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At least 37 records · Page 2Linked to original sources
PubMed1977

The turnover of collagen in the dental pulp of rat incisors.

The turnover of collagen in the dental pulp was studied using H3-proline and microchemical techniques. The incorporation of label into the whole tissue was very high, with most of the label being incorporated into the noncollagenous substances. The rate of disappearance of label from collagen approximated the disappearance of label from noncollagenous components, suggesting that the whole pulp was undergoing rapid remodeling. There seems to be more than one metabolic pool of collagen.

Animals↗
PubMed1979

Electrophysiological properties of human dental pulp cells.

Resting membrane potentials and electrotonic potentials of human dental pulp cells (peripheral and inner cells) were recorded from intracellular measurements. The results show a high resting membrane potential (- 80 mV) for peripheral cells and a low resting membrane potential (- 30 mV) for inner cells. The peripheral cells present rectification properties (outward going rectification and delayed rectification) and a negative post potential at the end of the depolarizing current. These properties are similar to those found in some receptor cells. On the basis of their morphological characteristics, these peripheral cells are compared to odontoblasts in their early stage of development.

Adolescent↗
PubMed1978

Histologic identification of mast cells in human dental pulp.

Previous investigators who attempted to identify mast cells in the dental pulp have used demineralizing or tooth-splitting procedures to obtain their tissue samples. However, Eda and Langeland15 found that the fluorescence of mast cells is destroyed by acid demineralizing agents. On the other hand, tooth splitting may damage the pulp by crushing it with forceps, or cutting and heating it with burs, stones, or discs. In the present study, we used the extirpated pulps from teeth in which endodontic access openings were made by means of high-speed rotary instruments with water spray. Metachromatic staining methods failed to demonstrate mast cells in any of the non-inflamed pulp specimens. Two of the inflamed pulp specimens revealed numerous mast cells which appeared intact and well preserved with no evidence of degranulation. As to the distribution of the mast cells, there was no correlation with the number and types of other inflammatory cells observed. Although several cells present in the specimens examined were suggestive of mast cells, only those cells that revealed definitive metachromasia were included in this study.

Cytoplasmic Granules↗
PubMed1978

Effect of experimentally induced marginal periodontitis and periodontal scaling on the dental pulp.

Experimental breakdown of the periodontal attachment apparatus was produced in six young adult monkeys to study the effect on the tissue of the dental pulp by (1) periodontitis, (2) scaling and plaque accumulation on exposed root dentin. Periodontal tissue breakdown was induced by the placement of ligatures around the neck of 92 permanent teeth. Subsequent plaque formation caused marked loss of periodontal tissue support, which after a period of 5--7 months amounted to 30--40% of the root length. One group of teeth received no further treatment. Other teeth were subjected to scaling and root planing. Following treatment, plaque was allowed to accumulate for 2, 10, and 30 days on the freshly planed root dentin surfaces. Histologic examination revealed that in comparison to teeth with normal periodontal conditions, 57% of the teeth exposed to periodontitis exhibited pathologic pulp tissue alterations. Secondary dentin formation and/or inflammatory cell infiltrates were observed within localized areas of the pulp subjacent to root surfaces exposed to periodontal tissue destruction. The changes within the pulp were of "mild" nature and only one tooth displayed signs of total pulp necrosis. Lateral canals communicating with both the pulp cavity and the exposed root surface were never detected. Teeth subjected to scaling and subsequent plaque accumulation in comparison with teeth with periodontitis alone exhibited no obvious aggravation or increased incidence of pathologic pulp reactions. The findings show that in the monkey (1) periodontal destruction limited to the cervical half of the root and (2) plaque accumulation on exposed root dentin does not cause severe alteration in the pulp of the roots involved.

Animals↗
PubMed1977

Effect of some heavy metals on protein and collagen biosynthesis in rabbit dental pulp in vitro.

Cadmium, zinc, copper, and mercury, being components of dental alloys, have been tests at concentrations from 20 to 120 micronM for their effect on the incorporation of 14C-proline into various fractions of rabbit dental pulp incubated in vitro. With cadmium and zinc and increased amount of 14C-activity was recovered from the TCA-soluble pool, whereas the further incorporation into total protein and collagen, i.e. 14C-hydroxyproline, was markedly inhivited. Copper and mercury, however, reduced the amount of label in the TCA-soluble fraction. Both metals exhibited a dose-dependent inhibitory effect on the hydroxylation step in collagen synthesis, whereas for mercury only, an inhibition of the general protein synthesis was indicated. With all four metals the proportion of 14C-labeled protein and hydroxyproline recovered from the medium was reduced, the effect being most prominent with cadmium and zinc.

Animals↗
PubMed1979

Fine structural observations of calcium storage in human dental pulp cells in primary culture.

Primary culture of explants of human dental pulp tissue allows the study of the cytophysiology and differentiation of the cultured cells over a two-week period. The distribution of calcium was found in two different experimental conditions : with and without a calcium loading, by mean of a lead technique checked by microprobe analysis. The existence of two cell populations was revealed. Intra-mitochondrial ring-like granules characterize type 1 cells when overloaded, while a strong calcium storage is detected in the rough endoplasmic reticulum, Golgi apparatus and mitochondrial (without any inner organization of the deposits) of the type 2 cells. Our results also show the presence of calcium on gap-junctions (revealed) by lanthanum method), and on the extracellular matrix (collagen fibres and complex carbohydrates). The ability of some mitochondria to store calcium (ring-like granules) suggests that the type 1 cells are fully differentiated in odontoblast-like cells and perhaps engaged in mineralization processes. The calcium binding sites, localized on the extracellular matrix may therefore be considered as the earliest foci of calcification.

Calcium↗
PubMed1979

The effects of etching enamel with acid on human dental pulp. A preliminary study.

Enamel acid-etching has become a widespread, popular clinical procedure in recent years. Numerous studies have investigated the nature of the acid-treated enamel. However, little or no information is presently available pertaining to the effects of acid treatment upon dental pulp tissue. A limited investigation was carried out on bilateral orthodontic extraction cases to determine the effects of enamel acid-etching upon healthy dental pulp. In each of five cases one premolar served as the experimental tooth, while the contralateral premolar served as the control. After a 24-hour postoperative interval there appeared to be no basic histologic difference between the experimental and control groups.

Acid Etching, Dental↗
PubMed1977

Properties and distribution of inorganic pyrophosphatase in rabbit dental pulp.

Some properties and the intracellular distriubtion of inorganic pyrophosphatase in rabbit dental pulp were determined. This enzyme was sensitive to Mg2+, and not inhibited by imidazol and CN- which are inhibitors of alkaline phosphatase. Inorganic pyrophosphatase was found predominantly in the supernatant fraction.

Alkaline Phosphatase↗
PubMed1979

Synthesis of procollagen by dental pulp cells from incisor in vitro.

Fibroblast-like cells were isolated from dental pulp of rabbit incisor, and were shown to synthesize and secrete procollagen. Analysis of the secreted procollagen and their CNBr peptides indicated that the prominent form was type I procollagen. Our results also suggested the presence of type III procollagen as a minor component synthesized by pulp cells in vitro.

Animals↗
PubMed1978

Blood flow and oxygen consumption in steroid-treated dental pulps.

This study examined pulpal blood flow and oxygen consumption by the dental pulps of dogs. Blood flow was measured by the radioactive microsphere method and oxygen uptake was determined by the indirect Warburg approach. These variables were assessed 2 days after the canine teeth had been exposed and treated with either a cotton pellet impregnated with 1 per cent prednisolone or normal saline. The analysis indicated that the pulpal blood flow as well as the oxygen consumption did not differ between the steriod-treated tooth and the corresponding saline-treated tooth in the same jaw.

Animals↗
PubMed1979

Microvascular pressure in the dental pulp and gingiva in cats.

Pressure in selected microvessels was measured directly on the exposed coronal or apical pulp in one of the upper canine teeth or on the gingiva in a total of 36 cats. The vessels were punctured with glass micropipettes, diameter 1-4 micrometer, and the pressure measured with a modified Wiederhielm servocontrolled counter-pressure technique. Pressures in corresponding vessels in coronal and apical pulp were similar. The pressure in pulpal arterioles, diameter 10-70 micrometer averaged 43 mm Hg, or 36% of mean systemic arterial pressure (PA), while pressure in the pulpal venules, diameter 10-80 micrometer, was on an average 19 mm Hg or 16% of PA. Capillary pressure measured in the coronal pulp averaged 35 mm Hg. Mean arterial systemic pressure was 124 mm Hg. The total vascular pressure drop within the pulp was only 20% of the total systemic arteriovenous pressure difference. Accordingly, only one fifth of the vascular resistance governing pulpal blood flow is situated within the pulp itself. This means that blood flow in the dental pulp in cats may be influenced by mechanisms located extrapulpally. In gingiva only venular pressure was measured, which averaged 19 mm Hg.

Animals↗
PubMed1977

Mapping of the trigeminal sensory complex of the cat. Characterization of its neurons by stimulations of peripheral field, dental pulp afferents and thalamic projections.

From a new systematic investigation of the 4 divisions of the trigeminal sensory complex, the following points are emphasized: 1. The subnucleus oralis receives a large representation from the oral cavity, a region also represented in the three other divisions of the trigeminal sensory complex. 2. Units responding to noxious mechanical stimulation have been found in two different loci: the subnucleus caudalis for the whole trigeminal area, and the subnucleus oralis for the oral cavity. 3. The dental pulp projects to the four divisions of the trigeminal sensory complex, but the heaviest projection is found in its rostral part (the main nucleus and subnucleus oralis). 4. Three distinct types of responses were found following dental pulp stimulation: primary, non primary and responses strongly enhanced by an increase in stimulus parameters.

Animals↗
PubMed1979

[The human dental pulp as viewed through a scanning electron microscope (author's transl)].

The human dental pulp was examined using a scanning electron microscope. The odontoblasts are pear-shaped and have a fine-grain surface structure. Tomes' process divides into fine branches before entering the predentin. Very few fibroblasts were found. These had stronger cell processes at the two terminal poles. Adhering to their surfaces were fine fibers. Collagenous and nerve fibers could not be accurately identified in the rich fibrillary network of the pulp. Stronger nerve fasciculi were readily observable through longitudinal sulci. Thinner fibers were seen to spread out in branches from some nerve bundles. The capillaries were observed to be surrounded by a sheath of fine fibrils.

Capillaries↗