The long-term fate of persisting deciduous molars and canines in 42 patients with severe hypodontia: a 12-year follow-up

Objectives: The decision to preserve or to extract a deciduous tooth without a successor hinges upon whether it can be expected to be stable over time. This study aimed to record the number and location of deciduous teeth and to examine the condition of deciduous canines and molars in a group of patients with severe hypodontia, both at baseline and at follow-up. Material and methods: A total of 50 patients participated in a follow-up study. The average age was 13.9 years (range 7-25 years) at baseline and 25.6 years (range 18-38 years) at follow-up. Of the 50 subjects, 44 had at least one persisting deciduous tooth at follow-up and 42 had at least one deciduous canine or molar at baseline. The presence of persisting deciduous teeth was identified on panoramic radiographs. Deciduous canines and second molars were classified as good or poor based on infraocclusion, root resorption, and restorations. Results: The mean number of persisting deciduous teeth per patient was 6.3 (range 1-16) at baseline and 2.6 (range 0-9) at follow-up. The tooth types with the highest tendency to remain were canines and second molars, and in particular canines in the mandible. Among the 42 participants with a deciduous canine or molar, 183 teeth were present at baseline, of which 112 were classified as good. At follow-up, 86 (77 per cent) of these were still present, with 65 (58 per cent) classified as good. The number of teeth classified as poor due to infraocclusion decreased much more from baseline to follow-up than those classified as poor due to root resorptions and restorations, indicating that infraoccluded teeth were lost during the observation period. Conclusions: Preserving deciduous canines and molars in good condition is often a dependable choice. Early infraocclusion is detrimental to the prognosis and often leads to tooth loss. Teeth with short roots proved to be more stable over time.