Factors influencing open gingival embrasures in orthodontic treatment: a retrospective clinical study.

Objective: This study aims to evaluate the incidence of open gingival embrasures (OGES) after orthodontic treatment and analyze its correlation with various clinical and radiographic parameters.

Methods: We retrospectively analyzed 330 orthodontic patients at West China Hospital of Stomatology from 2016 to 2023, categorizing them into Non-OGES (200) and OGES (130) groups based on post-treatment OGES presence in the central incisor area. Basic information of patients, pre- and post-treatment lateral cephalometric radiographs, and cone-beam computed tomography (CBCT) data were collected. Chi-square tests, two-sample t-tests, Welch's t-tests, and Mann-Whitney U tests were used to compare differences in gender, initial age, treatment duration, and cephalometric and CBCT indicators between the two groups. Binary logistic regression analysis was further employed to explore the clinical characteristics and cephalometric indicators of the study population.

Results: Univariate analysis revealed that the occurrence of maxillary central incisor OGES was significantly correlated with gender, initial age, treatment duration, and related cephalometric and CBCT indicators (P < 0.05). Similarly, the occurrence of mandibular central incisor OGES was also significantly associated with gender, initial age, treatment duration, and specific cephalometric changes (P < 0.05). Binary logistic regression analysis indicated that the occurrence of maxillary central incisor OGES was significantly related to initial age, treatment duration, and the change in the U1-SN angle, while the occurrence of OGES in the mandibular central incisor area was mainly related to initial age and treatment duration.

Conclusion: Orthodontic treatment plans should consider a variety of influencing factors, including initial age, treatment duration, anterior tooth angle and position, root-bone relationship, and the distance from the anterior tooth contact point to the alveolar crest, to prevent or reduce the occurrence of OGES after orthodontic treatment, thereby improving patients' aesthetic outcomes and periodontal health.