Evaluation of Newly Developed Double-layer Composite Resin Teeth for Crown Preparation Training.

OBJECTIVE: To evaluate and compare the crown preparation performance of preclinical dental students training with conventional composite resin teeth and newly developed double-layer composite resin teeth. METHODS: The newly developed composite resin teeth consisted of two layers with different colours and hardnesses. Twenty third-year undergraduate dental students (8 men, 12 women) were randomly assigned to the control group (Group 1, using conventional composite resin teeth; n = 10) or the experimental group (Group 2, using double-layer composite resin teeth; n = 10) to prepare metal-ceramic crowns. To practice, each student prepared one tooth per day for 2 days. For the baseline test and final test before and after the practice period, both groups used traditional teeth. The operation time was recorded and the prepared teeth were scored blindly by two experienced instructors. The time and scores were compared within and between groups to determine the difference (α = 0.05). RESULTS: Students in both groups spent less time (P < 0.05) and achieved better scores (P < 0.001) on the final test than the baseline test (P < 0.01). In the final test, no significant difference in operating time was found between the two groups (P > 0.05), but Group 2 yielded significantly higher scores (P < 0.05). CONCLUSION: Training with the double-layer composite resin teeth enabled students to progress more quickly in terms of operating time and achieve higher scores. Use of this newly-developed tooth in crown preparation teaching practice therefore yields highly promising results.