Unexpected early apical resorption of primary molars and canines

This was to examine the resorption pattern of primary molars and canines in dentitions with advanced apical resorption even though the permanent successor had barely begun root formation and to verify the resorption process histologically.

Panoramic or bite-wing radiographs were selected from a dentition archive of radiographs from 142 children with deviant resorption patterns.

There were 14 patients (10 boys, 4 girls) aged 6 years 2 months to 8 years 1 month selected. In 11 patients abnormal resorption occurred only in the roots (group I). In 3 patients resorption occurred in the roots as well as in the crown (group II). The degree of resorption was evaluated using Haavikko's five resorption stages, and the degree of development of the permanent successor was evaluated using Haavikko's ten formation stages [Haavikko, 1973]. For histologic study 7 teeth were decalcified, paraffin-embedded, sectioned and stained with hematoxylin and eosin and examined microscopically.

Group I: in 5 patients severe root resorption occurred before crown formation of the permanent successor was completed. In 6 children the abnormal resorption pattern was less severe. Group II: in 3 subjects full resorption of the root complex was observed as well as partial resorption of the crown. A histological analysis confirmed the resorption process.

This is the first study focussing on unexpected early resorption of primary molars and canines in 14 patients without agenesis. The study showed an abnormal resorption pattern of roots and crown of primary teeth before the permanent successor had barely begun root formation. This indicates that resorption of primary molars and canines may occur independently from eruptional processes in the succeeding permanent tooth.