A Cavity Preparation Evaluation System in the Skill Assessment of Dental Students.

The aim of this study was to compare a computerized, laser-scanning Cavity Preparation Skill Evaluation System (CPSES) with conventional teachers' eye-hand grading assessment of dental students' Class I cavity preparation evaluations. Thirty-eight cavity preparations of lower left first molars made by junior dental students at a dental school in China were tested from September 2013 to November 2014. The outline and retention form, smoothness, depth, wall angulation, and cavity margin index of the preparations were evaluated by CPSES and then by teachers' eye-hand grading. The mean difference in scores for each method was considered, as was the variability of scores within each method. Compared with the teachers' eye-hand grading method, CPSES provided objective evaluation results that had statistically significant differences (p<0.05). A questionnaire was also designed and distributed to the students; the response rate was 100%. The results indicated that most of the students recognized CPSES effects in the preclinical teaching; 92.1% perceived that CPSES provided high simulation and appropriate practice guidance for them; and 94.7% reported that the evaluation results provided by CPSES gave targeted and objective recommendations. These findings suggest that CPSES can consistently and reliably scan a student's tooth preparation, compare it to a theoretically ideal preparation, and provide objective feedback. The application of CPSES in preclinical operative training can help students better understand the desired parameters for occlusal cavity preparation skills and encourage students in their self-paced learning and independent practice.

[One year evaluation of endodontic microsurgery in 54 cases with persistent apical periodontitis].

OBJECTIVE: To evaluate the outcome of endodontic microsurgery in 54 cases with persistent apical periodontitis. METHODS: All surgical procedures were performed under a dental operating microscope after root canal treatment. Surgical procedures included periapical curettage, root-end resection, retropreparation with ultrasonic microtips, and root-end filling with mineral trioxide aggregate (MTA). Healing was monitored clinically and radiographically. RESULTS: One year later, 31 (57.41%) cases were cured, 19 (35.19%) cases were improved, 4 (7.41%) cases were failure. There were no statistical difference between sex, age, tooth location, size of the lesion and pathological features (P>0.05). CONCLUSION: The outcome of the present study indicates that endodontic microsurgery may result in a predictable treatment outcome in teeth with persistent periradicular lesions.

[Observation on the inhibiting effect of fluor protector on the demineralization of bovine enamel after exposure to some beverages].

OBJECTIVE: To investigate the role of Fluor Protector in the demineralization of bovine enamel after exposure to some beverages. METHODS: Twenty-four bovine teeth were divided into experimental and control groups. The enamel specimens of the experimental group were pretreated with Fluor Protector and then exposed to beverages; the enamel specimens of the control group were exposed to beverages directly. All the enamel specimens were exposed to beverages 10 times a day and 5 minutes each time. After 7 days' exposure to the beverages, all the specimens were observed by scanning electron microscope (SEM). RESULTS: Different degrees of solubilization of enamel prisms in the control group were demonstrated by SEM. The solubilization of enamel prisms in the experimental group was much more slight than that in the control group. CONCLUSION: Fluor Protector can inhibit the demineralization of enamel caused by beverages.