Novel Prosthesis Technique for Fabricating a CAD CAM Implant Superstructure Frame Using a 3D Printer

Background The CAD CAM system is applied to simplify implant superstructure fabrication and obtain an accurate clinical fit in multiple implant-retained prostheses. However, this process contains many complicated steps and specialized techniques for accurate reproduction along with the edentulous area. Recently, a 3D printed dental model has shown good efficacy in various fields. In implant dentistry, there is a possibility to simplify the complex prosthesis steps using a 3D printed dental model. Aim/Hypothesis A novel technique using a 3D printer-derived customized ring-frame index and bite plate (3D-CRIB) method in fully and partially edentulous patients can fabricate the superstructure with high accuracy and simplify complicated steps. Material and Methods Four edentulous patients were evaluated for implant treatment. The treatment plan in each case was multi-implant connection using a superstructure to avoid overload. After fixture placement, cone beam computed tomography (CBCT) was conducted for the 3D-CRIB method. A fixture model was printed for fabrication of the cobalt chromium ring-frame index to fix the implant-implant position and record the maxillo-mandibular relationship. In the second-stage operation, after fastening the intermediate abutment, a impression was obtained, and the implant-implant position was confirmed using the ring-frame index and auto-polymerization resin. The maxillo-mandibular relationship was recorded at the same time. Master cast models were fabricated using conventional impression and then costumed and mounted to the articulator using the ring-frame index. The titanium framework of the superstructure was milled with the CAD CAM system. Finally, hard resin was veneered onto the facing area. Results The screw-retained metal-resin superstructures were completed without the try-in step in every case. The period of superstructure fabrication was 2 weeks shorter on average than the conventional method. Retaining screws were fastened to the superstructure with a specific torque force without unnecessary friction, and minor occlusal adjustment was performed for resin contraction. For partially edentulous cases, the gap of proximal contact had been accurately reproduced. No adjustment at the proximal area was necessary for each superstructure. For the fully edentulous case, no difference in the centric relation and centric occlusion points was observed. During the maintenance period, retaining screw loosening and fracture, surface veneer chipping, and occlusal pain were not observed. In every case, good oral hygiene was maintained and satisfactory occlusion and esthetics were obtained as with the conventional method. Conclusions and Clinical Implications The 3D-CRIB method is a highly accurate fabrication method for complex implants that reduces the treatment period and need for complex clinical steps. The 3D-CRIB method using the 3D printed model is promising for application in next-stage digital dentistry.