Association between palatally displaced maxillary central incisors and lateral incisors: A retrospective cone-beam computed tomographic study.

Abstract

The objective of this study was to investigate the location, orientation and root development of maxillary lateral incisors in patients with palatally impacted central incisors. Comparison was made between the lateral incisor on the affected side and that on the normally erupted side. Cone-beam computed tomographic images from 20 patients (10 boys, 10 girls, mean age (9.01±1.52years old) with unilateral palatally impacted maxillary central incisors were imported into Dolphin imaging software 11.8 for 3-dimensional reconstruction and reorientation. Software measurement tools were used to measure the root length, crown distance, angle to palatal plane, distance to midline, and angle to midsagittal plane of the maxillary lateral incisors on both the impacted and unaffected sides. The Wilcoxon signed rank test indicated that lateral incisors on the impacted side were more proclined, at a mean angle difference of 29.47° in the sagittal plane (P<0.001). The mean length of the roots of the lateral incisors was 1.21mm shorter (P<0.05) on the affected side compared with the normal side, and the lateral incisor crowns on the impacted side were located at an average of 4.57mm closer to the palatal plane than on the normally erupted side (P<0.001). The angle of long axis of the lateral incisors on the affected side had a greater angulation to the midsagittal plane compared with the unaffected side, with a mean difference of 30.27° (P<0.001). Maxillary lateral incisors adjacent to palatally impacted maxillary central incisors side had abnormal root development and demonstrated angulation and position change compared with those adjacent to normally erupted central incisors.