ScienceDOI: 10.3290/j.ijcd.b3762733Pages 1-40, Language: EnglishSchubert, Oliver / Graf, Tobias / Schweiger, Josef / Güth, Jan-Frederik / Sciuk, Thomas / Erdelt, Kurt-Jürgen
Aim: The computer-aided manufacture of esthetically pleasing monolithic dental restorations presents with specific challenges. One vital parameter to consider is the translucency of the materials. Previous studies have proven a correlation between translucency and material thickness for various all-ceramic materials. The aim of the present study was to assess and define the relationship between thickness and translucency in modern resin-based restorative materials.Materials and methods Specimens fabricated from two resin nano ceramics (Cerasmart, Lava Ultimate), a polymer-infiltrated ceramic network (Vita Enamic), and a polymethylmethacrylate (TelioCAD) were examined, representing these different material classes. For each material, 12 specimens (n=12) were fabricated in five thicknesses (0.4 mm, 0.7 mm, 1.0 mm, 1.3 mm, 1.6 mm; N=240). The translucency was measured with a spectrophotometer. The total light transmittance for each specimen was calculated applying specialized software. Regression curves were fitted to the results and their coefficient of determination (R²) fit determined.Results Logarithmic regression curves showed the best R² approximation (Cerasmart, R² = 0.994; Vita Enamic, R² = 0.978; Lava Ultimate, R² = 0.997; TelioCAD, R² = 0.997) to the light transmission values.Conclusion The results of this study indicate that the translucency of resin-based materials can be calculated using a mathematical approach to estimate their optical behavior. Cerasmart, Lava Ultimate, Vita Enamic, and TelioCAD exhibit a logarithmic relationship between material thickness and translucency. By determining material-specific coefficients for this logarithmic function, the resulting translucency can be computed for any given material thickness.
Keywords: CAD-CAM, digital workflow, hybrid materials, mathematical analysis, PMMA, polymer infiltrated ceramic network, resin nano ceramics, translucency, translucency equation