Eight implants were placed in the posterior part of the mandible using computer-generated stereolithographic templates. Preoperative implant simulation was done on a 3D computer model created by reformatted computerized tomography data. The surgeon and the prosthodontist positioned the simulated implants in the most favorable position addressing all concerns with regard to anatomy, biomechanics, and esthetics. The length and diameter of each implant along with the angulation/collar of abutments required for a screw-retained prosthesis were determined.
Stereolithographic templates were then fabricated by incorporating the precise spatial position of the implants within the bone as previously planned during the computer simulation. The templates were fabricated to seat directly on the bone and were stable. The first template was used to complete osteotomies with a 2-mm twist drill followed by the second template for the 3-mm drill. Implants were placed and allowed to integrate for 4 months. After second-stage surgery, the definitive abutments were torqued into place followed by insertion of the definitive screw-retained prostheses. Dimensions of all implants and abutments were the same as planned during the computer simulation.