Effect of Drill Handle Force Applied to Digital Surgical Guides on Implant Deviation: An In Vitro Study

Introduction

This in vitro study evaluated how different forces applied to the dental drill handle during static computer-assisted implant surgery influence surgical guide deformation and implant placement accuracy.

Methods

Twenty-four virtual implants were divided into six groups (0–10 N, in 2 N increments). Surgical guides were scanned under loaded conditions, and deviations were quantified by superimposition with the baseline model.

Results

At high forces (≥ 8 N), buccal and palatal deformations increased markedly, with the 10 N group showing the largest displacement and angular deviation. Apical deviations (up to 1.554 mm) exceeded platform deviations (0.720 mm), and angular changes reached 9.595°. Under low forces (2–4 N), deformations were minimal, and anterior regions showed greater stability than posterior regions.

Conclusion

Forces above 6 N approach or exceed clinically acceptable thresholds, while 0 to 4 N produced the most precise outcomes. A single overload (≥ 8 N) can jeopardize surgical precision and long-term implant stability, underscoring the importance of controlling drill handle force. Clinicians are therefore advised to limit applied forces to ≤ 4 N to preserve surgical accuracy and minimize guide distortion.