Accuracy of dynamic navigation in placing tilted and straight dental implants: interim analysis from a cohort study

2K9BK ORAL COMMUNICATION CLINICAL INNOVATIONS

Background: Tilted implants are considered a reliable alternative to rehabilitate atrophic posterior areas of the jaws, avoiding invasive procedures. This approach requires surgical skills to achieve a correct implant position, preventing damages to anatomical structures. An auxiliary means to avoid implant malpositioning could be represented by dynamic navigation. In fact, this technique allows checking the drill position in real-time during the surgery, providing an accurate implant placement.

Aim/Hypothesis: The primary aim of this interim analysis was to report preliminary results of a prospective cohort study, comparing the accuracy of dynamic navigation in placing tilted and straight implants using a flapless approach. The secondary aim was to assess intraoperative complications.

Materials and Methods: Seven patients (mean age 63.8 years) needing an implant-prosthetic rehabilitation of a posterior maxillary atrophic area were recruited. The implant planning was performed on the preoperative cone-beam computed tomography (CBCT). 15 implants were placed by a single surgeon using a dynamic navigation system with a flapless approach. 7 implants were axially placed, while 8 have been tilted. Each patient received at least one straight implant and one tilted implant. Postoperative CBCTs were superimposed to the preoperative ones and the positions of the placed implants were compared to those of the planned ones. The implant placement accuracy was assessed measuring the linear deviations at the entry point, at the apical point and the vertical deviation. Accuracy data were collected and analyzed by a blind operator and complications were assessed. Interim data analysis was carried out to compare mean implant placement errors between straight and tilted implants.

Results: No intraoperative complications occurred. The median of implant length was 10 mm (IQR 1.5; range 10–13) for the implants axially placed and 12.25 mm (IQR 2.25; range 10–13) for tilted implants. The mean horizontal deviations measured at the implant entry point were 0.81 ± 0.40 mm (range: 0.45–1.52 mm) for the straight implants and 1.01 ± 0.53 mm (0.1–1.82 mm) for the tilted ones. The mean horizontal deviations measured at the implant apical point were 0.91 ± 0.53 mm (0.2–1.62 mm) for the straight group and 0.85 ± 0.51 mm (0.23–1.59 mm) for the tilted group. The mean vertical deviations were respectively 0.72 ± 0.56 mm (0.05–1.71 mm) and 0.49 ± 0.66 mm (0–2.07 mm). No significant differences between groups were found in terms of horizontal coronal error (mean difference 0.19; 95%CI −0.72–0.33; t = −0.78; P =  0.45), horizontal apical error (mean difference 0.05; 95%CI −0.52–0.63; t = 0.21; P = 0.84) or vertical error (mean difference 0.23; 95%CI −0.45–0.93; t = 0.73; P = 0.47).

Conclusions and Clinical Implications: The preliminary results of this study showed similar accuracy values for implants placed axially or tilted. Dynamic navigation can be considered a reliable technique to place implants in a safe and accurate way. It might simplify surgical procedures providing good accuracy also in challenging clinical conditions, like in case of preparation of tilted implant sites using a flapless technique.

Keywords: Dynamic navigation, Computer-guided surgery, Tilted implants, Accuracy.