The vast majority of materials used in bone tissue engineering and regenerative medicine are based on calcium phosphates due to their similarity with the mineral phase of natural bone. Among them, calcium phosphate cements, which are composed of a powder and a liquid that are mixed to obtain a moldable paste, are widely used. These calcium phosphate cement pastes can be injected using minimally invasive surgery and adapt to the shape of the defect, resulting in an entangled network of calcium phosphate crystals. Adding an organic phase to the calcium phosphate cement formulation is a very powerful strategy to enhance some of the properties of these materials. Adding some water-soluble biocompatible polymers in the calcium phosphate cement liquid or powder phase improves physicochemical and mechanical properties, such as injectability, cohesion, and toughness. Moreover, adding specific polymers can enhance the biological response and the resorption rate of the material. The goal of t...

INTRODUCTION Calcium phosphate cements (CPC) have many uses in orthopaedics as bone void fillers. There are many products on the market intended for various indications. CPCs have very good biological properties and stimulate bone ingrowth while being resorbed. However the handling of CPCs poses a problem. They must be mixed at the time of surgery and setting starts immediately after powder and liquid have been mixed, resulting in a limited working time. The handling is complicated and filter pressing often occurs. To solve this issue water can be exchanged for glycerol as mixing liquid. This allows for a virtually unlimited working time since the setting does not start until the cement is inside the body where it comes into contact with water. There are very few CPCs intended for treatment of vertebral compression fractures. For this indication good injectability and radio-opacity are very important. BaSO4 or ZrO2 are often used as radio-opacifying agents in polymer based bone ceme...

In early 1980-s, researchers discovered self-setting calcium orthophosphate (CaPO4) formulations (initially known as calcium phosphate cements), which were bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases formed pastes of variable viscosity, which set and hardened forming most commonly a bone-like non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite and rarely monetite with possible admixtures of un-reacted components. Since all these compounds were found to be biocompartible, bioresorbable and osteoconductive (therefore, in vivo they could be replaced with a newly forming bone), the self-setting CaPO4 formulations appeared to be very promising bioceramics for bone grafting purposes. Furthermore, due to their unique properties such as an easy shaping, moldability and injectability these formulations possess both an easy manipulation and a nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation, which are additional distinctive advantages. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading them by drugs, biomolecules and even cells for tissue engineering applications. However, due to the ceramic origin, the ordinary self-setting CaPO4 formulations exhibit both a brittle nature and a low bending/tensile strength, prohibiting their use in load-bearing sites; therefore, reinforced formulations have been introduced, which might be described as CaPO4 concretes. Thus, the discovery of self-setting properties opened up a new era in the medical application of CaPO4 and many commercial trademarks have been introduced as a result. Many more formulations are still in experimental stages. In this review, an insight into the self-setting CaPO4 formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided.

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 unreacted 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), 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 composites. The discovery of self-setting cements has opened up a new era in the medical application of calcium orthophosphates; several commercial formulations have already been introduced as a result. Many more compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.