Retrospective Analysis of the Survival of Dental Implants Placed by Dental Students: A 10-Year Chart Review.

OBJECTIVE: The aim of this study was to determine and analyze the survival rates of dental implants placed by undergraduate dental students under supervision at the University of Alberta's School of Dentistry over a 10-year period. METHODS: Charts from patients who received either single or multiple dental implants between 1 January 2007 and 31 July 2017 were reviewed. Patients' age, sex, American Society of Anesthesiologists (ASA) class and implant site data were extracted and compiled for statistical analysis. RESULTS: Of 299 implants placed in 189 patients, 1 failed and required removal. CONCLUSION: In this study, the survival rate of implants placed over a 10-year period was 99.7%. Supervision by certified specialists, strict case selection criteria and maintenance and care protocols at the university's dental clinic likely contribute to the high survival rate.

Dental faculty and student views of didactic and clinical assessment: A qualitative description study.

OBJECTIVE: Although assessment is essential to accurately represent student learning, little is currently known about student and faculty perceptions of assessment in dental schools. Our study aimed to explore faculty and student views of didactic and clinical assessments in the School of Dentistry at the University of Alberta. METHOD: Qualitative description informed the study design. Data were collected through focus groups and analysed inductively using manifest content analysis. RESULTS: Five focus groups were conducted with faculty (n = 34) and three with students (n = 19). Faculty and student views of assessment were related to improvements made (perceived positive changes), improvements needed (perceived limitations) and improvements recommended (recommendations to improve perceived limitations). Faculty and students reported that improvements made (eg adequacy of assessment to students' levels of training) varied across instructors, courses and learning environments. Both faculty and students perceived clinical assessments as less appropriate than didactic assessments. Faculty perceived limitations were mostly related to assessment appropriateness, especially assessment accuracy and comprehensiveness, whilst student perceived limitations included other issues related to appropriateness (eg misalignment with course objectives) as well as issues related to assessment volume, pace and scheduling. Similarly, faculty recommendations focused on enhancing the assessment of clinical competencies, whilst students' recommendations aimed to also improve assessment scheduling, volume and usage (eg for learning purposes). CONCLUSIONS: Faculty and student views of assessment complemented one another. Our data show that assessment in dental education is multidimensional, so that multilevel strategies may be needed to improve this component of dental curricula.

Effect of thickness, translucency, and firing protocol on the masking ability of a CAD/CAM zirconia-reinforced lithium silicate for different backgrounds.

PURPOSE: To evaluate the masking ability of computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia-reinforced lithium silicate (ZLS) glass-ceramic under the different material configurations of thickness, translucency, and finishing protocol as well as significance of the color difference due to the manufacturer's one-firing protocol. MATERIALS AND METHODS: Ninety high-translucency (HT) and low-translucency (LT) ZLS glass-ceramic discs of different thicknesses (1.0, 1.5, and 2.0 mm) were evaluated as a monolithic structure with and without the use of a one-firing protocol. Disc samples were placed onto the substrates for measurement; a spectrophotometer measured the L*, a*, and b* color attributes of each specimen. ∆E value was calculated for determining color differences in tooth-colored substrate specimens (shade B1) compared with three darker backgrounds (shade C2, and two metal substrates - gold and silver). ∆E values were then compared against clinically acceptable (∆E = 5.5) and ideal (∆E = 2.6) thresholds. Color differences between the control and test groups were evaluated under different effects using a series of one-sided paired t tests (P < 0.01). The 99% confidence interval (CI) for the true ∆E mean and P values are reported and discussed. A complementary regression analysis depicts the effect size of translucency and firing protocol. RESULTS: Over C2, a 1-mm thickness demonstrated P < 0.01 for the clinically acceptable threshold, whereas the ideal threshold was ensured only with P < 0.01 under a 2-mm thickness. Over silver, only the clinically acceptable standard was met with P < 0.01 under a 2-mm thickness. Over gold, a 1-mm thickness was clinically acceptable with P < 0.01, and the ideal standard was met with P < 0.01 under a 1.5-mm thickness. These results remained valid regardless of the firing protocol or translucency; however, significant (P < 0.01) yet small-sized effects were found for translucency and firing protocol over gold, and for translucency over silver, through multiple regression analysis. CONCLUSIONS: To achieve ideal masking, the minimum thickness of CAD/CAM ZLS glass-ceramic should be 1.5 mm over a gold background, and 2 mm over a C2 background. The silver background did not achieve ideal masking in any situation. The one-firing protocol did not affect the final color and can be used to increase restoration strength.

Fracture strength of CAD/CAM posterior ceramic crowns after manual enhancement of occlusal morphology.

PURPOSE: The aim of this study was to investigate the fracture strength of computer-aided design/computer-aided manufacturing (CAD/CAM) posterior ceramic crowns with and without post-milling manual enhancement of occlusal morphology (MEOM), as indicated especially with early CAD/CAM restorations that have limited capacity to generate natural occlusal morphology. MATERIALS AND METHODS: A mandibular molar of an acrylic tooth model was prepared to receive a CAD/CAM all-ceramic crown and was used as a master die to fabricate 80 prepared tooth replicas using an epoxy resin with an elastic modulus (E) of 18 GPa. The crown was designed using Cerec software's Biogeneric Copy Design mode (Sirona). Eighty identical monolithic crowns were fabricated by milling four types of ceramic blocks. Forty monolithic crowns (10 of each ceramic system) were randomly selected as the control group, and MEOM was performed for each of the other 40 crowns by a certified dental technician. Restorations were crystallized and glazed according to the manufacturers' instructions and firing protocols. All crowns were cemented to their respective die using resin cement, and loaded to fracture at a crosshead speed of 0.5 mm/min. The resultant fractures were classified into three modes. Data were statistically analyzed using the nonparametric Mann-Whitney U test at α = 0.05. RESULTS: The MEOM treatment decreased the fracture load for all ceramic brands. CONCLUSION: The MEOM procedure should be considered detrimental for monolithic CAD/CAM-generated crowns and should thus be avoided.