An in-vitro evaluation of shear bond strength between orthodontic attachment and monolithic zirconia, feldspathic porcelain, hybrid porcelain after different surface conditioning methods and surface properties after debonding

The aim of this study is to evaluate shear bond strength between orthodontic attachment and monolithic zirconia, feldspathic porcelain, hybrid porcelain after different surface conditioning methods in order to find out the best bonding method on surfaces and to evaluate surface properties after debonding and polishing. Non-carious 30 human second premolar teeth, 56 feldspathic porcelain, 56 monolithic zirconia and 56 hybrid porcelain were randomly divided into 4 subgroups (n=14/each): 1. Hydrofloric acid etch + silane; 2. Al2O3 air abrasion + silaen; 3. Silicoating (SiO2); 4. Diamond bur + silane. Control teeth group is etched with orthophosphoric acid gel. The specimens were stored in deionized water at 37°C for seven days and then subjected to thermocycling. The specimens were tested in Universal Instron machine to evaluate the shear bond strengths. Residual composite were removed after debonding with fiber composite burs (stainbuster) and polished with the porcelain polishing kit. Then the specimens tested on three dimensional white light interferometry to evaluate surface properties by taking 3D images. Scanning electron microscobe is used to evaluate ARI scores on button mesh bases. Data analysis was performed by using Kolmogorov Smirnov, Levene, Mann Whitney U ve Kruskal Wallis tests statistically. The highest shear bond strength value was found for HF acid etched feldspathic porcelain group (p<0.001). When HF acid etched subgroups were compared with other surface conditioning methods in all material and teeth groups, the shear bond values were found higher (p<0.001). According to the average surface roughness (Ra) values; the highest results were obtained for ceramic+Al2O3, enamic+Al2O3 and all diamond bur subgroups (p<0.0038).