Calcium Phosphate Cements: Chemistry, Properties, and Applications

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

This paper reviews recent studies on self-setting calcium phosphate cements (CPC). Discussions are focused on the cement setting reactions, the products formed, those properties of the cements that contribute to their clinical efficacy, and areas of future improvements that could make CPC useful in a wider range of applications. The strengths of CPC are considerably lower than ceramic calcium phosphate biomaterials and are also lower than some of the dental cements. On the other hand, the combination of self-setting capability and high biocompatibility makes CPC a unique biomaterial. Near perfect adaptation of the cement to the tissue surfaces in a defect, and a gradual resorption followed by new bone formation are some of the distinctive advantages of CPC. In its present state CPC appears to be suitable for a number of applications. Much remains to be done to further improve its properties to meet the requirements for different applications.

Related collections

Most cited references 21

Record: found
Abstract: not found
Book: not found

The operated Markov´s chains in economy (discrete chains of Markov with the income)

Grigoriy Sokolov (2015)

0 comments Cited 5168 times – based on 0 reviews

Bookmark

Record: found
Abstract: found
Article: found

Is Open Access

Solubility of Ca 5 (PO 4 ) 3 OH in the System Ca(OH) 2 -H 3 PO 4 -H 2 O at 5, 15, 25, and 37 °C *

H McDowell, T. M. Gregory, W E Brown (1977)

Solubility isotherms of hydroxyapatite, Ca5(PO4)3OH (OHAp), prepared by titrating a boiling aqueous suspension of Ca(OH)2 with 0.5 M H3PO4, were determined in the ternary system Ca(OH)2–H3PO4–H2O at 5, 15, 25, and 37 °C in the pH range 3.7–6.7 by equilibration with dilute H3PO4 solutions. The solubility product Ks , determined as a function of temperature by a generalized least-squares procedure from 41 experimental points, is given by the equation log K s = − 8219.41 / T − 1.6657 − 0.098215 T . The values of Ks and its dispersion at 25 and 37 °C are 3.04 (0.25) and 2.35 (0.27) × 10−59. There is a maximum in Ks near 16 °C, which may be due to the form of temperature dependence found earlier for the stability constants of the ion pairs CaH 2 PO 4 + and CaHPO 4 0 . The relative positions of the isotherms show that OHAp has a negative thermal coefficient of solubility. Thermodynamic functions for the dissolution of the salt are reported. The solubility data previously reported by others for OHAp at 25 °C were reviewed. The solubility products obtained by three of these investigators were comparable with our value of 3.0 × 10−59; their data were reevaluated by the method described here. We conclude that the best value for the solubility product at 25 °C is 4.7 (2.0) × 10−59.

0 comments Cited 54 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Changes in heated and in laser-irradiated human tooth enamel and their probable effects on solubility.

Susan B. Fowler, S. Kuroda (1986)

Enamel of intact human teeth laser irradiated in vitro under certain conditions is known to have less subsurface demineralization than unirradiated enamel on exposure to acid; consequently, the potential use of laser irradiance to reduce caries is apparent. The laser-induced physical and/or chemical changes that cause this reduced subsurface demineralization are not known. A laser-irradiated tooth enamel surface will have a temperature gradient that decreases towards the dentin junction. Dependent on irradiant conditions, the temperature may range from greater than 1400 degrees C at the surface to near normal at the dentin-pulp junction. Along this steep temperature gradient, different compositional, structural, and phase changes in the tooth enamel are to be expected. Identification of changes occurring along this gradient has bearing on understanding the dissolution reduction mechanism and, in turn, optimizing its effect. Changes in laser-irradiated material from the highest temperature region have been characterized, but those occurring in sequential layers of decreasing temperatures have not. Since the laser-induced changes are expected to primarily arise from localized heating, previously reported thermally induced changes in tooth enamel on heating in conventional furnaces were utilized to infer corollary changes along the gradient in laser-irradiated tooth enamel. These thermally inferred changes which resulted in modifications in the tooth enamel apatite and/or newly formed phases were correlated with their probable effects on altering solubility. A temperature gradient range from 100-1600 degrees C was considered with subdivisions as follows: I, 100-650 degrees C; II, 650-1100 degrees C; and III, greater than 1100 degrees C. Two of the products formed in range III, alpha-Ca3(PO4)2 and Ca4(PO4)2O, and also identified in the fused-melted material from laser-irradiated tooth enamel, are expected to markedly increase solubility in those regions that contain considerable amounts of these compounds. Products and changes occurring in range II, separate phases of alpha- and/or beta-Ca3(PO4)2 and a modified phase of apatite, may increase or decrease the solubility depending on the Ca/P ratio and the resultant amounts of alpha-, beta-Ca3(PO4)2 formed. Modifications in tooth enamel apatite effected in range I are expected to decrease its solubility; the formation of pyrophosphate in this range may have a substantial effect on reducing the solubility rate.(ABSTRACT TRUNCATED AT 400 WORDS)