Objective To study the relation on overfilling with gutta- percha point or paste and acute periapical periodontitis. Methods Collected sixty cases of acute periapical periodontitis which had been filled with gutta- percha point and paste within 1 week, and took dental radiographs. The cases that dental radiographs showed only guttapercha point was overfilling were assigned to group A（34 cases）, and the cases that dental radiographs showed only paste was overfilling were assigned to group B（26 cases）. The cases that dental radiographs showed both gutta- percha point and paste were overfilling were excluded. Sixty cases were divided into light group and severe group according to clinical sign. Measured gutta- percha point length or paste areas over apex. Took out the obturation material completely, adjusted occlusion when necessary and changed root canal medicament every day until clinical sign disappeared completely. Recorded the time of clinical sign disappeared completely. Results In group A, gutta - percha point length over apex averaged 1.01 mm on light cases, and 1.79 mm on severe cases. In group B, the paste areas over apex averaged 2.45 mm2 on light cases, and 8.26 mm2 on severe cases. Group A had 13 light cases and 21 severe cases, and group B had 18 light cases and 8 severe cases. In group A, the average time of clinical sign disappeared completely was 3.56 days, and in group B the average time was 6.19 days. The statistical test showed there were significant differences among these four couples. Conclusion The more overfilling, the more severe clinical sign was. Clinical sign caused by gutta- percha point overfilling was more severe. The time of clinical sign which caused by gutta- percha point overfilling disappeared completely was shorter.
