Panoramic radiographic evaluation of prevalence, distribution of the dense bone island and its influence on tooth movement among orthodontic patients

Abstract

Objectives: To investigate the prevalence, distribution of the dense bone island (DBI) among orthodontic patients and to evaluate the influence of DBI on orthodontic tooth movement using panoramic radiographs. Methods: The pre-treatment panoramic radiographs from 320 consecutively treated orthodontic patients were screened for the presence of DBI. The prevalence of the DBI was recorded according to the Geist & Katz’s classification. The post-treatment panoramic radiographs were examined for cases with premolar extraction and the DBIs closed to the adjacent teeth. The positional change of the roots and the sign of root resorption were recorded. Results: Fifty-two DBIs were detected in 48 patients (15%). Among them, 25 lesions (48%) were found to be associated with teeth (apical, interradicular or apical/interradicular) while 27 lesions (52%) had no relation to teeth. Thirteen cases with DBIs were related to extracted premolars for orthodontic reasons. No sign of DBIs obstructing the root movements during space closure was found. There was no obvious change in root resorption in these cases. Conclusions: The prevalence of DBI is similar with that in general population. In the light of this study, DBIs do not have significant effects on the orthodontic tooth movement and do not cause the root resorption. This study provides the evidence that the orthodontic treatment plan can utilize the space closed to the DBIs which will not cause potential side effects.