Effect of different surface treatments on microtensile bond strength of two resin cements to aged simulated composite core materials.

ABSTRACT

Objective: Roughening of the aged composite resin core (CRC) surface seems essential for durable adhesion. The aim of this study was to investigate the influence of various surface treatments and different resin cements on microtensile bond strength (μTBS) between two aged core build‑up composites (CBCs) and feldspathic ceramic. Materials and Methods: A total of 16 composite blocks made of two CBCs, Core.it and Build‑it were randomly assigned to four surface treatment groups after water storage and thermocycling (2 weeks and 500 cycles). Experimental groups included surface roughening with air abrasion (AA), hydrofluoric acid, pumice, and laser and then were bonded to computer‑aided design/computer‑aided manufacturing feldspathic ceramic blocks using two resin cements, Panavia F2 (PF), and Duo‑link (DL). The μTBS was tested, and the fracture mode was assessed. The data were analyzed with multiple analysis of variance to estimate the contribution of different surface treatments, resin cements, and two aged CRCs on μTBS. Statistical significance level was set at α < 0.05. Results: Surface treatment and cement type significantly affected bond strength (P < 0.001) but the type of CRC did not (P = 0.468). Between roughening methods, the highest and the lowest values of μTBS were sequentially obtained in AA and Er.YAG laser groups. The highest bond strength was in AA group cemented with PF (31.83 MPa). The most common failure mode was cohesive fracture in the cement. Conclusion: Different surface treatments had different effects on μTBS of aged CRCs to feldspathic ceramics. PF was significantly better than DL.