Korean J Orthod.  2009 Oct;39(5):300-309.

Correlation between menton deviation and dental compensation in facial asymmetry using cone-beam CT

• Park SB
• Park JH
• Jung YH
• Jo BH
• Kim YI

Abstract

OBJECTIVE
The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry.
METHODS
Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis.
RESULTS
From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (Delta Angle LM6-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (Delta Angle UM6-FH plane (dev.-ndev.)) (p<0.01). Two angular measurements (Delta Angle LM6-Mn plane (dev.-ndev.), Delta Angle UM6-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant r2 value of 0.589.
CONCLUSIONS
This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

Keyword

Cone-beam computed tomography; Presurgical orthodontics; Occlusal plane; Menton deviation; Facial asymmetry

MeSH Terms

Axis, Cervical Vertebra
Compensation and Redress
Cone-Beam Computed Tomography
Dental Occlusion
Facial Asymmetry
Female
Humans
Mandible
Molar
Tooth

Figure

• 

  Fig. 1 Reference planes. A, F-H plane was constructed by connecting both sides of Po and right of Or. MSR plane was perpendicular to FH plane passing through Na and Ba; B, Mn plane was constructed by Me and both sides of Go.

• 

  Fig. 2 Linear and angular measurements. A, Distance and angle of U3-FH plane on Ray-sum image which was set by overlapped images on the reference planes; B, distance and angle of UM6-FH plane on MRP image; C, distance and angle of LM6-Mn plane on MRP image.

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