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Biomedical subjects

A R Ten Cate

Publications and source records attributed to A R Ten Cate.

At least 19 recordsLinked to original sources
PubMed1996

The role of epithelium in the development, structure and function of the tissues of tooth support.

The roles of epithelium in the development, structure and function of the tissues of tooth support are reviewed. Epithelium is involved in initiating odontogenesis which includes the tissues of tooth support and this role is discussed. Particular attention is paid to Hertwig's epithelial root sheath and its participation in the formation of the hyaline layer on the root surface as well as its possible role in initiating the differentiation of cementoblasts. The possible functions of the epithelial cell rests are reviewed and it is concluded that as yet no function can be ascribed to them. Evidence for an increasing role for dental epithelium in tooth eruption is presented and the role of dental epithelium in establishing the dentogingival junction is discussed, with the conclusion drawn that this role temporary.

Animals↗
PubMed1991

The extent and distribution of intratubular collagen fibrils in human dentine.

Dentine of 27 permanent human teeth was examined by scanning electron microscopy. The teeth were incisors, canines, premolars and molars, ranging in age from 18 to 54 yr. Intratubular collagen was found in 65% of the dental tubules in inner dentine (closest to the pulp) with 16% of the tubules containing large collagen bundles occupying more than one-fifth of the lumen. In middle dentine the corresponding figures were 42 and 7%, and for outer dentine, 12 and 0% This pattern of distribution was the same for all tooth families examined and appeared to be unrelated to age.

Adolescent↗
PubMed1989

Biological determinants in implant design.

This paper considers whether fibro-osseous integration is a feasible outcome for dental implants and whether the mucosal-implant junction is a crucial factor for implant success. It is argued that the periodontal ligament is a connective tissue with specific origin determined early in development. Further, it is argued that fibroblasts of the ligament exhibit unique functional characteristics associated with tooth support and that these characteristics cannot, as yet, be duplicated in other fibroblasts. These specific attributes argue against the feasibility of fibro-osseous integration unless cells of the periodontal ligament are available to develop a fibrous attachment. With respect to the dentogingival junction, it is argued that this structure does not provide a functional seal around the normally functioning tooth and therefore a minor degree of inflammation in the connective tissue adjacent to an implant is acceptable. It is also argued that inflammation associated with fibro-osseous integrated implants is not the result of a deficiency in the epithelial attachment but rather is due to the inability of the connective tissue to withstand the forces applied to it.

Dental Implantation, Endosseous↗
PubMed1986

An ultrastructural study of tooth resorption in the kitten.

Eleven kittens of various ages were used to obtain teeth in situ at differing stages of exfoliation. The teeth were processed by routine techniques for examination by light and transmission electron microscopy. The dental hard tissues were eroded by odontoclasts supported by numerous blood vessels, fibroblasts, and macrophages. No evidence of intracellular collagen was found within any of these cells, indicating that helper cells are not required to remove the collagenous component of dentin and cementum. The loss of periodontal ligament during shedding involved the removal of cells and extracellular material. Two forms of fibroblastic cell death were identified: One, apoptotic cell death, involved condensation, and its occurrence suggests that exfoliation of deciduous teeth is a programmed physiological event; the other occurred in cells containing many profiles of collagen and involved the selective disruption of the mitochondria and eventual dissolution of cytosol. This form of cell death has not been previously described and is significantly different from necrotic cell death, which was not observed during exfoliation. Some fibroblasts maintained a normal morphology. These various cellular responses suggest that phenotypically different populations of fibroblasts may exist in the periodontal ligament. Collagen removal was an extracellular occurrence which did not seem to involve increased phagocytotic activity by fibroblasts.

Animals↗
PubMed1986

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Curriculum↗
PubMed1985

An immunocytochemical study of the human odontoblast process using antibodies against tubulin, actin, and vimentin.

An immunofluorescence technique was applied at the light microscope level to human third molar coronal dentin in order to localize the intracellular components tubulin, vimentin, and actin. Third molars were split immediately upon extraction, and immersed in periodate-lysine-paraformaldehyde fixative. The crowns were demineralized, dehydrated, and wax-embedded, and 6-micron sections were prepared. The sections were post-fixed in -20 degrees C acetone, and then incubated with monoclonal mouse anti-tubulin, anti-vimentin, or anti-actin antibodies, followed by fluorescein-conjugated sheep anti-mouse immunoglobulins. Intratubular immunofluorescence labeling for tubulin and vimentin was very similar in pattern and intensity and extended to the dentino-enamel junction. In contrast, the actin labeling appeared less intense and more punctate, and was located primarily in the pulpal half of the crown, although some labeling was detectable up to the dentino-enamel junction. The presence of tubulin-, vimentin-, and actin-containing structures extending to the dentino-enamel junction supports the hypothesis that the odontoblast process does extend to the dentino-enamel junction in the human, and is in agreement with earlier studies of rat molars.

Actin Cytoskeleton↗
PubMed1984

A combined scanning electron microscopy and immunofluorescence study demonstrating that the odontoblast process extends to the dentinoenamel junction in human teeth.

The extent of the odontoblast cell process has been the subject of controversy for many years. Using SEM we have examined the extent and morphology of the process on dentine surfaces of human teeth which were partially demineralized and collagenase digested. Third molars were extracted and split; the dentine surface was demineralized, digested by bacterial collagenase, fixed with glutaraldehyde, postfixed in osmium tetroxide, and prepared for SEM investigation. The SEM study revealed the presence of many processlike structures which extended from the odontoblast cell bodies up to the dentinoenamel junction (DEJ). These processes demonstrated lateral and terminal branching and some of them terminated in distended spheres. We have also applied an immunofluorescence technique at the light microscope level to these exposed dentinal surfaces to localize the intracellular microtubules. For this, a second series of third molars was processed in the same manner as for the SEM up to the fixation stage. Teeth were then fixed in periodate-lysine-paraformaldehyde, postfixed in -20 degrees C acetone, and then incubated with affinity-purified rabbit antitubulin antibodies, followed by fluorescein-conjugated goat antirabbit IgGs. Intratubular immunofluorescence labelling for tubulin was evident from the odontoblast cell bodies up to the DEJ. The presence of the tubulin-containing structures extending to the DEJ supports the hypothesis that the structures observed with the SEM are odontoblast processes and that the odontoblast processes do extend to the DEJ.

Adult↗
PubMed1984

The odontoblast process extends to the dentinoenamel junction: an immunocytochemical study of rat dentine.

The length and extent of the odontoblast cell process in dentine has been the subject of controversy for many years. Here an immunofluorescence technique has been applied at the light microscope level to rat coronal dentine to localize the intracellular components actin and tubulin. Adult rats were perfused with periodate-lysine-paraformaldehyde fixative, teeth were extracted, the molar crowns were demineralized, dehydrated, wax embedded, and 6 micron sections were prepared. The sections were postfixed in -20 degrees C acetone and then incubated with affinity-purified rabbit anti-actin or anti-tubulin antibodies, followed by fluorescein-conjugated goat anti-rabbit immunoglobulin. Intratubular immunofluorescence labeling for tubulin extended to the dentinoenamel junction, whereas labeling for actin, although extending to the dentinoenamel junction, was more prominent in the pulpal third of the rat dentine. Areas in which odontoblast processes are known not to occur, i.e., the atubular dentine, were not labeled by either antibody. The presence of actin- and tubulin-containing structures extending to the dentinoenamel junction is consistent with the hypothesis that the odontoblast process traverses the dentine for up to 3-4 mm, all the way to the dentinoenamel junction. Furthermore, the different staining patterns for actin-containing microfilaments as compared to tubulin-containing microtubules suggest that these two filamentous systems may have different roles in the function of the odontoblast process.

Actins↗
PubMed1983

A role for collagen phagocytosis by fibroblasts in scar remodeling: an ultrastructural stereologic study.

A role for collagen phagocytosis and intracellular degradation by fibroblasts during remodeling activity has been suggested by studies on several connective tissues characterized by high rates of collagen turnover and remodeling. The possible importance of such activity in the normal remodeling of scar tissue has been studied by a quantitative ultrastructural stereologic measure of collagen phagocytosis by fibroblasts at various post-wounding intervals in mouse skin scars. The results demonstrate a correlation between the peak periods of such phagocytic activity and the interval during which collagen fiber reorientation across the scar appears to take place.

Animals↗