Suitability of different substrates for reliable bond strength tests.

The aim of the present study was to analyze different substrates used to determine composite-dentine bond strength. It comprises 3 parts. In the first, results obtained using bovine and human dentin are compared. In the second, bond strength of composite-bovine dentin sections cut at different angles was studied. In the third part, the effect of different storage solutions on bond strength was analysed. Two methods were used to study the capacity of bovine dentin to reproduce "in vivo" conditions as closely as possible: a) bond strength tests. Tensile strength of composite samples mounted on flat dentin surfaces, treated with bonding agents, stored in artificial saliva at 37 degrees C was measured. b) Observation of exposed surfaces by scanning electron microscopy. Results showed that more reliable values were obtained when using bovine dentin stored in distilled water at 4 degrees C sectioned at an angle of 125 degrees to vestibular face and not further than 7 mm from the incisal edge.