The aim of this study is to find out histomorphologic change and cellular activity of condyle resulted from unilateral mastication by comparison of cell proliferation and apoptosis activity. 30 adult rats were dived to 15 experimental group and 15 control group randomly. Right upper and l ower molars were gently extracted in experimental group, to make unilateral mastication environment. All subjects were sacrificed at 1 week, 2 weeks and 4 weeks by chloroform, and their tissues were prepare to observation. Streptovidin-biotin system for BrdU stanning, was used to determine cellular proliferative activity. TUNEL method was used to determine apoptotic activity. The result for cellular activity was recorded at both of anterior portion and posterior portion of condyle. Hematoxylin and Eosin stanning was used for histiomorphological change. The results were as follows. There were more change in superficial layer than deep layer of condyle in cellular activity. In anterior portion of condyle cartilage, cellular proliferative activity of experimental group was lower than control group and apoptotic activity of experimental group was higher than control group. And apoptotic activity of extracted side in experimental group is the most. In posterior portion of condyle cartilage, cellular proliferative activity of extracted side in experimental group was higher than non-extracted side and control group, And apoptotic activity of extracted side in experimental group was the low. As a result of histomorphological change, there was hyperplasia in posterior region o f extracted side c ondyle i n experimental g roup, but t here was n o change i n unextracted side i n experimental group. There was histomorphological hyperplasia in posterior condyle of experimental group as results of high cellular proliferative activity. There was mainly apoptotic change of anterior portion condyle in experimental group. But there was no histomorphologic change. In other words, there was hyperplasia by increasing of cellular proliferative activity in posterior portion of nonfunctional side condyle. In functional side condyle, there was no histomorphological change in functional condyle, but there was change in cellular activity.

I. 서론
 II. 연구 대상 및 연구 방법
  1. 연구 대상
  2. 연구 방법
 III. 연구 성적
  1. 전방부위
  2. 후방 부위
  3. 조직형태학적 관찰 (H&E염색 결과）
 IV. 총괄 및 고안
 V. 결 론
 VI. 참고 문헌

• 이동준(단국대학교 치과대학 교정학교실) | Dong Jun Lee
• 차경석(단국대학교 치과대학 교정학교실) | Kyung Suk Cha
• 이진우(단국대학교 치과대학 교정학교실) | Jin Woo Lee
• 박경주(구강조직학교실) | Gyeong Ju Park correspondence