Normal orbit skeletal changes in adolescents as determined through cone-beam computed tomography.
BACKGROUND
To determine three-dimensional spatial orbit skeletal changes in adolescents over a 19 to 24 months observation period assessed through cone-beam computed tomography (CBCT).


METHODS
The sample consisted of 50 adolescents aged 11 to 17. All were orthodontic patients who had two CBCTs taken with an interval of 19 to 24 months between images. The CBCTs were analyzed using the third-party software Avizo. Sixteen anatomical landmarks resulting in 24 distances were used to measure spatial structural changes of both orbits. Reliability and measurement error of all landmarks were calculated using ten CBCTs. Descriptive and t-test statistical analyses were used to determine the overall changes in the orbits.


RESULTS
All landmarks showed excellent reliability with the largest measurement error being the Y-coordinate of the left most medial point of the temporalis grooves at 0.95 mm. The mean differences of orbital changes between time 1 and time 2 in the transverse, antero-posterior and vertical directions were 0.97, 0.36 and 0.33 mm respectively. Right to left most antero-inferior superior orbital rim distance had the greatest overall transverse change of 4.37 mm. Right most posterior point of lacrimal crest to right most postero-lateral point of the superior orbital fissure had the greatest overall antero-posterior change of 0.52 mm. Lastly, left most antero-inferior superior orbital rim to left most antero-superior inferior orbital rim had the greatest overall vertical change of 0.63 mm.


CONCLUSIONS
The orbit skeletal changes in a period of 19-24 months in a sample of 11-17 year olds were statistically significant, but are not considered to be clinically significant. The overall average changes of orbit measurements were less than 1 mm.
Department of Dentistry, University of Alberta, Edmonton, Canada.
B
B
Lee
Department of Dentistry, University of Alberta, Edmonton, Canada.
C
C
Flores-Mir
Department of Dentistry, University of Alberta, Edmonton, Canada. manuel@ualberta.ca.|Department of Medicine and Dentistry, School of Dentistry, University of Alberta, 5524 Edmonton Clinic Health Academy, 11405-87 Ave, Edmonton, T6G 1C9, Canada. manuel@ualberta.ca.
M O
MO
Lagravère
D000293:Adolescent; D000367:Age Factors; D059925:Anatomic Landmarks; D002508:Cephalometry / Q000379:methods; D002648:Child; D002657:Child Development / Q000502:physiology*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D009915:Orbit / Q000000981:diagnostic imaging* / Q000254:growth & development*; D012016:Reference Values; D012494:Sampling Studies; D012737:Sex Factors
Cone-beam computed tomography; Growth; Orbit; Orthodontics