Case 34 | Prosthodontic Award 2015 | Italy
Dr. Massimiliano Urso – DT Franco Sanseverino
Prosthetic driven implantology 2.0: digital innovation respecting prosthodontics tradition
A 75 years old caucasic healthy man (ASA 1) came to our attention reporting the abnormal mobility of a dental bridge present for more than 20 years in the upper right maxilla, extended from canine to first upper molar (both last pillars of the prosthetic restoration). After clinical and radiological evaluation we found a root decay of the canine responsible of bridge detachment, that suggested for extraction of the involved root. The impossibility to make a new dental bridge on natural teeth and the patient’s rejection to partial removable dentures, led us to evaluate the possibility to restore his edentulism with immediate load implant supported restoration made with the aid of a 3D planning software.
First of all, we took high precision impressions of both arches with a double viscosity VPS and a face bow record. The plaster casts obtained from the impressions, were individually scanned using a laboratory scanner, then mounted in articulator and finally scanned in occlusion reaching a digital reproduction of both arches correctly oriented in the three planes of the space.
Starting from virtual casts, the technician designed a project of the needed prosthetic restoration using a CAD software that generates “.stl” files compatible with “open” 3D simulation software and milling machines for the CAM stage.
Once completed the analysis from the prosthetic point of view, we focused our attention on virtual 3D surgical planning, positioning 3 implants in respect of anatomy and prosthetic virtual project. The file obtained from prosthetic/surgical evaluation was then used for surgical template and temporary prosthesis realization.
On the day of surgery, first of all the root of the canine was removed using a piezoelectric device to reduce the extraction injury and allow a better stability for the post-extractive implant. After inserting all the implants, the template was removed and the temporary abutment were screwed on the fixtures and then cemented to temporary restoration with self/light curing resin. The temporary bridge was left for 3 months to achieve implants osseointegration and ideal soft tissue healing.
Before completing the case with final restoration, the patient underwent a new CBCT wearing the same stent used for the first radiological evaluation to obtain a 3D imagine of the achieved result. Using a dedicated software the position of the implants was overlapped with the planned virtual position to check the discrepancies between planning and reality. The mean linear deviation was 0,945mm (Minimum: 0,790 – Maximum: 1,120 – SD: 0,139) and the average angular deviation was 2,08° (Minimum: 1,29 – Maximum: 2,53 – SD: 0,56). These data are in line with the best results reported in the international literature.
4 months after the surgery the digital work flow started in the first steps of the case ended with the realization of the final restoration: thanks once more to CAD/CAM technology, the technician designed and realized customized abutmets and the definitive metal framework using a CoCr sinter metal. The aesthetic ceramic coverage was done by using a CAD/CAM technology too: after milling a wax model of the final restoration, a silicon impression was made by using a verticulator to create a mold for pressable ceramic. This workflow led to a perfect occlusion since no adjustments were done when the restoration was finally consigned to the patient.
Within the limits of a case report, we can say that our digital workflow can be useful to reach a “state of the art” implant-supported prosthetic restoration, with a strict respect of patient’s occlusion from the beginning to the end. The followed protocol has also proved to be efficacious, since we have reached the predicted outcome, and efficient since we did it reducing the number of steps comparing to protocols usually followed by other authors.