive gap)- 0 (margin thickness), KE 150-50-0, KE 150-50-300 and KE 150-150-300. The crowns were loaded before cementation by using an Instron machine to simulate the masticatory load applied during a trial. Differences in means were compared using two-way ANOVA and a post-hoc test (Tukey Test). The level of significance was set at P = 0.05.ResultsThe fracture values, ordered from least to most resistant, were: KE 150-50-300 group, CHA 150-50-0 group, KE 150-50-0 group and KE 150-150-300 group. Two-way ANOVA revealed statistically significant differences between pairs of means (p 
       
  • Effect of multi-purpose primers on the bond durability between
           tri-n-butylborane initiated resin and gold alloy
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Haruto Hiraba, Hiroshi Nogawa, Hiroyasu Koizumi, Akihisa Kodaira, Shunsuke Akahane PurposeThis study investigated the influence of an interaction between sulfur-containing monomers and other monomers in multipurpose primers on the bond durability of a tri-n-butylborane (TBB)-initiated acrylic resin to a gold alloy.MethodsThe disk-shaped adherend materials were prepared from a gold alloy (Casting Gold M.C. Type IV). Two multipurpose-primers (Universal Primer, Monobond Plus), four metal primers containing an organic sulfur compound (M.L. Primer, Alloy Primer, Metaltite, and V-Primer), and three acidic primers (Estenia Opaque Primer, Acryl Bond, and Super-Bond Liquid) were used. The shear bond strengths were determined pre- and post-thermocycling to evaluate the bond durability. A statistical analysis of the results was performed using a non-parametric procedure, and the cohesive failure ratios of the debonded surfaces were compared.ResultsAmong the pre-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, Universal Primer, and Alloy Primer showed the greatest bond strengths. Among the post-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, and Universal Primer showed the greatest bond strengths, whereas Acryl Bond, Super-Bond Liquid, Estenia Opaque Primer, and the unprimed control showed the lowest. Similarly, the primers that did not contain either a sulfur compound showed an obvious reduction in the cohesive failure ratio.ConclusionsMulti-purpose primers containing a sulfur-containing monomer increased the bond strength of a TBB-initiated acrylic resin to a gold alloy. The proportion of the area of cohesive failure to the bonded area showed an interrelationship with the shear bond strength testing results.
       
  • Mechanical properties of computer-aided design/computer-aided
           manufacturing resin composites assuming perfect silane coupling using in
           silico homogenization of cryo-electron microscopy images
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Chunwoo Lee, Satoshi Yamaguchi, Keisuke Ohta, Satoshi Imazato PurposeThe aim of this study was to determine the mechanical properties of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites for dental restoration assuming perfect silane coupling by in silico homogenization analysis using a three-dimensional model constructed from cryo-electron microscopy (cryo-EM) images.MethodsThree-dimensional dataset of a commercial CAD/CAM resin composite block (RCB) was obtained using EM with cryo-stage and focused ion beam at −130 °C. The region of inspection was 1.8 μm × 1.4 μm × 1.2 μm, and 213 slices were obtained from this region. Each slice was processed (noise reduction, threshold setting, and segmentation) using image processing software to design an in silico model. From the processed image slices, a bulk three-dimensional object and stereolithography model were reconstructed using voxel modeling software. To evaluate the elastic modulus and Poisson’s ratio of the CAD/CAM RCB, homogenization analysis was performed.ResultsThe generated voxel model included 37,276,216 voxels, 42,472,040 patches of the surface, 2,123,672 nodes, a volume of 165,748,899, and a surface area of 175,206,723. The mean of the elastic moduli along each axis was 10.71 ± 1.79 GPa. The mean of the Poisson’s ratios of each plane was 0.23 ± 0.02.ConclusionsA CAD/CAM resin composite model was successfully reconstructed from cryo-EM images, suggesting that the established image processing method is useful for producing dental restorative materials containing nano-fillers and for predicting homogenized mechanical properties. The homogenized mechanical properties indicated that the mechanical properties of the CAD/CAM RCB assumed perfect silane coupling between the fillers and resin matrix.
       
  • Accuracy and retention of denture base fabricated by heat curing and
           additive manufacturing
    • Abstract: Publication date: January 2019Source: Journal of Prosthodontic Research, Volume 63, Issue 1Author(s): Akinori Tasaka, Satoru Matsunaga, Kento Odaka, Ken Ishizaki, Takayuki Ueda, Shinich Abe, Masao Yoshinari, Shuichiro Yamashita, Kaoru Sakurai PurposeThe aim of the present study was to compare the accuracy and retentive force of an experimental denture base fabricated using additive manufacturing and heat curing.MethodsA maxillary edentulous jaw model made of silicon was used. The shape data for the working cast and wax pattern of the experimental denture base were obtained using a dental laboratory scanner. Fabrication of the experimental denture bases was performed using heat curing and additive manufacturing. The shape data for the experimental denture bases was captured using an optical scanner. The shapes of the two experimental denture bases were compared with the shape of the working cast. A digital force gauge was used to measure the traction force. Pulling was maintained until the experimental denture base separated from the elastic model. Retention was set as the maximum value for the traction force. In order to compare the retentive force of the two experimental denture bases.ResultsThe experimental denture base fabricated using additive manufacturing was more accurate than the experimental denture base fabricated using heat curing. The experimental denture base fabricated using additive manufacturing demonstrated greater retentive force than the experimental denture base fabricated using heat curing.ConclusionsIn this study, the experimental denture base fabricated using additive manufacturing was more accurate and obtained greater retentive force than the experimental denture base fabricated using heat curing.
       
  • Longitudinal study on risk indicators for peri-implantitis using
           survival-time analysis
    • Abstract: Publication date: Available online 30 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Tomoaki Mameno, Masahiro Wada, Yoshinobu Onodera, Daiju Fujita, Hironobu Sato, Kazunori Ikebe PurposeThe purpose of this study was to evaluate the incidence of peri-implantitis and to identify potential associated risk indicators.MethodsThis longitudinal study included 477 patients treated with 1420 implants. Medical and dental histories were evaluated in all patients. The location, size, connection type, surgical protocol, use of prosthesis splinting and fixation type were evaluated for each implant. In peri-implant evaluation, minimum keratinized tissue width around implants, peri-implant probing depths, peri-implant bleeding and peri-implant suppuration were assessed. Bone resorption around implants was evaluated with intraoral radiographs at baseline and at follow-up examinations. The study endpoint was peri-implantitis, which was defined as the presence of bleeding on probing and/or suppuration with bone resorption>1 mm, in accordance with previous studies. Data were analyzed with mixed-effects Cox models.ResultsPeri-implantitis occurred in 15.3% of patients and 9.2% of implants. The overall 5- and 10-year cumulative implant survival rates were 0.95 (95% confidence interval [CI]: 0.93–0.96) and 0.83 (95% CI: 0.8–0.87), respectively. Age (hazard ratio [HR] = 0.94, 95% CI: 0.90–0.98, p 20% (HR = 2.61, 95% CI: 1.02–6.67, p = 0.04), maxillary placement (HR = 1.90, 95% CI: 1.11–3.23, p = 0.02) and number of occlusal supports (HR = 0.87, 95% CI: 0.77–0.99, p = 0.03) were significantly correlated with peri-implantitis development.ConclusionsWithin the limitations of this longitudinal study on risk indicators for peri-implantitis, age, inadequate plaque control, insertion in the maxilla and less occlusal support of natural teeth correlated with peri-implantitis development.
       
  • Effect of indirect restorative material and thickness on light
           transmission at different wavelengths
    • Abstract: Publication date: Available online 28 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Rafael Rocha Pacheco, Adriana Oliveira Carvalho, Carolina Bosso André, Ana Paula Almeida Ayres, Renata Bacelar Catanhede de Sá, Tiago Monteiro Dias, Frederick Allen Rueggeberg, Marcelo Giannini PurposeThe aim of this study was to evaluate the influence of indirect restorative material type and thickness on the transmission of different wavelengths from a broad-banded dental curing light.MethodsFour dental indirect restorative materials for computer-aided design and computer-aided manufacturing (CAD/CAM) were evaluated: [RC] resin/ceramic hybrid material (Lava Ultimate), [FC] feldspathic ceramic (VitaBlocs), and two zirconia-based ceramics ([ZK] Katana; and [ZL] Lava). Total loss of irradiance (TL) was measured for blue (WB, 425–490 nm) and violet (WV, 350–425 nm) wavelengths. Specimens of 15 × 15 mm with varying thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were fabricated (n = 5). A plasma-arc dental light-curing unit was used (Arc Light-II). To assess TL as a function of wavelength, a software (Spectra Suite v5.1) connected to a spectroradiometer (USB2000) and an integrating sphere (CTSM-LSM-60-SF) was used. Data was subjected to statistical analysis (two-way ANOVA and post-hoc Tukey test, α = 0.05).ResultsA 0.5 mm interposition resulted in TL from 50.5 to 67.2%, depending on material. Increased thickness resulted in higher TL for all materials. FC showed less TL compared to ZK. In general, WV showed higher TL than did WB, and WV/WB proportion decreased with increasing thickness.ConclusionsIndirect materials significantly reduced TL, and this effect is greater with increasing thickness. WV showed lower penetration compared to WB.
       
  • A thick frame decreases the fracture toughness of veneering ceramics used
           for zirconia-based all-ceramic restorations
    • Abstract: Publication date: Available online 20 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Shinobu Yamauchi, Shoko Miura, Shin Kasahara, Jirun Sun, Hiroshi Egusa PurposeTo investigate the influence of firing condition and thickness of a yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) frame on the fracture toughness of veneering ceramics.MethodsLayering and pressable ceramics without frames or on 0.8- and 1.2-mm-thick Y-TZP frames were fired with 5 schedules (normal and 4 customized conditions). The fracture toughness of the ceramics was measured at 0.5–2.5 mm from the frame by the indentation fracture method. Crystal structures at the measurement points were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM).ResultsUnder customized firing conditions, the fracture toughness of the layering ceramic significantly decreased, particularly near the frame. Use of a 1.2-mm-thick frame significantly decreased the fracture toughness of both layering and pressable ceramics compared to ceramics without the frame. The decreased fracture toughness only occurred close (0.5 and 1.0 mm) to the frame. XRD analysis showed identical diffraction patterns between points near and far from the frame, suggesting that the decreased fracture toughness was not due to crystal defects or impurities. SEM revealed many microcracks and large crystals in layering ceramic near the 1.2-mm-thick frame, possibly resulting from the thermal properties of the zirconia frame, such as large heat capacity and low thermal conductivity.ConclusionsModification of the firing conditions from the manufacturer’s instructions and inclusion of a thick Y-TZP frame decreased the fracture toughness of veneering ceramics at the interface, suggesting that a thick frame would pose a potent fracture risk in veneering ceramics used for zirconia-based all-ceramic restorations.
       
  • Efficacy of mandibular manipulation technique for temporomandibular
           disorders patients with mouth opening limitation: a randomized controlled
           trial for comparison with improved multimodal therapy
    • Abstract: Publication date: Available online 15 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Kazuhiro Nagata, Satol Hori, Ryo Mizuhashi, Tomoko Yokoe, Yojiro Atsumi, Wataru Nagai, Motoatu Goto PurposeManual therapy has been used for the treatment of patients with temporomandibular disorders (TMD) with mouth-opening limitations. However, the curative effect of manipulation differs among researchers, and its necessity remains controversial. The purpose of this study was to confirm the efficacy of manipulation using a randomized controlled trial (RCT).MethodsA total of 61 TMD patients who had mouth-opening limitation (upper and lower middle incisor distance ≤35 mm) were selected. They were divided into two treatment groups: conventional treatment (n = 30) and conventional treatment plus manipulation (n = 31). The conventional treatment included two types of self-exercise: cognitive behavioral therapy for bruxism and education. Mouth-opening limitation, orofacial pain, and temporomandibular joint (TMJ) sounds were recorded from baseline to 18 weeks after baseline. These parameters were statistically compared between the two treatment groups by using analysis of variance (ANOVA) and Scheffe’s test to assess mouth opening distance and pain; TMJ sounds were compared using Mann–Whitney U test.ResultsNo statistical difference was observed between the two treatment groups except for mouth-opening limitation after treatment at the first visit. Subgroup analyses, stratified according to the pathological type of TMD, indicated a similar trend.ConclusionsThe efficacy of manipulation seems to be limited, in contrast to our expectations, and improved execution of therapeutic exercises has a similar effect to that of manipulation during long-term observation. The advantage of manipulation was observed only during the first treatment session. The RCT was registered in the University Hospital Medical Information Network in Japan (UMIN-CTR: 000010437).
       
  • Effect of sleep restriction on somatosensory sensitivity including
           occlusal sensation in the orofacial area
    • Abstract: Publication date: Available online 14 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Hideta Nishimori, Takashi Iida, Hirona Kamiyama, Mika Honda, Manabu Masuda, Antoon De Laat, Osamu Komiyama PurposeTo investigate the effect of sleep restriction on somatosensory sensitivity related to occlusion.MethodsTwelve healthy participants participated in an experimental voluntary total sleep restriction (SR) study. In a study design, they were invited to sleep as usual, normal sleep (NS) or to restrict their sleep for four nights. Following the SR night, participants were followed for 3 consecutive days including the 2 sleep nights. In NS experiment, all participants were instructed to maintain NS both nights. During all nights, actigraphy data were collected and total sleep time was estimated. On days before and after sleep conditions, all participants underwent measurements of tactile detection threshold (TDT), interocclusal detection threshold (IDT), perception of unpleasantness (POU), and the Epworth sleepiness scale (ESS).ResultsAs expected, total sleep time on the first night in SR experiment was significantly shorter than on the second night in SR experiment and on the first night in NS experiment (P 
       
  • Palatal augmentation prosthesis (PAP) can improve swallowing function for
           the patients in rehabilitation hospital
    • Abstract: Publication date: Available online 13 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Mitsuyoshi Yoshida, Yuumi Endo, Rumi Nishimura, Shin Masuda, Junko Amano, Kazuhiro Tsuga PurposeThe aim of this study was to clarify the effects of fitting palatal augmentation prosthesis (PAP) on the swallowing function for the patients in rehabilitation hospital.MethodsThe subjects included 18 elderly hospitalized patients whose body mass index was
       
  • Influence of chewing on expression level of human beta-defensin 2 and
           secretory immunoglobulin A in the epithelium
    • Abstract: Publication date: Available online 8 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Akihiro Ishida, Takeshi Wada, Koichiro Ogami, Takayuki Ueda, Kaoru Sakurai PurposeThis study aimed to clarify the influence of chewing on human β-defensin 2 (hBD-2) and secretory immunoglobulin A (SIgA) expression levels.MethodsWe included 15 healthy males with no missing teeth (mean age, 25.5 ± 2.5 years). Subjects were instructed to chew a piece of gum for 30 min. Saliva and skin-extraction samples were collected before and after chewing for 15 and 30 min. hBD-2 and SIgA concentrations in the samples were determined using enzyme-linked immunosorbent assay (ELISA). hBD-2 and SIgA expression levels before and after chewing were analyzed using the Mann–Whitney U test, following the Friedman test. The significance level was 0.05.ResultsThe hBD-2 level in skin-extraction samples was significantly different before (99.4 ± 17.3 pg/mL) and after chewing for 30 min (142 ± 23.0 pg/mL). The SIgA level in skin-extraction samples was also significantly different before (2.39 ± 0.25 μg/mL) and after chewing for 30 min (3.61 ± 0.33 μg/mL). No significant difference was noted in either hBD-2 or SIgA secretion rate in saliva between before and after chewing.ConclusionsChewing gum for 30 min increased hBD-2 and SIgA expression levels in skin. Moreover, chewing gum could influence the secretion pattern of these two biomolecules on skin, but not in saliva.
       
  • Evaluation of the physical properties of a newly developed denture
           adhesive for patients with dry mouth
    • Abstract: Publication date: Available online 7 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Tomohisa Ohno, Ryoko Itatsu, Megumi Moriya, Yuji Sato, Yasunori Sumi PurposeElderly individuals with dry mouth wearing dentures require an appropriate denture adhesive. The purpose of this study was to evaluate the in vitro properties of a newly developed denture adhesive for patients with dry mouth and compare these with those of a currently available adhesive and oral moisturizing agent.MethodsWe developed a new gel-type denture adhesive with physical properties suitable for patients with dry mouth (DM). We subsequently performed in vitro comparisons among DM, New Poligrip (NP), and Biotene Oralbalance Gel (BT) with regard to the following properties: retention force, resistance to squeezing, and ease of removal. In accordance with the standards of the International Organization for Standardization (ISO10873:2010), the retention force was measured for dry samples (no water exposure, severe dry mouth model) and for samples exposed to water for 10 min (normal model) and 1 min (moderate dry mouth model). The resistance to squeezing was evaluated by pushing the samples out of syringes, while the ease of removal was evaluated by measuring the time required to wash the material from a polymethyl methacrylate plate.ResultsIn the severe dry mouth model, DM exhibited greater retention force than did NP and BT. Moreover, the resistance to squeezing was significantly lower for DM than for NP. Both BT and DM showed better ease of removal than did NP. NP was the most difficult to wash out with water.ConclusionsOur findings suggest that the newly developed denture adhesive DM is suitable for use in patients with dry mouth.
       
  • Performance and perception of dental students using three intraoral
           CAD/CAM scanners for full-arch scanning
    • Abstract: Publication date: Available online 6 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Khaled E. Ahmed, Ting Wang, Kar Yan Li, Wai Kuen Luk, Michael F. Burrow PurposeTo assess the average full-arch scanning time, perception and likelihood of future adoption of technology by final-year dental students using three different Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) intraoral scanning systems.MethodsFinal-year undergraduate Dental Students (FDS), with no prior experience of intraoral scanning, full-arch scanned (IOS) a mannequin head-mounted model under supervision. Three scanning systems were used, TRIOS Colour (TRIOS); True Definition (TDef); and CEREC AC OmniCam (CEREC). Thereafter, FDS completed a questionnaire to assess their perception of IOS. Data were analysed by Generalized Estimating Equations, Fisher’s exact tests and logistic regression.ResultsForty-nine FDS participated. Average full arch IOS time varied significantly (p 
       
  • Effect of a self-etching primer containing 4-META and sodium sulfite after
           phosphoric acid etching on bonding strength of MMA-TBB resin to human
           enamel
    • Abstract: Publication date: Available online 6 December 2018Source: Journal of Prosthodontic ResearchAuthor(s): Akihisa Kodaira, Hiroyasu Koizumi, Hiroshi Nogawa, Kentaro Okamura, Mitsuo Nakamura, Takayuki Yoneyama PurposeThe aim of this study was to evaluate the shear bond strength and durability of MMA-TBB resin to human enamel applied a self-etching primer with phosphoric acid etching.MethodsA self-etching primer (Teeth primer, TP) containing 4-methacryloyloxyethyl trimellitate anhydride (4-META) and sodium sulfite and two etchants having different phosphoric acid concentrations (K-etchant gel, KE, 35–45%: Red gel, RG, 20–25%) were used as treatment agent, and MMA-TBB resin was used as luting agent. Enamel surfaces were treated with six methods which were as follow: KE, RG, TP, KE + TP, and RG + TP. After enamel specimens were bonded with MMA-TBB resin and stored in distilled water for 24 h, the shear bond strength test was done at 0 thermocycling or 20,000 thermocycling. These results were statistically verified with Steel-Dwass multiple comparisons and Man–Whitney U test.ResultsThe shear bond strength of TP group, KE + TP group, and RG + TP group were significantly higher than KE group and RG group in pre-thermocycling. KE + TP group and RG + TP group were significantly higher than other groups in post-thermocycling.ConclusionsApplying TP with phosphoric acid etching can increased shear bond durability despite difference of phosphoric acid concentrations (35–45% or 20–25%).
       
  • In vitro 3D and gravimetric analysis of removed tooth structure for
           complete and partial preparations
    • Abstract: Publication date: Available online 27 November 2018Source: Journal of Prosthodontic ResearchAuthor(s): C. Monaco, A. Arena, J. Štelemėkaitė, E. Evangelisti, P. Baldissara PurposeTo quantify and to compare a gravimetric and three-dimensional (3D) analysis of the removed tooth structure for different complete crown preparations.MethodsA total of 80 molar resin teeth and 8 preparation finishing lines were chosen: 1 for metal ceramic crowns (MCC); 3 for zirconia all-ceramic crowns: knife edge (ZirKnE), chamfer (ZirCha), and shoulder (ZirSho); 4 for lithium disilicate: light chamfer (LDLCha), chamfer (LDCha), shoulder (LDSho) and table top. Teeth were individually weighed to high precision and then prepared following the preparation guidelines. The teeth were reweighed after preparation, and the amount of structural reduction was calculated. In addition, all teeth were scanned before and after preparation, and the 3D volume of removed dental tissue was calculated, superimposing the two .stl files, as a difference of the volumes before and after the preparation. Kruskal–Wallis statistical analysis was carried out to determine significant differences among the groups with a significance level of p 
       
  • The potential of three-dimensional printing technologies to unlock the
           development of new ‘bio-inspired’ dental materials: an overview and
           research roadmap
    • Abstract: Publication date: Available online 17 November 2018Source: Journal of Prosthodontic ResearchAuthor(s): Carlo Massimo Saratti, Giovanni Tommaso Rocca, Ivo Krejci PurposeBio-inspiration is an approach in engineering aimed at optimizing artificial systems by borrowing biological concepts from nature. This review sets out to summarize the fundamental aspects employed by nature to avoid premature dental failures. On the basis of these findings, it then defines and evaluates rules for ‘post-modern’ manufacturing processes to imitate or regenerate complex biological systems.Study selectionA thorough literature search was conducted using PubMed, the Cochrane Library database and Google Scholar. Peer-reviewed articles and other scientific literature provided up-to-date information addressing two topics: (a) how natural dental tissues combine to create a structure as tough, strong and highly resistant to fatigue failure as tooth, and (b) how ‘bio-inspiration’ can be applied to the manufacture of dental restorations, taking into consideration the limitations of techniques currently used in dentistry.ResultsBio-inspired concepts have already been successfully applied in a range of engineering fields to enhance the toughness and strength of artificial materials. The area of technology with greatest potential to unlock the development of these new approaches is additive manufacturing. Consequently, these technologies and concepts could be applied to dentistry to improve the mechanical properties of dental restorations. Three-dimensional (3D) printing technologies also offer a new and promising prospect of regenerating dental tissues.ConclusionsConsidering the limitations to both conventional and subtractive computer-aided design/computer-aided manufacturing (CAD/CAM) methods, further research should focus on new, additive 3D-printing techniques. This may open new research paths in dentistry that will enhance the clinical performance of artificial dental materials.
       
  • Effect of veneering materials on fracture loads of implant-supported
           zirconia molar fixed dental prostheses
    • Abstract: Publication date: Available online 13 November 2018Source: Journal of Prosthodontic ResearchAuthor(s): Tomohide Kondo, Futoshi Komine, Junichi Honda, Hiroki Takata, Yuta Moriya PurposeTo determine the effect of veneering material and framework design on fracture loads of implant-supported zirconia molar fixed dental prostheses (FDPs).MethodsSixty-six zirconia FDPs were manufactured onto two implants and classified as uniform thickness (UT) or anatomic design (AD). These framework design groups were then further divided into three subgroups (n = 11): feldspathic porcelain-veneered zirconia FDPs (PVZ), indirect composite-veneered zirconia FDPs (IVZ), and metal–ceramic FDPs (MC). The FDPs were luted on the implant abutments and underwent fracture load testing. Significant differences were assessed by the Kruskal–Wallis test and Mann–Whitney U-test (α = 0.05).ResultsFor UT group, median fracture load was significantly higher for the IVZ (1.87 kN) and MC (1.90 kN) specimens than for the PVZ specimens (1.38 kN) (p 
       
 
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