Investigation of repair bond strength of A self-cured universal adhesive after different surface treatment

The aim of our study is to investigate the repair bond strength of self-cured universal adhesive using different surface treatments and adhesive systems, to investigate the type of failure that occurs after the test, and to find an effective repair protocol for nanohybrid composite resin. In this in vitro study, 160 composite disk samples prepared using Harmonized ™ nanohybrid universal composite (Kerr Corp., Orange CA, USA) were kept in 37 ° C distilled water for 24 hours after polymerization, followed by 4-stage OptiDisc ™ (Kerr Corp., Polished with Orange CA, USA). Then, in the baths at 5 ° C and 55 ° C (± 2 ° C) temperature respectively, 5000 cycles were kept in the thermal cycle device such that the transfer time was 5 s and the waiting time was 30 s. In this study, Tokuyama Universal Bond, Prime Bond Universal, Gluma Bond Universal and Clearfil SE Bond 2 adhesive systems were used, and each adhesive system was divided into 4 subgroups as control, bur, silane and Er, Cr: YSGG laser (n = 10). Following the adhesive application, composite material was applied to each sample with the help of plastic molds (3x4 mm) and polymerized with light. The shear bond strength test was carried out in the universal test device with a piston head speed of 1 mm / min and by applying force until fracture occurred. After shear bond strength test, the micromorphology of the broken surfaces of all samples were examined using a stereomicroscope (Nikon SMZ 800, Nikon Corporation, Tokyo, Japan). The data obtained from the study were made with the IBM SPSS Statistics for Windows (Version 20.0) program and significance level was considered as 0.05 (p-value) in statistical analysis. The normality test of numerical variables was checked with the Kolmogorov Smirnov and Shapiro Wilk test. In cases where numerical variables show normal distribution, Two Way Analysis of Variance and Tukey test were used to determine which binary groups originate from the difference. When the data obtained are evaluated according to surface treatments and adhesive systems; The average bond strength of the silane surface treatment applied was significantly higher than the control, burr and laser treatments (p <0.001, p = 0.035 and p = 0.022, respectively), The average bond strength of the Tokuyama Universal adhesive system is Gluma Bond Universal, Prime & Bond Universal. and Clearfil SE Bond adhesive systems were found to be significantly lower (p <0.001, p = 0.043 and p <0.001, respectively). According to the results of the study, it is recommended to apply an additional silane step in order to increase the bond strength in the repair of composite restorations with universal adhesives. There are not enough studies on the bond strength of Tokuyama Universal, a newly developed adhesive system, and more in vitro and in vivo studies are needed to fully evaluate its effectiveness. Keywords: bond strength, composite repair, Er, Cr: YSGG laser, self cured universal adhesive, silane