An in vitro assessment of the accuracy of guided tilted and axial implant placement in the edentulous mandible.

Abstract

Purpose: To assess the precision of implant placement when comparing tilted orientations to axial orientations, utilizing a fully guided surgical protocol in an edentulous mandibular model.

Materials and methods: Fourteen rubber-coated mandibular models were scanned with fiducial markers using a commercial benchtop surface scanner, followed by cone beam computed tomography for implant planning through a dual-scan protocol. The models were randomly divided into control and experimental groups. In the control group, each model was planned for four axially oriented implants. Conversely, the experimental models were planned for two axially oriented implants near the lateral incisors and two posteriorly tilted implants at a 30-degree angle. A mucosal-supported, pin-retained surgical guide was designed and 3D-printed, facilitating the fully guided implant placement. All implants received scan bodies and were rescanned for evaluation of the trueness between the planned and the actual implant location using the implant planning software. Mixed model ANOVA was used to detect differences between groups with regards to angular deviation, offset at base, and offset at tip.

Results: A total of 56 implants were placed across all models. Fourteen posterior implants in each group served as control and experimental conditions, while the remaining 28 anterior implants acted as secondary control. No significant differences were observed between the experimental and control groups in terms of angular deviation (p = 0.7001), offset at base (p = 0.6409), or offset at tip (p = 0.6931). Analysis comparing anterior implant deviations between groups and anterior to posterior implant deviations within the control arches also was not significant. However, secondary analysis revealed a significant difference between anterior and posterior implants within the experimental group for offset at base (p = 0.0087) and offset at tip (p = 0.0288).

Conclusions: Despite the limitations inherent to a benchtop study, the findings suggest that there are no statistically significant 3D deviations at the base or apex, nor in angular deviations, when comparing tilted and axial implant placements using a digital workflow and fully guided protocols in an edentulous model.