ABSTRACT
It is known that radicular cyst is one of the most important odontogenic inflammatory cysts and the existence of cholesterol needles in the wall of radicular cyst, raises the question about the probability of its existence in the cyst fluid and the relationship between the presence and concentration and the degree of inflammation occurring in the cyst. 20 radicular cysts from 20 patients were obtained, histological study was conducted for each tissue sample and study standardized testing and dosage of cholesterol in the fluid. After evaluating the results, cholesterol was found in 65% of the cysts and its concentration in the fluid was medium [m = 188 mg/dl] to high [m = 297 mg/dl] in 55% of them. The correlation between the cholesterol concentration in the cyst fluid and all of the presence of cholesterol needles and haemosiderin granules in the wall of the same cyst and also the degree of inflammation in the same cyst was positive [p=0.002], [p < 0.001] and [p=0.002] respectively. There was not a significant correlation between the presence of cholesterol needles and the degree of inflammation in the cyst [p=0.716]. The cholesterol concentration in the radicular cyst fluid can be used as an indicator for the presence of cholesterol needles and haemosiderin granules in the cyst, and it might be a feature of the degree of inflammation in the cyst