First detection, characterization, and application of amorphous calcium phosphate in dentistry

Abstract

Background/purpose: This literature review provides an overview of the first detection, structure, chemical composition, morphology characterization, phase transformation, and clinical application of amorphous calcium phosphate (ACP) to dentistry. Materials and methods: ACP is the essential mineral phase formed in mineralized tissue and the first product to be used as artificial hydroxyapatite. ACP is unique among the calcium phosphates in that it lacks the long-range, periodic atomic scale order of crystalline calcium phosphates. Its X-ray diffraction patterns are broad and diffuse with a maxima at 25° 2θ, and no other different features compared with well-crystallized hydroxyapatite. Under electron microscopy, its morphologic form appears as small spheroidal particles of a few tenths of a nanometer in scale. In aqueous media ACP is easily transformed into crystalline phases such as octacalcium phosphate and apatite, due to the growth of the microcrystal. Results: ACP has better osteoconductivity and biodegradability than tricalcium phosphate and hydroxyapatite in vivo. Moreover, it can increase alkaline phosphatase activity of mesoblasts, enhance cell proliferation activity, and promote cell adhesion. The unique role of ACP in the formation of mineralized tissues makes it a potentially useful candidate for use in materials for tissue repair and regeneration. The same properties may make ACP suitable as a potential remineralizing agent for dental applications. Conclusion: Recently developed bioactive ACP-filled composites are potentially effective antidemineralizing/remineralizing agents for the preservation and repair of teeth.

Keywords

• amorphous calcium phosphate
• apatite
• biomineralization