Gingival Changes During Orthodontic Treatment with Conventional and Self-Ligating Brackets: A Prospective Non-Randomized Comparative Study

Abstract

Fixed orthodontic appliances create retentive surfaces that promote biofilm accumulation and may alter gingival health. Conventional and self-ligating brackets differ in ligature system and bracket-wire interface geometry, factors theoretically linked to differential plaque retention. Systematic reviews have not demonstrated consistent periodontal superiority of either system, and patient-level factors may be at least as relevant as bracket selection. Prospective observational cohort study with non-randomized, clinician-determined bracket allocation (2024-1 to 2025-2), Faculty of Dentistry, Universidad de Cartagena, Colombia. Forty patients (20 conventional, 20 self-ligating), aged 16-40 years, were evaluated at baseline (T1) and after 6 months of active treatment (T2). Gingival outcomes were probing depth, gingival color, bleeding on probing, dental mobility, sensitivity, and gingival recession (Cairo classification); baseline gingival phenotype, age, sex, and oral hygiene were also recorded. Between-group change scores (∆=T2-T1) were compared using bivariate, non-parametric tests (Mann-Whitney U, Kruskal-Wallis). Mean age was 25.15±8.10 years. No statistically significant between-group differences were detected during the six-month follow-up for any gingival outcome (all p>0.05). In bivariate analysis, baseline gingival phenotype was associated with bleeding on probing (p=0.004) and, exploratorily, with dental mobility (p=0.026); neither association remained significant after correcting for the full set of 28 comparisons performed (adjusted α=0.0018), and both should be regarded as hypothesis-generating. No statistically significant differences were detected between bracket types during this six-month, non-randomized comparison; estimates were imprecise, and residual confounding by indication cannot be excluded. Gingival phenotype showed a preliminary, exploratory association with periodontal response that requires confirmation in larger, adequately controlled, multivariable studies before it can inform clinical practice.