Objective       To investigate the effect of the physiological healing process of dental extraction wound on bone structure reconstruction around bone-implant interface.       Methods       Eight male Beagle dogs were randomly divided into four groups according to different healing time (1

3

8 and 12 weeks) after dental extraction. The third and the fourth premolars (P3 and P4) were extracted from each dog. The microscrews were implanted into the adjacent areas of P3 and P4 in the experimental group

and were implanted into the areas of the second premolar (P2) and the first molar (M1) in the control group. The dogs were sacrificed at 1

3

8 and 12 weeks

and histomorphological observation was performed at different healing time after implantation.       Results       At 1 week after implantation

obvious inflammatory reactions were observed at bone-implant interface in both of the experimental group and the control group. New bone was formed on the bone-implant interface of the control group

and bone resorption was detected in the experimental group at 3 weeks after implantation. At 8 weeks after implantation

bone matrix became calcification

and the reticulated bone  transformed into lamellar bone at the bone-implant interface in both of the experimental group and the control group. At 12 weeks after implantation

there was obvious bone formation between the threads of the microsrews in both of the experimental group and the control group.       Conclusion       The healing process after implantation is affected by dental extraction. At the early stage of implantation

the degree of inflammatory reaction and bone absorption at bone-implant interface was more significant in the experimental group than that in the control group

thus increasing the immediate loading risk.