Лако-красочные материалы — производство

A luting agent should have minimal solubility in the aqueous oral fluids while displaying good wetting properties. It should possess low initial viscosity to allow for proper seating of the restoration and for adequate narrowing of the margin between restoration and tooth. A wide margin, commensurate with a thick layer of poorly flowing, viscous cement in the luting space, will cause exposure of a proportionately large area of cement to the oral environment with consequent erosion effects, the development of microleakage, and potential secondary caries resulting from bacterial ingress. The cement should not be toxic or irritant to the pulp; it should provide thermal and, ideally, electrical insulation, features of particular importance for the luting of metallic restora­tions, such as gold crowns. In an ideal luting process the cement should bond chemically to the enamel and restoration adherends; with currently available materials, however, the bonding effect is largely or entirely one of micromechanical interlocking, as the material, utilizing existing surface roughness, flows into, and occupies, the microscopic interstices on the adherend surfaces. Once hardened in the assembly, the cement must assume sufficient

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strength for the microscopic protrusions into the interstices (tags) to withstand without fracture the occlusal masticatory (compressive and deformation) forces exerted onto the restored tooth.