Relación entre los cambios de la altura anterior de la corona clínica de incisivo central superior derecho con el nivel de inserción del frenillo labial después de un tratamiento de ortodoncia con alineadores en pacientes atendidos en la clínica odontológica vía oral

Abstract

Modern orthodontics aims to correct malocclusions through controlled tooth movement while preserving periodontal health, which is essential for treatment stability and long-term outcomes. Although gingival recession is frequently associated with orthodontic therapy, limited evidence exists regarding the influence of labial frenum insertion levels on changes in clinical crown height during clear aligner treatment. Therefore, this study aimed to evaluate the relationship between changes in the clinical crown height of the maxillary right central incisor following clear aligner therapy and periodontal and biomechanical variables in patients treated at the Vía Oral Clinic in Bucaramanga between 2021 and 2024. A retrospective longitudinal analytical observational study was conducted on 120 patients aged 15 to 56 years. Data were collected and managed in Microsoft Excel and analyzed using Stata 16.0 through univariate and bivariate analyses, including paired Student’s t-tests, Kruskal–Wallis tests, and Dunn’s post hoc comparisons, with a significance level of p < 0.05. The results showed statistically significant differences in crown height variation according to labial frenum insertion level (p = 0.003), with greater changes observed in gingival (0.23) and papillary (0.30) insertions compared with mucosal insertions (0.01). Additionally, patients treated with PETG aligners exhibited greater crown height variation (0.26) than those treated with polyurethane aligners (0.016), while medium trim lines (0.29) were associated with greater changes than high or low trim designs. Buccolingual angulation movements and the use of Class II elastics (0.33) were also significantly associated with increased clinical crown height. These findings suggest that labial frenum insertion level, aligner material, and trim line design are associated with changes in clinical crown height during clear aligner therapy. Careful periodontal assessment should therefore be incorporated into treatment planning, particularly for patients with low frenum insertions or those requiring Class II elastics and stiffer aligner materials such as PETG, to optimize periodontal health and aesthetic outcomes.