Feasibility of computerized color formulation for layered composite restorations

Objectives: The aim of this study is to evaluate a novel computerized color matching technique for layered composite restorations compared to a conventional perceptual method.

Methods: Three experienced dentists and six fourth-year (DMD-4) students placed composite restorations in pre-prepared standard shade guide tabs. Seven sets of experiment shade tabs; EST (18 tabs with 6 shades for each of class II, VI and V) were prepared for composite restorations. The full range of Venus composite restorative material (Heraus-Kulzer) was used. Three sets of EST were restored by experienced dentists and 2 sets were restored by DMD-4 students using conventional method for color matching. Two sets of EST were restored by 2 experienced dentists following a computerized formula that indicated both the shades and the thickness of the layers. The formulas were obtained by utilizing a newly developed method with a dental spectrophotometer Crystaleye (Olympus) and its dedicated software. Visual evaluation for color matching was performed by 6 examiners based on a scale, where: Excellent Match; Acceptable Match; Poor Match (require redo). Fisher's Exact was used for a statistical analysis.

Results:

The color matching performed by experienced dentists required correction 22% of the time, while color match corrections were required 52% of the time for DMD-4 students. Color matching performed using the computerized color matching system required color correction for only 8% of the samples. p≤ 0.001 Fishers Exact.

Conclusion: The results suggest that the computerized formulas resulted in more acceptable restorations than that was achieved without it, and that it can enable dentists to achieve a better color matched composite restoration and reduced rate of color correction.