Comparing Shear Bond Strength and Adhesive Remnant Index between Light Cure Composite, No Mix Composite, and No Bond Composite; An In Vitro Study

In orthodontic brackets, unlike restorative materials or porcelain, the shear bond strength of the adhesives used is important because the oblique forces from food or objects or the tension of the adhesive food affect the brackets. This study aimed at measuring and comparing shear bond strength and adhesive remnant index of light cure composite, no mix (self-cure) composite, and no bond composite (GC Orthoconnect).

A total of 27 non-carious and sound human premolar teeth were used. The samples were divided into three groups, including light cure composite, self-cure composite, and no bond composite (GC Orthoconnect). After bonding and thermocycling process, the metal brackets (American Orthodontics) were then debonded using universal testing machine. Adhesive remnant index (ARI) score was assessed.

The highest and lowest SBS mean values were seen in self-cure group (18.0402±5.71665) and light cure group (7.7890±3.98995), respectively. There were significant differences in SBS values between all groups except between the no bond group and the self-cure group (P= 0.18, P>0.05). The highest ARI scores were 0 in the self-cure group and 3 in the no bond group and the light cure group.

The no bond composite provided acceptable overall shear bond strength and compared to light cure composite showed higher shear bond strength and lower bond failure.