Prevalence and Etiology of Dental Ankylosis in Primary Teeth

Abstract

Abstract: Dental ankylosis is a condition characterized by abnormal fusion of the cementum of the tooth with the surrounding alveolar bone, leading to the loss of the periodontal ligament (PDL). This fusion disrupts the normal tooth eruption process, especially in primary teeth, and prevents them from reaching the correct occlusal plane. The exact cause of ankylosis in primary teeth is not fully understood and is the subject of ongoing research. However, it is believed to be multifactorial, including potential contributing factors such as trauma, genetic predisposition, bone disorders, systemic diseases, and infections. Research shows that ankylosis predominantly affects the first lower primary molars, with secondary ankylosis sometimes occurring due to traumatic events. Following the first lower primary molars, the first upper primary molars, second lower primary molars, and second upper primary molars are also frequently affected. Infra-occlusion is approximately 10 times more common in the mandible than in the maxilla and often occurs bilaterally. Clinically, ankylosed teeth cannot be exposed to post-eruption movements and can remain fixed in the infra-occlusion position. The severity of infra-occlusion can vary from mild to complete retention. Histological examinations of ankylosed teeth reveal that resorbed root areas may be replaced by both cementum and bone, establishing a direct connection between the tooth and the surrounding bone. In addition, PDL remnants may be present despite fibrosis and reduced cell number. Treatment goals for infra-occluded primary molars with successive teeth include facilitating the natural eruption of the permanent tooth while protecting the affected tooth and surrounding gum and bone tissue. The goals in the treatment of ankylosed teeth are to preserve the affected tooth as much as possible, protect adjacent tissues, prevent interference with normal growth, enable orthodontic interventions, preserve the aesthetic appearance, and restore normal function.