Monday, March 21, 2011

Interpositional osteotomies for the atrophic posterior mandible - A Concept whose time has come?

The atrophic posterior mandible has been a challenge to restore with implants. A variety of approaches have been suggested ranging from short implants, distally angled implants (All-on-4), onlay grafts, nerve transposition and distraction osteogenesis. However interpositional grafts seem to offer a more predictable and complication free technique for augmenting the posterior mandible where there is atleast 4 to 6 mm of remaining bone above the IAN.
This paper in addition to being an excellent addition to the growing literature on this technique offers a more than adequate review of the relevant literature.

The International Journal of Oral & Maxillofacial Implants
January/February 2011
Volume 26 , Issue 1

Implant Rehabilitation of the Edentulous Posterior Atrophic Mandible: The Sandwich Osteotomy Revisited

Jose Luis López-Cedrún, MD, DDS, PhD

Purpose: Treatment of the posterior atrophic mandible has long been a challenge in implant dentistry and maxillofacial surgery. The objective of this study was to reevaluate the safety and efficacy of the sandwich osteotomy and bone grafting in patients with moderate to severe posterior mandibular atrophy. Materials and Methods: This retrospective study included patients with an edentulous posterior mandible in which there was not enough bone above the dental nerve to insert implants at least 10 mm in length; patients with adequate bone volume but with an excessive interocclusal distance at the posterior occlusal region were also included. Twenty-three patients with 30 sites of moderate to severe posterior atrophy were treated using a sandwich osteotomy above the mental nerve and an interpositioned block of autologous or allogeneic bone. Success criteria were based on the possibility of implant insertion after bone grafting. Results: The average gain in height was 5.3 mm (range, 2 to 10 mm). Partial loss of alveolar height was observed in only one patient from the allogeneic graft group. Patients were followed for 12 to 93 months after bone grafting. No signs of infection were observed. Minor dehiscence of the surgical wound occurred in four segments, but healing ultimately occurred in every patient. Sixty-five implants were placed, and none were lost during follow-up. Insertion of implants of 10 mm or more in length was successfully achieved in 90.8% of the sites, and partial success (ie, bone segments suitable for insertion of shorter implants) was seen in the remaining sites. Conclusions: Moderate to severe posterior mandibular atrophy can be successfully treated by interpositional sandwich osteotomy and bone grafting, allowing for the subsequent placement of implants and fixed prostheses in all segments. Int J Oral Maxillofac Implants 2011;26:195–202

Key words: atrophic mandible, dental implants, inlay bone grafting, sandwich osteotomy

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