The Award contest 2017/ 24 February 2017/

Case 87 | The Award 2017 | Italy

Dr. Marco Castagnola / DT Mario Balzarini

A CASE OF FULL-MOUTH REHABILITATION WITH COMPUTER GUIDED IMPLANT SURGERY AND CAD/CAM METAL-CERAMIC FRAMEWORKS

A 61 – year – old woman was referred to our office with missing teeth in the maxilla and partially edentulous dentition in the mandible . The chief complaint was missing teeth and inability to chew. Her residual teeth had a poor prognosis: clinical and radiographic examination revealed a severe generalized periodontitis with mobility of the remaining teeth.

After discussing different treatment options, the decision was made to extract the remaining teeth, and place 4 dental implants in the mandible and in the maxilla to support a full-arch implant-fixed metal-ceramic prostheses.

The patient agreed to simultaneous maxillary and mandibular immediate implant placement with computer-guided surgery and immediately loaded implant-supported interim complete fixed dental prosthesis to avoid any removable denture during the phase of osseointegration.

An impression of dental arches was taken and the casts were mounted in a semi adjustable articulator to study carefully the case.

A set-up of existing teeh and a waxing of missing teeth was made to obtain an aesthetic and functional relationship of dental arches. The final position of teeth was duplicate in a radiografic guide containing barium sulfate.

The DICOM files generated from the CBCT imaging were imported and merged in virtual implant planning software (3D Implant – Bionova – Italy) in the dental office. A virtual prosthetically driven surgical plan was completed on the basis of the diagnostic informations obtained from waxing, and CBCT imaging.

Then, two surgical stereolithographic templates, mandibular and maxillary were created based on the implant surgical plan.

Four implants analogues were inserted in maxillary and mandibular plaster by dental technician using surgical guides. The provisional abutments were screwed to the analogues and an interim fixed metal -composite prostheses were created using occlusal relation registered with radiographic templates at the beginning of therapy. The prostheses had a metal sleeves around provisional abutments to compensate implants discrepancies.

The day of the surgery, after endovenous sedation and local anesthesia,the teeh were extracted and the implant guides were fitted over the postextraction alveolar ridge and stabilized with anchor pins.

Four implants (Vector Whitek BL -Italy) were inserted in mandible and four in the maxilla maxilla under an insertion torque up to 60 Ncm. The posterior maxillary implants were tilted distally engaging the mesial wall of the sinuses and providing a wider anterior-posterior spread.

The anchor pins and the templates were removed from the alveolar ridges, provisional abutments (GT Whitek – Italy) were screwed to the implants and the flaps were repositioned with primary closure.

Mandibular and maxillary prostheses were seated above the arches and the patient was invited to clench in centric occlusion. The prostheses were fixed to provisional abutments with a dual cure composite cement (Max-Cem Kerr) inserted into the space between the sleeve and the cylinder through a hole on vestibular surface. After polymerization, the prostheses were removed , finished and polished by technician, and screwed to implant with 25 Ncm torque.

The following week the healing was complete.

After 3 months of osseointegrtaion ,two plaster impression were taken .

Thanks to 45° conical connection , the upper plaster impression was removed without any angled abutment for screw type prostheses ,although divergence of implant axes were up to 60 degrees.

The fabrication of metal substructure using computer-aided design and computer-aided manufacturing (CAD/CAM) techniques was made by Bego Medica GmbH & Co .

Final ceramisation was made by the technician and the fixed metal – ceramic framework was screwed to implants with 30 Ncm torque. Vestibolar inclination of implant 21 has been resolved with a telescopic crown cemented over the framework.