Black triangles can be formed due to the defect or absence of the gingival papilla, which increases the risks of food impaction, caries, and periodontal disease, and affects the esthetics of anterior teeth. The incidence of black triangles after orthodontic treatment is from 38% to 58%. The formation of black triangles is influenced by patient-related factors and factors related to orthodontic treatment. This article discusses the factors related to orthodontic treatment and the formation of interdental black triangles and provides reference for preventing the formation of this problem.