Morphologic quantification of the maxilla and the mandible with cone-beam computed tomography.
BACKGROUND
The purpose of this pilot study was to use cone-beam computed tomography (CBCT) to determine the volumes of the maxilla and the mandible in subjects with skeletal Class I, Class II, and Class III malocclusions. Hypothesis 1 was that the volume (size) of a skeletal Class II maxilla is larger than those of Class I and Class III. Hypothesis 2 was that the volume of a skeletal Class III mandible is larger than those of Class I and Class II.


METHODS
Thirty women patients were classified into 3 groups according to their skeletal pattern: skeletal Class I (0 degrees < or =ANB <6 degrees ), Class II (ANB > or =6 degrees ) and Class III (ANB <0 degrees ). The volumes of the maxilla and the mandible were measured with CBCT. CB MercuRay (Hitachi Medico, Tokyo, Japan) and CB works software (CyberMed, Seoul, Korea) were used to process the images.


RESULTS
There was a trend that skeletal Class III subjects might have significantly greater mandibular volume compared with Class II subjects (P = 0.089). The ratios of maxilla-to-mandible volumes between the skeletal Class II and Class III groups were significantly different (P = 0.005). Differences were observed in the ratios of maxillary and mandibular volumes across the 3 groups.


CONCLUSIONS
Hypotheses 1 and 2 were rejected; there was no trend for Class III subjects to have larger mandibles (P = 0.089) compared with Class II subjects. The ratio of the maxilla and mandible volumes in skeletal Class III subjects was significantly larger (P = 0.005) compared with Class II subjects.
National University of Singapore, Singapore. pndtd@nus.edu.sg
Toshio
T
Deguchi
Shinya
S
Katashiba
Toru
T
Inami
Kelvin W C
KW
Foong
Chan Yiong
CY
Huak
D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000295:instrumentation / Q000592:standards*; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000473:pathology*; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D008437:Maxilla / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D009929:Organ Size; D019252:Radiography, Dental, Digital; D055815:Young Adult