The influence of ceramic surface treatments on the tensile bond strength of composite resin to all-ceramic coping materials

Statement of problem

An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but the fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studied extensively.

Purpose

The purpose of this study was to evaluate the tensile bond strength of composite resin to 3 different all-ceramic coping materials with various surface treatments.

Material and methods

Thirty specimens (10 × 10 × 2 mm) each of lithium-disilicate ceramic (IPS Empress2 [E]), alumina ceramic (In-Ceram Alumina [I]), and zirconia ceramic (Zi-Ceram [Z]) were fabricated. Feldspathic ceramic (Duceram Plus [F]) was used as the control. Each material was divided into 3 groups (n=10), and 3 different surface treatments were performed: airborne-particle abrasion with 50-μm alumina particles (Ab); airborne-particle abrasion with 50-μm alumina particles and acid etching with 4% hydrofluoric acid (Ae); or airborne-particle abrasion with 30-μm alumina particles modified with silica acid (Si). After surface treatment of ceramic specimens, composite resin cylinders (5-mm diameter × 10-mm height) were light polymerized onto the ceramic specimens. Each specimen was subjected to a tensile load at a crosshead speed of 2 mm/min until fracture. The fracture sites were examined with scanning electron microscopy to determine the location of failure during debonding and to examine the surface treatment effects. Two-way analysis of variance and the Duncan multiple comparison test (α=.05) were used to analyze the bond strength values.

Results

There were significant differences in the bond strengths for both ceramics (P<.001) and surface treatments (P<.001) and the interaction (P<.001). The Duncan analysis yielded the following statistical subsets of the bond strength values: (FAe, ISi, EAe, ZSi) > FAb > (FSi, EAb, ESi) (IAb, IAe) > (ZAe, ZAb). The results illustrate no differences within the parentheses but statistically significant differences among the groups.

Conclusion

Alumina and zirconia ceramic specimens treated with a silica coating technique, and lithium disilicate ceramic specimens treated with airborne-particle abrasion and acid etching yielded the highest tensile bond strength values to a composite resin for the materials tested.