Incidence of Open Gingival Embrasure During Orthodontic Treatment and Associated Factors: A Systematic Review.

Aim: The aim of the present systematic review is to assess the incidence of open gingival embrasure (OGE) and associated factors during orthodontic treatment in individuals in permanent and healthy dentition. Material and Methods: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases (Medline, Cochrane, Embase, Scopus) were searched through July 2025 to answer the following PEO question: 'In individuals in permanent and healthy dentition, what is the incidence of interdental OGE during orthodontic treatment and what are the associated factors?' (Prospero: CRD420251084329). The eligibility criteria included clinical studies assessing the incidence of OGE during orthodontic treatment in patients in permanent dentition without periodontitis. A qualitative synthesis was undertaken by systematically summarising the characteristics of the studies, as well as the demographic, periodontal and orthodontic variables, incidence outcomes and associated factors, using a dual-reviewer process with consensus resolution. Due to substantial heterogeneity across the studies, the findings were synthesised narratively. The Robins-E tool was used to assess the risk of bias and the grade approach was used for certainty of evidence assessment. Results: Ten studies involving 1246 patients were included in the analysis. The risk of bias was generally of 'some concerns' and the certainty of evidence ranged from low to very low. The incidence of OGE during orthodontic treatment ranges from 18% to 78%. Among the various associated factors reported, the most frequently statistically significant ones were the distance from the contact point to the crestal bone, crown morphology, crowding and age. Although formal quantitative synthesis was precluded due to clinical and methodological heterogeneity, consistent directional trends across studies, support the relevance of these factors in the development of OGE during orthodontic treatment. Discussion: The appearance of OGE is relatively frequent during orthodontic treatment. These results could be useful in better understanding and preventing the contributing factors. Further large-scale, well-designed prospective longitudinal observational cohorts are required to provide more robust data.