J Korean Assoc Oral Maxillofac Surg.  2017 Aug;43(4):239-246. 10.5125/jkaoms.2017.43.4.239.

New method for an evaluation of the esthetical improvements resulting from a mandibular angle reduction

• Kim JH
• Han SJ
• Kim MY

• KMID: 2391354
• DOI: http://doi.org/10.5125/jkaoms.2017.43.4.239

Abstract

OBJECTIVES
This paper proposes Han's ratio as an objective and quantitative comparative result obtained from pre and postoperative data in patients with a mandibular angle reduction.
MATERIALS AND METHODS
Thirty patients, 12 men and 18 women, who visited the Department of Oral and Maxillofacial Surgery with the chief complaints of skeletal mandibular prognathism and prominent mandibular angle were selected. The subjects were classified into 3 groups according to the types of surgical procedures involved. Group A consisted of patients who underwent mandibular angle resection and mandibular setback. Group B was comprised of patients with mandibular angle resection, mandibular setback and genioplasty. Group C consisted of patients with mandibular angle resection, mandibular setback, Le Fort I osteotomy, and genioplasty. The landmarks placed in pre and postoperative frontal photographs were used to obtain the Han's ratio in each group. The Han's ratios were compared pre- and postoperation and according to the surgical techniques applied.
RESULTS
Of the 3 groups who had undergone a mandibular angle resection, all showed a statistically significant increase in Han's ratio. On the other hand, there was no statistically significant difference based on the surgical techniques used.
CONCLUSION
The ratio of the lateral lower face proposed in this study is a potential indicator of postoperative esthetic enhancement in mandibular angle reduction surgery.

Keyword

Mandibular angle; Orthognathic surgery; Surgery; Plastics; Facial analysis

MeSH Terms

Female
Genioplasty
Hand
Humans
Male
Methods*
Orthognathic Surgery
Osteotomy
Plastics
Prognathism
Surgery, Oral
Plastics

Figure

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  Fig. 1 Schematic drawing of curved ostectomy using reciprocating saw after sagittal split ramus osteotomy.

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  Fig. 2 Diagram of ostectomy design under the mental foramen after fixation of proximal segment to distal segment of mandible.

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  Fig. 3 Liner measurements and reference landmarks used in this study. (Pu: midpoint of pupil, Ch: most lateral point between upper and lower lip, C1: intersection of a line drawn from Ch perpendicular to Po-Bo and a line between Ba-Bo, C2: intersection of a line drawn from Ch perpendicular to Po-Bo and mandibular outline, Bo: mandibular outline, Ea: intersection of outlines of face and earlobe)

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  Fig. 4 Liner measurements and reference landmarks are showing in the preoperative (A) and postoperative (B) frontal facial photographs. Refer to Fig. 3 for the definition of landmarks.

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  Fig. 5 Preoperative (A, B) and postoperative (C, D) changes of a frontal facial photograph and cephalometric lateral radiograph in Group A. The ratio increased from 0.67 to 0.72 after the surgery.

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  Fig. 6 Preoperative (A, B) and postoperative (C, D) changes of a frontal facial photograph and cephalometric posteroanterior radiograph in Group B. The ratio increased from 0.60 to 0.68 after the surgery.

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  Fig. 7 Preoperative (A, B) and postoperative (C, D) changes of a frontal facial photograph and cephalometric posteroanterior radiograph in Group C. The ratio increased from 0.65 to 0.71 after the surgery.

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