[Reaction time in electric excitation of the healthy dental pulp].
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Dental Pulp↗
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The clinical and histological evaluation of cresatin with calcium hydroxide on the human dental pulp.
Metacresylacetate with calcium hydroxide in a methylcellulose base produces clinically and radiographically successful pulpotomies, when performed on sound primary teeth. Under sterile conditions, with proper surgical and restorative technique, pulp tissue will heal with metacresylacetate with calcium hydroxide-methylcellulose. The dental pulp will form on osteodentin bridge and the pulp adjoining the bridge will remain histologically viable and free of inflammation. Methylcellulose with sterile distilled water does not produce as favorable a histological reaction as metacresylacetate with calcium hydroxide-methylcellulose. No dentinal bridging was in evidence and there were present in the radicular pulp varying degrees of inflammation.
Calcium Hydroxide↗
Neural form of voltage-dependent sodium current in human cultured dental pulp cells.
Intradental, i.e. pulpal, cells may play an important part in sensory transduction in teeth, although the cellular mechanisms and the identity of the specific cell types involved are still unclear. Because the majority of cells in dental pulp are derived from neural crest, it seemed likely that these might have the membrane properties of other neural-derived cells found in the peripheral or central nervous system. The patch-clamp recording technique was used to show that cells in explant cultures from human dental pulp contain a voltage-gated, tetrodotoxin-sensitive inward current. Mean activation potential of the current was -42 +/- 2.5 mV and the voltage at half-inactivation was -79.4 +/- 5.3 mV, suggesting a neural-like sodium conductance. In addition, these cells were immunoreactive to glial acidic fibrillary protein, growth-associated protein (GAP-43), and vimentin, further suggesting that dental pulp contains a population of cells with membrane properties similar to neuronal satellite cells. These cells may contribute, either directly or indirectly, to somatosensation in teeth.
Adolescent↗
Blood flow and vascular pressure in the dental pulp. Summary.
The present summary is a review and a discussion of the following papers (I-V), submitted as partial fulfillment of the requirements for the degree of Doctor Odontologiae at the University of Bergen. I. Blood flow in the dental pulp in dogs measured by local H2 gas desaturation technique. Arch. Oral Biol. 1975, 20, 73-79. Co-author: K. Aukland II. The effect of variations in arterial blood pressure and baroreceptor reflexes on pulpal blood flow in dogs. Arch. Oral. Biol.1975, 20, 345-349 III. Effect of vasodilating drugs on external carotid and pulpal blood flow in dogs: "Stealing" of dental perfusion pressurE. Acta Physiol. Scand. 1976, 97, 75-87 IV. Nervous control of blood flow in the dental pulp in dogs. Acta Physiol. Scand. 1978, 104, 13-23. Co-author: G. Naess V. Microvascular pressure in the dental pulp and gingiva in cats. Acta Odontol. Scand. 1979, 37, 161-168. Co-author: G. Naess Other papers are referred to in the conventional manner.
Adrenergic Fibers↗
Cyclic Amp phosphodiesterase activity in normal and inflamed human dental pulp.
Cyclic AMP phosphodiesterase (cAMP PDE) seems to be important in pulp tissues. High levels of cAMP PDE have been demonstrated to be in dental pulp cells. In the present study cAMP PDE activity was analyzed in normal healthy human dental pulps, in reversible pulpitis and in irreversible pulpitis. Enzymatic cAMP PDE control values for normal healthy pulps were 12.14 +/- 3.74 nmols/mg of proteins. In reversible pulpitis the cAMP PDE activity increased almost 2.5 times. In irreversible pulpitis specimens the values increased 4.5 times compared with normal healthy pulps activity. The differences between the groups (control vs. reversible pulpitis and vs. irreversible pulpitis) were statistically significant. These results could point to a role of cAMP PDE in the initial pulp response after injury.
3',5'-Cyclic-AMP Phosphodiesterases↗
Histomorphological response of dogs' dental pulp capped with white mineral trioxide aggregate.
This study was conducted to observe the response of dogs' dental pulp to white mineral trioxide aggregate (MTA) when used as pulp capping material. The pulp of 15 dogs' teeth was experimentally exposed and capped with white MTA. The animals were sacrificed two months later and the specimens were prepared for histomorphological study. The pulp capped with white MTA showed a healing process with complete dentin bridge formation in all samples. In some cases, there was not a tubular dentin shape, but only a structure with an interesting morphological aspect sealing the exposure site. Only 2 specimens exhibited pulp inflammation. In conclusion, the data obtained in this study showed that white MTA has the necessary properties of a pulp capping material.
Aluminum Compounds↗
Dentinogenic activity of allogenic plasma fibronectin on dog dental pulp.
The response of ectomesenchymal cells of dog dental pulp to implantation of Millipore filters supplemented with bovine plasma fibronectin was evaluated after observation periods of one or four weeks. Two concentrations of plasma fibronectin were used (0.2 and 1 mg/mL). Experiments also included implants treated with control solutions (PBS or 1 mg/mL of dog albumin). Formation of a layer of elongated, polarized cells was demonstrated in direct contact with the implants treated with 1 mg/mL of plasma fibronectin solution, after one week post-operatively. Microfilamentous organization and orientation of rough endoplasmic reticulum was observed mainly in the supranuclear zone of the polarized cells. Implants treated with the same solution were consistently surrounded by a thick layer of dentinal matrix after four weeks of their exposure to pulp sites. Implants treated with control solutions or with the low concentration of fibronectin never showed any sign of cell polarization and matrix synthesis. These data provide evidence that the pulp cells can express their odontoblastic phenotype in response to a surface containing concentrated fibronectin (even allogenic), without the need of other molecules as exogenous inductive factors.
Albumins↗
Immunocytochemical evidence for the site of O-methylation in rat dental pulp.
Immunocytochemical observations by light and electron microscopy of catechol-O-methyltransferase (COMT) were conducted in dental pulp by use of a specific antibody to soluble rat-liver COMT and the peroxidase-antiperoxidase technique. Immunoreactive deposits were found in macrophages. The pattern of localization suggests that COMT may function in extraneuronal inactivation of catecholamines in dental pulp.
Animals↗
Comparison of three lasers on dental pulp chamber temperature change.
Previous studies have reported dental pulp chamber temperature changes using only one beam size per laser. This study was designed to evaluate the effects of beam size, wattage, and energy density on pulp chamber temperature changes of extracted human teeth for three lasers (CO 2, Argon, Nd:YAG). During laser irradiation of the outer enamel surface, a thermocouple was placed in the pulp chamber which measured and recorded the temperature changes. This was done for each combination of lasing dosimetry parameters. In all cases the recorded temperatures increased with the increase in beam size for a given energy density (J/cm 2) and wattage. Also, the recorded temperatures increased with increased energy density for a given wattage and beam size.
Dental Pulp Cavity↗
Polymorphism of EsD by isoelectric focusing: phenotyping in human tissues, dental pulps, hair roots, and semen.
The polymorphism of EsD was investigated in tissues of various human organs, dental pulps, hair roots, and seminal stains by isoelectric focusing. The method yielded an excellent resolution of the isoenzyme components. The time limits of determination were: in organ tissues 3 weeks, in dental pulps 1 week, and in hair roots several days. The 7-1 type was less stable than the common types. Phenotyping was possible from fresh semen samples, but was unsuccessful from dried seminal stains after storage. The results show that the EsD typing by isoelectric focusing is of practical use for medicolegal individualization of organs, teeth, and hairs.
Carboxylesterase↗
Electron probe micro-analysis of human dental pulp stones.
The mineral composition of ten human dental pulp stones presenting various morphological aspects has been studied by electron probe micro-analysis. The denticles were composed of two major chemical elements: Ca and P with mean concentrations 32.12% and 14.69% respectively giving a Ca/P weight ratio of 2.19 which is very close to the weight ratio of pure stoichiometric hydroxyapatite (2.15). The concentration of some other elements was much lower (0.88% for F; 0.75% for Na; 0.51% for Mg). The other analysed constituents (K, Cl, Mn, Zn, Fe) were present at trace concentrations. The mineral composition of sound human dentine from one tooth containing a pulpal calcification was also analysed for comparative purpose.
Calcium↗
[Effects of Anhidrin on dog's dental pulp in vivo].
The purpose of the article was to investigate in vivo effects of Anhidrin, a cavity cleansing agent, on dog's dental pulp. Following class V cavity preparation, with a depth referred to caries media, dentine walls were cleaned with Anhidrin. Cavity floor was lined with denatured dentine powder and permanently filled with silver amalgam. Animals were sacrificed after experimental period of 14, 45 and 90 days, respectively. Decalcified tooth sections were prepared by standard histologic technique stained with HE. The results achieved using light microscopy showed the most intensive changes in pulp tissue beneath cavity preparations treated with Anhidrin 14 days postoperatively, characterized with hyperaemia and bleeding in odontoblast and subodontoblast layer, reduction in odontoblast number and disturbed cell arrangement. In the second experimental period after 45 days, the changes were less expressed. Ninety days after the operation pulp tissue appeared in normal histologic structure of sound dental pulp, with significant layers of tertiary dentine beneath the area of cavity preparation and application of Anhidrin.
Animals↗
Quantification of lactate-dehydrogenase and cell viability in postmortem human dental pulp.
Understanding pulp repair and regeneration requires being familiar with this tissue's behavior under extreme conditions, such as postmortem state where an abrupt interruption of tissue blood supply occurs. The purpose of this study was to quantify cell viability and the amount of lactate-dehydrogenase (LDH) expressed in human pulp tissue 6, 12, and 24 hours postmortem to establish how long dental pulp remains viable after death. Pulp samples were obtained from 14 unidentified corpses of people who had received lethal injuries in car accidents or from gunshot wounds; they had at least three caries- and restoration-free incisors. Half of each sample was used for determining cell viability at three different time intervals. The rest of each sample was used for quantifying LDH expression at the same time intervals. Another 14 pulp samples were obtained from live patients' healthy premolars where extraction was indicated for orthodontic reasons to assess normal LDH value in pulp tissue. The results showed cell viability decreasing from 89 to 68 to 41% measured 6, 12, and 24 hours postmortem, respectively. LDH expression in healthy pulps was 246 U/mg pulp weight. Expression increased after death from 249 U/mg at 6 hours to 337 U/mg at 12 hours. LDH expression decreased to 131 U/mg 24 hours postmortem. These findings are valuable in understanding dental pulp survival capability under extreme conditions that may have important clinical significance in terms of repair and regeneration.
Analysis of Variance↗
Presynaptic control of noradrenaline release from sympathetic nerves in human dental pulp.
This study was undertaken to determine whether release of noradrenaline from sympathetic nerves in human dental pulp in vitro was modulated by presynaptic adrenoceptors and by dopamine receptors. Pulp was incubated for 30 min with 3H-noradrenaline (0.6 mumol/l) and then perfused continuously with Krebs solution. Field stimulation of the sympathetic nerves at 5 Hz increased the overflow of 3H into the perfusate three-to fourfold. The stimulation-induced overflow of 3H was abolished by tetrodotoxin (0.1 mumol/l) and under Ca(2+)-free conditions, indicating that the increased 3H was derived from nerves. The stimulation-induced overflow was inhibited by noradrenaline (0.1 and 1.0 mumol/l), the alpha 2-adrenoceptor agonist UK14,304 (0.1 mumol/l), dopamine (1.0 mumol/l) and the dopamine receptor agonist, apomorphine (1.0 mumol/l). When the receptor agonists were noradrenaline or dopamine, desipramine (0.3 or 3.0 mumol/l) was present to prevent their uptake by the sympathetic nerves. Clonidine (1.0 mumol/l; tested at 2 Hz as well as 5 Hz) and the alpha 1-receptor agonist methoxamine (1.0 mumol/l) were without effect. The alpha 2-receptor antagonist/rauwolscine (0.1 mumol/l) prevented the inhibitory effects of noradrenaline and UK14,304, but had little effect on the inhibition produced by dopamine. Inhibition of the stimulation-induced overflow by apomorphine was prevented by the dopamine receptor antagonist haloperidol (0.1 mumol/l). The resting overflow of 3H was unaffected by any of the above agents except dopamine, which caused a small increase. It is concluded that the sympathetic nerves in human dental pulp possess inhibitory presynaptic alpha 2-adrenoceptors and dopamine receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Evaluation of Gram's method of staining for the prognosis of root canal treatment in nonvital dental pulps.
An evaluation of Gram's method of staining of 601 nonvital dental pulps was performed. It gave positive results in 60.1% of the cases, the most frequent finding was gram-positive cocci. Preoperative x-ray status correlated significantly with the staining results but the size of the radiolucency did not. Previously treated teeth gave less positive staining results than other teeth. There was an obvious correlation between presence of bacteria and various complications (p < 0.001), but no differences were noted between the combinations of bacteria. The teeth that were the most resistant to complications seemed to be the lower canines. The staining results did not correlate with sex, systemic diseases, or preoperative symptoms. We believe that Gram's method of staining is a useful, rapid aid in root canal therapy, especially in complicated cases.
Adolescent↗
Altered gene expression in human cleidocranial dysplasia dental pulp cells.
Cleidocranial dysplasia (CCD) is an autosomal dominant disorder characterised by defects of bone and tooth development. The dental manifestations in CCD patients include supernumerary teeth, delayed tooth eruption, tooth hypoplasia and absence of cellular cementum formation. This disorder is associated with mutations in the osteoblast-specific transcription factor Runx2. To identify morphological and molecular alterations associated with CCD dental tissues, human primary dental pulp cell cultures were established from age- and sex-matched CCD and normal patients. Dental pulp cells were compared for general morphology, proliferation rates, and gene expression profiles using cDNA microarray technology. CCD pulp cells were about four-fold larger than normal cells, however the normal pulp proliferation rates were two- and three-fold greater at time points tested than the CCD cells. Of the 226 genes analysed by blot microarray, 18.6% displayed significant differences at least two-fold in expression levels. This includes 25 genes (11.1%) that were up-regulated, while 17 (7.5%) that were down-regulated in the CCD cells as compared to the normal cells. Expression of selected genes was further verified by quantitative real-time polymerase chain reaction (qRT-PCR). Comparison between the CDD and normal cells revealed that gene expression of cytokines and growth factors, such as leukemia inhibitory factor (LIF), interleukin-6 (IL-6) and transforming growth factor beta receptor II (TGF-betaRII) and vascular endothelial growth factor B (VEGFB) were higher while bone morphogenetic protein 2 (BMP2) was lower in the CCD cells. Furthermore, potential Runx2 binding sites were found in all putative target gene promoters. This study suggests that in addition to bone and tooth cell differentiation, Runx2 may be involved in controlling cell growth during tooth development.
Case-Control Studies↗
Immunohistochemical localization of mu-opioid receptors in human dental pulp.
Studies in both animal and clinical models suggest that opioids exert their analgesic effects not only through activation of receptors in the CNS but also through interaction with peripheral opioid receptors. This study evaluated the presence and distribution of mu-opioid receptors in human dental pulp. Human third molars indicated for extraction were removed, fixed in 4% paraformaldehyde and 0.2% picric acid, and decalcified in 10% EDTA and 7.5% polyvinylpyrrolidone. The teeth were cut using a cryostat, and the avidin-biotin peroxidase immunohistochemistry technique was used. Immunostaining for mu-opioid receptors was detected along the nerve bundle of the radicular as well as coronal dental pulp. Positive immunostaining was also observed in the individual nerve fibers in the coronal region. This demonstration of opiate receptors on pulpal nerve fibers suggests a peripheral site in the dental pulp where endogenous or exogenous opioids can interact with mu-opioid receptors.
Dental Pulp↗
Identification of lymphocyte antigens in human dental pulps.
The aim of the experiment was to study the immune reaction of cells in both healthy and inflamed human dental pulps. For this it was necessary to identify, in particular, populations of lymphocytes in the pulp, and also other cells involved in the immune reaction. By using monoclonal antibodies which specifically recognize subpopulations of the T lymphocytes, we were able: 1) to directly determine the phenotype of the cells of the pulp, 2) to examine the interactions of the different cell populations. The study was based on 30 permanent human dental pulps and the method was that of indirect immunofluorescence on frozen sections. The monoclonal antibodies used were the antibodies OKT and anti-Leu of types anti-Leu1, anti Leu3a, OKT4, OKT8 and OK1a. The results obtained were evaluated statistically. Two important points stand out from this study: 1) in the healthy samples there is preferential localization of lymphocytes at the periphery of the pulp and 2) there is a predominance of the OKT8+ cytotoxic suppressor subpopulation in both the healthy and the inflamed pulps.
Adolescent↗