Accuracy and wear evaluation of the customized zirconia guided sleeves

This in vitro study investigated the accuracy and wear conditions of three drill sleeve distances (0.01, 0.02, and 0.03 mm) for 3D-guided stents in simulated clinical dental implant surgery. Fifteen sets of upper and lower partially edentulous epoxy tooling board models with four edentulous first molar sites were prepared in a Nissin Simple Manikin II and set on a dental chair. Sixty computer-aided design and computer-aided manufacturing (CAD/CAM) designed and guided stents with three drill sleeve distances were prepared in this study. The maximum height (Sz) of the wear roughness of drills, maximum deviation, and drilling time were observed. The highest maximum horizontal deviations were observed at the upper first molar (0.48 ± 0.12 mm, p < 0.001). The highest maximum vertical and angular deviations were observed at the lower left first molar (1.08 ± 0.35 mm and 5.61^◦ ± 1.21^◦, respectively, p < 0.001). Only angular deviation significantly differed among the three drill sleeve distances (p = 0.046); the 0.03 mm distance exhibited the maximum angular deviation (3.92^◦ ± 1.87^◦ ). The bigger drill sleeve distance (0.03 mm) was associated with more wear roughness (8.70 ± 2.29 µm) of the drills. Guided stents with varying drill-sleeve distances (0.01, 0.02, and 0.03 mm) exhibited no significant difference in preparation drilling time and abrasive wear. In practice, the optimal drill sleeve distance for single-type CAD/CAM-guided stents of dental implantation was 0.01 mm.