Evaluation and comparison of shear bond strength and adhesive remnant index score in brackets bonded with probiotics impregnated orthodontic adhesive and commercially available orthodontic adhesive - An in vitro study

Background: White spot lesions are one of the main drawbacks of fixed orthodontic mechanotherapy. Probiotic bacteria have been included in mouthwashes and lozenges to check the activity of S.mutans on surface enamel. Aim: Aim of the present study was to evaluate and compare shear bond strength and adhesive remnant index scores of orthodontic brackets bonded with probiotic impregnated (Lactobacillus rhamnous) orthodontic adhesive and conventional light cure orthodontic adhesive.  Materials and methods: In this in-vitro study, two groups were tested in one group brackets were bonded to extracted maxillary premolars using probiotic impregnated composite and in the other with conventional light cure composite resin. Shear bond strength was assessed using universal testing machine. Adhesive remnant index scores were assessed on the same samples. Results: Shear bond strength of the new composite resin was significantly decreased when compared to conventional light cure composite (p=0.001). There was no significant difference in ARI scores (p=0.51) between the groups.  Conclusions: The shear bond strength of the novel probiotic impregnated composite was significantly reduced. Though there was no significant variation in ARI scores when compared to control, avenues to improve the shear bond strength should be assessed.