A comparison of the effectiveness of standard anterior bracket placement versus smile arc protection method: A randomized clinical trial.

Abstract

Objectives: This randomized two-arm parallel trial aimed to compare the effectiveness of standard anterior bracket positioning with the smile arc protection (SAP) method in terms of occlusal and smile morphometric indices, and perceived post-treatment smile aesthetics.

Methods: Patients needing nonextraction orthodontic treatment were randomly assigned to either the SAP or standard bracket placement group. Inclusion criteria were ages 11 to 25 years, nonextraction treatment, and good oral hygiene, all treated using the Roth 0.018 system. Primary outcomes assessed occlusal and smile morphometric changes using cephalograms, study models, and photographs. Perceived smile aesthetics was evaluated with the Visual Analogue Scale (VAS). Statistical analyses included independent t-tests, paired t-tests, Mann-Whitney U test, Wilcoxon signed rank test, and analysis of covariance.

Results: Forty-two patients (mean age, 19.5 ± 5.5) were randomized evenly between the SAP and standard groups. Baseline characteristics were similar, and one patient from the SAP group was excluded. No significant differences were found between the groups for occlusal and smile morphometric variables before and after treatment (P > 0.05). Post-treatment, the smile arc significantly improved in the SAP group compared to both the standard method (P = 0.005) and its pretreatment state (P = 0.005). VAS scores from orthodontists and laypersons showed no significant differences (P > 0.05), but general dentists rated the SAP group's smiles as more attractive (P = 0.002).

Conclusions: The SAP method was more effective in achieving a consonant smile arc than conventional bracket positioning. While other occlusal and morphometric changes showed no significant differences, general dentists found the SAP group's smiles more attractive. Further research is needed to confirm these results.

Registration: The research was registered in the Iranian Registry of Clinical Trials (IRCT) database with the identification code IRCT20220108053669N3.