This study aimed to measure ramal lengths and angles on panoramic radiography applying a polar coordinate system for analyzing facial asymmetry within normal range. Panoramic radiographs taken from 15 males and 15 females (mean age 31.33±3.7 yrs in males and 28.87±2.72 yrs in females) with symmetric-looking faces were selected. The polar coordinate system, length of condylar and ramal height and angles between the ramus tangent and the connecting line of the most inferior point of bilateral orbital rim were measured from panoramic radiographic images. Bilateral differences in the ramal and condylar heights and angles were determined by asymmetric index. The polar coordinate applied for analyzing facial asymmetry uses length and angle measure. The normal range of facial asymmetry was measured using mean and standard deviation of asymmetry index of length and angle measure. A new analysis method using polar coordinate system on panoramic radiograph may provide more accurate analysis for facial asymmetry.

Abstract
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS and METHODS
    1. 연구대상
    2. 파노라마방사선사진과 투사방법
    3. 안면선의 길이 측정과 각도 측정
    4. 자료분석
Ⅲ. RESULTS
Ⅳ. DISCUSSION
Ⅴ. CONCLUSION
REFERENCES

• 배신길(전남대학교 치의학전문대학원) | Shin Gil Bae (School of Dentistry, Chonnam National University)
• 송인자(광주여자대학교 간호학과) | In-Ja Song (Department of Nursing, Kwangju Women's University)
• 이재서(전남대학교 치의학전문대학원 구강악안면방사선학교실, 치의학연구소) | Jae-Seo Lee (Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University)
• 강병철(전남대학교 치의학전문대학원 구강악안면방사선학교실, 치의학연구소) | Byung-Cheol Kang (Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University)
• 이은주(전남대학교 치의학전문대학원 구강해부학교실, 치의학연구소) | Eun Joo Lee (Department of Oral Anatomy, School of Dentistry, Dental Science Research Institute, Chonnam National University)
• 윤숙자(전남대학교 치의학전문대학원 구강악안면방사선학교실, 치의학연구소) | Suk-Ja Yoon (Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University) Correspondence