Inclination of the infraorbital canal studied on dry skulls expresses the maxillary growth pattern: a new contribution to the understanding of change in inclination of ectopic canines during puberty.
OBJECTIVE
The purpose of this study was to analyze the correlation between direction of the infraorbital canal and maxillary width on frontal radiographs of dry human skulls.


METHODS
Forty-two symmetrical, dry human skulls (late adolescence and adult) with no dental or skeletal anomalies. Frontal radiographs were taken of each skull placed in the Frankfort horizontal plane, with a radiopaque marker in the infraorbital canal. The maxillary transversal growth pattern was expressed as the infraorbital transversal angle (IOt) formed between a line through the contour of the bilateral orbita (lo) and a line parallel to the infraorbital marker. Three cephalometric widths were measured on the skulls, two anteriorly (the width of the piriform aperture (AP) and the interorbital width (IO)) and one posteriorly (the palatal width (PW)). A general linear model was used for statistical analysis.


RESULTS
The direction of the infraorbital canal (66.08°, 95% CI: 62.53-69.64) depended on the transversal growth: an increased PW of 1 mm resulted in a decreased IOt of 1.84° (p=0.041); an increase in IO of 1 mm resulted in an increased IOt of 2.24° (p=0.017); and an increased AP of 1 mm resulted in a decreased IOt of 3.30° (p=0.066).


CONCLUSIONS
The study indicates that the direction of the infraorbital canal in frontal view reflects the transversal growth of the maxilla. A wide maxilla posteriorly resulted in a small infraorbital transversal angle. These findings might explain the different inclination of ectopic canines.
Caspersen
Louise M
LM
Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark.
Christensen
Ib J
IJ
Kjær
Inger
I
D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D003481:Cuspid / Q000473:pathology*; D003724:Dental Arch / Q000033:anatomy & histology; D057918:Fiducial Markers; D006801:Humans; D016014:Linear Models; D008437:Maxilla / Q000033:anatomy & histology / Q000254:growth & development*; D009296:Nasal Cavity / Q000033:anatomy & histology; D009915:Orbit / Q000033:anatomy & histology*; D010159:Palate / Q000033:anatomy & histology; D011627:Puberty; D014079:Tooth Eruption, Ectopic / Q000209:etiology*; D055815:Young Adult