A comparison of crown preparation grading via PrepCheck versus grading by dental school instructors.

Recent reports in the literature demonstrate the influence that digital dentistry is having on the preclinical training of dental students. However, none of these articles have discussed the use of PrepCheck (Sirona Dental Systems) in the evaluation of preparation taper in a preclinical environment. The present study compared the subjective grading of student tooth preparations by experienced, well-calibrated faculty with objective digital grading of the same preparations by means of the PrepCheck software. Sixty-nine sophomore dental student preparations were first subjectively graded by their dental instructors, and then the preparations were evaluated by the PrepCheck software. Neither the students nor the instructors were aware that the second PrepCheck evaluation was going to occur. The statistically significant results of this study conclude that the subjective instructor grades were inflated compared with the digital PrepCheck grades. The inflated grading by the instructors may give students a sense that their progress is better than it actually is. The objective, exact nature of the PrepCheck evaluation gives students immediate feedback regarding their preclinical preparations. Although taper was the only parameter examined in this study, PrepCheck allows the operator to examine many other features of a student's preparation. Also made evident in this study is the fact that the present standard for preparation taper is unattainable in a preclinical environment and needs to be readjusted to a wider, attainable range.

The Effect of a Digital Manufacturing Technique, Preparation Taper, and Finish Line Design on the Marginal Fit of Temporary Molar Crowns: An In-Vitro Study.

The aim of this study is to investigate the combined effect of a digital manufacturing technique (subtractive vs. additive), preparation taper (10° vs. 20° TOC), and finish line (chamfer vs. shoulder) on the marginal adaptation of temporary crowns following cementation with a compatible temporary cement. Four mandibular first molar typodont teeth were prepared for full coverage crowns with standard 4 mm preparation height as follows: 10° TOC with the chamfer finish line, 10° TOC with the shoulder finish line, 20° TOC with the chamfer finish line and 20° TOC with the shoulder finish line. Each of the four preparation designs were subdivided into two subgroups to receive CAD/CAM milled and 3D-printed crowns (n = 10). A total of 80 temporary crowns (40 CAD/CAM milled and 40 3D-printed) were cemented to their respective die using clear temporary recement in the standard cementation technique. The samples were examined under a stereomicroscope at ×100 magnification following calibration. Linear measurements were performed at seven equidistant points on each axial surface and five equidistant points on each proximal surface. One-way ANOVA analysis and Tukey HSD (Honestly Significance Difference) were performed. The best marginal fit was seen in group 8, while the poorest fit was noted in group 2. Shoulder finish lines and 10° TOC resulted in higher marginal gaps, especially in CAD/CAM milled group. The selection of 3D-printed crowns may provide a better marginal fit within the range of clinical acceptability. Marginal gaps were within clinical acceptability (50 and 120 µm) in all groups except group 2.

Effect of Apical Third Enlargement to Different Preparation Sizes and Tapers on Postoperative Pain and Outcome of Primary Endodontic Treatment: A Prospective Randomized Clinical Trial.

INTRODUCTION: The purpose of this study was to evaluate the effect of apical preparation size and taper on postoperative pain and healing after primary endodontic treatment. METHODS: One hundred and twenty patients with asymptomatic mandibular first molars with radiographic evidence of periapical pathology and with a periapical index (PAI) score ≥3 were randomly assigned to 2 groups, group 1 and 2, based on apical enlargement to 2 and 3 sizes larger than the initial apical binding file (IABF), respectively. Each group was further divided into subgroups A and B depending on the apical enlargement taper of 4% and 6%, respectively. Endodontic treatment was performed, and the final apical enlargement in all the groups was performed as follows: group 1A, 2 sizes larger than the IABF with a 4% taper; group 1B, 2 sizes larger than the IABF with a 6% taper; group 2A, 3 sizes larger than the IABF with a 4% taper; and group 2B, 3 sizes larger than the IABF with a 6% taper. Postoperative pain was assessed at 6, 12, 24, 48, and 72 hours. Clinical evaluation and the change in the PAI score on radiographs were assessed at the 3-, 6-, and 12-month follow-ups. RESULTS: No significant difference in postoperative pain was found. The success rate was lowest (57.1%) in group 1 subgroup A as evidenced by the significant change in the PAI score between group 1 subgroup A and the rest of the groups at the 6- and 12-month follow-ups. CONCLUSIONS: Apical preparation to 2 sizes larger than the IABF with a 4% taper is insufficient and results in significantly lower success rates compared with larger preparation sizes and tapers.

Effects of Clinical Training and Case Difficulty on the Radiographic Quality of Root Canal Fillings Performed by Dental Students in Saudi Arabia.

INTRODUCTION: The aim of this study was to evaluate the effects of training duration and case difficulty on the radiographic quality of root canal fillings performed by dental students in Saudi Arabia. METHODS AND MATERIALS: A longitudinal cohort study was conducted at King Saud University. Root canal treatments performed by 55 dental students from 2012-2014 were included in the study. Each student treated at least five teeth during the first year of clinical endodontic training and another five teeth during the second year. Case difficulty was assessed based on tooth position in the dental arch and preoperative conditions. The radiographic quality of the root canal filling was evaluated by two endodontists blinded to treatment completion date. The evaluation criteria were adequate obturation, presence of mishaps and preparation taper. The data were statistically analysed using univariate and multivariate logistic regression analyses; and the level of significance was set at 0.05. RESULTS: Inadequate obturation and mishaps were significantly less prevalent in teeth treated after 2 years of clinical training. The odds ratios for inadequate obturation and mishaps increased significantly as tooth position moved posteriorly. Inadequate obturation and more mishaps were significantly more prevalent in teeth with preoperative conditions. Preparation taper was not significantly affected by training duration or case difficulty. CONCLUSION: The quality of root canal fillings performed by Saudi students was adversely affected by case difficulty. The radiographic quality of root canal fillings improved significantly after 2 years of clinical training. Preparation taper outcome is likely dependent on the preparation technique and instrument taper.