Comparative push‐out test of dense HA implants and HA‐coated implants: Findings in a canine study

Ogiso, Makoto; Yamamura, Masao; Kuo, Pai Tsun; Borgese, D; Matsumoto, Toshio

doi:10.1002/(sici)1097-4636(19980305)39:3<364::aid-jbm4>3.3.co;2-p

Cited by 9 publications

(19 citation statements)

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“…20 In contrast, no reduction in coating thickness has been reported in unexposed hydroxyapatite-coated implants inserted in coxal bone of dogs for 10 months. 34,35 Therefore, another important variable of coating integrity is whether an implant is exposed to the oral environment, loaded, and in function. It is likely that the longer these hydroxyapatite dental implants remain in situ, the more the coating is stripped away from the underlying metallic surface.…”

Section: Microanalysis Of Control and Retrieved Specimens § A Sem Mmentioning

confidence: 99%

“…It is likely that the longer these hydroxyapatite dental implants remain in situ, the more the coating is stripped away from the underlying metallic surface. 20,34,35 Although at this stage in the study we have not investigated these mechanisms specifically, there are a number of factors involved in coating failure. Dissolution at the coating grain boundaries and release of calcium phosphate particulates into the local biological environment may induce an inflammatory response.…”

Section: Microanalysis Of Control and Retrieved Specimens § A Sem Mmentioning

confidence: 99%

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A Methodological Study for the Analysis of Apatite‐Coated Dental Implants Retrieved From Humans

MacDonald

Betts²,

Doty³

et al. 2000

Ann Periodontol

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The stability of thermally processed hydroxyapatite coatings for oral and orthopedic bioprostheses has been questioned. Information on the chemical changes, which occur with hydroxyapatite biomaterials post-implantation in humans, is lacking. The purpose of this investigation was to begin to examine post-implantation surface changes of hydroxyapatite-coated implants using scanning electron microscopy (SEM), x-ray microanalysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD). Three retrieved dental implant specimens from humans following clinical failure due to peri-implantitis were examined. Unimplanted cylinders served as controls. Clinically, the retrieved specimens were all enveloped by a fibrous tissue capsule with bone present at the apical extent of the implant. SEM analysis showed that the retrieved surfaces were coated with both calcified and proteinaceous deposits. EDAX scans of the retrieved specimens demonstrated evidence of hydroxyapatite coating loss reflected by increasing titanium and aluminum signals. Other foreign ions such as sodium, chloride, sulfur, silica, and magnesium were detected. XRD of the control specimens showed that the samples were predominantly apatite; however, two peaks were detected in the diffraction pattern, which are not characteristic of hydroxyapatite, indicating that small amounts of one or more other crystalline phases were also present. The retrieved specimens showed slightly larger average crystal size relative to the control sample material, and the non-apatite lines were not present. FTIR evaluation of the retrieved specimens revealed the incorporation of carbonate and organic matrix on or into the hydroxyapatite. Narrowing of and increased detail in the phosphate peaks indicated an increase in average crystal size and/or perfection relative to the controls, as did the XRD results. Based on these results, we conclude that chemical changes may occur within the coating, with the incorporation of carbonate and concomitant reduction in hydroxyapatite coating thickness. Thermodynamic dissolution-reprecipitation of the coating itself and subsequent surface insult by bacterial and local inflammatory components may be involved with these changes.

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Section: Microanalysis Of Control and Retrieved Specimens § A Sem Mmentioning

confidence: 99%

Section: Microanalysis Of Control and Retrieved Specimens § A Sem Mmentioning

confidence: 99%

A Methodological Study for the Analysis of Apatite‐Coated Dental Implants Retrieved From Humans

MacDonald

Betts²,

Doty³

et al. 2000

Ann Periodontol

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“…In characterizing the interfacial mechanical properties of a bone/cement interface, experimental approaches have been the most frequently used methods, including tensile tests [10,11] or push-in tests for measuring the tensile or shear strength [12][13][14]. Such experimental configurations were often applied to evaluate factors affecting the bonding strength and the extent of their influence.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the fracture characteristics of the interfacial bond between bone and cement: experimental and finite element approaches

Chiang

Hung

2010

J Mech Sci Technol

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“…On the other hand, the ratio of the push-out value of HA-coated implants to that of dense HA implants in canine bone was shown to decrease over time, due to weakening of the HA coating, with no clear decrease in thickness. In contrast, the dense HA implants were durable throughout the experimental period (Ogiso et al, 1998). This weakening of the HA coating could not be accounted for solely by its high solubility.…”

Section: Introductionmentioning

confidence: 82%

The Process of Physical Weakening and Dissolution of the HA-coated Implant in Bone and Soft Tissue

1998

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Hydroxyapatite (HA)-coated implants were developed to promote osseointegration of titanium implants and to overcome the mechanical drawbacks of solid HA implants. Although many clinical reports on the prognosis of HA-coated implants have reported high success rates, the risks of dissolution and weakening of the coating have been noted. We hypothesized that the chemical and mechanical stability of HA coating are affected by its microstructural characteristics. The present study investigates differences in the microstructures of available HA-coated implants, before and after implantation into the coxal bones of dogs for periods ranging from 3 weeks to 10 months and under the coxal periosteum of dogs for 10 months. The results of transmission electron microscopy and energy-dispersive x-ray analysis revealed that crystallization of super-fine HA crystals occurred in the amorphous phase of the HA coating and progressed over time. This crystallization weakens HA-coated implants by making the amorphous phase brittle, causing stress accumulation within the coating, and causing a decrease in the binding strength between the coating and the substrate. Furthermore, the HA coating dissolved in soft tissue. Dissolution started with the super-fine HA crystals in the crystallized portion that was originally part of the amorphous phase.

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Comparative push‐out test of dense HA implants and HA‐coated implants: Findings in a canine study

Cited by 9 publications

References 0 publications

A Methodological Study for the Analysis of Apatite‐Coated Dental Implants Retrieved From Humans

A Methodological Study for the Analysis of Apatite‐Coated Dental Implants Retrieved From Humans

Investigation of the fracture characteristics of the interfacial bond between bone and cement: experimental and finite element approaches

The Process of Physical Weakening and Dissolution of the HA-coated Implant in Bone and Soft Tissue

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