Shear bond strength comparison of self-etching primer and conventional bonding method in metallic and ceramic brackets, in vivo study

Abstract

The use of self-etching primers for bonding in orthodontic purposes has been preferred due to the combination of conditioning and priming agents into a single product and reducing contamination risk, although concerns exist about bond strength following the use of these primers between enamel surfaces and brackets. The present in vivo study determined the effects of using a self-etching primer on the shear bond strength of metal and ceramic orthodontic brackets as compared to the conventional acid-etching technique. Materials and Methods: In this in vivo study, 112 first maxillary and mandibular premolars of 28 orthodontic patients were selected and bonded using metal (Dyna Lock) and ceramic (Clarity) brackets or using conventional acid-etch or self-etch primer (Transbond Plus) together with Transbond XT adhesive paste. The teeth were extracted after 30 days and debonded and their shear bond strength was recorded. The remaining adhesive was also determined in all groups. The data were subjected to student t, chi-square and mann-whitney U tests. Results: In metal brackets, the mean shear bond strength was 10.631.42 MPa in conventional and 9.381.53 MPa in SEP technique with significant differences (p=0.004). No significant differences were noted between two techniques in ceramic brackets (7.21.32 vs. 6.921.03 MPa respectively). The frequency of 1 and 2 ARI indices and debonding in adhesive interface were the most in all groups. No significant differences were observed regarding ARI index or debonding types using different brackets or bonding techniques. Conclusion: Due to the acceptable shear bond strength of SEP technique for bonding metal orthodontic brackets along with other advantages of this technique, it can be used as an alternative for conventional acid-etching, however, ceramic brackets should achieve adequate bond strength when applied for bonding to enamel surfaces.