title: HRTEM study of biological crystal growth mechanisms in the vicinity of implanted synthetic hydroxyapatite crystals.
abstract: Calcium phosphates are widely used as biomaterials. Ultrastructural assessments are of the utmost importance in our understanding of interfacial phenomena. The aim of this study was to learn more about the newly formed crystal growth mechanisms. The interfaces between implanted synthetic hydroxyapatite crystals (HAS) and newly formed crystallites were thoroughly examined on a molecular level. The bone-grafting material (HAS) was implanted into two adult patients, and small biopsies were recovered 6 months after implantation. The raw biomaterial was analyzed by x-ray diffraction and high-resolution transmission electron microscopy (HRTEM). Six months after their implantation, the HAS aggregates were surrounded by a mineralized bone matrix. Tiny crystallites also filled the spaces between the HAS crystals within the aggregates. These newly formed crystallites growing at the surfaces of the implanted HAS crystals appeared to be apatitic. The crystallographic investigations of the nucleation and growing mechanisms of the newly formed crystallites were performed by HRTEM in association with computer simulation and mathematical processing of digitized images. A relationship was noted between the orientation axes of crystallites growing nearby and the zone axes of the implanted HAS, thus strongly suggesting a guiding or substratum role of the HAS particles.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 424, Fédération de Recherches Odontologie, Strasbourg, France.
authors.forename: J
authors.initials: J
authors.lastname: Hemmerlé
authors.forename: F J
authors.initials: FJ
authors.lastname: Cuisinier
authors.forename: P
authors.initials: P
authors.lastname: Schultz
authors.forename: J C
authors.initials: JC
authors.lastname: Voegel
mesh_terms: D000328:Adult; D001706:Biopsy; D018786:Bone Substitutes / Q000737:chemistry*; D001842:Bone and Bones / Q000648:ultrastructure; D002908:Chronic Disease; D003460:Crystallization; D003461:Crystallography; D015921:Dental Implants; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D008854:Microscopy, Electron / Q000379:methods; D010518:Periodontitis / Q000473:pathology; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D014086:Tooth Mobility / Q000473:pathology; D014961:X-Ray Diffraction
chemical_list: D018786:Bone Substitutes; D015921:Dental Implants; D017886:Durapatite