Self-Setting Calcium Orthophosphate Formulations: Cements, Concretes, Pastes and Putties

In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases after mixing form a viscous paste that after being implanted sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite, sometimes blended with un-reacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with a newly forming bone), self-setting calcium orthophosphate cements represent a good correction technique of non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities, and easy manipulation. Nearly perfect adaptation to the tissue surfaces in bone defects and a gradual bioresorption followed by new bone formation are additional distinctive advantages of calcium orthophosphate cements. Besides, reinforced formulations are available; those are described as calcium orthophosphate concretes. Furthermore, formulations with high viscosity, such as pastes and putties are also known. The discovery of self-setting formulations has opened up a new era in the medical application of calcium orthophosphates; several commercial compositions have already been introduced as a result. Many more formulations are in experimental stages. In this review, an insight into the self-setting calcium orthophosphate formulations, as excellent biomaterials suitable for both dental and bone grafting applications, has been provided.