[The coherence between 3 evaluation methods of biocompatibility]

Three successive series of tests (the primary including cytocompatibility tests and the secondary in vivo and usage tests) can be used to evaluate the biocompatibility of dental materials. The products are only submitted to secondary tests in case of satisfactory results obtained with primary tests. A coherence between the results of primary and secondary tests is necessary before performing in vivo tests. The aim of this paper is to study the coherence between two primary tests and a secondary test. The biocompatibility of Sealite and a pulp canal sealer was studied 4 and 12 weeks after mixing, according to two primary models (cell culture on agarose and a toxicity study of the extraction products) and a secondary model (intrabony implantation in the rabbit). The two primary tests gave different results for Sealite and the pulp canal sealer. Only the agarose cell culture and the intrabony implantation in the rabbit have given similar statistical results. The biological evaluation of biomaterials should begin with a study of the mechanism of action of the cytotoxic products using several in vitro tests. These latter are unable to predict the behaviour of a biomaterial in an in vivo test.