Linear measurements of finish line length associated with various preparation designs using CAD/CAM technology

Purpose

The aim of this study was to measure the length of finish lines associated with various commonly used preparation designs using high technology CAD/CAM.

Materials and methods

A total of 80 extracted human permanent teeth (including 4 distinct morphologies) were divided into 8 groups according to the type of preparation design (all-ceramic crown, ceramic onlay, or ceramic veneer) and tooth type (upper first molar, lower first premolar, upper central incisor and lower central incisor). The length of the finish line for each specimen was measured after performing tooth preparation using Dental Wings 7Series 3D Scanners. The measured lengths associated with the various preparation designs were analyzed.

Results

The length of the finish line was significantly different between complete- and partial-coverage tooth preparations, in which the partial coverage had a longer finish line than the complete coverage.

Conclusion

The complete-coverage preparations evaluated in this study exhibited significantly shorter finish lines compared to the partial-coverage preparations.

Clinical significant

The risk of recurrent caries has been directly related to the marginal integrity of any restoration. However, the relationship between the length of the finish line and recurrent decay may also be significant. Therefore, obtaining baseline information regarding the differences in finish line length of various preparation designs is important.