title: Diametral tensile strength and compressive strength of a calcium phosphate cement: effect of applied pressure.
abstract: The diametral tensile strength (DTS) and compressive strength (CS) of a calcium phosphate cement comprised of tetracalcium phosphate and dicalcium phosphate anhydrous were studied. Cement powder and water were mixed at a powder/liquid ratio of 4.0. The resulting cement pastes were placed in molds and a pressure ranging from 0-2.8 MPa was applied for various lengths of time (0.5-24 h). DTS and CS measurements were conducted on 24-h wet samples. The strength was found to be significantly (p<0.05) affected by the pressure but not by the time. Samples prepared under a pressure of 0.7 MPa had a mean DTS value of 10.8+/-1.0 MPa (n = 5), which is comparable to the values reported in the literature for the same cement prepared under similar conditions. In contrast, the mean CS value obtained in the present study, 66.1+/-5.0 MPa (n = 5), was significantly higher than the value (51+/-4.5 MPa) previously reported. The higher CS may be attributed to an improved mold design that may reduce sample damage during demolding, and to the use of a loading device that applied a constant pressure to the sample during setting. The average standard deviation of the mean for the 19 DTS sample groups (n = 5 in each group) was 1.1 MPa, corresponding to 9.6% of the mean DTS value. The average standard deviation of the 7 CS sample groups (n = 5 in each group) was 4.5 MPa, corresponding to 7.1% of the mean CS value. Published 2000 John Wiley & Sons, Inc.
authors.affiliation: American Dental Association Health Foundation, Paffenbarger Research Center, Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: L C
authors.initials: LC
authors.lastname: Chow
authors.forename: S
authors.initials: S
authors.lastname: Hirayama
authors.forename: S
authors.initials: S
authors.lastname: Takagi
authors.forename: E
authors.initials: E
authors.lastname: Parry
mesh_terms: D001843:Bone Cements / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D019245:Compressive Strength; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods; D011312:Pressure; D013718:Tensile Strength; D014867:Water
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; D014867:Water