PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Dentin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1997

The dentine disc. A review of its applicability as a model for the in vitro testing of dentine hypersensitivity.

The dentine disc has been extensively used as a model for assessing potential desensitizing agents in vitro by scanning electron microscopy (SEM). Although the disc provides a readily available and reproducible test substrate, this paper addresses the problems associated with this model such as the natural variation in the dentine tubules and the resulting differences in surface morphology. At the ultrastructural level the surface of a single etched disc exhibits variations in the size, density, orientation and extent of etching of the cut dentine tubules. In the present study a precise control procedure was designed which allowed greater correlation between test and control surfaces. Two adjacent areas of the same disc were used, one as the test surface, the other the control. Two proprietary desensitizers were examined using this methodology. This study has shown that the dentine disc is a good, reliable model for in vitro screening and testing of potential desensitizing agents, providing such controls are applied.

Dentin↗
PubMed1998

Perfusing dentine with horse serum or physiologic saline: its effect on adhesion of dentine bonding agents.

Freshly prepared dentine specimens of human teeth were perfused with either horse serum or physiologic saline. After application of AllBond2, ART Bond, Syntac or an experimental dentine bonding agent called P-Bond, a composite cylinder was added and cured at the same time. After 1500 thermal cycles with constant imitation of intrapulpal pressure, the shear bond strengths were measured. Resulting shear bond strength values were analysed with Students t-test or Mann-Whitney Test. The values for AllBond2 were not significantly different. The values for ART Bond (P < 0.05) and for Syntac (P < 0.05) were significantly higher if the dentine was perfused with horse serum. For P-Bond (P < 0.001) the values were significantly higher if the dentine was perfused with physiologic saline. According to these results it does not seem to be appropriate to take a clear decision as to which of the two perfusing media investigated might be more suitable to imitate in vivo conditions.

Animals↗
PubMed2006

HEMA diffusion from dentin bonding agents through various dentin thicknesses in primary molars.

PURPOSE: To evaluate in vitro HEMA diffusion amounts from three dentin-bonding systems in primary molars with various remaining dentin thicknesses. METHODS: Occlusal cavities were prepared with remaining dentin thickness of 0.5, 1 and 2 mm respectively. Chambers that contain 1 ml of distilled water were attached to each tooth. The groups were treated with Total Etch + Syntac Single Component, Syntac Single Component and Clearfil SE Bond. Water eluates were removed after 72 hours for analyses by HPLC. RESULTS: The cumulative HEMA release amounts were significantly different between all groups (P< 0.05). Decreasing dentin thickness and acid-etching significantly increased pulpward diffusion of HEMA.

Acid Etching, Dental↗
PubMed1997

Gene expression patterns of murine dentin matrix protein 1 (Dmp1) and dentin sialophosphoprotein (DSPP) suggest distinct developmental functions in vivo.

Although the precise mechanisms of the conversion of predentin to dentin are not well understood, several lines of evidence implicate the noncollagenous proteins (NCPs) as important regulators of dentin biomineralization. Here we compared the in vivo temporospatial expression patterns of two dentin NCP genes, dentin matrix protein 1 (Dmp1), and dentin sialophosphoprotein (DSPP) in developing molars. Reverse transcription-polymerase chain reaction was performed on embryonic day 13 to 1-day-old first molars using Dmp1- and DSPP-specific primer sets. Dmp1 transcripts appeared at the late bud stage, while DSPP mRNA was seen at the cap stage. Expression of both genes was sustained throughout odontogenesis. In situ hybridization analysis revealed interesting differences in the expression patterns of these genes. While Dmp1 and DSPP showed coexpression in young odontoblasts before the start of mineralization, the expression of these genes was notably distinct at later stages. Dmp1 expression decreased in secretory odontoblasts after the appearance of mineral, while high levels of DSPP were sustained in odontoblasts. In early secretory ameloblasts, DSPP expression was transient and down-regulated with the appearance ofdentin matrix. Interestingly, Dmp1 expression became evident in ameloblasts during the maturative phase of amelogenesis. In contrast to Dspp expression that was tooth-specific, Dmp1 was expressed by osteoblasts throughout ossification in the skeleton. Probes directed to the "DSP" and "DPP" regions of the DSPP gene showed identical patterns of mRNA expression. These data show that the developmental expression patterns of Dmp1 and DSPP are distinct, implying that these molecules serve different biological functions in vivo.

Animals↗
PubMed2001

Bactericidal effect of dentin primer containing antibacterial monomer methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human carious dentin.

The aim of this study was to investigate the bactericidal effect of a dentin primer incorporating the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human dentinal carious lesions. To evaluate the antibacterial activity of MDPB against anaerobes, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against obligate anaerobes and facultative anaerobic strains of lactobacilli were determined. Bacteria were recovered from carious dentin samples obtained from the teeth of patients, and the bactericidal activities of the experimental primer containing 5% MDPB and three commercially available primers were compared by counting the number of viable cells after contact with diluted solutions of each primer for 30 s. MDPB showed strong antibacterial activity against anaerobes, the MIC and MBC values ranging from 3.9 to 31.3 micrograms/ mL-1 and 15.6-125 micrograms/ mL-1, respectively. Experimental primer containing MDPB was the most bactericidal among the materials tested (ANOVA, Fisher's PLSD test, P < 0.05) and was able to kill the bacteria completely even when diluted 40 times, while the three commercial products exhibited little activity at 40 times dilution. These results indicate that incorporation of MDPB into dentin primer could be beneficial for eliminating the residual bacteria in cavities.

Analysis of Variance↗
PubMed2004

Deletion of dentin matrix protein-1 leads to a partial failure of maturation of predentin into dentin, hypomineralization, and expanded cavities of pulp and root canal during postnatal tooth development.

The dentin matrix protein-1 (DMP-1) gene is identified in odontoblasts during both embryonic and postnatal development. In vitro study suggests that this noncollagen acidic phosphoprotein plays a role in mineralization. However, deletion of the Dmp-1 gene has little effect on tooth development during embryogenesis. To address the role of DMP-1 in tooth during postnatal development, we analyzed changes of dentinogenesis in Dmp-1 null mice from 3 days after birth to 1 year. Here we show that Dmp-1 null mice postnatally develop a profound tooth phenotype characterized by a partial failure of maturation of predentin into dentin, enlarged pulp chambers, increased width of predentin zone with reduced dentin wall, and hypomineralization. The tooth phenotype of these mice is strikingly similar to that in dentin sialophosphoprotein (Dspp) null mice and shares some features of the human disease dentinogenesis imperfecta III. We have also demonstrated that DSPP levels are reduced in Dmp-1 null mice, suggesting that DSPP is probably regulated by DMP-1 during dentinogenesis. Finally, we show the absence or delayed development of the third molar in Dmp-1 null mice, which is probably secondary to defects in Dmp-1 null bone. Taken together, these studies suggest that DMP-1 is essential for later dentinogenesis during postnatal development.

Animals↗
PubMed2002

Cytotoxicity of low pH dentin-bonding agents in a dentin barrier test in vitro.

The reaction of three-dimensional cultures of pulp-derived cells in a dentin barrier test was recorded after exposure to All-Bond 2, Prime & Bond NT, Syntac SC, Syntac Classic, and Prompt L-Pop. The materials were applied on bovine dentin disks in a perfusion chamber, and the experiments were performed with (0.3 ml/h, 2 ml/h) and without perfusion of the pulpal part of the chamber. The cell reaction was recorded (MTT assay) and related to noncytotoxic controls. Bonding agents with low pH did not show any cytotoxicity. Syntac Classic decreased the cell activities to 38% to 72%, depending on different experimental conditions, and was more cytotoxic than Syntac SC. Perfusion (2 ml/h) reduced the cytotoxicity for Syntac Classic and increased cell activities from 52% to 72%. Because low pH bonding agents did not show toxic reactions in this dentin barrier test, pulp damage caused by the tested substance is unlikely if a dentin layer protects the pulp.

Animals↗
PubMed1995

The influence of air-drying on hyper-remineralization of demineralized dentine: a study on bulk as well as on thin wet section of bovine dentine.

The influence of air-drying on the remineralization of demineralized bovine dentine was examined in wet bulk samples, in dried bulk samples as well as in wet thin sections. Bulk samples of bovine dentine were first demineralized in an acidic gel (pH = 5) at 37 degrees C for 3 weeks. After 24-hour pre-treatment of either air-drying or immersion in water, the bulk samples were remineralized in a solution containing 1.5 mM Ca, 0.9 mM phosphate and 10 ppm F (pH = 7) at 37 degrees C for 2, 4 or 8 days. Separately thin sections prepared from demineralized bulk dentine were immersed in water for 24 h and were also exposed to the remineralization solution for 2, 4 or 8 days. The results show that air-drying of the bulk samples increased remineralization of dentine considerably; the microradiographic parameters (ld, delta Z and la) show that the degree of remineralization ranks: thin wet sections > bulk dried > bulk wet. Especially, the remineralization inside lesions was greatly enhanced in thin sections and dried samples. It is presumed that the increased remineralization in dried samples is caused by a 'sponge effect', in which the remineralization fluid is sucked up in a dried shrunken lesion, resulting in fast and deep penetration of remineralization solution and/or presumably increased nucleation.

Air↗
PubMed1993

Hypersensitive dentin: testing of procedures for mechanical and chemical obliteration of dentinal tubuli.

This study examined by scanning electron microscopy the effect of various mechanical and chemical procedures in obliterating dentinal tubuli. Dentin blocks containing open, cross-sectioned dentinal tubuli were separated into one experimental and one control area. The mechanical treatments consisted of 20 seconds of continuous instrumentation with sharp and dull curets, finely textured inserts for the EVA reciprocating handpiece, metal and plastic inserts for a sonic scaler, and metal inserts for an ultrasonic scaler. Chemical treatments included a light-cured dental resin and active obliterating agents including sodium, stannous and hydrogen fluorides, potassium oxalate, glycerin, ferric oxalate, and potassium nitrate. These substances were applied to the test surfaces for 2 minutes and allowed to dry. One half of the chemically treated specimens were then sprayed with water in order to evaluate the retention of the obliterating agents. The results revealed that among the mechanical treatments, the sharp curet gave the most consistent and complete obliteration of the tubuli. The plastic inserts had no tubular occluding effects. Among the chemical procedures, the light-cured resin resulted in the most complete obliteration of the tubuli, while the fluoride agents and glycerin had no effect. It can be hypothesized that combining instrumentation with a sharp curet causing a heavy smear layer and occlusion of tubuli apertures, followed by application of a light body resin, may prove to be a rational method of desensitizing hypersensitive dentin surfaces. However, this combined treatment should be evaluated in clinical trials.

Curettage↗
PubMed2005

A novel primer on dentin bonding of 4-META/MMA-TBB to collagen-depleted dentin.

The purpose of this study was to investigate the efficacy of an experimental dentin primer consisting of ascorbic acid (AA) and ferric chloride (Fe). Three exprimental primers - 10 wt%AA and 0.075 wt%Fe (i.e., 10AA-0.075Fe), 10AA-0Fe, and 0AA-0.075Fe - were prepared. Flattened dentin surfaces were first treated with phosphoric acid and NaClO, and subsequently primed using each experimental solution. Besides the experimental solutions, 10 wt% citric acid and 3 wt% ferric chroride (10CA-3Fe) was also used. A stainless steel rod was bonded to the dentin surface with Super-Bond C&B. 10CA-3Fe/Super-Bond C&B was then used as a control. Tensile bond strengths were evaluated after 24-hour immersion in water. 10AA-0.075Fe showed significantly high bond strength compared to 10AA-0Fe, 0AA-0.075Fe, 0AA-0Fe, and 10CA-3Fe. No significant differences were found between 10AA-0.075Fe and Super-Bond C&B system. The experimental primer consisting of 10 wt% ascorbic acid and 0.075 wt% ferric chloride improved the bonding between Super-Bond C&B and dentin conditioned with phosphoric acid and NaClO.

Acid Etching, Dental↗
PubMedDate not supplied

Effect of preliminary treatment of the dentin surface on the shear bond strength of resin composite to dentin.

This study evaluated the effect of two dentin disinfectants (Consepsis, Tubulicid), one aqueous HEMA solution (Aqua Prep), a combination of Aqua Prep and Tubulicid and an air abrasion treatment (50 microns aluminum oxide) on the shear bond strength (SBS) of two acetone-based single bottle adhesives (One Step and Prime & Bond 2.1). The occlusal surfaces of 167 freshly extracted human third molars were ground flat to expose the dentin, then polished with a 600 grit-polishing disc. The teeth were randomly assigned to 12 test groups (two bonding agents, six pretreatment protocols). The exposed dentin was etched with 35% phosphoric acid for 20 seconds, rinsed and briefly (1-2 seconds) air dried. Six pretreatment protocols were then applied. The air abrasion groups were exceptional, as etching was carried out only after pretreatment. One Step, or Prime & Bond 2.1 was applied according to the manufacturer's instructions. Cylinders of Z-100 composite were bonded to the flat dentin surfaces by transparent gelatin capsules. Specimens were thermocycled in water baths between 5 degrees and 55 degrees C, then sheared in an Instron Testing Machine. One-way and two-way ANOVA and Tukey HSD post-hoc tests were used for statistical analysis. In the One Step group, Consepsis yielded a significantly higher SBS (17.8 MPa) than air abrasion (9.5 MPa), Control (11.8 MPa) and Aqua Prep + Tubilicid (11.9 MPa), and a comparable SBS with Tubilicid (12.5 MPa) and Aqua Prep (14.8 MPa). In the Prime & Bond 2.1 group, Aqua Prep (24.9 MPa) showed a significantly higher SBS than all other groups: air abrasion (9.3 MPa), Control (9.97 MPa), Tubilicid (12.2 MPa), Consepsis (13.0 MPa) and Tubilicid + Aqua Prep (13.3 MPa).

Acetone↗
PubMed2006

Effect of filler addition on the bonding parameters of dentin bonding adhesives bonded to human dentin.

PURPOSE: To determine the effect of filler addition on two total-etch, single component bonding systems on the bond strength, displacement at debonding, stiffness of debonding and energy absorbed to debonding of resin composites to human dentin. METHODS: Two dentin bonding systems with no-filler (OS and SB) and filler-added (OSP and SBP) versions were studied. The dentin surfaces of human teeth were exposed with 600-grit SiC. TPH Spectrum A2 was used to bond to the dentin surfaces in the form of a truncated cone, 3 mm in diameter at the bonding surfaces and 5 mm in diameter at the base. Bonded specimens were stored in distilled water at 37 degrees C for 24 hours. They were then debonded in tension with a universal testing machine at a cross-head speed of 0.5 mm/minute. Displacement at debonding, stiffness and energy to debonding were calculated based on the stress-displacement curve. RESULTS: Bond strength, displacement at debonding and energy to debonding (measured and elastic) were influenced by the brand of the adhesive (OS/OSP vs. SB/SBP), but were not influenced by the filler addition based on two-way analysis of variance. Bond strength was in the range of 24.4-30.1 MPa, and there were significant differences between the bond strengths of OS and SB. Displacement and energy to debonding (measured and elastic) were different between the adhesives. Bond strength, bond stiffness and energy to debonding (measured) showed significant correlations.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1994

The effects of current dentinal adhesives on the dentinal surface.

The effects of the dentinal surface treatments from six currently available commercial dentinal adhesives are presented. The adhesives are All-Bond 2, etched and unetched, Syntac, Prisma Universal Bond 3, Scotchbond Multipurpose, Tenure Solution, and Adhesive By Choice. Unerupted third molar human teeth were sectioned and treated with the appropriate adhesive according to the manufacturer's directions. After the teeth were treated, they were processed for observation by scanning electron microscopy. Scanning-electron microscopic photomicrographs were made of each step in the process to show the effects of the constituents, including the adhesives, on the dentinal surface. For All-Bond 2, unetched, the smear layer was not removed before the primer and the adhesive were applied. The primer for Prisma Universal Bond 3 altered the smear layer by reacting with it but did not produce a large demineralized zone in the dentin. All the other adhesives did remove the smear layer before the tooth was treated with the primer and adhesive.

Acid Etching, Dental↗
PubMed1989

Multinucleated cells formed on calcified dentine from mouse bone marrow cells treated with 1 alpha,25-dihydroxyvitamin D3 have ruffled borders and resorb dentine.

Osteoclast-like multinucleated cells were formed from mouse bone marrow mononuclear cells, and their morphology on coverslips and on calcified dentine slices was compared by means of transmission electron microscopy. Addition of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] to bone marrow cells cultured on coverslips greatly stimulated the formation of multinucleated cells within 8 days. These multinucleated cells had the cytological features of osteoclasts (abundant pleomorphic mitochondria, a large number of vacuoles and lysosomes, many stacks of Golgi membranes, and an extensive canalicular system), but they developed neither ruffled borders nor clear zones. The multinucleated cells appeared to result from direct fusion of mononuclear progenitor cells, whose structural features were similar to those of multinucleated cells. Like isolated osteoclasts, both multinucleated cells and their precursors exhibited an intense reaction for tartrate-resistant acid phosphatase (TRACP) in the cisterns of endoplasmic reticulum and lysosomes. Multinucleated cells formed from alveolar macrophages in the presence of 1 alpha,25(OH)2D3 were totally negative for TRACP reaction. When marrow cells were cultured on dentine slices in the presence of 1 alpha,25(OH)2D3, some of the multinucleated cells were located in the shallow resorption lacunae of dentine surfaces, and they developed the characteristic ruffled borders and clear zones. The narrow extracellular spaces of the ruffled borders, the adjacent pale endocytotic vacuoles, and the dark lysosomes located in the perinuclear cytoplasm of the multinucleated cells contained numerous apatite crystals delete in resorption lacunae. These results indicate that 1) the multinucleated cells formed on coverslips from mouse marrow cells treated with 1 alpha,25(OH)2D3 exhibit non-functional basic features of osteoclast morphology, and 2) differentiation of the multinucleated cells into functional osteoclasts requires some components of calcified dentine.

Acid Phosphatase↗
PubMed1981

Nonocollagenous proteins of dentin. Isolation and partial characterization of rat dentin proteins and proteoglycans using a three-step preparative method.

The purpose of this study was to develop a method for fractionation of dentin proteins and proteoglycans into pools. The sequential procedure consisted of: (1) addition of 1.0 M CaCl2 to solutions of EDTA extracts of rat dentin in the presence of protease inhibitors to form a CaCl2 precipitate (Fraction I), (2) dialysis of the resultant supernatant against 0.1 M formic acid to form an acid precipitate (Fraction II), and (3) passage of the 0.1 M formic acid supernatant over a Sephadex G-50 column to obtain a high molecular weight, excluded peak (Fraction III) and a lower molecular weight, included peak (Fraction IV). Each of the four fractions was characterized by amino acid analysis, slab gel electrophoresis and ion-exchange chromatography on DEAE-cellulose. Fraction I contained almost exclusively phosphoproteins while Fraction II consisted of several acidic proteins, albumin, proteoglycans and a protein with a relatively low level of organic phosphate. A unique glycoprotein with an apparent Mr = 95,000 was found in Fraction III along with smaller amounts of other proteins, including albumin and a phosphoprotein with a relatively low level of organic phosphate. Fraction IV contained several low molecular weight, gamma-carboxyglutamate-containing proteins similar to those found in bone. The data show that the method selectively fractionates the proteins and proteoglycans of rat dentin. Furthermore the method is rapid and allows preparative steps to be performed in the presence of protease inhibitors. This new procedure should be a useful step in the comprehensive isolation of dentin proteins in experiments designed to study their detailed chemical nature and metabolism.

Albumins↗
PubMed2006

Dentin matrix protein 1 regulates dentin sialophosphoprotein gene transcription during early odontoblast differentiation.

Dentin mineralization requires transcriptional mechanisms to induce a cascade of gene expression for progressive development of the odontoblast phenotype. During cytodifferentiation of odontoblasts there is a constant change of actively transcribed genes. Thus, tissue-specific matrix genes that are silenced in early differentiation are expressed during the terminal differentiation process. Dentin sialophosphoprotein (DSPP) is an extracellular matrix, prototypical dentin, and a bone-specific gene, however, the molecular mechanisms by which it is temporally and spatially regulated are not clear. In this report, we demonstrate that dentin matrix protein 1 (DMP1), which is localized in the nucleus during early differentiation of odontoblasts, is able to bind specifically with the DSPP promoter and activate its transcription. We have identified the specific promoter sequence that binds specifically to the carboxyl end of DMP1. The DNA binding domain in DMP1 resides between amino acids 420 and 489. A chromatin immunoprecipitation assay confirmed the in vivo association of DMP1 with the DSPP promoter. Interactions between DMP1 and DSPP promoter thus provide the foundation to understand how DMP1 regulates the expression of the DSPP gene.

Base Sequence↗
PubMed1988

A longitudinal study of dentine lead levels, intelligence, school performance and behaviour. Part I. Dentine lead levels and exposure to environmental risk factors.

Dentine lead levels were obtained for a sample of 996 children who were participants in a longitudinal study of child development. Mean dentine lead levels were just over 6 micrograms g-1 and had a log normal distribution. The relationship between dentine lead values and a number of variables (social background, residence in old weatherboard housing, residence on busy roads, pica) describing exposure to sources of lead was analysed. This showed that all factors made small but statistically significant contributions to variations in dentine lead values and that collectively these factors explained 10% of the variance in lead values. The implications of these results are discussed.

Achievement↗