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Biomedical subjects

A R Ten Cate

Publications and source records attributed to A R Ten Cate.

15 recordsLinked to original sources
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

More or less.

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Curriculum↗
PubMed1978

The keratinization potential of crevicular epithelium: an experimental study.

Free grafts, consisting of nonkeratinized crevicular epithelium and supporting connective tissue, were placed into recipient beds prepared in nonkeratinized alveolar mucosa of the rhesus monkey. Four weeks later these grafts clinically resembled keratinized gingiva and this was confirmed by biopsy and histological examination. Electron microscopy indicated that the connective tissue supporting the crevicular epithelium changed to resemble that supporting keratinized gingiva in the 4-week graft. These findings were interpreted to indicate that crevicular epithelium has the potential to keratinize and that this potential is only realized when the inflammation is resolved in its supporting connective tissue.

Animals↗
PubMed1978

A fine structural study of coronal and root dentinogensis in the mouse: observations on the so-called 'von Korff fibres' and their contribution to mantle dentine.

The fine structure of mantle dentine formation has been studied in the mouse molar. No evidence was found for the presence of collagenous von Korff fibres arising from the dental papilla, passing between odontoblasts and fanning out to form the collagenous matrix of mantle detine. Instead, large collagen fibrils were first demonstrable in the matrix peripheral to the dential aspect of an extensive junctional complex system occurring at the necks of the odontoblasts. The orientation of the fibres was at right angles to the future amelo-dentinal junction in coronal dentinogenesis, but parallel to the root surface in radicular dentinogenesis. These large collagen fibrils formed the mantle dentine. It is concluded that von Korff fibres, as strictly defined, are artefacts. Photographs in the literature purporting to show von Korff fibres are attributable to obliquity of section. Also, is suggested that the difference in fibril orientation in coronal and root mantle dentine is the reason for the conflicting opinions on the pattern of fibril orientation in this tissue.

Animals↗
PubMed1977

Sutural development: structure and its response to rapid expansion.

This fine structural study of the suture, its development, structure, and response to rapid expansion has shown that the sutural complex is best described in terms of the functional activity of two cell populations, namely, the osteocytic and fibrocytic series, which have the ability to remodel the tissues which they form. It is suggested that the previous detailed descriptions of differences in fiber orientation and vascular distribution reflect functional activity of a suture at any given time rather than immutable anatomic characteristics. Development of the suture and its rapid expansion showed many similarities in that growth during development and orthopedic expansion both separate the joint. If the initial inflammatory aspect of rapid expansion is ignored, the response of the suture is one of osteogenesis and fibrillogenesis, followed finally by remodeling. It is also suggested that sutural expansion involves injury followed by a proliferative repair phenomenon which, in other tissues, usually leads to the formation of scar tissue. However, the ability of sutural connective tissue fibroblasts to remodel ultimately leads to regeneration of the suture. Finally, programmed cell death has been shown to be an important feature in the development of the suture.

Activator Appliances↗
PubMed1977

Glossary of terms.

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Dictionaries as Topic↗
PubMed1976

The role of fibroblasts in the remodeling of periodontal ligament during physiologic tooth movement.

Our findings indicate a cellular basis for the connective tissue remodeling which takes place during physiologic tooth movement. This cell is the fibroblast which is capable of synthesizing and degrading collagen simultaneously and, utilizing this ability, the orderly control of collagen remodeling within the periodontal ligament is possible. It is suggested that this cellular basis of connective remodeling will have a direct significance for orthodontic tooth movement once control mechanisms have been established.

Amino Acids↗
PubMed1975

Effects of ascorbic acid on health parameters in guinea pigs.

The maximal response of a selection of ascorbic-acid-dependent parameters to a range of intakes of ascorbic acid has been shown to occur at virtually one level of intake in the present experiments. Further, this response occurred with intakes that produced only 1/2 saturation or less of tissues with ascorbic acid. Excessive intakes did not enhance effects, and, as in the case of serum copper levels, may have a detrimental effect. In view of the known factors that may influence requirements and the intralaboratory variability in experimental conditions, the more reasonable approach to the interpretation of dose response data is likely to relate the response to the accompanying degree of tissue saturation, rather than to an absolute level of ascorbic acid intake.

Animals↗