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At least 469 records · Page 26Linked to original sources
PubMed1990

Peptidergic nerves in human dental pulp. An immunocytochemical study.

The peptidergic innervation of human dental pulp was studied with indirect immunofluorescence and immunoperoxidase techniques. Pulpal nerve fibres displaying immunoreactivity for cholecystokinin, calcitonin gene-related peptide, C-terminal flanking peptide of neuropeptide tyrosine, leucine-enkephalin, methionine-enkephalin, neuropeptide K, neuropeptide tyrosine, peptide with N-terminal histidine and C-terminal isoleucine, somatostatin-28, substance P and vasoactive intestinal polypeptide were observed. Immunoreactive axon varicosities were detectable within radicular and coronal nerve trunks and within the nerve plexus of Raschkow in the para-odontoblastic region. Many peptidergic nerve fibres were observed in association with blood vessels of various sizes. Substance P- and calcitonin-gene-related peptide-immunoreactive axons were visible in the odontoblastic layer. The occurrence of VIP- and PHI-immunoreactive fibres lends support to the hypothesis that human tooth may be supplied by parasympathetic nerves. The immunocytochemical results here shown provide a morphological basis to previous experimental studies concerning the possible roles of neuropeptides in nociception mechanisms, control of the blood flow and modulation of the inflammatory response in dental tissues.

Dental Pulp↗
PubMed1987

Blood flow changes in the dental pulp of the cat and rat measured simultaneously by laser Doppler flowmetry and local 125I clearance.

Blood flow changes in the dental pulp of lower canine teeth of mature cats and incisors of mature rats were investigated with simultaneous laser Doppler flowmetry and local 125I-clearance (wash-out) during electrical sympathetic stimulation, efferent stimulation of n. alveolaris inferior (IAN) (cats) and i.a. infusions of substance P (SP) (cats). Stimulation (1-4 Hz, 4 V., 1.5 ms) of the cervical sympathetic trunk produced frequency-dependent decreases in both laser Doppler output and disappearance rate of iodine tracer from the dental pulp. For the effects of sympathetic stimulation, the correlation (r2) between the results obtained by the two methods was 0.89 (12 observations, six animals). Blood flow measurements by both methods were increased following i.a. infusions of SP (r2 = 0.64, six observations, three animals). However, upon stimulation of IAN (10 Hz 10 V, 5 ms) the laser Doppler flow values showed an increase while the local 125I clearance rate was unaffected or even decreased. The discrepancy between the results obtained following IAN stimulation indicates that the two methods reflect blood flow changes in different parts of the pulpal vascular bed and that the flow is unevenly distributed to these parts during antidromic IAN stimulation. The laser Doppler flowmetry seems to reflect the total blood flow in the coronal pulp and therefore this non-invasive method may be useful for monitoring blood flow changes in the tooth.

Animals↗
PubMed1986

Ampicillin concentrations in human serum, gingiva, mandibular bone, dental follicle, and dental pulp following a single oral administration of bacampicillin.

Ninety-six patients who underwent the extraction of impacted mandibular third molars in a nonfasting state were given a single oral dose of bacampicillin preoperatively. Specimens of serum from venous blood (n = 107), gingiva (n = 57), mandibular bone (n = 68), dental follicle (n = 56), and dental pulp (n = 43) were obtained during the operation and assayed for ampicillin content. The mean peak concentrations in serum, gingiva, mandibular bone, dental follicle, and dental pulp all occurred approximately 90 minutes after administration. The concentration ratios of the tissues to the corresponding serum at the peak time were 0.50, 0.20, 0.34, and 0.61, respectively. Bacampicillin showed good absorption by the intestine, and sufficient concentrations of the resulting metabolite, ampicillin, were found in the oral tissues.

Administration, Oral↗
PubMed1991

A scanning electron microscopic study of the contraction of vascular wall cells in dog dental pulp.

Ultrastructural changes in vascular wall cells in dog dental pulp after removal of connective tissue components were studied by scanning electron microscopy following administration of norepinephrine (0.2 mg/kg). Contracted smooth-muscle cells were frequently seen in arterioles of all sizes. The surfaces of these cells were highly irregular with numerous evaginations and invaginations, varying considerably in configuration and size. Many evaginations ran longitudinally or obliquely to the long axis of the vessel. Some meandering evaginations were also observed as, rarely, were small spherical or bulbous projections. Spidery smooth-muscle cells frequently seen in the tunica media of terminal arterioles and thought to be primitive smooth-muscle cells exhibited fewer irregularities than the typical spindle-shaped smooth-muscle cells beneath them. Pericytes in the larger post-capillary venules (20 microns or larger in diameter) often showed evaginations and invaginations, mainly running parallel to the vessel axis. On the other hand, no surface irregularities could be seen in pericytes of either the smaller post-capillary venules (less than 20 microns in diameter) or the capillaries, although occasional evaginations running parallel to the vessel axis were noted on the outer surface of the endothelium.

Animals↗
PubMed1991

[Study on the diagnosis of the deciduous tooth pulpitis by the blood picture in the dental pulp].

The purpose of this study was to investigate the method of diagnosis of deciduous tooth pulpitis to make sure of the extent of the inflammation for more appropriate pulp therapy. The subjects were 100 decayed deciduous teeth of the 81 normal healthy children aged from 2y9m to 11y2m, which justified the vital pulp amputation therapy according to Nagasaka's deciduous tooth pulpitis diagnosis criteria. The blood picture was compared with the histological structure of the coronal pulp and then observed after treatment. The diagnosis of the deciduous tooth pulpitis was considered by the blood picture in the dental pulp. The results were as follows. 1. As to the blood picture in the deciduous dental pulp, it was suggested that the lymphocyte ratio was able to be taken for the discrimination of the deciduous tooth pulpitis, because ratio of lymphocyte in the coronal pulp was higher than its normal values in the peripheral blood picture regardless of the age. 2. As to the histological structure of the removed coronal pulp, the inflammatory degree was divided into 4 types; (-) no evidence of inflammation, (+) slightly confined infiltration of the inflammatory cells, (++) slightly or moderately diffused infiltration, ( ) severely diffused infiltration, when the numbers of the case at each degree type were (-) 0, (+) 37, (++) 47 and ( ) 16 cases. 3. As to the ratio of the lymphocyte ratio over 60% against all at each degree type, (+) 86.5% and (++) 61.7% were much higher than ( ) 0%. 4. The ratio of cases in which it was difficult to control bleeding at ratios of the coronal pulp amputations were type (+) 32.4% and (++) 25.5% in type, however, type ( ) showed high rate (62.5%). 5. As a result of the clinical and X-ray examination after vital pulp amputation therapy, the number of poor case was 12 of 42 cases (28.6%) in type (+) (++) and 4 of 4 cases (100%) in type ( ). 6. This result suggests that the vital pulp amputation therapy is not adequate when it is hard to control bleeding and the lymphocyte ratio of blood picture in the coronal pulp shows under 57%.

Child↗
PubMed2003

Angiogenic growth factors released in human dental pulp following orthodontic force.

OBJECTIVE: The aim of this study was to investigate if a combination of five diffusible angiogenic growth factors were released in human dental pulp during orthodontic force application, by using growth factor neutralising antibodies (NAs) to block their effects. MATERIALS AND METHODS: Dental pulps from 18 premolar teeth treated with orthodontic fixed appliances for 2 weeks were divided vertically, and each half pulp further sectioned and co-cultured with a section of rat aorta in collagen surrounded by growth media. NAs (anti-h VEGF, anti-h FGF2, anti-h PDGF, anti-TGFbeta and anti-h EGF) were added to the media of the co-cultures from one half of each pulp from 10 teeth. The co-cultures from the remaining eight teeth acted as controls. Sections of rat aorta alone were also cultured with and without NAs. Cultures were examined daily by light microscopy for growth and number of microvessels. RESULTS: NAs significantly reduced microvessel numbers in the co-cultures, but not in the rat aorta alone cultures. CONCLUSIONS: The results show that a combination of these angiogenic growth factors are released in the pulp following orthodontic force.

Adolescent↗
PubMed1987

[Evaluation of an in vivo perfusion technic for the dental pulp in rats as validated by demonstration of the release of prostaglandins].

Many different biologically active substances contribute to the metabolism of dental pulp. Until now, release of these substances has been evaluated only by in vitro studies. The aim of this study was to establish a technique of perfusion allowing the evaluation in vivo of the secreting activity of dental pulp. In order to validate this technique, the in vivo release of prostaglandins, substances which seem to play a key role in pulpal metabolism was measured. The "push-pull" perfusion technique was used, whereby a physiological medium was made to bath the pulpal surface by aspiration. Pulp was exposed by opening an upper incisor in an anaesthetized rat. The perfusion was kept constant by means of a device composed of cannula, catheters, and micropumps which produced a flow followed by an aspiration of the liquid. Every ten minute fraction was analysed by high performance liquid chromatography. Ten minutes after the beginning of perfusion, the results showed a kinetic for PGE2 and PGF2 alpha release, characterized by a base level of 7.4 +/- 6.7 and 28.6 +/- 12.0 pg/min respectively. These were interrupted by a very high peak as compared to base level (19 times higher for PGE2 and 6.6 times for PGF2 alpha), occurring fifty minutes after trepanation. This experiment is the first attempt made in vivo and in situ, to measure biologically active substances of pulpal origin.

Animals↗
PubMed2000

Transient expression of heat shock protein (Hsp)25 in the dental pulp and enamel organ during odontogenesis in the rat incisor.

The expression of heat shock protein (Hsp) 25 during odontogenesis in the dental pulp and enamel organ of rat incisors was investigated by immunocytochemistry and confocal microscopy. In the process of dentin formation, immature odontoblasts first exhibited Hsp 25-immunoreactivity, and increased in immunointensity with the advance of their differentiation. In the dental pulp, in contrast, intense immunoreaction in the mesenchymal cells became weak or negative in parallel with the progress of cell differentiation. The immunoreaction for Hsp 25 in the enamel organ revealed a characteristic stage-related alteration during amelogenesis. In secretory ameloblasts, the immunoreaction for Hsp 25 was found throughout their cell bodies, intense reactivity being located near the proximal and distal terminal webs. At the maturation stage, ruffle-ended ameloblasts (RA) consistently showed Hsp 25-immunoreactivity throughout the cell bodies, whereas smooth-ended ameloblasts (SA) lacking a ruffled border were weak in immunoreaction at the distal cytoplasm. Other cellular elements of the enamel organ were negative. The subcellular localization of Hsp 25-immunoreactivity in this study appeared essentially identical to that of actin filaments as demonstrated by confocal microscopy using rhodamine-labeled phalloidin. These immunocytochemical data suggest that the Hsp 25 molecule is involved in reinforcement of the cell layer following cell movement during odontogenesis and in the formation and maintenance of the ruffled border of RA.

Actins↗
PubMed1999

[The effects of basic fibroblast growth factor on proliferation and differentiation of human dental pulp cells in vitro].

OBJECTIVE: To evaluate the effects of human basic fibroblast growth factor (hbFGF) on proliferation and differentiation of human dental pulp cells in vitro. METHODS: The syntheses of DNA, collagen, fibronection (FN), alkaline phosphatase (ALP) and bone morphogenetic protein (BMP), and the expression of agglutinin were measured with imagine processing and analysis system. RESULTS: hbFGF at concentration of 1-10 micrograms/L stimulated the cell proliferation measured by MTT colorimetric assay, and promoted incorporation of 3H-thymidine at 1-100 micrograms/L. The expression of type I collagen, FN, Con A receptor, and ALP significantly increased at hbFGF concentration of 10-1,000 micrograms/L, but the expression of type III collagen and WGA receptor markedly decreased at the same concentration. There was no significant difference in expression of BMP. CONCLUSION: bFGF has the capability to promote the differentiation of dental pulp cells to odontoblasts in culture.

Alkaline Phosphatase↗
PubMed1996

Biological behavior of human dental pulp cells in response to carious stimuli analyzed by PCNA immunostaining and AgNOR staining.

The change in proliferative and metabolic activities of human dental pulp cells responding to carious stimuli was studied by means of immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and silver-binding nucleolar organizer region (AgNOR) staining. We classified the pulp tissues into five groups according to the progression of dental caries, ranging from grade 0 (the pulp of noncarious teeth) to grade 4 (the pulp of perforated carious teeth). PCNA-positive pulp cells were detected only in advanced dental caries (grades 3 and 4), and the difference in immuno-positive rate was significant between the two grades (p <0.001). However, the mean number of AgNORs per nucleus increased even in the early phase of dental caries, significant differences being detected between grades 1 and 2 (p<0.005), 2 and 3 (p<0.005), and 3 and 4 (p<0.001). Our data suggested that the metabolic activity of dental pulp cells was enhanced in the early phase of dental caries. However, proliferation of pulp cells occurred later in small degrees during fully developed caries such as grades 3 and 4. The slow and weak response in cellular proliferation might contribute to the usual fragility of the pulp to various assaults including caries or pulpitis.

Adult↗
PubMed1996

Characteristics and effects of calcified degenerative zones on the formation of hard tissue barriers in amputated canine dental pulp.

The purpose of this research was to study under undecalcified conditions the presence, ultrastructural features, and contributions of the degenerative zone beneath the necrotic zone and whether it had effects on the formation of reparative dentin in canine incisors and premolars. The research was conducted over a period of 14 days after experimental pulpotomy using calcium hydroxide as a pulp-capping agent. On the first day following pulp exposure and capping with calcium hydroxide, electron-dense spherical bodies were observed under the necrotic zone. Energy dispersive X-ray point analysis confirmed that these electron-dense deposits contained calcium and phosphorus. By the third day, varying amounts of minute von Kossa-positive granules could be observed light-microscopically between the two zones of necrosis and underlying vital pulp tissue. Migration and proliferation of pulpal cells, most probably mesenchymal cells, were observed adjacent to the von Kossa-positive zone. The ultrastructure of the von Kossa-positive zone consisted of degenerated cells, electron-dense spherical bodies, and electron-dense shortened dilating fibrils. By the seventh day, short cylindrical-shaped cells collected at the coronal end of the vital pulp tissue. By the fourteenth day, the specimens having a uniform von Kossa-positive zone exhibited rapid differentiation of odontoblasts and tubular dentin formation. In contrast, only some specimens having an irregular von Kossa-positive zone exhibited osteodentin formation and the beginning of odontoblast differentiation beneath the osteodentin. These findings suggest that this calcified degenerative zone has an important effect on the reparative process of pulp tissue after pulpotomy.

Animals↗
PubMed1990

Distinct stimulatory effect of platelet-activating factor on prostaglandin I2 and thromboxane A2 biosynthesis by rat dental pulp.

Platelet-activating factor (PAF-acether), but not lyso PAF, stimulated the production of both PGI2 and TXA2 by rat dental pulp tissue in vitro. However, there were differences in the dose- and time-dependence of the stimulatory effects. PAF-acether antagonists, Bn 52021, CV 3988 and kadsurenone, dose dependently inhibited PAF-acether-induced PG production. BN 52021, CV 3988 also dose dependently inhibited TX production, but kadsurenone was almost without effect on TX production. Pretreatment of the tissues with PAF-acether or phorbol 12-myristate 13-acetate completely abolished the effect of the second challenge with PAF-acether. The stimulatory effects of PAF-acether and the calcium ionophore A23187 on PGI2 production were completely blocked by removal of extracellular calcium, whereas the effects on TXA2 production were not. TMB-8, an intracellular calcium antagonist, completely inhibited PAF-acether-induced PG production, whereas it slightly inhibited TX production. H-7, a protein kinase C inhibitor, and neomycin, a phospholipase C inhibitor, completely inhibited PAF-acether-induced PG and TX production, whereas W-7, a calmodulin inhibitor, did not. These results suggest that PAF-acether stimulates PGI2 and TXA2 production in rat dental pulp by interacting with distinct PAF-acether receptors, and that these receptors are coupled to independent signal transduction pathways which have a different dependence on extra- and intracellular calcium.

Animals↗
PubMed1988

The effects of colchicine on prostaglandin I2 and thromboxane A2 biosynthesis in the rat dental pulp.

Pulp tissues isolated from rats treated with either colchicine (0.5, 0.75 or 1.0 mg/kg) or beta-lumicolchicine (1.0 mg/kg) for 24 h were incubated in Tyrode buffer. Prostaglandin (PG) I2 and thromboxane (TX) A2 released into the medium were determined by radioimmunoassay as their stable metabolites, 6-keto-PGF1 alpha and TXB2, respectively. Colchicine generally enhanced PGI2 and TXA2 production concomitantly with hypocalcaemia, except that 0.5 mg/kg dosage had no significant effects. This enhancement was greater in PGI2 than in TXA2 synthesis, but was not observed in PGI2 release from aortic tissue. beta-Lumicolchicine (1.0 mg/kg) had no effect on PG and TX synthesis, nor on serum calcium. Kinetic studies revealed that after a lag period of more than 12 h, 1.0 mg/kg colchicine caused a progressive increase in the production of PGI2 and TXA2, which reached a maximum at 24 h and decreased thereafter gradually to the basal level within 168 h (7 days). In contrast, the hypocalcaemic effect of colchicine appeared rapidly, reached a maximum within 3 h and gradually recovered to the control level within 7 days. Colchicine at concentrations of 1-1000 microM had no stimulatory effect on PGI2 and TXA2 biosynthesis when incubated in vitro with isolated pulp tissues; it was inhibitory at higher concentrations. The enhancing effect of colchicine treatment on PGI2 and TXA2 production in dental pulp tissue may be caused indirectly by interaction of this agent with microtubules, but the precise mechanisms are unclear. Thus, a drug known to affect dentinogenesis modifies arachidonic-acid metabolism in dental pulp.

Animals↗
PubMed1999

Stimulatory effect of laser irradiation on calcified nodule formation in human dental pulp fibroblasts.

The purpose of the present study was to investigate the effect of laser irradiation on calcified nodule formation in human dental pulp (HDP) cells. HDP cells were irradiated once with a Ga-Al-As laser for 5 and 10 min, and calcified nodule formation was determined by von Kossa staining. The laser irradiation increased the number of calcified nodules in a time-dependent manner. The activity of alkaline phosphatase and production of collagen and osteocalcin in conditioned medium were measured. Both were higher in the irradiated group than in the nonirradiated group. These results suggested that formation of calcified nodules in HDP cells, as well as in alkaline phosphatase activity, the production of collagen and osteocalcin were enhanced by laser irradiation.

Alkaline Phosphatase↗