Application of CAD/CAM Systems in the Fabrication of Bar-Supported Structures on Dental Implants

Abstract

The use of CAD/CAM technology in the fabrication of bar-supported implant structures provides exceptionally high precision (up to 5 μm compared to 50–70 μm in casting), ensuring ideal fit, reducing production time (to as little as one day), and enabling the creation of complex, customized designs from high-strength materials (such as zirconia) that consider anatomy and biocompatibility. This approach minimizes the risk of peri-implantitis and ensures superior aesthetics and functionality that are unattainable with traditional methods.
For cast bar-supported implant structures, the microgap between the implant and the prosthetic structure is 390 ± 70 μm for cobalt–chromium alloy and 800 ± 40 μm for titanium alloy, which necessitates the use of additional corrective technologies. To improve the accuracy of implant-supported bar structures, CAD/CAM milling from solid blocks of various materials is employed.
The study aimed to evaluate the precision of CAD/CAM-milled bar structures supported by dental implants used in prosthetic treatment, as a function of the material employed and the number of supporting implants.
Materials and methods. A total of 20 patients were examined, including 12 women and 8 men aged from 35 to 77 years, all of whom had 4 or 6 dental implants previously placed in the mandible. Using CAD/CAM systems and 5-axis milling machines, 20-bar constructs supported by 4 or 6 implants were fabricated from either titanium or cobalt–chromium alloy. The total number of supporting implants was 100.
Conclusions. Based on the data obtained in the course of the study, the following clinical recommendations can be formulated for the fabrication of implant-supported bar constructions:
1. Both titanium and cobalt-chromium alloys may be used as suitable materials.
2. In prosthetic treatment supported by either 4 or 6 dental implants, CAD/CAM milling enables the fabrication of high-precision constructions.
3. CAD/CAM milling allows for the production of constructions with consistently acceptable accuracy.
Thus, the fabrication of implant-supported bar constructions using 5-axis milling machines is recommended as the method of choice for the prosthetic rehabilitation of patients with complete edentulism.