Preliminary application and evaluation of digital step-by-step tooth-preparation templates

Abstract

Statement of problem: Tooth preparation is a fundamental technique, and inaccurate preparation may lead to excessive irreversible tooth removal or insufficient restorative space. The conventional process depends mostly on operator experience, and variable quality is inevitable. Whether a tooth preparation template would be beneficial, especially for inexperienced dentists, is unclear.

Purpose: The purpose of this preliminary study was to evaluate the application of new digitally designed step-by-step templates to guide tooth preparation.

Material and methods: A laboratory scanner was used to obtain digital scans of dental casts. A 3-dimensional reverse engineering software program was used for the step-by-step digital design. The data for a series of guide templates were imported into a computer-aided manufacturing (CAM) machine for milling. Ten experts and 10 inexperienced dentists prepared teeth on a dentoform in a mannequin head. They were instructed to complete the preparation within 20 minutes both with and without the step-by-step template. The prepared crowns were subsequently scanned with an intraoral scanner, the scans were imported into a preparation evaluation software program, and various indexes were scored. The t test was used to analyze the differences between the 2 methods of tooth preparation in each group (α=.05).

Results: No significant differences were found in total scores with and without the guide templates in the expert group (P=.256), but the scores in the inexperienced group differed significantly between the 2 preparation methods (P<.001). In undercut comparisons, the 2 methods of preparation did not differ significantly in the expert (P=.912) or inexperienced groups (P=.601). However, the scores for taper and occlusal reduction were significantly higher in the inexperienced group when using the guide template (P<.001).

Conclusions: The new digitally designed step-by-step tooth preparation guide template significantly improved the efficiency and quality of tooth preparation for inexperienced dentists when preparing multiple teeth.