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Quantitative analysis with a digital registration method of three-dimensional implant placement accuracy by novice
Zhengda Wu1, Sha Li1, Yu Zhang2
1Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China.
Statement Of Problem:
Freehand implant placement by novices has been reported to be prone to 3-dimensional (3D) positional errors that may compromise clinical outcomes. Quantitative characterization of these errors and effective feedback methods in early implant training remain limited.
Purpose:
The purpose of this in vitro study was to quantitatively evaluate the positional deviations of implants placed by novice dental students during their first in vitro freehand surgeries using a digital registration method.
Material And Methods:
This study was conducted using mandibular simulation models derived from a standard patient. Optimal implant position was preoperatively planned based on cone beam computed tomography (CBCT) and digital model data. A total of 88 novice dental students, without prior implant experience, placed single implants freehand on 3D printed mandibular models in a Typodont head model following standardized instructions. Implant positions were evaluated using a digital registration method by superimposing planned and actual implant data. Linear deviations at the entry and apical points (mesiodistal, buccolingual, and apex-entry direction), as well as angular deviations were calculated in 3D coordinates. Data were analyzed using 1-sample t tests or Wilcoxon signed-rank tests to assess deviations from planned positions (α=.05), and implant positions were interpreted using predefined clinical safety thresholds.
Results:
Most implants showed buccal and distal deviations at both the entry and apical points. Mean entry point deviations were 0.98 mm buccally and 0.67 mm distally, while apical deviations averaged 1.52 mm in both directions. Mean depth deviation was 0.35 to 0.39 mm, and the overall angular deviation was 6.93 degrees. All implants remained within mesiodistal safety limits. Buccolingual deviations reduced bone thickness to <1.5 mm in 42 placements and 40 implants exceeded the predefined vertical safety range.
Conclusions:
Novice operators demonstrated clinically relevant deviations in freehand implant placement, particularly in buccal and distal directions. The use of digital registration enabled accurate assessment and effective feedback of positional errors.
