Ultrasonography-Guided Dental Implant Surgery: A Feasibility Study.

Objective: To evaluate the feasibility of ultrasound-image-based computer-assisted implant planning and placement.

Materials and methods: Intraoral scans, cone-beam computerized tomography (CBCT), and ultrasound (US) scans with a custom positioning device were acquired in nine patients. Prosthetic-driven surgical guides were planned and fabricated based on ultrasound images and intraoral scans. Implants were then placed. Postoperative implant position was obtained intra-surgically by intraoral scan. Aside from the ultrasound-based plan, conventional implant planning was performed by the same operator on a pre-surgical CBCT for comparison. Linear deviations between ultrasound and CBCT-planned implant positions were measured and compared with the intra-surgical implant position, and the position deviations between two consecutive plannings were performed on the same CBCT by the same operator. The linear deviation between the 3D scan surface of the edentulous region and the ultrasonographic soft tissue profile segmentation was also assessed with reverse-engineering software. Means, standard deviations, and root mean square differences (RMSD) were calculated for every variable.

Results: All the ultrasound-planned implants were successfully placed, and no complications were recorded. The mean deviations in angles, shoulders, and apexes were 5.27 ± 1.75° (RMSD: 5.53°), 0.92 ± 0.26 mm (RMSD: 0.95 mm), and 1.41 ± 0.61 mm (RMSD: 1.53 mm), respectively, between the US and CBCT-planned implants; 2.63 ± 0.43° (RMSD: 2.66°), 1.16 ± 0.30 mm (RMSD: 1.19 mm), and 1.26 ± 0.27 mm (RMSD: 1.28 mm) between the planned implant and intra-surgically recorded positions; and 2.90 ± 1.36° (RMSD: 3.18°), 0.65 ± 0.27 mm (RMSD: 0.70 mm), and 0.99 ± 0.37 mm (RMSD: 1.05 mm) between two consecutive CBCTs planning performed by the same operator. The mean deviation between the 3D surfaces of model scans and ultrasound-derived soft tissue profile in the edentulous area was 0.19 ± 0.08 mm.

Conclusions: Ultrasound-guided implant surgery represents a feasible non-ionizing alternative to conventional static guided implant surgical protocols for implant placement in sites with favorable characteristics.