Attachment of gingival tissues to the protruding post of an endosseous dental implant is of great importance for the prognosis of its clinical success. Little is known about the requirements an implant material must meet to secure a durable permucosal seal. The objective of this study, therefore, was to gain insight into the morphology of epithelial cell-implant interfaces for a number of well-known or potential implant materials.Guinea pig epithelial cells were cultured on gold, titanium, carbon, hydroxylapatite, carbonate apatite, and modified polystyrene substrates The metallic and carbon substrates were obtained by vapor-phase deposition of thin films on polystyrene carriers. This technique allowed for the preparation of ultra-thin sections for transmission electron microscopy containing substrate as well as the cells adhering to it. The cultures on apatite were decalcified prior to sectioning.The results revealed that as attachment structures, focal contacts, extracellular matrix contacts, and hemidesmosome-like contacts could be distinguished. Hemidesmosome-like contacts were only observed on apatite and polystyrene and not on the metallic or carbon surfaces.The results of this study suggest the existence of some, as yet unknown, property of the substrate that determines the nature and the structure of the contact site with epithelial cells.
Long-term (8 and 24 month) reactions of the (hypo) dermis of the guinea pig to solid and porous (50 vol%) acrylic implants and four human biopsies from porous subcutaneous acrylic implants were studied light microscopically. The solid implants were encapsulated by dense connective tissue. Mobility was evidenced by the loss of 4 out of 36 after 2 yr and was considered the explanation for the occurrence of ectopic cartilage and mineralized material at some solid implants' surfaces after 2 yr. A dense capsule was not evident with the porous implants, instead vascularized collagenous connective tissues penetrated into and filled the pores, thus anchoring the implant to the body. None of these implants, was lost. Notwithstanding the presence of some multinucleated giant cells, scattered inflammatory cells and loosely packed inflammatory foci with both implant materials, the materials were considered well-tolerated by the body. The histology of the human biopsy did not differ significantly from the porous animal implants.
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