Abstract: Objective　 To compare the primary stability, osseointegration and the new bone formation ability of self-tapping and non-self-tapping implants in immediate implant, and provide basis for clinical application of self-tapping implants. Methods Thirty-six healthy male adult Beagle dogs with well-developed body were selected and numbered randomly as No. 1-36. After minimally invasive tooth extraction, immediate implant placement was performed. Two self-tapping implants (BLE, TLE) and two non-self-tapping implants (BL, TL) were implanted in the mandibular of each experimental dog. Thirty-six Beagle dogs were sacrificed 4, 8, and 12 weeks after implant placement. The insertion torque analysis of all implanted implants was performed, and the primary stability and the long-term stability of the self-tapping dental implants were analyzed using the resonance Frequency Analysis. Micro-CT was used to observe and calculate the bone volume fraction (bone volume/total volume, BV/TV, %) and number of trabeculae and trabecular spacing to analyze the bone remodeling around the implant. The fluorescent marker tetracycline hydrochloride was used to trace the bone remodeling. Laser confocal microscope was used to observe, analyze and compare the new bone area of self-tapping implants and non-self-tapping implants. Results Analyzing the insertion torque and ISQ value during implant placement, the results of the self-tapping group were better than those of the non-self-tapping group (p<0.05). The ISQ values of 4 weeks, 8 weeks, and 12 weeks after implantation were significantly higher in the BLE group than in the BL group (p<0.05). The TLE group was significantly higher than the TL group 4 weeks and 8 weeks after implantation. However, 12 weeks after implantation, the TLE group was basically consistent with the TL group. Bone volume fraction and new bone area of self-tapping group were both superior to non-self-tapping group (p<0.05). Conclusion In immediate implantation, the primary stability and the osseointegration ability of self-tapping implants are better than those of non-self-tapping implants, while new bone formation ability is a little stronger .

Key words: immediate implantation, dental implant, self-tapping implants, primary stability, Beagles