Color formulation algorithm of self-curing acrylic resin for the fabrication of facial prostheses

This study investigated the law of color formation in various color mixtures of dental acrylic resin powder, with the aim of realizing quick and accurate color matching of facial prostheses.

Self-curing acrylic resin in crown, gingival, and clear colors was used to prepare 62 disk-shaped specimens (diameter, 30 mm; thickness, 5 mm). For each specimen, 2 g of different colored powders were mixed with 1 g of liquid and polymerized. Color values (L*, a*, and b*) were measured using a spectrophotometer. First-order linear (M₁), second-order quadratic (M_2S), second-order interactive (M_2I), and complete second-order (M_2C) models were applied to predict the relationship between component concentrations and color values. Multiple linear regression analysis was performed to assess the fitness of the observed and predicted colors. Differences in fitness were evaluated using repeated measures analysis of variance.

M_2C showed a significantly better fit between the observed and predicted values compared with the other models.

The new model satisfied the requirements for clinical application. Using this formula, the mixing ratio of the powder of self-curing acrylic resin can easily be calculated to match skin colors. This formula will contribute to the fabrication of facial prostheses with suitable color, using dental material.