Mineralization at the interface of implants.

Clinic for Cranio-, Maxillofacial Surgery, University of Münster, Germany.
International Journal of Oral and Maxillofacial Surgery (Impact Factor: 1.52). 10/2006; 35(9):783-90. DOI: 10.1016/j.ijom.2006.03.013
Source: PubMed

ABSTRACT Osseointegration of implants is crucial for the long-term success of oral implants. Mineralization of the bone's extracellular matrix as the ultimate step of a mature bone formation is closely related to implant osseointegration. Osteogenesis at oral implants is a complex process, driven by cellular and acellular phenomena. The biological process of the maintenance and emergence of minerals in the vicinity of oral implants is influenced to a great extent by biophysical parameters. Implant-related structural and functional factors, as well as patient-specific factors, govern the features of osteogenesis. To understand the influence of these factors in peri-implant bone mineralization, it is important to consider the basic biological processes. Biological and crystallographic investigations have to be applied to evaluate mineralization at implant surfaces at the different hierarchical levels of analysis. This review gives insight into the complex theme of mineral formation around implants. Special focus is given to new developments in implant design and loading protocols aimed at accelerating osseointegration of dental implants.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Current in vitro models have provided insights into collagenmineralization. However, the role of the collagen fibrillar framework in the formation of carbonated hydroxylapatite (CHA) has not been clarified due to difficulties in processing biomimetic fibrillar collagen gels with tailored properties. In this work, reconstituted collagen gels underwent various degrees of plastic compression (PC) to produce sheets, rolls and strips of controlled collagen fibrillar densities (CFDs, 0.2, 3.5, 14.1 weight%). Increasing levels of PC corresponded with a decrease in the thickness of the gels and their roughness, indicating a more compacted nano-fibrillar structure. Immersion in simulated body fluid resulted in the bulk mineralization of the various matrices. Increased CFD was positively correlated with the extent of CHA formation in the gels and with the volume fraction of mineralized fibrils. Tensile mechanical testing demonstrated that the apparent modulus and ultimate tensile strength of the gels increased with CFD and mineralization extent. Exposing collagen gels to cationic and anionic dye solutions indicated that an increase in CFD also corresponded with an increase in the extent and concentration of dyes bound to the collagenous framework. The results suggested that the increase in CFD altered gel electrostatic properties and generated a microenvironment more favorable to crystal formation.
    Soft Matter 10/2011; 7(21):9898-9907. · 4.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The spatially resolved phase identification of biologically relevant calcium phosphate phases (CPPs) in bone tissue is essential for the elucidation of bone remodeling mechanisms and for the diagnosis of bone diseases. Analytical methods with high spatial resolution for the discrimination between chemically quite close phases are rare. Therefore the applicability of state-of-the-art ToF-SIMS, XPS and EDX as chemically specific techniques was investigated. The eight CPPs hydroxyapatite (HAP), β-tricalcium phosphate (β-TCP), α-tricalcium phosphate (α-TCP), octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate (DCP), monocalcium phosphate (MCP) and amorphous calcium phosphate (ACP) were either commercial materials in high purity or synthesized by ourselves. The phase purity was proven by XRD analysis. All of the eight CPPs show different mass spectra and the phases can be discriminated by applying the principal component analysis method to the mass spectrometric data. The Ca/P ratios of all phosphates were determined by XPS and EDX. With both methods some CPPs can be distinguished, but the obtained Ca/P ratios deviate systematically from their theoretical values. It is necessary in any case to determine a calibration curve, respectively the ZAF values, from appropriate standards. In XPS also the O(1s)-satellite signals are correlated to the CPPs composition. Angle resolved and long-term XPS measurements of HAP clearly prove that there is no phosphate excess at the surface. Decomposition due to X-ray irradiation has not been observed.
    Applied Surface Science 01/2014; 309:27–32. · 2.54 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of platelet rich plasma (PRP) in bone repair remains highly controversial. In this work, we evaluated the effect of lyophilized PRP on bone regeneration when associated with a silicon stabilized hydroxyapatite tricalcium phosphate scaffold in a rabbit calvarial defect (Skelite™). Critical defects were created in the calvaria of twenty-four rabbits. The periosteum was removed and the defects were either left empty or filled with allogeneic PRP gel; Skelite particles; Skelite and PRP gel. Four animals were killed after 4 weeks, 10 animals after 8 and 10 after 16 weeks. Specimens were processed for X-ray microtomography (μCT) and for resin embedded histology. μCT analysis revealed significant osteoid-like matrix and new bone deposition in PRP + Skelite group at both 8 and 16 weeks in respect to Skelite alone. Histologically, PRP + Skelite defects were highly cellular with more abundant osteoid deposition and more regular collagen fibres. Moreover, in vitro migration assays confirmed the chemotactic effect of PRP to endothelial and osteoprogenitor cells. We conclude that the addition of PRP influenced the local tissue microenvironment by providing key cryptic factors for regeneration, thereby enhancing progenitor cell recruitment, collagen and bone matrix deposition, and by creating a bridging interface between the scaffold and bone.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 08/2013; · 1.25 Impact Factor


Available from