Matrix change of bone grafting substitute after implantation into guinea pig bulla.
BACKGROUND
Many different surgical techniques have been developed to remove open mastoid cavities. In addition to autologous materials, alloplastic substances have been used. A very slow absorption of these materials and extrusion reactions have been reported. We investigated a newly developed, highly porous bone grafting material to eliminate open mastoid cavities, in an animal model. To characterise the transformation process, the early tissue reactions were studied in relation to the matrix transformation of the bone material.


METHODS
NanoBone (NB), a highly porous bone grafting material based on calcium phosphate and silica, was filled into the open bullae from 20 guinea pigs. The bullae were examined histologically. Energy dispersive X-ray spectroscopy (EDX) was used to investigate the change in the elemental composition at different sampling times. The surface topography of the sections was examined by electron microscopy.


RESULTS
After 1 week, periodic acid-Schiffs (PAS) staining demonstrated accumulation of glycogen and proteins, particularly in the border area of the NB particles. After 2 weeks, the particles were evenly coloured after PAS staining. EDX analysis showed a rapid absorption of the silica in the bone grafting material.


CONCLUSIONS
NanoBone showed a rapid matrix change after implantation in the bullae of guinea pigs. The absorption of the silica matrix and replacement by PAS-positive substances like glycoproteins and mucopolysaccharides seems to play a decisive role in the degradation processes of NB. This is associated with the good osteoinductive properties of the material.
Department of Otorhinolaryngology, University of Rostock, Rostock, Germany. christoph.punke@med.uni-rostock.de
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Punke
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Zehlicke
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Just
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Holzhüter
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Gerber
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Pau
D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000008:administration & dosage*; D016025:Bone Transplantation; D004338:Drug Combinations; D017886:Durapatite / Q000008:administration & dosage*; D006003:Glycogen / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D006168:Guinea Pigs; D008297:Male; D008416:Mastoid / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D016348:Osseointegration; D012822:Silicon Dioxide / Q000008:administration & dosage*; D013052:Spectrometry, X-Ray Emission / Q000379:methods
D018786:Bone Substitutes; D004338:Drug Combinations; D006023:Glycoproteins; D006025:Glycosaminoglycans; C534915:NanoBone; D012822:Silicon Dioxide; D006003:Glycogen; D017886:Durapatite