Evaluation of collum angle of maxillary incisors on impacted vs non impacted canine Side: A CBCT analysis

Abstract

The angle which is formed between the crown axis and root axis of an upper central incisor is called collum angle and this angle serves as an important morphological feature for normal development of the dentition and plays a vital role during diagnosis and treatment planning and may vary in different malocclusions i.e; skeletal and dental malocclusions. To quantify and compare the collum angle (crown root angulation) of maxillary incisors (central and lateral incisor) in subjects with unilateral permanent maxillary canine impaction between the impacted and non impacted side using Cone Beam Computed Tomography (CBCT). Thirty subjects with unilateral permanent maxillary canine impaction who had to undergo fixed orthodontic treatment were selected and their CBCT images were analysed. The collum angle of maxillary central and lateral incisor on impaction and non impaction side was measured using CBCT imaging. Descriptive statistical analysis was carried out and the mean±standard deviation was calculated and comparison between two sides was made by using paired t-test and a p value of less <0.05 was considered as statistically significant. The collum angle of central and lateral incisor between impacted and non impacted side were averaged. Thus, the mean±standard deviation and standard error of the collum angle (n-30) were calculated for maxillary central incisor and lateral incisor on both sides. The mean±sd of the collum angle of maxillary central incisor on impacted and non impacted side was 1.39±7.16 and 2.33±5.86 respectively with a p value of 0.282, while as the mean±sd of the collum angle of maxillary lateral incisor on impacted and non impacted side was 3.09±6.26 and 5.24±5.28 respectively with a p value of 0.060 which was considered as statistically insignificant between the two sides. A decrease in collum angle was found on impaction side with a more decreased value for lateral incisor when comparison was made with non impaction side, but no statistically significant difference was found.