Morphology of palatally impacted canines: A case-controlled cone-beam volumetric tomography study.
BACKGROUND
The aim of this study was to investigate the relationships between an apical curvature or a hook and the crown/root ratio in subjects with and without palatally impacted maxillary canines.


METHODS
An experimental group of 44 patients (17 boys, 27 girls; mean age, 13.6 years) with 59 palatally impacted maxillary canines was selected from the records of patients referred to a radiology practice for cone-beam imaging. If a patient had bilateral palatally impacted canines, 1 canine was randomly selected for analysis. The palatally impacted canine group was matched for age and sex with 49 normal subjects (25 boys, 24 girls; mean age, 13.2 years) with 98 canines. Cone-beam DICOM files were imported into In Vivo imaging software (version 5.3; Anatomage, San Jose, Calif) for analysis. The angulations and linear variables of the maxillary canines were measured by using the software measurement tools. Chi-square and independent t tests were used to test for differences between the groups.


RESULTS
The presence of a hook at the apical third and other root curvature were significantly different between the 2 groups (P <0.001 and P <0.05, respectively). Of the 44 palatally impacted canines, 16 (36.4%) had an apical hook and only 1 canine in the control group had an apical hook (1.0%). The mean root length of the palatally impacted canines was 2.66 mm shorter (P <0.001), and the mean crown/root ratio was significantly greater for the palatally impacted canines compared with the nonimpacted group (P <0.001).


CONCLUSIONS
Palatally impacted canines have a greater tendency to develop apical hooks and are less likely to develop other root curvatures than are nonimpacted canines. Also, they have shorter roots resulting in larger crown/root ratios compared with the control group.
Faculty of Dental Sciences, University of Peradeniya, Peradeniya, Sri Lanka; Discipline of Dento Maxillofacial Radiology, School of Dentistry, University of Queensland, Brisbane, Queensland, Australia. Electronic address: kalaniz2004@yahoo.com.
Pilana Vithanage Kalani Shihanika
PV
Hettiarachchi
Discipline of Orthodontics, School of Dentistry, University of Queensland, Brisbane, Queensland, Australia.
Richard John
RJ
Olive
Discipline of Dento Maxillofacial Radiology, School of Dentistry, University of Queensland, Brisbane, Queensland, Australia.
Paul
P
Monsour
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D054893:Cone-Beam Computed Tomography; D003481:Cuspid / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla; D009811:Odontometry; D010159:Palate; D014095:Tooth, Impacted / Q000000981:diagnostic imaging* / Q000473:pathology*