Self-ligation vs. elastomer: one-year follow-up study examining bracket archwire ligation technique on microbial colonization and white spot lesion formation

White spot lesions (WSLs) are a common complication of fixed orthodontic treatment, largely due to increased plaque accumulation around brackets and the resulting challenges in maintaining oral hygiene. Although many studies have examined changes in oral microbial flora during orthodontic therapy, few have directly compared plaque levels between conventional elastomeric‑ligating (EL) brackets and self‑ligating (SL) brackets, or quantified plaque accumulation with objective measures. This prospective 1‑year longitudinal study aimed to: (1) compare plaque bacteria at the bracket–tooth interface using EL versus SL brackets, (2) assess bacterial levels after initiating elastomeric chain use, (3) evaluate ATP‑driven bioluminescence as a method for quantifying total oral bacteria, and (4) measure WSL formation through photographic analysis and laser fluorescence (DIAGNOdent).