title: Evaluation of hydroxylapatite/poly(L-lactide) composites: mechanical behavior.
abstract: By mixing hydroxylapatite (HA) into L(-)-dilactide monomer, prior to polymerization to poly(L-lactide) (PLLA), hydroxylapatite filled poly(L-lactide) composites were obtained. This study reports about the mechanical properties of these composites compared with unfilled PLLA. It was concluded that a 30 wt% HA/PLLA composite has better compressive and tensile strengths, higher stiffness and Vickers hardness number than unfilled PLLA (Mv: 125-150,000). Gas sterilization (ethylene oxide) affects molecular weight and flexural strength significantly. Implantation studies revealed loss of 50% of initial flexural strength within 3 weeks, and a faster decline of flexural strength was observed in phosphate buffered saline than in the subcutis of goats. From a mechanical point of view storage at -20 degrees C proved to be a safe method. In its current state HA/PLLA composites can not be used as implant materials that have to resist major forces. However, such composites might be useful in non-loadbearing applications in orthopedic or maxillofacial surgery.
authors.affiliation: Department of Biomaterials, School of Medicine, University of Leiden, The Netherlands.
authors.forename: C C
authors.initials: CC
authors.lastname: Verheyen
authors.forename: J R
authors.initials: JR
authors.lastname: de Wijn
authors.forename: C A
authors.initials: CA
authors.lastname: van Blitterswijk
authors.forename: K
authors.initials: K
authors.lastname: de Groot
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D017886:Durapatite; D005027:Ethylene Oxide; D005260:Female; D006041:Goats; D006244:Hardness; D006882:Hydroxyapatites; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011091:Polyesters; D011108:Polymers; D019736:Prostheses and Implants; D013242:Sterilization; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D006882:Hydroxyapatites; D011091:Polyesters; D011108:Polymers; C033616:poly(lactide); D017886:Durapatite; D005027:Ethylene Oxide