Abstract:

Objective To study the effects of implants implanted under zero IT and Bio-Oss collagen on the process of osseointegration. Methods Three Beagle dogs were divided into four quadrants: upper right, upper left, lower left and lower right according to the dentition. The 2nd, 3rd, and 4th premolars were extracted in each quadrant. Three months after the extraction, in each quadrant and each position, three implants of the same size under three kinds of implantation modes were randomly implanted: control group(35 N·cm), experimental group A(0 N·cm), and experimental group B(0 N·cm+Bio-Oss collagen). One experimental dog was sacrificed at 12 weeks, 18 weeks, and 24 weeks after the operation, respectively, and the general observation was carried out. At the same time, the Resonance Frequency Analysis(RFA) was used to measure the implant stability quotients(ISQ) of each group.Micro-CT was taken; bone volume(BV) and total volume(TV) were measured with CTAn software; BV/TV value was calculated, and statistical analysis on various data obtained in the experiment was performed. Results ① A total of 6 implants failed in this experiment. Two implants failed in each group and the overall survival rate was 83%. By observing the specimens at the time of execution, it was found that the horizontal position of some of the mandibular implants at different time points in each group were significantly decreased compared with the initial implantation position;some of the implants had marginal bone loss(MBL), and the neck was exposed. ② The ISQ value of the control group increased with time, which was the highest at 18 weeks, and decreased at 24 weeks, while the ISQ value of the experimental group A decreased with time. The ISQ value of the experimental group B decreased significantly at 18 weeks, and increased at 24 weeks. There was no significant difference in the ISQ values between the groups at three time points;the ISQ value of the experimental group B was statistically different between 18 weeks and 24 weeks(P<0.05), and there was no statistical difference between the other groups at each time period (P>0.05). ③ Obvious bone formation was observed in 0 IT group at 12 weeks by imaging. There was no significant statistical difference between the BV/TV of each group(P>0.05), and there was no significant statistical difference between different time periods. Conclusion Implants without IT can also achieve goodosseointegration degree and the use of Bio-Oss collagen under torqueless implantation can promote the process of osseointegration.

Key words: primary stability, insertion torque, implant stability quotient, osseointegration, implant