What condition is characterized by the cementum of a tooth's root fusing with the surrounding bone?

Ankylosis is a condition in which the cementum of a tooth's root fuses with the surrounding alveolar bone. This fusion prevents normal mobility of the tooth and can lead to alterations in the dental arch and occlusion. Typically, ankylosis occurs in permanent teeth, particularly in children or adolescents following trauma or dental procedures that affect the periodontal ligament. The abnormal connection between tooth and bone can also pose challenges for proper dental alignment and positioning as the individual grows.

The other conditions listed do not involve this specific fusion of tooth materials with bone. Gingivitis involves inflammation of the gums, often due to plaque buildup, and doesn't affect the root structure directly. Periodontitis is a more severe form of gum disease that affects the supportive structures of the teeth, leading to loss of attachment and bone but not fusion. Pulpitis refers to inflammation of the dental pulp and relates primarily to internal tooth issues, again not involving the cementum and bone interaction characteristic of ankylosis.