Impact of primary molars with periapical disease on permanent successors: A retrospective radiographic study

To clarify the effects on the development, position and morphology of the permanent successors of primary molars affected by apical periodontitis (AP).

A total of 132 panoramic radiographs of children aged from 4 to 10 were screened out and a total of 159 mandibular second primary molars with chronic apical periodontitis（AP）(93 males and 66 females) were analyzed. The maturation values of permanent successors were interpreted and scored according to Nolla's method and compared with normal ones'. The proportion of abnormalities in the morphology and orientation of permanent successors were counted, and the differences between men and women was analyzed. The distribution of various abnormalities in different age groups was also analyzed.

There were significant differences in development of permanent successors in this study compared with the normal ones' in all age groups, among which the differences were statistically significant in males aged in 4,5,7 groups and females aged in 4,6 (P < 0.05). The proportions of permanent successors involved with dental follicle broken, malposition and malformation were 78.94%, 42.1%, 8.42% and 82.50%, 38.75%, 15.00%, respectively, with no gender difference. And the highest proportion of these three were all found in 9 years old age group.

AP of primary teeth can lead to accelerated or delayed development of permanent successors to some extent, and may also lead to changes in their shape and direction.