The summed frequency of peri-implantitis and implant failure is commonly less than 5% over 10 years of follow-up for modern implants when using established protocols.

The purpose of the present clinical study was to evaluate the 5-year results of the first 12 implants inserted at the University of Berne in regenerated bone following successful ridge augmentation with the membrane technique. The patients were recalled and examined with clinical and radiographic parameters routinely utilized in prospective studies with standard implants in non-regenerated bone. Based on clinical and radiographic findings, all 12 implants were considered successfully integrated according to strict criteria of success. The detailed analysis of clinical parameters revealed no differences to results of prospective studies on standard implants in non-regenerated bone. All implants demonstrated ankylotic stability which was confirmed by a mean Periotest value of -2.08. The radiographic analysis showed stable bone crest levels with a mean bone loss between the 1- and 5-year examination of 0.30 mm. However, 2 implants exhibited a bone loss of more than 1 mm between the 1- and 5-year examination. Therefore, the prognosis of these 2 implants seems questionable at the present time. It can be concluded that bone regenerated with the membrane technique reacts to implant placement like non-regenerated bone, since all 12 implants achieved successful tissue integration with functional ankylosis. Furthermore, this bone is also load-bearing, since all 12 implants maintained osseointegration over a 5-year period.

Saliva can reach mineralized surfaces in the oral cavity; however, the relationship between saliva and bone resorption is unclear. Herein, we examined whether saliva affects the process of osteoclastogenesis in vitro. We used murine bone marrow cultures to study osteoclast formation. The addition of fresh sterile saliva eliminated the formation of multinucleated cells that stained positive for tartrate-resistant acid phosphatase (TRAP). In line with the histochemical staining, saliva substantially reduced gene expression of cathepsin K, calcitonin receptor, and TRAP. Addition of saliva led to considerably decreased gene expression of receptor activator of nuclear factor kappa-B (RANK) and, to a lesser extent, that of c-fms. The respective master regulators of osteoclastogenesis (c-fos and NFATc1) and the downstream cell fusion genes (DC-STAMP and Atp6v0d2) showed decreased expression after the addition of saliva. Among the costimulatory molecules for osteoclastogenesis, only OSCAR showed decreased expression. In contrast, CD40, CD80, and CD86-all costimulatory molecules of phagocytic cells-were increasingly expressed with saliva. The phagocytic capacity of the cells was confirmed by latex bead ingestion. Based on these in vitro results, it can be concluded that saliva suppresses osteoclastogenesis and leads to the development of a phagocytic cell phenotype.

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Reference 1. Effects of platelet rich plasma (PRP) on human gingival fibroblast, osteoblast and periodontal ligament cell behaviour.