Roughness, surface energy, and superficial damages of CAD/CAM materials after surface treatment

Abstract

Objectives: The aim of this study was to examine the effects of surface pre-treatment on CAD/CAM materials including ceramics, zirconia, resin-infiltrated ceramic, and resin-based composite.

Materials and methods: Specimens were made of ten CAD/CAM materials (Celtra Duo, Degudent, D; Vita Suprinity, Vita, D; E.max CAD, Ivoclar-Vivadent, FL; E.max ZirCAD, Ivoclar-Vivadent, FL; Vita Enamic, Vita, D; Cerasmart, GC, B; LAVA Ultimate, 3M, D; SHOFU Block HC, SHOFU, US; Grandio Blocs, VOCO, D; BRILLIANT Crios, Coltene, CH) and pretreated to represent clinical procedures (Hf 20 s/5%; phosphoric acid 20 s/37%; Monobond etch and prime (Ivoclar-Vivadent, FL); water-cooled diamond bur (80 μm; 4 μm); Al₂O₃-blasting (50 μm/1 bar, 50 μm/2 bar, 120 μm/1 bar, 120 μm/2 bar); untreated; manufacturer's instructions). SEM-analysis (Phenom, FEI, NL) of the surfaces was performed (magnifications ≤ 10,000×). Roughness values R_a, R_z (KJ 3D, Keyence, J), and surface energy SE (OCA15 plus, SCA20, DataPhysics, D) were determined (statistics: non-parametric Mann-Whitney U test/Kruskal-Wallis test for independent specimen, α = 0.05).

Results: Kruskal-Wallis revealed significant (p < 0.001) differences for all materials with different surface treatments. Roughness ranged from R_a = 0.05 μm (VS; D4)/R_z = 0.41 μm (VS; D4) to R_a = 1.82 μm (EMA; SB120/2)/R_z = 12.05 μm (CS; SB 120/2), SE from 22.7 mN/m (VE; M) to 52.8 mN/m (CD; M). SEM analysis showed material-dependent damages after pre-treatment.

Conclusion: Different CAD/CAM materials require individual pre-treatment for optimized and protective surface activation.

Clinical relevance: Cementation is a key factor for clinical success. Given the variety of available CAD/CAM materials, specific procedures are needed.

Keywords: CAD/CAM; Ceramic; Composite; Damage; Defect; Lithium disilicate; Lithium silicate; Resin-based material; Roughness; Surface energy; Zirconia-reinforced ceramic.