TCP is hardly resorbed and not osteoconductive in a non-loading calvarial model.

Tricalciumphosphate (TCP) has been used as a ceramic bone substitute material in the orthopedic field as well as in craniofacial surgery. Some controversies exist concerning the osteoconductive potential of this material in different implantation sites. This study was designed to evaluate the biological response of calvarial bone towards TCP granules under non-loading conditions to assess the potential of TCP as a biodegredable and osteoconductive bone substitue material for the cranial vault. Full-thickness non-critical size defects were made bilaterally in the calvaria of 21 adult Wistar rats. One side was filled by TCP granules, the contralateral side was left empty and used as a control. Animals were sacrified in defined time intervals up to 6 months. Bone regeneration was analyzed with special respect toward the micromorphological and microanalytical features of the material-bone interaction by electron microscopy and electron diffraction analysis. Histologic examination revealed no TCP degradation even after 6 months of implantation. In contrast, a nearly complete bone regeneration of control defects was found after 6 months. At all times TCP was surrounded by a thin fibrous layer without presence of osteoblasts and features of regular mineralization. As far as degradation and substitution are concerned, TCP is a less favourable material tinder conditions of non-loading.

[1]  H. Kurita,et al.  In vivo study of calcium phosphate cements: implantation of an alpha-tricalcium phosphate/dicalcium phosphate dibasic/tetracalcium phosphate monoxide cement paste. , 1997, Biomaterials.

[2]  J. Bidwell,et al.  Nuclear Matrix Proteins and Osteoblast Gene Expression , 1998, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[3]  M. Neo,et al.  Temporal and spatial patterns of osteoblast activation following implantation of beta-TCP particles into bone. , 1998, Journal of biomedical materials research.

[4]  U. Meyer,et al.  No mechanical role for vinculin in strain transduction in primary bovine osteoblasts. , 1997, Biochemistry and cell biology = Biochimie et biologie cellulaire.

[5]  J. Davies,et al.  Extracellular matrix production by osteoblasts on bioactive substrata in vitro. , 1988, Scanning microscopy.

[6]  S. Kwon,et al.  The effects of calcium phosphate cement particles on osteoblast functions. , 2000, Biomaterials.

[7]  P. Klopper,et al.  Tissue response to dense apatite implants in rats. , 1980, Journal of biomedical materials research.

[8]  G. Lange,et al.  Histological and ultrastructural appearance of the hydroxyapatite-bone interface. , 1990 .

[9]  L E Lanyon,et al.  Using functional loading to influence bone mass and architecture: objectives, mechanisms, and relationship with estrogen of the mechanically adaptive process in bone. , 1996, Bone.

[10]  E. Munting,et al.  Bone repair of defects filled with a phosphocalcic hydraulic cement: an in vivo study , 1993 .

[11]  Xing‐dong Zhang,et al.  Tissue responses of calcium phosphate cement: a study in dogs. , 2000, Biomaterials.

[12]  C. S. Chen,et al.  Geometric control of cell life and death. , 1997, Science.

[13]  Y. Bando,et al.  Differences in ceramic-bone interface between surface-active ceramics and resorbable ceramics: a study by scanning and transmission electron microscopy. , 1992, Journal of biomedical materials research.

[14]  H. Schliephake,et al.  Reconstruction of calvarial defects by bioresorbable ceramics: an experimental study in rats , 1997, Oral and Maxillofacial Surgery.

[15]  S. Lynch,et al.  Comparison of porous bone mineral and biologically active glass in critical-sized defects. , 1997, Journal of periodontology.

[16]  W. Kalk,et al.  Biodegradation of four calcium phosphate ceramics;in vivo rates and tissue interactions , 1991 .

[17]  J M Brady,et al.  Biodegradable ceramic implants in bone. Electron and light microscopic analysis. , 1971, Oral surgery, oral medicine, and oral pathology.

[18]  U. Joos,et al.  The effect of magnitude and frequency of interfragmentary strain on the tissue response to distraction osteogenesis. , 1999, Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons.

[19]  H. Kurita,et al.  Experimental cranioplasty and skeletal augmentation using an alpha-tricalcium phosphate/dicalcium phosphate dibasic/tetracalcium phosphate monoxide cement: a preliminary short-term experiment in rabbits. , 1998, Biomaterials.

[20]  I. Stewart,et al.  The electron microscopic and X-ray diffraction examination of a lithium zinc silicate glass-ceramic , 1967 .

[21]  U. Meyer,et al.  Attachment Kinetics and Differentiations of Osteoblasts on Different Biomaterials , 1993 .

[22]  T. Glant,et al.  Suppression of Osteoblast Function by Titanium Particles*† , 1997, The Journal of bone and joint surgery. American volume.

[23]  J. Fages,et al.  Short-term implantation effects of a DCPD-based calcium phosphate cement. , 1998, Biomaterials.

[24]  M. Neo,et al.  Analysis of osteoblast activity at biomaterial-bone interfaces by in situ hybridization. , 1996, Journal of biomedical materials research.

[25]  Rejda Bv,et al.  Tri-calcium phosphate as a bone substitute. , 1977, Journal of bioengineering.

[26]  D Buser,et al.  Evaluation of filling materials in membrane--protected bone defects. A comparative histomorphometric study in the mandible of miniature pigs. , 1998, Clinical oral implants research.

[27]  R. Cancedda,et al.  Osteobiology, Strain, and Microgravity: Part I. Studies at the Cellular Level , 2000, Calcified Tissue International.

[28]  L L Hench,et al.  Surface-active biomaterials. , 1984, Science.