Advisory Committee Chair
Advisory Committee Members
Chung How Kau
Date of Award
Degree Name by School
Master of Science in Dentistry (MScD) School of Dentistry
Objective: The primary aim of this study was to determine if there is a difference in the mesiodistal crown-root angulation of maxillary lateral incisors between patients with impacted maxillary canines and a control population. Secondary aim 1 compared the same angle measured on panoramic radiographs to determine if a difference existed between the CBCT measurement and the panoramic radiograph measurement. Secondary aim 2 looked to determine if there was a correlation between maxillary lateral incisor tooth width and the mesiodistal crown-root angulation. Materials and Methods: CBCT's were reformatted so that the mesiodistal crown-root angulation of maxillary lateral incisors could be measured from the true facial viewpoint. A root measures >180° when the root is distal to the crown and <180° when the root is mesial to the long axis of the crown. 32 lateral incisors were measured in the study group with ipsilateral impacted canines. 34 lateral incisors were measured in the control group. For the first secondary aim 45 lateral incisors that had a panoramic radiograph in addition to the CBCT had the crown-root angulation measured on the panoramic radiograph. For the next secondary aim 40 maxillary lateral incisor mesiodistal widths were measured on a digital models and a correlation coefficient was determined. Results: Primary aim: The mean angle for study group (n=32) was 173.00 and the mean angle for control group (n=34) was 183.65. This difference was statistically significant. Secondary aim 1: The difference between the means of lateral incisors measured on CBCT's compared to panoramic radiographs was 0.036° which is not a significant difference. Secondary aim 2: The relationship between the maxillary lateral incisor crown-root angulation as measured on both CBCTs and panoramic radiographs and tooth width are positively correlated and statistically significant (rho = 0.49 p = 0.001 and rho = 0.42, p = 0.01, respectively). Conclusions: The mesiodistal crown-root angulation of maxillary lateral incisors in patients with impacted canines is significantly smaller than in patients without impacted canines. This can be viewed on a panoramic radiograph without need for a CBCT. Clinicians can use this association as an aid in diagnosing impacted canines.
Purnell, Samuel Philip, "Investigation of lateral incisor crown root angulation and impacted maxillary canines" (2014). All ETDs from UAB. 2760.