Surface Characteristics of CAD/CAM Composites After Adjustments: a Comparison of Polishing Protocols

Objectives: Objectives
To assess the surface roughness and gloss of two CAD/CAM composite materials before and after surface adjustment and after polishing with chair side polishing protocols.
Methods: Methods
Twenty samples (13.5 mm X 11 mm X3mm) of each CAD/CAM composite material - Cerasmart 270 (GC, Japan) and Lava Ultimate (3M ESPE, USA) - were prepared using a diamond wire saw machine and divided into two groups (n=10). Group (1) followed a 5-step polishing protocol using Soflex-discs (3M ESPE, USA), Diapolisher polishing paste (GC, Japan), and Enhance-cup (Dentsply, Germany). Group (2) followed a 2-step protocol using Diacomp Plus Twist polishers (EVE, Germany). Surface roughness values (Sa, Sp, Sv and Sq) were measured using a white light profilometry (Proscan 2200, Scantron, UK) and surface gloss was evaluated using a glossmeter - at four stages:(A) baseline, (B) after polishing (C) after surface adjustment using a yellow-band diamond bur, and (D) after repolishing following adjustment.
Results: Results
Data shows a significant difference in surface roughness and gloss between the samples after polishing and re-polishing using the 5-step and 2-step polishing protocols (p 0.05). For surface roughness, no significant difference was observed between the 5-step and 2-step protocols immediately after polishing. However, a significant improvement in roughness was noted after re-polishing with the 5-step polishing protocol (p 0.05). For surface gloss of the Cerasmart composite, no significant difference was observed between the 5-step and 2-step protocols immediately after polishing and re-polishing. In contrast, for Lava composite, the 2-step protocol resulted in significantly higher gloss than the 5-step protocol after both polishing and re-polishing (p 0.05).
Conclusions: Conclusion
Both polishing protocols were effective in producing smooth surfaces for the two composites. However, for surface gloss, the 2-step protocol demonstrated superior performance, achieving higher gloss levels in compared to the 5-step protocol.