Factors influencing the accuracy of guided palatal miniscrew insertion in young adults

OBJECTIVE: To evaluate the in vivo accuracy of guided palatal miniscrew insertion, focusing on the effect of insertion side, frontal insertion angle, and miniscrew length. MATERIALS AND METHODS: In all, 52 palatal miniscrews were inserted using computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides in 20 patients (average age: 19.74 years ± 6.83). Digital models were acquired after miniscrew insertion and scanbody application. Then, linear and angular discrepancies between planned and realized miniscrew positions were evaluated by superimposing the reference model with the final postinsertion model. Discrepancies are recorded and compared to absolute precision (hypothetical). The effect of side, frontal insertion angle, and miniscrew length on accuracy were investigated. RESULTS: Mean linear total discrepancies were 1.10 ± 1.01 mm and 1.71 ± 1.10 mm at the miniscrew head and tip points, respectively. Mean angular discrepancies were 5.90 ± 6.06° in the transverse (XY), 2.65 ± 2.47° in the sagittal (YZ), and 3.02 ± 2.65° in the coronal (XZ) plane. All discrepancies were significantly different to absolute precision (p < 0.001), although not to an extent considered clinically relevant. Neither side nor frontal insertion angle (clinical factors), or miniscrew length (structural factor) significantly impacted accuracy. CONCLUSION: CAD/CAM surgical guides ensured clinically acceptable accuracy despite significant deviations from absolute precision. The insertion side, frontal insertion angle, and miniscrew length had minimal influence on accuracy, and therefore on outcome. Further studies should explore the effects of additional clinical, procedural, anatomical, and structural variables.