Imaging Sci Dent.  2013 Mar;43(1):31-36. 10.5624/isd.2013.43.1.31.

Normal range of facial asymmetry in spherical coordinates: a CBCT study

• Yoon SJ
• Wang RF
• Na HJ
• Palomo JM

• KMID: 2167444
• DOI: http://doi.org/10.5624/isd.2013.43.1.31

Abstract

PURPOSE
This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT).
MATERIALS AND METHODS
CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was 1.01+/-0.66 mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined.
RESULTS
All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates.
CONCLUSION
The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

Keyword

Cone-Beam Computed Tomography; Imaging, Three-Dimensional; Facial Asymmetry

MeSH Terms

Cone-Beam Computed Tomography
Facial Asymmetry
Female
Humans
Imaging, Three-Dimensional
Reference Values

Figure

• 

  Fig. 1 3D reconstruction image of CBCT. A. Three orthogonal reference planes are established. B-D. Condylar landmarks and gonion landmarks and the menton are identified.

• 

  Fig. 2 Spherical coordinates of a facial line, the ramal lateral (RL) is seen. v is the distance of the lines; θ, the midsagittal inclination, is the angle inclination from the midsagittal reference plane; ϕ, the coronal inclination, is the angle inclination from the coronal reference plane. The mandible is cropped for understanding.

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