Department of Oral Pathology, Dental Science Research Institute, College of Den디'suy， Chonnam National University It is well known that the expansion of radicular and dentigerous cyst is related to the change of osmotic pressure, while the prolifera디on ofthe 비피19 epithelium in odontogenic keratocyst. When the dentigerous cyst and odontogenic keratocyst has secondary infection, they present the loss of unique sπuctures and epithelial hyperplasia. There is a question whether inflammatory reaction affects cystic formation, expansion and their treatment. Present study is to evaluate the relationship between inflammation and epithelial hyperplasia using immunohistochemial study. Followings are result; 1. 까1e age of patients ranged from 10 to 73 years (mean age, 39 years) in radicular 이5t， 10 to 71 years (mean age, 35 years) in dentigerous cyst and 10 to 54 years (mean age, 23.4 years) in odontogenic keratocyst. The sex distribution of patient distributed 32 cases for male and 16 cases for female in radicular cyst, 13 and 10 in dentigerous cyst and equally 5 and 5 in odontogenic keratocyst. 2. Inflammatory cyst in the present study distributed 44/48 cases (9 1.7%) for radicular cyst, 15/ 23 cases for dentigerous cyst and 1/ 10 case for odontogenic keratocyst. 3. Evaluation of inflammatory reaction and antigen expression, ki-67 , cox-2 and glut-1 expression increase in the inflammatory radicular and dentigerous cyst. 4. In odontoge띠c keratocyst, expression of antigens increase regardless of inflammation. Above results showed that inflammation stimulate the proliferation of lining epithelium leading to cystic expansion.