Preventive Management of a Primary Tooth with Ankylosis

Objectives: This study aimed to investigate preventive management strategies and optimal intervention timing for dental ankylosis of primary teeth complicated by suspected pre-eruptive intracoronal resorption (PEIR), providing an evidence-based framework for clinical diagnosis and management. Methods: This case retrospectively reports a 7-year-old patient with an ankylosed mandibular left second primary molar (tooth 75), exhibiting radiographic features suggestive of pre-eruptive intracoronal resorption. The patient was in the mixed dentition stage with dental crowding. Preventive and interceptive orthodontic management was implemented to address space deficiency and guide occlusal development. The timing of extraction and space maintenance of tooth 75 was guided by space regaining, PEIR lesion progression, and crown development of tooth 35. Results: The permanent successor of tooth 75 (tooth 35) erupted successfully, dental crowding was alleviated, and a favorable occlusion was established. Conclusions: Early diagnosis and timely, individualized intervention for ankylosed primary teeth play an important role in preventing malocclusion and promoting normal eruption of the permanent successor tooth.