[An model study of computer-guided endodontic microsurgery].

To assess and compare the accuracies and operating time of endodontic microsurgery performed by operators with different levels of experience in endodontics using computer-guided techniques including dynamic and static navigations in a surgical simulation model. Six pairs of three dimensional (3D)-printed models of upper and lower jaws were set up on dental manikins. A total of 120 teeth (10 teeth each jaw) were included in the models. Microsurgeries of osteotomy and root-resection were performed on the models by two operators with different experience, namely novices and experts, under of free hand (FH)(=20), dynamic navigation (DN)(=20), and static navigation (SN)(=20) conditions, respectively. The duration of each operation was recorded. Cone-beam CT was taken for 3D-printed models before and after the operation. The path of preoperative surgery planning was simulated. The linear deviations at the entry and the end point and the angular deviation of the access path between the simulated and the actual operation were compared by the software. Significant difference of the entry deviation was observed between the novices and the experts in the FH group [(1.44±0.49) and (1.02±0.58) mm] (=4.67, =0.020). There were no significant differences between the novices and the experts in the end point and angular deviations (>0.05). For the novices, the entry deviations in both DN and SN groups [(0.76±0.32) and (0.66±0.20) mm] were significantly lower than those in FH group (=7.58, <0.001; =8.66, <0.001). The angular deviations in the abovementioned two groups (5.0°±3.5°, 3.9°±2.1°) were significantly lower than that in FH group (10.9°±6.1°) (=7.38, <0.001; =8.70, <0.001). For the experts, significant differences were found only in the angular deviations among DN, SN and FH groups (3.6°±1.9°, 3.2°±1.7° and 8.2°±3.9°) (=5.74, =0.001; =6.29, <0.001). The operation durations were significantly shortened for both the novices [(4.80±2.15), (1.09±0.48) min] (=14.60, <0.001; =20.10, <0.001) and the experts [(3.40±1.96),(1.02±0.34) min] (=5.86, <0.001; =9.37, <0.001) by using DN and SN techniques. Regarding the differences between tooth types, in FH group, the operating time on the anterior teeth was significantly shorter than that on the posterior teeth (=8.14, <0.001; =5.20, =0.007), while in DN and SN groups, there were no significant differences in the operating time between two tooth types (>0.05). No significant differences were discovered in the accuracies on the anterior and posterior teeth among three techniques or between two kinds of operators (>0.05). Dynamic and static navigation techniques could assist the clinicians, especially the novices, to improve the accuracies and shorten the operating time of osteotomy and root resection microsurgeries.