市販アパタイト系裏装材の諸性質

As inorganic components of dental hard tissue, calcium phosphates whose compositions resemble each other are applied to various uses, and these compounds are the materials on which the present discussion is focussed. Hydroxyapatite (HAP) and its precursor, α-tricalcium phosphate (α-TCP) in particular, each harden when mixed with water or an organic acid solution. These hardened compounds are capable of protecting the pulp. For this reason, they are commercially available as pulp capping materials and as base materials, and have come to be applied clinically.<BR>Base materials in the prosthetic field must possess excellent adhesiveness and strong mechanical properties as well as the pulp-protective effect and a blocking effect on physicochemical stimulation because they are used for the cavity wall of the vital tooth and for the core.<BR>Noting apatite base materials with excellent bioaffinity, the bond strength of each apatite base material to the natural dentin of the tooth, which is a requirement or any base material, was determined and the mechanical properties are also discussed in 6 types of commercially-available apatite base materials consisting of 3 types of HAP material and 3 types of α-TCP material, on the basis of prosthetic clinical application, in the present study.<BR>The results are summarized as follows:<BR>1. As a result of the adhesiveness test, APAMENT of the HAP group showed the maximum level (33kgf/cm²), and BONETRIX of the α-TCP group showed the minimum level (9kgf/cm²).<BR>2. There was no consistent bond strength tendency according to the type, rather, there was more difference among the products than between the types.<BR>3. As a result of the compression test, VITACEMEN of the α-TCP group showed the maximum level (573kgf/cm²) and BIOMENT of the HAP group showed the minimum level (310kgf/cm²).<BR>4. As a result of the tension test, AP LINER of the HAP group showed the maximum level (63kgf/cm²), and BONETRIX of the α-TCP group showed the minimum level (28kgf/cm²).<BR>5. As a result of the test for Vickers hardness, APATITE LINER TYPE II of the α-TCP group showed the maximum level (31Hv), and AP LINER of the HAP group showed the minimum level (10Hv).<BR>6. In assessing compression strength and Vickers hardness by qtest, the α-TCP cements showed higher values on testing for mechanical properties than those of the other types at a significant difference of 99%. The HAP cements showed a greater tensile strength than the α-TCP cements at a significant difference of 99%.