Risk assessment of bovine spongiform encephalopathy transmission through bone graft material derived from bovine bone used for dental applications

Background: Several commercial products are currently available for clinica l application as bone graft substitutes. These products can be broadly clas sified into two categories: synthetic and natural. Bovine bone is a popular source for several of the natural bone substitutes. The availability of bo vine derived xenogenic bone substitutes has made it possible to avoid traum atic and expensive secondary surgery to obtain autogenous bone once thought essential for effective bone replacement. While autogenous bone still rema ins the undisputed "gold standard" in bone grafting, the realization that b one requirement in several clinical applications is as effectively met by x enografts has lead to their widespread use. But the convenience of using xe nografts is tempered by the possibility of disease transmission from cattle to humans. The recent incidents of bovine spongiform encephalopathies (BSE ) in humans have underscored this likelihood. In this paper, we report a ri sk analysis performed to assess the possibility of such disease transmissio n from a commercially available bone graft substitute (BGS) that is popular ly used in clinical dentistry. Methods: An extensive review of current literature on the status of risk as sessment of BSE transmission was conducted, and two risk assessment models were identified as applicable to the present study. Risk assessment models developed by the German Federal Ministry of Health and by the Pharmaceutica l Research and Manufacturers Association of America were applied to BGS. Results: Results from the analyses conducted using both models showed that the risk of disease (BSE) transmission from BGS was negligible and could be attributed to the stringent protocols followed in sourcing and processing of the raw bovine bone used in the commercial product. Conclusions: Based on the risk analysis, it is evident that the risk of BSE infection from BGS is several orders of magnitude less than that posed by the risk of death related to, lightning, tornadoes, or similar remote event s, However, this low risk can only be maintained as long as an effective an d active risk management program is implemented in operations that involve processing xenogenic tissue for human use.