Reynaldo Todescan

Use of a tapered, porous-surfaced dental implant in combination with osteotomes to restore edentulism in the difficult maxilla.

The maxilla is the more difficult arch to restore with endosseous dental implants because of hurdles such as low bone density, narrow buccopalatal width, minimal bone height, and proximity to the maxillary sinus. In this article, a technique to resolve all of these problems using a short, tapered, porous-surfaced implant and a placement protocol using hand osteotomes rather than surgical burs is presented.

Performance of titanium alloy sintered porous-surfaced (SPS) implants supporting mandibular overdentures during a 20-year prospective study.

OBJECTIVE This study was undertaken to assess short, sintered porous-surfaced (SPS), press-fit implants with mandibular overdentures to restore edentulous patients with severe mandibular resorption. MATERIALS AND METHODS Implant lengths of 7, 8, 9, and 10 mm were used, all with 2-mm polished collars, making the designed intrabony lengths 5, 6, 7, and 8 mm. Each patient received three non-splinted implants placed using a two-stage protocol. RESULTS Only 22 (with 53 implants) of the original 52 patients were available after 20 years. All but one of these patients was functioning with their implant-retained overdentures. Life table analysis accounted for all patients and implants, and showed a 20-year survival of 73.4%. Analysis of carefully standardized radiographs revealed mean cumulative bone loss after 20 years of 0.67 mm relative to the polished collar-SPS junction. CONCLUSIONS Short SPS implants with mandibular overdentures can provide an acceptable treatment over a 20-year period for fully edentulous patients with severe alveolar resorption.

Peri-Implant Crestal Bone Loss: A Putative Mechanism

Purpose. The immunological mechanisms of peri-implant crestal bone loss have, hitherto, not been elucidated. We hypothesized that bacterial products from the microgap cause upregulation of cytokines in otherwise healthy peri-implant cells, which results in osteoclast formation and, ultimately, in bone resorption. Materials and Methods. We used RT-PCR and ELISA to assay mediators of osteoclastogenesis in rat and human macrophages (r-and hMO); bone marrow derived stromal cells (r-and hBMCs); and human gingival fibroblasts (hGF)—with or without stimulation by LPS. TRAP positive multinucleate cells were assessed for their resorptive ability. Results. We show that IL-1α, IL-1β, and IL-6 were expressed by all examined cell types, and TNF-α was upregulated in hGF. Secretion of IL-1α and IL-1β proteins was stimulated in hMO by LPS, and IL-6 protein secretion was highly stimulated in hBMCs and hGF. Both LPS and RANKL stimulated macrophages to form osteoclast-like TRAP positive cells, which resorbed calcium phosphate substrates. Conclusion. Taken together, the results of our study support the hypothesis that bacterial endotoxins upregulate enhanced mediators of osteoclastogenesis in resident cells found in the healthy peri-implant compartment and that the local synergistic action of cytokines secreted by such cells results in the genesis of resorptively active osteoclasts.