According to the natural growth process, this situation is mainly common in the elderly. With the increase of age, the gums will shrink a little, but it will only cause slight dentin hypersensitivity. However, periodontal disease is also a major factor leading to the formation of the "black triangle". The alveolar bone wraps the root, and the gum is attached to the alveolar bone. When our alveolar bone is inflamed and absorbed, the bone mass begins to decline, so the gums and nipples attached to the alveolar bone will shrink back.

A large part of the reason for the black triangle is that the teeth are not cleaned well, leading to dental plaque and calculus, leading to gingival atrophy. Paying attention to cleaning teeth can effectively reduce the black triangle.