Effects of surface preparation with sodium hypochlorite on shear bond strength and residual adhesive of orthodontic brackets on primary and permanent teeth

Objective: To investigate the effects of surface preparation with sodium hypochlorite (NaOCl) on bracket shear bond strength and amount of residual adhesive on primary and permanent teeth. Materials and Methods: 24 permanent premolars, 12 in each group (groups I and III), and 24 primary molars, 12 in each group (groups II and IV) were included. In group I and II, 37% phosphoric acid was applied to the tooth surfaces, without using any other agent. In Group III and IV, 5.25% NaOCl was first applied. Following washing and drying, surface roughening was performed with phosphoric acid. The shear bond strengths (SBS) of the brackets bonded to the tooth surfaces was measured. After debonding, the base of each bracket was examined for adhesive remnant index (ARI) scores. Results: There were no statistically significant differences in SBS values between primary and permanent teeth with and without preparation with NaOCl(P>0.05). Mean SBS(18.55±14.98 MPa) was higher in permanent premolars subjected to surface deproteinization with NaOCl (group III) when compared with other groups, but the difference was not significant. There was no significant difference in ARI scores between the groups. Conclusions: The bond strength of orthodontic brackets or the distribution of ARI scores were similar between groups with and without NaOCl pretreatment. Hence, it can be concluded that conventional bonding procedures applied without any additional preparation to primary teeth are sufficient and the debonding of brackets didn’t cause any harm to enamel surfaces