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Immediate restoration in the fully edentulous maxilla region

Preoperative SimPlant planning showing the scan prosthesis. (DTI/Photo Dr Marcelo Silva c/o Max Cohen, DDS)
Max J. Cohen, USA

Max J. Cohen, USA

Fri. 29 April 2011

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This clinical case required optimal implant placement based upon a restoratively driven treatment plan and guided surgery. To achieve this goal, we made use of CT scans, SimPlant planning software, the new Zimmer guided surgery instrumentation and the new Materialise Dental Immediate Smile model. The patient was a 49-year-old white female in good health, completely edentulous in the maxilla and wearing a complete upper denture.

On the lower, she wore an implant-retained overdenture.

The planning phase for the case began with a CT scan utilizing the i-Cat and the Materialise Dental Dual Scan protocol. The patient’s existing denture was transformed into a scan prosthesis by gluing eight Dual Scan Markers (Materialise Dental) on the surface. A radiolucent bite index was made to secure the prosthesis in the correct position.

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The patient was scanned in the i-Cat 17-19 while wearing the convert prosthesis and the bite index. In a second scan, the convert prosthesis was scanned alone. The resulting CT data were loaded into SimPlant, and the scan prosthesis was superimposed upon the study using the SimPlant Dual Scan wizard (Fig. 1).

Using SimPlant, the optimum implant positions were determined based upon available bone, a minimum of 3 mm between implants, and the design of the final restoration (Fig. 2). The resulting treatment plan was submitted to Materialise Dental for fabrication of a SurgiGuide and a Materialise Dental Immediate Smile model.

I received the Immediate Smile model, which contained a duplicate of the scan prosthesis, a bone model with a silicone soft tissue, and a mucosa-supported SurgiGuide. The bone model came with eight openings corresponding to each of the eight implant positions as designed in the SimPlant plan and corresponding exactly in size to the dimensions of Zimmer analogs.

The bone model comes with a screw fixation system, which allows me to recover the analogs. The silicone soft tissue on the model also corresponds to the realistic soft tissue. I also received written drilling instructions and a prolongation report detailing the depth and size of each osteotomy.

Zimmer analogs were placed in the Immediate Smile model (Fig. 3). The duplicate of the scan prosthesis was used to mount the bone model with the soft tissue on an articulator (Fig. 4), giving correct orientation and vertical dimension. This made it possible to fabricate a provisional that would be used for immediate loading following implant placement.

The mounted model was then used to create an orientation jig for the SurgiGuide (Fig. 5). The jig assures that the SurgiGuide is positioned in the mouth exactly the same way as the scan prosthesis was positioned in the mouth.

This is a very important step for a mucosa-supported SurgiGuide because of the flexibility of the soft tissue (mucosa). Both the duplicate of the prosthesis and SurgiGuide fit perfectly onto the Immediate Smile model, allowing for fabrication of an accurate orientation jig on an articulator.

The surgical guide was placed in the patient’s mouth, and the tissue was punched utilizing a tissue punch (Figs. 6–8). Then the surgical guide was again oriented in her mouth with the orientation jig created on the articulator and stabilized with three SurgiGuide fixation screws (Fig. 9). Utilizing the Zimmer Guided Surgery Instrumentation and guided surgery drills (Fig. 10), all eight osteotomies were created and completed using minimally invasive flapless surgery (Figs. 11, 12). The Zimmer guide is a SAFE system, accurately providing for depth as well as size.

The right and left molar (#3 and #14) osteotomies were created short of the maxillary sinus. Then using the new Zimmer Sinus Crestal Approach (SCA) sinus lift kit, I extended these two osteotomies into the left and right maxillary sinuses. Alloplastic bone (Puros) was placed into the sinus cavity through the osteotomy and spread using the paddle-shaped spreading bur. Then all eight implants were placed. Each had initial stability exceeding 35 ncm.

The decision was made to immediate load only the six implants that did not involve the sinus cavity. Therefore, healing heads were placed on implants #3 and #14, and non-engaging titanium temporary cylinders were placed on #5, #6, #8, #9, #11 and #12 (Fig. 13). The provisional, which the laboratory fabricated, was attached to the titanium cylinders using cold cure acrylic, thus creating a screw-retained provisional (Figs. 14, 15).

A postoperative CT scan showed how accurately the eight implants were placed in the bone using a
mucosa-supported SurgiGuide with orientation jig (made on the Immediate Smile model) (Figs. 16–18).

The accuracy and success of this case was achieved through CT scanning, SimPlant planning with restorative model overlay, the Zimmer Guided Surgery Instrumentation and the Materialise Dental Immediate Smile model.

The surgical guide allowed for minimally invasive surgery and greatly reduced time of surgery. The Immediate Smile also reduced chair time by allowing for fabrication of the temporaries well in advance of surgery.

Acknowledgements
Laboratory procedures and photography: Dr Marcelo Silva c/o Max Cohen, DDS.

About the author

Max J. Cohen, DDS, is in private practice in Dunwoody, Ga. He can be contacted at MaxJCohen@hotmail.com.

Editorial note: This article was originally published in Implant Tribune Vol. 6 No. 4, April 2011.

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