Association between root resorption and tooth development: A quantitative clinical study.

INTRODUCTION

The aim of this study was to verify less resorption of incompletely developed roots compared with those that were fully developed during the same orthodontic treatment and to test the value of the amount of external apical root resorption for predicting tooth development.

METHODS

A sample of 524 patients aged 10-15 years was selected following the inclusion criteria. For each subject, pretreatment and posttreatment digital panoramic and lateral radiographs were collected, and tooth development was determined from each radiograph. Through calculations, the amount of root resorption was assessed by a created and scientific approach for large-scale application using radiographs with only 8 measurement indexes for each patient. Other basic information and treatment parameters regarded as possible risk factors were also collected from standardized recordings or radiographs. The root length between the groups or in the single group were compared with t tests and correlation analyses. Linear univariate and multivariate regression analyses were used to test identify predictors for root resorption and to develop a prediction model.

RESULTS

There was a statistically significant difference in the amount of root resorption with tooth development before correction (P <0.001) as well as after correction (P = 0.002). There was a statistically significant correlation (P <0.001) but no difference between pretreatment and posttreatment root length in the immature tooth group because of less root resorption. In the multivariate analyses, tooth development (P <0.001), treatment duration, apex horizontal movements, apex vertical movements, and previous orthodontic treatment were included in the final model as risk factors, and tooth development had the highest beta value.

CONCLUSIONS

There is an association between root resorption and tooth development, and tooth development is an important predictor of root resorption. Patients with immature teeth are at a much lower risk of apical root resorption.