A clinically relevant validation method for implant placement after virtual planning.

PURPOSE: To design a relevant method to compare the virtual planned implant position to the ultimately achieved implant position and to evaluate, in case of discrepancy, the cause for this. MATERIALS AND METHODS: Five consecutive edentulous patients with retention problems of the upper denture received four implants in the maxilla. Preoperatively, first a cone-beam CT (CBCT) scan was acquired, followed by virtual implant planning. Then, a surgical template was designed and endosseous implants were flapless installed using the template as a guide. To inventory any differences in position, the postoperative CBCT scan was matched to the preoperative scan. The accuracy of implant placement was validated three-dimensionally (3D) and the Implant Position Orthogonal Projection (IPOP) validation method was applied to project the results to a bucco-lingual and mesio-distal plane. Subsequently, errors introduced by virtual planning, surgical instruments, and validation process were evaluated. RESULTS: The bucco-lingual deviations were less obvious than mesio-distal deviations. A maximum linear tip deviation of 2.84 mm, shoulder deviation of 2.42 mm, and angular deviation of 3.41 degrees were calculated in mesio-distal direction. Deviations included errors in planning software (maximum 0.15 mm), for surgical procedure (maximum 2.94 degrees ), and validation process (maximum 0.10 mm). CONCLUSIONS: This study provides the IPOP validation method as an accurate method to evaluate implant positions and to elucidate inaccuracies in virtual implant planning systems.