title: Premixed acidic calcium phosphate cement: characterization of strength and microstructure.
abstract: By using a premixed calcium phosphate cement (CPC), the handling properties of the cement are drastically improved, which is a challenge for traditional injectable CPCs. Previously premixed cements have been based on apatitic cements. In this article, acidic cement has been developed and evaluated. Monocalcium phosphate monohydrate and beta-tricalcium phosphate were mixed with glycerol to form a paste. As the paste does not contain water, no setting reaction starts and thus the working time is indefinite. Powder/liquid ratios (P/L) of 2.25, 3.5 and 4.75 were evaluated. Setting time (ST) and compressive strength (CS) were measured after 1 day, 1 week and 4 weeks in phosphate buffered saline (PBS) solution, and the corresponding microstructure was evaluated using electron microscopy and X-ray diffraction. The ST started when the cements were placed in PBS and ranged from 28 to 75 min, higher P/L gave a lower ST. Higher P/L also gave a higher CS, which ranged from 2 to 16 MPa. The microstructure mainly consisted of monetite, 1-5 microm in grain size. After 4 weeks in PBS, the strength increased. As acidic cements are resorbed faster in vivo, this cement should allow faster bone regeneration than apatitic cements. Premixed cements show a great handling benefit when compared with normal CPCs and can be formulated with similar ST and mechanical properties.
authors.affiliation: Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden. jonas.aberg@angstrom.uu.se
authors.forename: J
authors.initials: J
authors.lastname: Aberg
authors.forename: H
authors.initials: H
authors.lastname: Brisby
authors.forename: H B
authors.initials: HB
authors.lastname: Henriksson
authors.forename: A
authors.initials: A
authors.lastname: Lindahl
authors.forename: P
authors.initials: P
authors.lastname: Thomsen
authors.forename: H
authors.initials: H
authors.lastname: Engqvist
mesh_terms: D001843:Bone Cements; D002130:Calcium Phosphates; D019245:Compressive Strength; D008422:Materials Testing; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; C485838:calcium phosphate, monobasic, anhydrous