ABSTRACT:Background of the study:
External apical root resorption (EARR) is the permanent loss of root structure involving the apical region which can be attributed to the forces acting on to the teeth by fixed appliance & more commonly seen in the upper incisors. The aim of this study was to analyse the amount of EARR (external apical root resorption) of maxillary incisors and to evaluate the root shape by comparing with periapical and panoramic films and also to evaluate the contribution of the gender and duration (pre & post space closure).
Methodology: 30 subjects undergoing orthodontic treatment were selected for this study and were divided into 15 male and 15 female patients within the age range of 12-26 yrs. Totally 120 teeth were scanned (central & lateral). At the pre-treatment stage, standardized intraoral periapical films and digitalized panoramic films were taken. Crown and root lengths of the four maxillary incisors on the scanned periapical and panoramic films were measured. At post space closure follow up films were obtained and EARR were measured. All measurements were performed for each tooth separately. Any image distortion between the crown lengths for pre-treatment and post space closure films was corrected by using correction factor (CF). A root shape assessment was performed for each tooth by a 5 parameter ordinale scale which was categorized into the following, D----dilacerated, O----bottle shaped, B----blunted, P----pointed, N----normal. All the data underwent statistical analysis for comparison between groups.
Results: Out of 120 teeth scanned through periapical and panoramic films, both central and lateral incisor showed EARR and the amount was greater for the maxillary lateral incisors compared to -bcxthe central incisors which was more evident in panoramic films. Based on gender, females showed more EARR compared with males and tendency being more for maxillary lateral incisors and the frequency of abnormal shapes in panoramic films were more compared with periapical films.
Conclusions: The study concluded that all maxillary incisors showed significant root resorption post space closure, the amount of EARR being more for lateral than central incisors in both the films. Females showed more EARR than males and it was more clinically significant for lateral incisors. Root shape are more difficult to assess on panoramic films as the amount of root resorption will be exaggerated.