OBJECTIVETo compare the therapeutic efficacy both apexification and revascularization in the immature anterior teeth of animal model with apical periodontitis, and observe the histological situation of revascularization in the root canal.

METHODSSix immature anterior teeth of one animal model (dog) aged approximately 4.5 months was selected. Afterwards, periapical periodontitis pattern were established, the samples were randomly divided into the experimental group (revascularization, 3 teeth) and the control group (apexification, 3 teeth). To compare the development of root and the healing of periapical inflammation, the involved teeth were respectively radiographed 1, 4, 8 weeks after surgery. The animals were sacrificed after 8 weeks, and the closure of apical foramen and the content of root canal were observed by hematine-eosine (HE) staining.

RESULTSThe postoperative radiography after 1 week and 4 weeks, the apical foramen size and the periapical radiolucency of the samples was shown no perceptual change. After 8 weeks, the experimental group periapical radiolucency area was obviously more narrowing, and had a apical closure tendency whereas the thickness of the root canal walls had imperceptible changed. While the control group periapical radiolucency change varied. The granulation tissue could be seen within the lumen of the experimental group, which contained a large number of irregular calcification, the calcification was obvious in the apical and adjacent the root canal wall. A small quantity of hard tissue was deposited in the apical of the control group.

CONCLUSIONRevascularization may increase the recovery of immature anterior teeth with chronic periapical inflammation, the vital regenerative tissue within root canal is the granulation tissue contained calcification.