Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2011 Aug;19(4):337-42.
doi: 10.1590/s1678-77572011005000007. Epub 2011 Jun 3.

Hydroxyapatite crystallinity does not affect the repair of critical size bone defects

Marcio Baltazar Conz  1 , José Mauro Granjeiro, Gloria de Almeida Soares
Affiliations

Hydroxyapatite crystallinity does not affect the repair of critical size bone defects

Marcio Baltazar Conz et al. J Appl Oral Sci. 2011 Aug.

Abstract

Objective: The physicochemical properties of hydroxyapatite (HA) granules were observed to affect the biological behavior of graft materials. The aim of this work was to analyze the tissue response of two HA granules with different crystallinity and Ca/P ratio in vivo.

Material and methods: The HA granules were produced in the Biomaterials Laboratory (COPPE/UFRJ). The testing materials were HA granules presenting a Ca/P molar ratio of 1.60 and 28% crystallinity (HA-1), and a Ca/P molar ratio of 1.67 and 70% crystallinity (HA-2). Both HAs were implanted into a critical-size calvaria rat defects.

Results: To note, in the control group, the bone defects were filled with blood clot only. Descriptive and histomorphometric analyses after 1, 3, and 6 months postoperatively showed mild inflammatory infiltrate, mainly comprising macrophage-like and multinucleated giant cells, and an increase in the volume density of the fibrous tissues (p<0.05), which was in contrast to the similar volume density of the newly formed bone and biomaterials in relation to the control group.

Conclusion: Thus, we concluded that HA-1 and HA-2 are biocompatible and non-degradable, and that crystallinity does not affect bone repair of critical size defects.

PubMed Disclaimer

Figures

Figure 1
Figure 1
HA-1 and HA-2 x-ray diffraction (XRD)
Figure 2
Figure 2
Photomicrography of rat skulls at the periods of 1 and 6 months. A) Control group (blood clot), 1 month; the interface between old bone (OB) and new bone (NB) presents a line (arrow); asterisk (*) shows the connective tissue. B) Control group, 6 months; the old bone (OB) and new bone (NB) separated by connective tissue; interestingly, an animal of five presented endochondral ossification in the center of the bone defect (inner figure). C) HA-1 group, 1 month; presence of new bone (NB) and multinucleated giant cells (arrows) and connective tissue (*) were observed surrounding HA particles and new bone (NB); D) After 6 months, a fibrous connective tissue (FCT) was enriched by newly-formed blood vessels (arrows) and multinucleated giant cells in contacting HA particles (circle). E) Section showing the border of the bone defect presenting old bone (OB) – new bone (NB) interface (straight line) and HA-2 particles (*) surrounded by fibrous connective tissue (FCT) close to the border and at the center of critical size defect. Magnifications: 40x (A, C, D, inner figure in B); 12.5x (B, E)
See this image and copyright information in PMC

References

    1. Accorsi-Mendonça T, Conz MB, Barros TC, Sena LA, Soares GA, Granjeiro JM. Physicochemical characterization of two deproteinized bovine xenografts. Braz Oral Res. 2008;22:5–10. - PubMed
    1. Bertazzo S, Zambuzzi WF, Campos DD, Ogeda TL, Ferreira CV, Bertran CA. Hydroxyapatite surface solubility and effect on cell adhesion. Colloids Surf B Biointerfaces. 2010;78:177–184. - PubMed
    1. Bohner M. Calcium orthophosphates in medicine: from ceramics to calcium phosphate cements. Injury. 2000;31:37–47. - PubMed
    1. Bosch C, Melsen B, Vargervik K. Importance of the critical-size bone defect in testing bone-regenerating materials. J Craniofac Surg. 1998;9:310–316. - PubMed
    1. Carneiro E, Garcia RB, Oliveira RC, Moraes FG, Menezes R, Letra A, et al. Microscopic and radiographic analysis of the effect of particle size of demineralized bovine cancellous bone matrix on the repair of bone defects in femurs of rabbits. J Appl Oral Sci. 2005;13:157–162. - PubMed

LinkOut - more resources