The effect of clinical sandblasting with different powders on the surface roughness of cores for metal-ceramic crowns and their fracture resistance after the addition of repair material
Author(s): Mohammed Thamir Yassin* and Shatha Abdullah Salih
Abstract
Background/ purpose: The most frequently encountered issue with metal-ceramic restorations is the fracture of veneering porcelain. This in vitro study aims to evaluate the effect of clinical sandblasting with 50 μm aluminum oxide and 30 μm silica-coated particles on the surface roughness of metal cores and the subsequent effect on their fracture resistance after the addition of specific adhesive and packable composite as a repair material. Materials and Methods: Metal cores (n=21) were digitally designed and three-dimensionally printed by selective laser melting technique by ProX 100 3D printer (3D Systems, Inc). These cores were randomly divided into three groups: Group A: n=8, sandblasted with 50 μm aluminum oxide, and veneered with packable Z350 composite. Group B: n=8, sandblasted with 30 μm silica-coated particles and veneered with packable Z350 composite. Group C: control group (n=5), sandblasted in the laboratory with 250 μm aluminum oxide and veneered with porcelain (Vintage PRO–SHOFU0). All the specimens were tested for surface roughness by the TAYLOR-HOBSON profilometer. After adding the veneering material, all the specimens were subjected to a fracture resistance test through a universal testing machine. Results: One-way ANOVA test showed a significantly higher difference for the specimens sandblasted in the laboratory using 250 μm aluminum oxide. Fracture resistance values showed no significant difference between groups A and B. Conclusion: Groups A and B showed no significant difference in surface roughness, but their fracture resistance values were above the acceptable clinical limit.