Abstract: Objective: To establish an animal model to study how to remove osseointegrated dental implants by thermal stimulation. Methods: Four mongrel dogs of 1-2 years old were selected as experimental animal. The third or fourth mandibular premolars were extracted and dental implants were placed in the edentulous area after 2 months. The osseointegration was confirmed by clinical and radiological examination after 3 months. The right side of each dog was randomly selected as experimental group for thermal stimulation, and the left side as blank control group. 48±1℃ for 1min (A), 53 ± 1 ℃ for 2.5min (B), and 59 ± 1 ℃ for 3.5min (C) were used to stimulate the experimental group respectively. The probing depth (PD), modified plaque index (mPLI), implant stability quotient (ISQ), radiological manifestations, and probability to remove the implants by torque wrench of bilateral implants were observed and measured before and 4 weeks after thermal stimulation. SPSS22.0 statistical software was used to analyze the statistical data of the experiment. Results: There was no significant difference between experimental group and control group on ISQ, mPLI, and PD before and 4 weeks after stimulation A and B, and there was no obvious change in radiography. The implant could not be removed by torque wrench. Compared with the control group in stimulation C, the ISQ of the experimental group decreased significantly (P<0.05), and the X-ray shows linear low density image around the implant, and the bone density around the low density image increased slightly. But there was no significant difference in mPLI and PD. On the experimental group, the implants could beremoved with the torque of 50Ncm, and the control group could not be removed. Two months after the removal of implant, the alveolar bone healed well. Compared with the pre-operation, there was no significant change in alveolar ridge width and height. Conclusion: The dog model of removing osteointegrated implants with minimal trauma by thermal stimulation is successfully established. The animal experiment demonstrates that appropriate thermal stimulation (59 ± 1 ℃ for 3.5 min) can destroy the bone around dental implant limitedly.

Key words: Dental implant , Osseointegration, Thermal stimulation, Minimally invasive , Extraction