Atrophic Posterior Maxillan and Mandible: Alveolar Ridge Reconstruction with Mandibular Block Autografts

Author(s):

Michael A Pikos, DDS

Date Added:

1/10/2005

Autogenous bone grafts have been used for many years for alveolar ridge augmentation and are still considered to be the gold standard for jaw reconstruction. The use of these grafts with osseointegrated implants was originally discussed by Brånemark et al., who used the iliac crest as the donor site. For repair of most localized alveolar defects, however, bone grafts from the mandible offer advantages over iliac crest grafts. These include the proximity of donor and recipient sites, convenient surgical access, decreased donor site morbidity and decreased cost.

There is usually loss of alveolar bone height in the posterior maxilla and mandible secondary to trauma, pathology and periodontal disease and after tooth removal. Tooth loss results in buccal plate compromise and a reduction in alveolar width. This bone resorption process continues in a medial direction until a knife-edged ridge forms and precludes implant placement. The cortical plate may be minimal or absent, further complicating implant placement. In addition, alveolar height is decreased in the posterior maxilla as a result of pneumatization (partial or complete) of the maxillary sinus after tooth loss. Finally, occlusal forces are greater in the posterior than in the anterior area of the mouth, necessitating appropriate surgical and prosthetic treatment planning for long-term success.

The recipient site must be evaluated for both hard and soft tissue deficiencies, esthetic concerns and the overall health of the adjacent teeth. Some cases require soft tissue procedures to be done prior to or simultaneous with block grafting, as well as in conjunction with implant placement or stage II surgery. These include use of connective tissue grafts, palatal epithelial grafts and human dermis. Conventional radiographs are obtained and include periapical, occlusal, panoramic and lateral cephalometric views. Computed tomography and interactive software are also used for many cases. Mounted models are used to evaluate interocclusal relationships and ridge shape and provide valuable information for implant placement. A diagnostic wax-up of the simulated reconstructed ridge and dentition is a useful guide in obtaining presurgical information concerning graft size and shape, along with evaluating the occlusion. This also provides a base for template fabrication. The primary goal of posterior arch implant reconstruction is to create a biomechanically sound support for the implant prosthetic complex.

This article focuses on posterior maxillary and mandibular osseous augmentation in a staged approach for implant placement. Both horizontal and vertical deficiencies are addressed with the use of symphysis and ramus buccal shelf donor block bone via case presentations.