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The Use of Implant Simulation in Prosthetic Rehabilitation of a Class II Maxilla*

Dr. Thierry Claeys - maxillofacial surgeon, Belgium - and Lth. Johan Kint - prosthodontist, Belgium - work closely together as a team, combining their skills to produce the best possible surgical, esthetical and functional results for their patient. Their philosophy is that implant treatment should begin with the patient’s prosthetic needs. After the type of prosthetic reconstruction is chosen, the appropriate number of implants is determined. Then, with the help of different imaging modalities, Dr. Claeys and Lth. Kint evaluate the patient’s jaw to determine the available bone quality and volume. The following case illustrates their methodology: The patient is a 67 years old doctor whose maxilla had been totally edentulous for more than 20 years. It was the desire of the patient to have a stable and retentive prosthetic reconstruction without prior surgical intervention. To obtain the final treatment plan, the following examinations where performed: a temporary teeth set-up, the medical image processing and the implant simulation.

1. The temporary teeth set-up

The wax set-up in the articulator (Hanau) showed a large inter-maxillary gap in the distal region (fig. 1). Based on this and the
fact that the anatomy of the edentulous maxilla was flat with a shallow palate, they concluded that it was not possible to create
a fixed prosthesis in the distal area.


2. Medical Imaging

Although the clinical examination and the panoramic radiographs showed adequate bone volume, the CT scan revealed an atrophic maxilla (fig. 2). Horizontal and vertical bone resorption was evident in the anterior and the alveolar height in the posterior was also inadequate for implants (fig. 3). Dr. Claeys and Lth. Kint strive for a bilaterally balanced occlusal pattern in Class II maxilla-treatment plans. Group guidance should occur at both the active and passive sides without anterior interference. A barretained
overdenture is not indicated here.

The final treatment plan consisted of a force-breaking posterior frame prosthesis retained by anterior ITI implants. The implants were restored with crown and bridge extra-coronary CEKA attachments (2 degrees of freedom). This type of anchor gives pure retentive function to the frame while minimizing stress to the most distally placed implants and peri-implant areas. Extra retention and comfort was obtained by placement of two palatal clips, giving the prosthesis a degree of freedom in the axial plane (fig. 4). The doctors reasoned that placing as many implants as possible in the anterior would increase stability and minimize extension of the removable frame.

3. Implant simulation

Since the final location and angulation of the implants determine the esthetical and functional results, it was decided that a
SurgiGuide drill guide would be required to achieve precise implant placement in a predictable fashion. Based on the temporary teeth set-up, a radiopaque CT scan appliance was made (fig.5). The patient was then scanned on a CT scanner with the appliance in place. Then the CT data was processed to produce a SimPlant study that included 2D and 3D images of the maxilla with the desired location of the teeth to be restored provided by the CT scan appliance. Dr. Claeys and Lth. Kint then used their SimPlant software to simulate possible treatment planning solutions, choosing the most ideal treatment plan for their patient (fig. 6). The SimPlant treatment plan was then used
to produce a SurgiGuide drill guide that would fit perfectly on the patient’s maxillary bone (fig. 7), with drill guides to accurately position each implant exactly as it had been simulated in the SimPlant treatment plan. The implants were quickly and easily placed using the SurgiGuide and the healing abutments were immediately positioned. After an integration period of six months, the implants were uncovered and the prosthesis was installed. Because of the accurate placement of the implant, the prosthesis could be created with the normal prosthetic lab techniques.

 

Please contact us if you have an interesting SurgiGuide / SimPlant case you want to share with your colleagues.

 

 

Dr. Claeys and Lth. Kint use SurgiGuides when:

  • Accurate and predictable location and
    angulation of multiple implants are
    required
  •  Adequate bone volume is doubtful


Dr. Claeys and Lth. Kint concluded that when using a SurgiGuide, based on a computer based treatment plan, the placing of the implants is more accurate and predictable and the surgery is more simple.

Biography

Dr. Th. Claeys: Maxillo-facial surgeon - St.Elisabeth Ziekenhuis - Zottegem Dr. J. Kint: Prosthodontist - dental treatment under general anesthesia - St.-Elisabeth Ziekenhuis - Zottegem

* Published in DentistNews, Volume 6, September 2002.
Apollonia cv - Ieper - Belgium.

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