Replacement of the condyle and ascending ramus by a modular endoprosthesis in Macaca fascicularis--part 3: evaluation of peri-implant bone remodeling.

Purpose: To assess whether the fixation of a condyle-ascending ramus mandibular modular endoprosthesis, using bone cement, will result in stress-related bone resorption in the Macaca fascicularis.
Materials and Methods: The right condyle and ascending ramus were resected in 8 adult monkeys and replaced by a modular endoprosthesis, fixed with polymethylmethacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The bone mineral density was assessed using dual-energy x-ray absorptiometry in the region anterior to the stem and using micro-computed tomography in the buccal, lingual, and inferior regions adjacent to the stem.
Results: The bone mineral density of the 3-month specimens was greater than that at 6 months in the buccal, lingual, and inferior regions adjacent to the stem. However, the difference was statistically significant only in the inferior aspect. No significant difference was found in the bone mineral density in the region anterior to the stem between the 3- and 6-month specimens.
Conclusion: A minimal reduction in bone density around the stem of the endoprosthesis was observed between 3 and 6 months after placement. This reduction did not result in any adverse clinical events.
(Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)