Accuracy of surgical guides made from conventional and a combination of digital scanning and rapid prototyping techniques

Statement of problem. Surgical guides aid in accurately placing dental implants to achieve a predictable restorative outcome. Which surgical guide fabrication technique results in the most accurately fitting surgical guide is unknown. Purpose. The purpose of this investigation was to determine the internal fit of dental implant surgical guides on dentate and edentulous ridges by using implant surgical guides fabricated from conventional and computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. Material and methods. Eighty surgical guides were fabricated from conventional and CAD/CAM techniques; half were designed from Kennedy Class 2 (K2) casts, and half were designed from Kennedy Class 3 (K3) casts. Conventional surgical guides were fabricated from acrylic resin. The CAD/CAM surgical guides were scanned by using cone beam computed tomography (CBCT) or an optical scan (OS). The guides were printed with stereolithography (SL) or 3-dimensional digital printing (3DP). All surgical guides were cemented to their respective design casts, sectioned, and measured at standardized locations. A 2-way ANOVA and the post hoc Fisher least square difference t test was performed (alpha=.05). Results. The 2-way ANOVA indicated that the difference between surgical guide groups and Kennedy class was statistically significant (P<.05) and the interaction between groups and Kennedy class was statistically significant (P<.05). The OS/3DP CAD/CAM guide was the best-fitting cast for the K2 cast group, and the conventional guide was the best-fitting guide for the K3 group. Conclusions. Conventionally fabricated and OS surgical guides have greater accuracy of fit than CBCT scanned surgical guides.