Effects of synthetic diamond abrasives on the surface quality of CAD-CAM restorative materials

Külünk Ş., Kısakürek S., Çetiner R. B., Külünk T.

Journal of Prosthetic Dentistry, 2026 (SCI-Expanded, Scopus)

Abstract

Statement of problem: Finishing and polishing protocols can markedly influence the surface quality of computer-aided design-computer-aided manufacturing (CAD-CAM) restorative materials; however, the performance of synthetic diamond abrasives across different microstructures remains unclear. Purpose: The purpose of this in vitro study was to evaluate the effects of various finishing and polishing procedures on the surface roughness, gloss, and contact angle of 4 CAD-CAM restorative materials. Material and methods: Eighty rectangular specimens (15×1.5×1.5 mm) were prepared from a polymer-infiltrated ceramic (Enamic), ceramic-reinforced composite resin (Cerasmart), fiber-reinforced composite resin (Trinia), and feldspathic ceramic (Vita Mark II). After standardized grinding with 600-, 800-, and 1000-grit silicon carbide papers, specimens were assigned to 4 groups (n=5): control (C), rubber-cup polishing (RC), rubber-cup polishing followed by diamond polishing paste (RC+DP), and rubber-cup polishing followed by synthetic diamond abrasives (RC+SD). Surface roughness (Ra), gloss, and contact angle were measured using a contact profilometer, glossmeter, and drop-shape analyzer, respectively. Data were analyzed using 2-way analysis of variance and the Tukey post hoc test (α=.05). Results: Both polishing procedure and material type significantly affected surface roughness, gloss, and contact angle values (P<.001), with significant interactions between the 2 factors for all parameters. Trinia exhibited the highest roughness and lowest gloss, whereas Cerasmart and Enamic demonstrated smoother surfaces after polishing. The RC+SD protocol generally produced lower Ra values and higher gloss and contact angles compared with RC and RC+DP (P<.001). Conclusions: Finishing and polishing protocols substantially influence the surface quality of CAD-CAM restorative materials. Synthetic diamond abrasives generally produce smoother surfaces, higher gloss, and increased hydrophobicity. Polishing protocols incorporating synthetic diamond abrasives may be considered a reliable approach across different CAD-CAM restorative materials.