Institute for Facial Esthetics

Prosthodontic Insights Newsletter

May 2000 Volume 13, Number 1

A New Procedure For Rehabilitating
the Severely Resorbed Maxilla
by Christina Darle

Professor Brånemark and his team have developed a dental implant for placement in the Zygoma region. The first implant was placed in 1989 and since that time, 81 patients have been treated with a 96.8% success rate.

The incidence of implant loss in the severely resorbed posterior maxilla is around 15% with the benefit of a sinus graft . Current treatment modalities aimed at reducing implant loss in these patients frequently involved different types of grafting procedures. These procedures vary extensively and involve everything from using allografts, alloplasts, and xenograft materials to harvest bone matrix from the patient’s chin, hip, tibia or calvarium. Membranes are recommended by some, but not by others. Most studies involve limited patient material and applied procedures and used materials differ more than they correspond. There is a lack of consensus on all specifics relating to the procedure of grafting the severely resorbed posterior maxilla.

The lack of consensus was recognized by the dental community in a Consensus conference on sinus grafts conducted in 1996. The fact that it took two years to finalize the results clarifies the difficulties described above. The main conclusion from the conference was that "The material was so multivariate and multifactorial that it was difficult to draw definite conclusions, these must await controlled perspective studies."

While alternate procedures were being explored, Professor Brånemark once more applied his lateral and uninhibited thinking in an attempt to answer the basic question "How can we, in a simpler, safer and higher predictable manner, restore function to those patients who have so severely resorbed jaws that standard implants are bound to provide unacceptable results?" Extensive studies were done evaluating the craniofacial bone and its load bearing capacity. It was found that in close proximity to the defect area, the os zygoma consistently demonstrated dense bone quality and acceptable bone volume. This bone is similar to the dense type bone which we already know provides the most predictable anchorage in the mandible. Brånemark believed that this would be a significant improvement compared to conducting extensive grafting procedures.

Professor Brånemark’s team then designed the zygoma fixture and the first patient was treated in 1989 at which time the clinical follow-up began. To date Professor Brånemark has treated 81 patients with fixtures in the zygoma region, including 24 maxillectomies, and 3 cleft defects. A total of 164 fixtures have been placed, of which 24 were (regular type fixtures) ranging in length from 13 - 30 mm, and 140 were specifically designed zygoma fixtures. Five of these were placed in four partially edentulous patients. The follow-up ranges from 0 - 10 years as follows: 10 years - 5 fixtures; 5 to 9 years - 54 fixtures; less than 5 years - 105 fixtures. No fixtures failed in the maxillectomy or cleft patients. After successfully treating maxillectomy and cleft patients, the procedure was developed also for non-defect sites pertaining to the severely resorbed posterior maxilla. To date, the overall success rate for this new fixtures is 96.8% and it has been estimated that the need for grafting is reduced by approximately 75% with this technique. A multicenter study was initiated in 1998 and 50 patients have been treated to date. The study will run for five years.

Talk of the Times, Nobel Biocare SE, 1999. Article #26577

References:
Brånemark PI, Svensen B, Van Steenberghe D. Ten year survival rates of fixed prosthesis on four of six implants ad modum Brånemark in full edentulism. Clin Oral Implants Res 1995;6:227-31

Jensen OT, Shulman, LB, Block MS, Iacono VJ. Report of the sinus consensus conference of 1996. Int J Oral Maxillofac Implants 1998;13 (supplement)

Download PDF for Insights May 2000, Vol. 13, No. 1

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