Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials

OBJECTIVES: The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials. MATERIALS AND METHODS: Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield(®)), a glass ionomer based fissure sealant (Vitremer(®)), and two microhybrid composite resins (Filtek Z250 and P90(®)). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P < 0.05). RESULTS: No difference in hardness was encountered between deciduous and permanent teeth (P < 0.05) or modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested. CONCLUSIONS: Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load.