Abstract: Objective To verify the feasibility and accuracy of the microsphere diffusion method by the method of electron microscopy; meanwhile, to measure and compare the four different micro-gaps of the four different implant-abutments stressed by different horizontal loads. Method Four kinds of implant based micro-gap models were constructed in vitro (Group A: Anatomic all ceramic abutment; Group B: SynOcta octagonal titanium base; Group C: Procera titanium base all ceramic abutment; Group D: Procera all ceramic abutment, Polystyrene microspheres were added into the implants (0.2-5 μm). At the same time, the different horizontal loads (0, 50, 100, 150 N) were given. The maximum particle size of micro diffusion was measured by laser particle size analyzer. At the same time, the time required to measure the maximum width was recorded. On the other hand, scanning electron microscopy was used to measure the width of the slit of the 8 observation points of each slit model, and the maximum value was obtained. The differences between the two methods were analyzed by t test. Results ①There was no significant difference in the accuracy of the micro slit width between the microspheres diffusion method and the electron microscope (P<0.05). ②Micro diffusion method to detect micro slit width took up to 15 minutes. ③When there was no external load, the micor-gaps of A and D groups were significantly larger than B, C groups (P<0.05). ④In B, C groups, 100N and 150 N load micro-gaps were significantly greater than 0 N (P<0.05); 150 N load of micro-gap was significantly greater than 50 N (P<0.05). Conclusion Microsphere diffusion method is simple, efficient and accurate to measure the maximum width of micro-gap between implant and abutment. The result of the experiment shows that the micro-gap of the implant-procelain interface is significantly larger than that of the implant-titanium interface, meanwhile, the micro-gap of the implant-titanium interface will increase significantly when stressed by the larger horizontal loads.

Key words: Polystyrene, Microspheres, Diffusion, Implant-abutment, Microgap