A new guide for enhancing dental implant placement: an in vitro assessment of accuracy

This study aimed to design a new surgical guide for controlling the mesiodistal distance between implant osteotomies and adjacent teeth as well as the osteotomy depth in partially edentulous patients. The guide kit was designed with design software and milled with a CNC (computer numerical control) router. The guide consisted of 2 components-stoppers and crown guides-for determining the drilling depth and mesiodistal position, respectively. The stoppers were designed in 7.5-, 9.5-, and 11.5-mm lengths, and the crown guides were fabricated with outer diameters of 5.0, 6.0, 7.0, and 8.0 mm. The accuracy of the guide was assessed by preparing a total of 20 implant osteotomies in 4 partially edentulous models and comparing the dimensions of the actual osteotomies to the values that were predicted to occur with the use of the surgical guides. Osteotomies were prepared using the 7.5-mm stopper with either the 7.0- or 8.0-mm crown guide. Cone beam computed tomography (CBCT) was used to obtain images for analysis of osteotomy-tooth mesiodistal distances, which were predicted to be 3.0 or 5.5 mm, depending on position; interosteotomy mesiodistal distances, which were predicted to be 3.0 mm; and osteotomy depth, which was predicted to be 11.5 mm. A 1-sample t test was used to determine if there were significant differences between the predicted values and the measurements of the guided osteotomies on the CBCT images of the mandibular models, and an independent t test was conducted to compare the results of 3.0- and 5.5-mm osteotomy-tooth distances (α = 0.05). Differences between the predicted and actual values of the interosteotomy mesiodistal distance (P = 0.516) and osteotomy depth (P = 0.847) were not statistically significant. The actual osteotomy-tooth mesiodistal distances were significantly different from the predicted values of 3.0 (P = 0.000) and 5.5 mm (P = 0.001), with higher mean differences of 0.46 and 0.60 mm, respectively. The designed guide had a high accuracy in achieving optimal linear interosteotomy mesiodistal distances and osteotomy depths, and the obtained mean values were clinically acceptable.