(58) The Accuracy of Guided Implant Surgery with Different Field of View of Cone-Beam Computed Tomography

Introduction: Cone-beam computed tomography (CBCT) is becoming a gold standard for implant planning and guided surgery. Although a smaller size of field of view (FOV) can reduce the radiation exposure to patients, it captures the less surface area for registration purpose, and it eventually might influence the accuracy of static computer-aided implant surgery (s-CAIS). Best of the author’s knowledge, there is no study to compare the accuracy of the guided implant placement with different sizes of FOVs. Thus, the purpose of this study is to evaluate the size of the FOV has an influence on the accuracy of the implant with s-CAIS. The secondary aim is to evaluate the influence of maxillary or mandibular arches in the accuracy of s-CAIS.

Methods: A total of 8 Identical CBCT scannable implant training models (8 maxillae and 8 mandibles) with edentulism of all first premolars were used in this study. Surface scans were completed with one intra-oral scanner and the files were converted to STL format. Implant sites were randomly assigned to two different sizes of FOV: small (5cm x 5cm) and medium (10cm x 10cm) and those files were stored as DICOM. Each implant was virtually planned based on optimum prosthetic position with implant planning software with STL and DICOM data. Surgical guides were designed in a 4-teeth span. The experimental guided implant surgery was performed by one experienced periodontist. A total 32 implants were placed through s-CAIS protocol. Postoperative intraoral scans were performed on models with scan-bodie. To determine the accuracy of S-CAIS, the mean angular deviation, 3D deviation at crest and apex was calculated separately. Data analysis used two-way ANOVA models to evaluate the effects of the size of FOV and jaw on the degree and amount of deviation.

Results: One sample was excluded from the statistical analysis due to the dislodgement of the filler in the implant model. The mean angular deviation was 3.53 ± 1.39 degrees in the test group (n=16) and 2.99 ± 0.88 degrees in the control group (n=15). The mean 3D deviation at crest and at apex was 0.53 ± 0.15 mm in the test group and 0.49 ± 0.15 mm in the control group. The mean 3D deviation at apex was 1.11 ± 0.38 mm in the test group and 0.97 ± 0.27 mm in the control group. Size of FOV failed to show significant effect (p≥0.198) on angle, 3D deviation at crest, and 3D deviation at apex. No significant difference was found between maxilla and mandible for the 3D deviation at angulation, crest level and apex level. 3D deviation at crest of mandible was significantly higher than maxilla for small FOV (p=0.036) but no significant difference was found for medium FOV (p=0.220). However, The interactions between FOV and jaw were not significant for any of the other measurements (p>0.06).

Conclusions: Using small FOV in s-CAIS exhibited comparable accuracy with using medium FOV in s-CAIS. The location of the implant sites in maxilla or mandible had no significant effect on the accuracy of s-CAIS in this study.

Lead Author’s Contributions to the Research Project: The lead author was responsible for the data collection, implant planning software operation, surface scanning operation and the composition of the abstract.