Effect of different enamel pretreating agents on bonding efficacy and survival rates of orthodontic brackets: In vitro study and split-mouth randomized clinical trial

Introduction: This double in vitro study and randomized clinical trial aimed to investigate the bonding failure rates of orthodontic brackets after enamel pretreatment with agents showing different particle sizes. Methods: For the in vitro study, 80 bovine teeth were randomly divided into 4 groups according to the pretreating method used and their particle sizes: erythritol (14 μm), glycine (18-22 μm), sodium bicarbonate (70 μm), and no pretreatment. Scanning electron microscopy microphotographs were performed after pretreatment. Then, brackets were bonded, and shear bond strength was calculated. For the clinical study, agents with low (erythritol) and high (sodium bicarbonate) particle sizes were chosen. Twenty consecutive patients willing to start fixed orthodontic treatment with vestibular stainless steel brackets were enrolled. Patients were randomly divided into 2 groups following a split-mouth design. Group A underwent a 5-second enamel pretreatment procedure with erythritol for teeth belonging to maxillary left and mandibular right quadrants, whereas the remaining quadrants were pretreated for 5 seconds with sodium bicarbonate powder. In group B, quadrants were inverted. Then, brackets were bonded on the vestibular surfaces of teeth, and patients were visited monthly for 12 months to assess bond failures. Periodontal evaluation of probing pocket depth, bleeding on probing, plaque index, and papilla bleeding index was conducted before bonding and after 1, 3, 6, and 12 months. Results: The in vitro study showed that erythritol and control presented significantly higher shear bond strength values for other agents. Bicarbonate showed the lowest values. In the clinical study, 20 patients (aged 16.4 ± 3.9 years) were enrolled, and all completed the study. Erythritol showed a significantly lower failure rate (3%) than sodium bicarbonate (7.5%). Kaplan-Meier survival plots showed statistically significant differences in risk of failure between the 2 groups during the 12-month follow-up. Conclusions: Enamel pretreatment with erythritol can be a viable technique to reduce failure rates of orthodontic brackets. Registration: The trial was not registered. Protocol: The protocol was not published before trial commencement. Funding: No funding or grant was received for this research.