Retrospective evaluation of clear aligners' adverse effects on open gingival embrasures among orthodontic patients

Open gingival embrasures (OGEs), commonly called "black triangles," are a frequent esthetic and periodontal complication reported in patients undergoing clear aligner therapy. This retrospective study analyzed clinical records of 80 patients treated between 2020 and 2022 to assess the prevalence and risk factors of OGEs. Digital records and casts were evaluated for OGEs, with variables such as age, gender, treatment duration, incisor movement, interproximal reduction (IPR) and aligner compliance analyzed using chi-square and logistic regression. Data showed OGEs in 48.75% of patients, most commonly between maxillary central incisors, with significant associations to incisor proclination and lack of IPR. Thus, we show that careful planning of tooth movement and contact point management is essential to minimize OGEs in clear aligner therapy.