The early host and material response of hydroxyapatite/?-tricalciumphosphate porous ceramics after implantation into the femur of rats

Zhang, Jianguo; Zhang, Xingdong; Müller-Mai, C.; Groß, Ulrich

doi:10.1007/bf00122392

Cited by 30 publications

(14 citation statements)

References 30 publications

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“…20 Since then, several authors provided a radically changed surface topography which, as previously discussed with a different HA have concurred with this interpretation, including Ravaglioli et al, 22 who described an interfacial lamina ceramic implant, may provide bonding sites. 25,27,47 Other authors also noted a change in the surface mor-1-2 Ȑm thick at the surface of HA implants which ''is similar to the cementing lines found inside phology of bone-bonding ceramics in vivo, 48 although we found no evidence of dissolution of the AW-GC bone tissue. '' In accord with our previous modeling and the deimplant surface as was reported in longer-term experiments.…”

Section: Discussionsupporting

confidence: 57%

Scanning electron microscopy of the bone-bioactive implant interface

Davies

Baldan

1997

J. Biomed. Mater. Res.

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Rods of three bioactive materials, apatite/wollastonite glass ceramic (AW-GC), bioactive glass (BG), and dense slip-cast hydroxyapatite (HA), were implanted in the femora of 23 Wistar rats for periods of 1-4 weeks. The samples were harvested following vascular perfusion fixation and the femora freeze-fractured for scanning electron microscopy to expose the bone/implant interface. The focus of our observations was when new bone was forming on the implant surfaces irrespective of the implantation period. Scanning microscopy of the hydroxyapatite rods demonstrated that in areas where bone bonding had occurred, the implant surface was composed of globular accretions which fused to form a cement-like matrix to which collagen fibers were attached. Dissolution of individual grains of the implant surface created a roughened surface topography. Such features were not found in the transcortical portions of these implants. Similar globular accretions were also found on the surface of bulk AW-GC, although bone apposition was not disrupted by the critical point-drying procedure, and thus the interface was more difficult to image. Nevertheless, the collagen of the bony compartment interdigitated with an interfacial layer which was morphologically similar to that found on HA. The most surface reactive material, BG, demonstrated an interfacial structure where the surface reactive calcium phosphate layer was clearly distinguished from the underlying bulk implant material. However, this layer was separated from the overlying collagen-containing bony compartment by a second, thinner, calcified layer which corresponded to the cement line matrix into which the collagen fibers were inserted. Our results show that the new bone interface formed with these three bioactive materials is morphologically comparable to that of cement lines found naturally in bone-remodeling sites, and that this interfacial layer is formed on the chemically active surface of the biomaterial. The degree to which the cement line matrix interdigitated with the implant was a product of the reactivity of the implant surface.

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Section: Discussionsupporting

confidence: 57%

Scanning electron microscopy of the bone-bioactive implant interface

Davies

Baldan

1997

J. Biomed. Mater. Res.

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“…The first cells to arrive-macrophages-are rapidly replaced by osteoblasts and osteoclasts, which produce and remodel bone in the ceramic implant. 20,21,46 In the calvaria group, there were more macrophages than osteoblasts, resulting in less bone colonization in these defects than in the femora and tibia. 15,46,47 The implantation site may therefore also lead to different cell populations and cellular events depending on the type of bone (long bones such as the femur and tibia and flat bones such as the calvaria).…”

Section: Discussionmentioning

confidence: 99%

“…Different animal species have also been used to evaluate bone substitutes. For instance, in vivo studies have been conducted in rats, 10,15,20 rabbits, 8,16,[21][22][23][24][25] dogs, 13,26,27 sheep, 9 and goats. 28 As these animals are different in terms of their metabolisms and bone physiology, direct and strict comparison between all these studies is difficult.…”

Section: Introductionmentioning

confidence: 99%

Small‐animal models for testing macroporous ceramic bone substitutes

et al. 2004

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The aim of this study was to compare the bone colonization of a macroporous biphasic calcium phosphate (MBCP) ceramic in different sites (femur, tibia, and calvaria) in two animal species (rats and rabbits). A critical size defect model was used in all cases with implantation for 21 days. Bone colonization in the empty and MBCP-filled defects was measured with the use of backscattered electron microscopy (BSEM). In the empty cavities, bone healing remained on the edges, and did not bridge the critical size defects. Bone growth was observed in all the implantation sites in rats (approx. 13.6 -36.6% of the total defect area, with ceramic ranging from 46.1 to 51.9%). The bone colonization appeared statistically higher in the femur of rabbits (48.5%) than in the tibia (12.6%) and calvaria (22.9%) sites. This slightly higher degree of bone healing was related to differences in the bone architecture of the implantation sites. Concerning the comparison between animal species, bone colonization appeared greater in rabbits than in rats for the femoral site (48.5% vs. 29.6%). For the other two sites (the tibia and calvaria), there was no statistically significant difference. The increased bone ingrowth observed in rabbit femurs might be due to the large bone surface area in contact with the MBCP ceramics. The femoral epiphysis of rabbits is therefore a favorable model for testing the bone-bonding capacity of materials, but a comparison with other implantation sites is subject to bias. This study shows that well-conducted and fully validated models with the use of small animals are essential in the development of new bone substitutes.

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“…HA has been widely used as a bulk implant in non-load bearing areas of the body and as coatings on implant metals. HA is a bioactive ceramic, which can bone of bone, because it is very similar to the mineral part of bone [18,19]. It has a fracture toughness of approximately 1 MPa/m [20].…”

Section: Disscusionsmentioning

confidence: 99%