Abstract: Objectives To track patients after mandibular cyst fenestration with the application of plugger device, and to explore the relationship between the frequency of flushing and reduction in cyst diameter.Methods 47 mandibular cyst patients who had fenestration surgery were included in the sample. The patients were divided into two groups according to the number of flushing: Group A flushed≦ 2 times/day, Group B ≧ 3 times/day. The reduction in cavity size was measured from panoramic radiographs and classified into as follows: effective - the maximum diameter of the cyst reduced by ≥50%; improvement - the maximum diameter of the cyst reduced by <50%; no change or increase in size. Data analysis was conducted by chi-square test.Results In the A group, there were 8 cases of effectiveness, 10 cases of improvement, and 4 cases of no change or increase in size. In the B group, there were 18 cases of effectiveness, 5 cases of improvement, and 2 cases of no change or increase in size. The effective rate of group A was 36.4% and in group B it was 72% (χ2=6.01, P<0.05). Conclusions There is a significant relationship between daily flushing times and cyst size reduction. Patients who are flushed more than 3 times/day have a greater reduction.

Key words: jaw cyst, capsule , plugger, fenestration decompress