Evaluation of the Effects of Digital Manufacturing, Preparation Taper, Cement Type, and Aging on the Color Stability of Anterior Provisional Crowns Using Colorimetry.

Abstract

BACKGROUND Replicating the 3-dimensional (3D) color of natural teeth in artificial substitutes is challenging. Fixed dental prosthodontics require aesthetic, color-stable provisional restorations. Recent milling and 3D printing digital manufacturing techniques offer improved outcomes. This study assesses color stability in various digital manufacturing methods, tapers, and aging effects on anterior provisional resin restorations. MATERIAL AND METHODS Two all-ceramic tooth preparations on typodont teeth with 10° and 20° tapers were converted into experimental dies. Forty temporary crowns were manufactured using 3D printing and computer-aided design/computer-aided manufacturing (milling). Within these 2 groups, 10 crowns were cemented using a regular and clear provisional cement. All samples were thermocycled to simulate clinical use of 6 months. Color difference formula (CIEDE2000) indicated changes between before and after cementation (ΔE00) and between after cementation and after thermocycling (ΔE00[II]). The color change was considered significant in terms of clinically perceptible (ΔE00 ≤0.62) and acceptable (ΔE00 ≤2.62) changes. One-way ANOVA (P value of less than 0.05) calculated overall differences, which were established using a Fisher post hoc test. RESULTS Crowns cemented with clear cement showed fewer color changes irrespective of the manufacturing technique or taper. Notably, only the 10° 3D-printed crown with clear cement had an imperceptible color change at the pre-/post-cementation phase. Meanwhile, the 10° and 20° milled crowns with regular cement exhibited unacceptable color changes after thermocycling. CONCLUSIONS For long‑term temporization in the aesthetic zone, properly optimized 3D-printed provisional restorations cemented with clear cement had better color stability.