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IntroductionProsthodontics is a challenging subject for dental students. This study explores the incidence of exam anxiety among prosthodontics students and the variables that moderate it.MethodsA cross-sectional, self-administered questionnaire was distributed to fourth-year undergraduate students immediately before examinations, with a 77% response rate (55.7% female, 44.3% male).ResultsA lack of time to prepare before exams and an inability to recall before exams were the main factors affected by gender. In addition, 63.5% of male students agreed that social media and mobile phones are distractions, while 81.8% of female students disagreed (P<0.001). Within the removable prosthodontic courses (preclinical or clinical), 61.0% of students agreed that a lack of time to prepare before exams is an issue with the clinical course, while 58.5% of the students moderately agreed it is an issue with the preclinical course (P=0.044). A lack of time to prepare, fear of failure, and the time of the examination were of greater concern with regard to quizzes than with mid-term examinations.ConclusionThis study highlights the presence of exam anxiety among prosthodontics students, as well as how that anxiety is influenced by gender, clinical courses, and the type of exam. This study suggests that students should be taught strategies to improve their study, life and time-management skills in order to overcome exam anxiety. This study additionally suggests that improving success rates in dental school requires placing an increased focus in the curriculum on test competency and examination patterns.

IntroductionComputer-aided design (CAD) and computer-aided manufacturing (CAM) monolithic crowns are gaining momentum. Limited evidence exists about the effect of tooth preparation total occlusal convergence (TOC) on marginal and internal gap distances in addition to load to fracture values.AimThe aim of this study was to evaluate, by microcomputed tomography (µCT), the influence of 12° and 20° TOC on marginal and internal adaptation of zirconia-reinforced lithium silicate (ZLS) crowns. Moreover, values of load to fracture with and without initial cyclic loading (CL) were compared.Material and methodsForty ZLS crowns were fabricated on dies with TOC of 12° and 20°, 20 crowns for each group. µCT was used to compare marginal and internal adaptation. Each specimen was measured at 140 points distributed on all tooth preparation surfaces for 2D gap distance assessment. 3D gap volume was also evaluated. Crowns were then cemented and divided into two subgroups; the first was stored in distilled water (no cyclic loading [NCL] subgroup), the second was subjected to CL (CL subgroup).ResultsFactorial repeated measures ANOVA followed by Bonferroni post hoc in addition to independent and dependent t-tests were used for statistical analysis. Marginal gap, absolute marginal discrepancy, and occlusal gap measurements showed significant differences between the measurement sites. Static load to fracture values showed significant differences between TOC groups for both NCL (P=0.011) and CL (P=0.025) subgroups.ConclusionAn increase of TOC from 12° to 20° did not affect marginal and internal adaptation but resulted in higher values of load to fracture of ZLS crowns. CL simulating 1 year of service did not result in fatigue failure.

BackgroundLately, computer-aided design and computer-aided manufacturing (CAD/CAM) has broadly been successfully employed in dentistry. The CAD/CAM systems have recently become commercially available for fabrication of complete dentures, and are considered as an alternative technique to conventionally processed acrylic resin bases. However, they have not yet been fully investigated.ObjectiveThe purpose of this study was to inspect the effects of mechanical polishing and chemical polishing on the surface roughness (Ra) and contact angle (wettability) of heat-cured, auto-cured and CAD/CAM denture base acrylic resins.MethodsThis study was conducted at the Advanced Dental Research Laboratory Center of King Abdulaziz University from March to June 2017. Three denture base materials were selected: heat cure poly-methylmethacrylate resin, thermoplastic (polyamide resin) and (CAD\CAM) denture base resin. Sixty specimens were prepared and divided into three groups, twenty in each. Each group was divided according to the polishing techniques into (Mech P) and (Chem P), ten specimens in each; surface roughness and wettability were investigated. Data were analyzed by SPSS version 22, using one-way ANOVA and Pearson coefficient.ResultsOne-way analysis of variance (ANOVA) and post hoc tests were used for comparing the surface roughness values between three groups which revealed a statistical significant difference between them (p1<0.001). Heat-cured denture base material of (Group I) in both methods, showed the highest mean surface roughness value (2.44±0.07, 2.72±0.09, Mech P and Chem P respectively); while CAD\CAM denture base material (group III) showed the least mean values (1.08±0.23, 1.39±0.31, Mech P and Chem P respectively). CAD/CAM showed the least contact angle in both polishing methods, which were statistically significant at 5% level (p=0.034 and p<0.001).ConclusionMechanical polishing produced lower surface roughness of CAD\CAM denture base resin with superior smooth surface compared to chemical polishing. Mechanical polishing is considered the best effective polishing technique. CAD/CAM denture base material should be considered as the material of choice for complete denture construction in the near future, especially for older dental patients with changed salivary functions, because of its wettability.