Published online by Cambridge University Press: 31 January 2011
A sintered aggregate of hydroxyapatite, Ca10(PO4)(6(OH)2, designed for in vitro simulation of some of the physicochemical processes of dental decay is described and characterized. Diffusivity at 35°C (by tritiated water effusion) was (2.9 + 0.6) ⊠ 10−6 cm2/s. The apparent density (2.50 ± 0.04) g/cm3 gave a porosity of 20.8 ± 1.3 vol % based on the theoretical density of hydroxyapatitc. Estimates of the volume percent porosity from water vapor desorption and tritiated water effusion were 19.2 ± 2.9 and 20.7 ± 1.4, respectively Pore-size distribution measurements using mercury porosimetry showed that most of the porosity (approximately 17% of the sample volume) was concentrated between 30 and 60 nm equivalent pore radius. The material, which has been successfully used to simulate some aspects of the dental decay process, should find further application in this and related fields.