Abstract: Objectives To compare the accuracy of implant placement using free-hand implantation (FH), surgical guide (SG), dynamic navigation (DN), and guide and navigation (SG with DN). Methods Using four different implantation methods, 192 implants were equally distributed into 48 identical mandibular models with bilaterally homologous tooth implantation sites. According to the preoperative cone beam computed tomography (CBCT) of the experimental model, the appropriate implantation position was planned, so that the four implantation methods used the same planning information for implant placement. Post-implantation CBCT was registered with preoperative planning data to measure post-implantation 3D deviation and parallelism. Results The accuracy obtained with computer-assisted implantation (CAIS) was significantly higher than that obtained with free-hand implantation (P<0.01), The three-dimensional deviation of the SG group and the DN group at crest were 0.63（0.29）（0.55~0.71）mm and 0.57（0.19）（0.52~0.63）mm, respectively; and the three-dimensional deviation at apex were 0.72（0.27）（0.65~0.80）mm and 0.62（0.20）（0.56~0.68）mm, the difference between the two groups was not statistically significant （P>0.05）; the deviations of the SG with DN group at crest and apex were 0.33 （0.13）（0.29~0.37）mm and 0.35（0.14）（0.31~0.39）mm, and the difference with other groups was statistically significant (P<0.05). When SG was used, the deviation in the horizontal direction at crest was smaller (SG and SG with DN groups); while when DN was used, the deviation in angle was smaller (DN and SG with DN groups). Conclusion CAIS can improve the accuracy of implantation, and the best accuracy can be obtained when the surgical guide and dynamic navigation are used in combination.

Key words: Accuracy, Dental implantation, Computer-assisted implantation, Static guide system, Dynamic navigation system