Accuracy of bi-coordinate and multi-coordinate handpiece calibration methods for robot-assisted implant placement

Abstract

Statement of problem

To ensure accurate robot-assisted surgery, it is essential to identify the handpiece position at the end effector of the robotic arm. Clinically, the relationship between the optical tracking device and the handpiece has been typically confirmed by using a calibration plate at the end effector of the robotic arm. However, the accuracy of the handpiece calibration methods for robot-assisted implant placement remains unclear.

Purpose

The purpose of this in vitro study was to evaluate the accuracy of bi-coordinate and multi-coordinate handpiece calibration methods, as well as the multi-coordinate handpiece plate under partial obstruction, in the context of robot-assisted implant placement.

Material and methods

In total, 120 implants were divided into 6 groups based on the calibration plate used in the study: bi-coordinate handpiece calibration plate for the maxilla (Bmx), bi-coordinate handpiece calibration plate for the mandible (Bmn), multi-coordinate handpiece calibration plate for the maxilla (Mmx), multi-coordinate handpiece calibration plate for the mandible (Mmn), partially obscured multi-coordinate handpiece calibration plate for the mandible with the primary coordinate unblocked and the auxiliary coordinate covered (MmnPrim), and partially obscured multi-coordinate handpiece calibration plate for the mandible with the auxiliary coordinate unblocked and the primary coordinate covered (MmnAux). Calibration of the robotic arm was conducted separately for each group. Then the robot autonomously performed osteotomies and implant placements at the first and second premolars according to the preoperative plan. Following surgery, the robotic software program calculated the deviation values between the planned and actual implant positions. Differences between the test groups were analyzed using 1-way analysis of variance (ANOVA) and the Bonferroni post hoc test (α=.05).

Results

The ranges of angular deviation and 3-dimensional deviations at the implant platform and apex across the 6 groups were 0.30 degrees to 0.48 degrees, 0.31 to 0.36 mm, and 0.31 to 0.38 mm, respectively. No statistically significant differences were found among the groups (P>.05).

Conclusions

Both the bi-coordinate and multi-coordinate handpiece calibration methods demonstrated acceptable accuracy for robot-assisted implant placement. The multi-coordinate calibration plate provides a feasible method for robot calibration in scenarios where the mandible is partially obstructed.