Effects of hydroxyapatite implants on primary mineralization during rat tibial healing: Biochemical and morphometric analyses

Schwartz, Zvi; Braun, Gur; Kohavi, David; Brooks, B. P.; Amir, D.; Sela, J.; Boyan, Barbara D.

doi:10.1002/jbm.820270808

Cited by 41 publications

(25 citation statements)

References 36 publications

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“…By examining the tissue at the transmission electron microscope (TEM) level at various times following abla-tion (days 3, 6, 8, 12, 14, 18, 21, 23, and 28), we were able to define the morphological changes in matrix vesicles during this process (Sela et cil., 1987;Schwartz et al 1989Schwartz et al , 1993b (Fig. 2).…”

Section: (111) the Rat Tibial Model Of Endosteal Bone Formationsupporting

confidence: 64%

“…Similar changes in phospholipid composition have been described for matrix vesicles isolated from growth plate cartilage (IV) Mineralization of Bone around Implants Bone healing around orthopedic and dental implants is sensitive to the surface characteristics of the implanted material (for a review, see Schwartz and Boyan, 1994). To determine if implants promote or inhibit bone-bonding through modulation of the ability of the cells to mineralize their extracellular matrix, we used the tibial marrow ablation model to examine matrix vesicles in endosteal tissue surrounding various materials and compared the results with those of endosteal healing in the absence of implanted material (Sela et al, 1981c;Schwartz et al, 1987Schwartz et al, , 1989Schwartz et al, , 1991Schwartz et al, , 1992cSchwartz et al, , 1993bBraun et al, 1995). As shown in Fig.…”

Section: (111) the Rat Tibial Model Of Endosteal Bone Formationmentioning

confidence: 99%

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Primary Mineralization At the Surfaces of Implants

Sela

Groß

Kohavi

et al. 2000

Critical Reviews in Oral Biology & Medicine

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Osteogenesis around implants is affected by the physical and chemical characteristics of the biomaterials used. The osteoprogenitor cells must migrate to the implant site and synthesize and secrete a mineralizable extracellular matrix. Because this is neo-bone formation, the mechanism by which the cells calcify their matrix involves extracellular organelles called matrix vesicles in a process termed "primary mineralization". Two different methods for assessing the effects of implant materials on primary mineralization are presented in this report. In the first approach, different implant materials used in dentistry and orthopedic surgery were placed in rat tibial bones after marrow ablation. Two groups of implants were used, bone-bonding and non-bonding materials. We examined the effects of the materials on calcification morphometrically by quantitating changes in matrix vesicle morphology and distribution in endosteal tissue around implants as compared with normal endosteal bone healing. In addition, matrix vesicles were isolated from the endosteal tissue around the implant as well as from the contralateral limb and were examined biochemically. The results demonstrated that bone-bonding materials induced a greater increase in matrix vesicle enzyme activity than did non-bonding materials. However, all materials caused changes in matrix vesicles that were different from those seen in normal endosteal bone formation following injury. The effects of implant materials on biochemical markers of mineralization, including specific activities of matrix vesicle alkaline phosphatase and phospholipase A2 and phosphatidylserine content, demonstrated a high correlation with the morphometric observations with regard to enhancement and/or delay of primary mineralization. In the other approach, we used a radioisotopic method to evaluate the effects of implant materials on primary mineralization. This analysis revealed that implants alter bone healing, as shown by the differential uptake of 99mTc and 32P in different bone compartments. Decreased 32P uptake by the organic phase in the presence of bone-bonding implants suggests that cleavage of 99mTcMD32P into its technetium and methylene diphosphonate moieties was inhibited by the presence of the implants. In summary, these approaches to evaluating the effects of materials on primary mineralization demonstrate that the marrow ablation model can easily distinguish between bone-bonding and non-bonding materials. The use of this model can be valuable in the development of new materials.

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Section: (111) the Rat Tibial Model Of Endosteal Bone Formationsupporting

confidence: 64%

Section: (111) the Rat Tibial Model Of Endosteal Bone Formationmentioning

confidence: 99%

Primary Mineralization At the Surfaces of Implants

Sela

Groß

Kohavi

et al. 2000

Critical Reviews in Oral Biology & Medicine

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“…By variations in composition, crystallinity and density, in vivo characteristics of these materials can be influenced. 2,5,9,21 The resorbtion rate, which appears to be inversely proportional to the mechanical strength, can be influenced to a large extent. 14,23,26 The crystallinity, size of micropores, and the process of sintering (heating) influence the resorbability of calcium phosphates.…”

Section: Introductionmentioning

confidence: 99%

Autologous bone versus calcium‐phosphate ceramics in treatment of experimental bone defects

Bloemers¹,

Blokhuis²,

Bakker³

et al. 2003

J Biomed Mater Res

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Autologous bone grafting is currently considered the treatment of choice for correction of large bone defects. However, to avoid morbidity associated with autologous bone harvesting many artificial bone-substitute materials have been developed over the years. A new generation of resorbable materials is emerging, with promising results so far. In order to investigate the possibility to use one of these new materials as an alternative with better results than hydroxyapatite, an experimental study was performed. A new resorbable calcium phosphate particles and paste forms, the latter of which hardens in situ after application. In 28 sheep, a 3-cm segmental tibial defect was made and intramedullary fixed by an interlocking nail. Twelve weeks after defect filling, radiological, biomechanical, and histological examinations were performed. Mean radiographic and biomechanical tests results were compared with the Mann-Whitney test. Significance was set at p<0.05. Radiographically, the resorbable paste group performed better than all other groups. Biomechanical investigations showed a higher torsional stiffness (p=0.049) for the resorbable calcium-phosphate paste group in comparison with autologous bone. On histological examination, no adverse effects were observed in the calcium-phosphate groups. Resorption by osteoclasts was seen in the resorbable implants. In conclusion, the current study shows an advantageous radiological and mechanical outcome for resorbable calcium phosphates. This indicates that these new materials might be a potential alternative for autologous bone grafting in humans.

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“…1 But once it does occur, it proceeds in a normal, if somewhat reduced, fashion. 11 The variation in results of both studies may be due to the small cavity size (1 ϫ 1 cm). More detailed quantitative analysis is necessary to determine the role of HA in the bone healing rate.…”

Section: Discussionmentioning

confidence: 98%

Scanning electron microscopy observation of vascularization around hydroxyapatite using vascular corrosion casts

Chang

Lin

1999

J. Biomed. Mater. Res.

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An intimate relationship exists between the regenerative response of the vascular and osseous elements following hydroxyapatite (HA) implantation. In order to fully comprehend the 3-dimensional vascular architecture around HA, dense HA particles were implanted into the tibiae of dogs. Following healing periods of 2 weeks, 1 month, and 3 months, the tibiae were prepared by the corrosion cast technique. Under scanning electron microscopy (SEM) observation, the characteristic vascular morphology of the HA-implanted cavity was successfully demonstrated. The initial vascularization began in the form of loose sinusoidal capillaries. Many sinusoids formed a complex network by anastomosing with each other. The newly formed vessels extended centripetally from the peripheral cavity wall and from the periosteal surface. Under greater magnification, the tapered vascular sprouting was shown to project into the space that was previously occupied by an HA particle. The presence of vascular sprouting is clearly an important indicator of angiogenesis. Increasing vascularization was demonstrated with time. The presence of vessels in the Haversian's canal indicated the more established vascularization. Almost full vascularization of the HA-implanted cavity was seen 3 months after implantation. The vascular organizational layout of the cavity was also clearly shown in the fractured transverse-sectioned sample. In the control without HA implantation, the central region of the cavity showed a hollow pattern in the initial stage. The vascularization looked like it was collapsing and not fully filling the cavity. However, remarkable differences of the final vascular pattern could not be found between the study and control group after 3-month implantation. The study provides the time-lapsed 3-dimensional vascular changes of the HA-implanted cavity, as well as the value of the corrosion cast technique in examining the bony circulation.

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Effects of hydroxyapatite implants on primary mineralization during rat tibial healing: Biochemical and morphometric analyses

Cited by 41 publications

References 36 publications

Primary Mineralization At the Surfaces of Implants

Primary Mineralization At the Surfaces of Implants

Autologous bone versus calcium‐phosphate ceramics in treatment of experimental bone defects

Scanning electron microscopy observation of vascularization around hydroxyapatite using vascular corrosion casts

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