Clinical outcomes and cost effectiveness of computer‐guided versus conventional implant‐retained hybrid prostheses: A long‐term retrospective analysis of treatment protocols

1 Background

Computer‐guided systems were developed to facilitate implant placement at optimal positions in relation to the future prosthesis. However, the time, cost and, technique sensitivity involved with computer‐guided surgery impedes its routine practice. The aim of this study is to evaluate survival rates and complications associated with computer‐guided versus conventional implant placement in implant‐retained hybrid prostheses. Furthermore, long‐term economic efficiency of this approach was assessed.

2 Methods

Patients were stratified according to implant placement protocol into a test group, using computer‐guided placement, and a control group, using traditional placement. Calibrated radiographs were used to measure bone loss around implants. Furthermore, the costs of the initial treatment and prosthetic complications, if any, were standardized and analyzed.

3 Results

Forty‐five patients (149 implants in the test group and 111 implants in the control group) with a minimum follow‐up of 5 years, and a mean follow‐up of 9.6 years, were included in the study. While no significant difference was found between both groups in terms of biologic and technical complications, lower incidence of implant loss was observed in the test group (P < 0.001). A statistically significant difference in favor of the non‐guided implant placement group was found for the initial cost (P < 0.05) but not for the prosthetic complications and total cost (P > 0.05).

4 Conclusions

Computer‐guided implant placement for an implant‐supported hybrid prosthesis is a valid, reliable alternative to the traditional approach for implant placement and immediate loading. Computer‐guided implant placement showed higher implant survival rates and comparable long‐term cost to non‐guided implant placement.     

Clinical application of 3D technology for tooth autotransplantation: A case report

This report presents two cases of tooth autotransplantation using cone‐beam computed tomography (CBCT), the three‐dimensional (3D) simulation dental planning software and a computer‐aided rapid prototyping (CARP) model. Two hopeless teeth of adult patients were replaced as their third molar teeth. Before deciding the autotransplantation, diagnostic CBCT images were acquired and imported to SimPlant software. The SimPlant dental program was used for surgical simulation prior to autotransplantation, which created 3D images of the available donor teeth and recipient site tooth and superimposed the images to display their morphological similarity. Efficient modification of the recipient socket was designed preoperatively. The CARP model of the donor tooth was prepared as a substitute for the donor tooth that would be fit into the new recipient socket during bone preparation. Autotransplantation was favourably performed in 5–6 min. Transplanted teeth healed up without clinical abnormality. The postoperative follow‐up time was up to 6 years.     

Conventional Multi‐Slice Computed Tomography (CT) and Cone‐Beam CT (CBCT) for Computer‐Aided Implant Placement. Part II: Reliability of Mucosa‐Supported Stereolithographic Guides

Purpose: Deviations of implants that were placed by conventional computed tomography (CT)‐ or cone beam CT (CBCT)‐derived mucosa‐supported stereolithographic (SLA) surgical guides were analyzed in this study. Materials and Methods: Eleven patients were randomly scanned by a multi‐slice CT (CT group) or a CBCT scanner (CBCT group). A total of 108 implants were planned on the software and placed using SLA guides. A new CT or CBCT scan was obtained and merged with the planning data to identify the deviations between the planned and placed implants. Results were analyzed by Mann‐Whitney U test and multiple regressions (p < .05). Results: Mean angular and linear deviations in the CT group were 3.30° (SD 0.36), and 0.75 (SD 0.32) and 0.80 mm (SD 0.35) at the implant shoulder and tip, respectively. In the CBCT group, mean angular and linear deviations were 3.47° (SD 0.37), and 0.81 (SD 0.32) and 0.87 mm (SD 0.32) at the implant shoulder and tip, respectively. No statistically significant differences were detected between the CT and CBCT groups (p = .169 and p = .551, p = .113 for angular and linear deviations, respectively). Conclusions: Implant placement via CT‐ or CBCT‐derived mucosa‐supported SLA guides yielded similar deviation values. Results should be confirmed on alternative CBCT scanners.     

Accuracy and surgical feasibility of a CBCT‐based stereolithographic surgical guide aiding autotransplantation of teeth: in vitro validation

Summary The aims of this study were to determine the accuracy of a 3D computer model and stereolithographic (STL) replica when compared to the real tooth and to develop a cone beam computed tomography (CBCT)‐based planning technique including surgical guide fabrication. A STL surgical guide and a tooth replica were fabricated using SimPlant Pro 12.1. To validate this process, tooth segmentation and replica design were prepared for comparison to an optical scan of the corresponding tooth. For surgical intervention, a dry dentate mandible was scanned using a Scanora CBCT and the donor tooth was segmented. The donor tooth was repositioned, and two guides were designed. These tooth replica and guides were used in socket preparation of the dry mandible. The 3D computer model of the segmented teeth and related STL models showed satisfactory results with an acceptable accuracy. The surfaces were within 0·25 mm distance, but in some areas up to 2·5 mm deviation were seen. The results showed that 79% of the points was between 0·25 and ?0·25 mm, 3% was overestimated (>0·25 mm) and 18% was underestimated (in vivo planning of CBCT‐based autotransplantation.