Enhancement of bone regeneration and graft material resorption using surface-modified bioactive glass in cortical and human maxillary cystic bone defects.
OBJECTIVE
Bioactive glass bonds to bone through a calcium phosphate layer that mimics the structure of the mineral phase of bone. Formation of this layer is inhibited in the presence of serum protein. The authors hypothesize that creation of a calcium phosphate layer on the surface of bioactive glass before implantation will enhance bone regeneration and graft material resorption in bone defects.


METHODS
Bioactive glass particles covered with a layer of amorphous calcium phosphate (BG-ACP), bioactive glass particles covered with a layer of hydroxycarbonate apatite (BG-HCA), and unmodified bioactive glass particles (as a control) were prepared and implanted in cortical bone defects in dogs or in human maxillary cavities. Ungrafted sites were also used as a control.


RESULTS
Histomorphometric analyses showed significantly more bone tissue regeneration and graft material resorption in the defects filled with BG-HCA than in those filled with BG-ACP or unmodified bioactive glass (P < .0001). Moreover, measurements of radiographic density of the grafted areas suggested a higher rate of bone regeneration in defects filled with the modified bioactive glass than in those filled with unmodified bioactive glass or in the ungrafted control. Bone formation was significantly greater in defects filled with unmodified bioactive glass particles than in ungrafted defects.


CONCLUSIONS
The enhancement of bone regeneration could be explained by the ability of the apatite layer to facilitate bone adsorption and enhance calcium release, which stimulates osteoblast differentiation and bone formation.


CONCLUSIONS
Results of both the clinical and animal studies suggest that the use of surface-modified bioactive glass covered with a hydroxycarbonate apatite layer has the potential to accelerate bone formation and graft material resorption better than unmodified bioactive glass.
El-Ghannam
Ahmed
A
University of Kentucky, Center for Biomedical Engineering, Wenner Gren Research Laboratory, Graduate School, School of Dentistry, Lexington, Kentucky 40506-0070, USA. arelgh2@uky.edu
Amin
Hany
H
Nasr
Tamer
T
Shama
Ashraf
A
D000327:Adsorption; D000818:Animals; D001031:Apatites / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D015519:Bone Density; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000737:chemistry*; D001842:Bone and Bones / Q000473:pathology / Q000601:surgery*; D002130:Calcium Phosphates / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D002454:Cell Differentiation; D002516:Ceramics; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004285:Dogs; D005260:Female; D005898:Glass / Q000737:chemistry*; D006801:Humans; D007570:Jaw Cysts / Q000473:pathology / Q000601:surgery*; D008297:Male; D008439:Maxillary Diseases / Q000473:pathology / Q000601:surgery*; D010006:Osteoblasts / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D013499:Surface Properties
D001031:Apatites; D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D002254:Carbonates; D020099:Coated Materials, Biocompatible; C485828:alpha-tricalcium phosphate; C519480:amorphous calcium phosphate; C425330:bioactive glass 45S5; C413465:hydroxycarbonate apatite; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous