Accuracy of implant placement in the posterior maxilla as related to 2 types of surgical guides: a pilot study in the human cadaver.

Statement of problem The position of implants may have an effect on obtaining osseointegration without complications and on the outcome of the prostheses. Purpose The purpose of this study was to compare the accuracy of implant placement with computer-guided surgery and freehand surgery in the atrophic area of the posterior maxilla. Material and methods Six human cadavers (Kennedy-Applegate class I) were included in the study. The specimens were randomly classified into 2 categories by using a computer: computer-guided surgery (n=3) and freehand surgery (n=3). Thirty-nine implants were planned with the software. Two types of surgeries were performed. The preoperative computed tomography data were matched with the postoperative computed tomography data by using voxel-based registration software. The position of the planned implants was compared to the actual position of the implants. A multivariate analysis was used for each variable (bone density, length of implant, implant angulation, and surgical technique) to evaluate the effect of these variables on the implant accuracy (α=.05). Results The statistical tests (Kolmogorov-Smirnov bootstrap) found that guided surgery offered significantly better accuracy for the platform ( P =.002), apex ( P =.001), and angle ( P P =.186). The bone density did not influence the implant placement accuracy. Conclusions Computer-guided surgery was more accurate than a freehand approach for placing implants into bilateral edentulous zones in the posterior maxilla.