J Korean Assoc Oral Maxillofac Surg.  2014 Feb;40(1):11-16. 10.5125/jkaoms.2014.40.1.11.

Three-dimensional evaluation of lingual split line after bilateral sagittal split osteotomy in asymmetric prognathism

• Song JM
• Kim YD

• KMID: 1960966
• DOI: http://doi.org/10.5125/jkaoms.2014.40.1.11

Abstract

OBJECTIVES
The aim of this study was to evaluate the pattern of lingual split line when performing a bilateral sagittal split osteotomy (BSSO) for asymmetric prognathism. This was accomplished with the use of cone-beam computed tomography (CBCT) and three-dimensional (3D) software program.
MATERIALS AND METHODS
The study group was comprised of 40 patients (20 males and 20 females) with asymmetric prognathism, who underwent BSSO (80 splits; n=80) from January 2012 through June 2013. We observed the pattern of lingual split line using CBCT data and image analysis program. The deviated side was compared to the contralateral side in each patient. To analyze the contributing factors to the split pattern, we observed the position of the lateral cortical bone cut end and measured the thickness of the ramus that surrounds the mandibular lingula.
RESULTS
The lingual split patterns were classified into. The true "Hunsuck" line was 60.00% (n=48), and the bad split was 7.50% (n=6). Ramal thickness surrounding the lingual was 5.55+/-1.07 mm (deviated) and 5.66+/-1.34 mm (contralateral) (P=0.409). The position of the lateral cortical bone cut end was classified into three types: A, lingual; B, inferior; C, buccal. Type A comprised 66.25% (n=53), Type B comprised 22.50% (n=18), and Type C comprised 11.25% (n=9).
CONCLUSION
In asymmetric prognathism patients, there were no differences in the ramal thickness between the deviated side and the contralateral side. Furthermore, no differences were found in the lingual split pattern. The lingual split pattern correlated with the position of the lateral cortical bone cut end. In addition, the 3D-CT reformation was a useful tool for evaluating the surgical results of BSSO of the mandible.

Keyword

Orthognathic surgery; Cone-beam computed tomography; Prognathism

MeSH Terms

Cone-Beam Computed Tomography
Humans
Male
Mandible
Orthognathic Surgery
Osteotomy*
Prognathism*

Figure

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  Fig. 1 Orientation of three-dimensional images and measurement point. A, B. Reference plane and orientation. C. Level of measurement at the mandibular lingual. D. Measurement of ramal thickness.

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  Fig. 2 The five types of lingual split pattern. A. Type I. B. Type II. C. Type III. D. Type IV. E. Type V.

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  Fig. 3 Position of the lateral cortical bone end. A. Lingual. B. Inferior. C. Buccal.

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