Characterization of malar deficiency in Class I and Class III individuals using CBCT

Introduction. In many individuals with the Class III malocclusion, the malar prominences appear flat and hollow. The purpose of this study is to characterize, compare and contrast malar prominence using CBCT in untreated Class I and Class III individuals. Materials and methods. 58 Class I CBCT (26 male, 32 female) of Caucasian patients and 58 Class III CBCT (26 male, 32 female) of Caucasian patients age 12 to 18 years old were included in the sample. Horizontal and oblique slices were taken of the malar area from each CBCT. A pattern profile analysis was completed on each slice of both the hard and soft tissue malar prominences and measurements were made relating the analysis to the patient's midline and cranial base. Results. According to the pattern profile analysis, the Class III male horizontal slices had larger measurements (P<.05) in both the soft and hard tissue than did the Class I by 0.6 to 1.7 mm. In the female sample, no significance differences existed in the Class I and Class III pattern profile analysis measurements on the horizontal or oblique slices. Cranial measurements showed anterior malar positional differences, with the Class III more posterior. Class I male and female pattern profile analysis and cranial measurement comparisons were not significant. The Class III male and female pattern profile analysis comparison found the Class III males to be significantly larger (P < .03) for all points on the hard tissue horizontal and the oblique slices by 0.9 to 2.1 mm. Cranial measurements depict that the males had significantly larger measurements. Conclusions. The Class III male was found to have a larger malar prominence than the Class I male. The Class I and III females had similar prominence of the malar complex, but the anterior component of the Class III female's malar complex was more posteriorly positioned. The Class I male and female had similar size and position of the malar complex. The Class III male's malar complex was larger, positioned further laterally and elongated more anteriorly compared to the female Class III. No difference was found in the shape of the malar prominences.