Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Dentin Solubility”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 253 records · Page 14Linked to original sources
PubMed1986

Isolation and characteristics of collagenolytic enzyme produced by Candida albicans.

In media containing collagen as the nitrogen source, the pathogenic yeast Candida albicans secreted a collagenolytic enzyme. Purification of the enzyme from a culture filtrate was achieved by DEAE-Sephacel chromatography at pH 6.7. The molecular weight was found to be 46,000 by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the isoelectric point was at pH 4.2. The pH optimum lay between 3.5 and 4.0, and above pH 6.0, the enzyme underwent alkaline denaturation. The enzyme was heat labile, and a decrease in activity was found above 55 degrees C. The enzyme activity was inhibited by the addition of urea, cysteine, and pepstatin. No other inhibitor among those tested had any effect. The C. albicans enzyme degraded both the native acid-soluble collagen and the insoluble dentinal collagen.

Candida albicans↗
PubMed2003

Effects of water and water-free polar solvents on the tensile properties of demineralized dentin.

OBJECTIVES: The aim of this study was to test the null hypothesis that the tensile properties of demineralized dentin are not influenced by the hydrogen bonding ability of anhydrous polar solvents. METHODS: Dentin disks 0.5mm thick were prepared from mid-coronal dentin of extracted, unerupted, human third molars. 'I' beam and hour-glass shaped specimens were prepared from the disks, the ends protected with nail varnish and the central regions completely demineralized in 0.5M EDTA for 5 days. Ultimate tensile stress (UTS) and low-strain apparent modulus of elasticity (E) were determined with the specimens immersed for 60 min in water, methanol, HEMA, acetone or air prior to testing in those same media. Apparent moduli of elasticity were measured on the same specimens in a repeated measures experimental design. The results were analyzed with a one-way ANOVA on ranks, followed by Dunn's test at alpha=0.05. Regression analysis examined the relationship between UTS or E and Hansen's solubility parameter for hydrogen bonding (delta(h)) of each solvent. RESULTS: The UTS of demineralized dentin in water, methanol, HEMA, acetone and air was 18(7), 29(7), 31(6), 41(13) and 146(27)MPa, x(SD), n=10. Low-strain E for the same media were 11(7), 43(12), 79(21), 132(31) and 253(115)MPa. Regression analysis of UTS vs delta(h) revealed a significant (p<0.0005, r=-0.69, R(2)=0.48) inverse, exponential relationship. A similar inverse relationship was obtained between low-strain E vs delta(h) (p<0.0001, r=-0.93, R(2)=0.86). SIGNIFICANCE: The tensile properties of demineralized dentin are dependent on the hydrogen bonding ability of polar solvents (delta(h)). Solvents with low delta(h) values may permit new interpeptide H-bonding in collagen that increases its tensile properties. Solvents with high delta(h) values prevent the development of these new interpeptide H-bonds.

Acetone↗
PubMed1991

The isolation and partial characterization of a rat incisor dentin matrix polypeptide with in vitro chondrogenic activity.

In vivo implants of demineralized dentin matrix into muscle induce the formation of bone within the muscle. As with bone matrix implants, the bone induction appears to follow a chondrogenic pathway. Outgrowth cells from explants of neonatal rat muscle respond to bone matrix, in vitro, by expressing a heightened synthesis of sulfated proteoglycans and type II collagen, phenotypic of cartilage. The in vitro cell culture system has been used as an assay to monitor the isolation of the factor responsible for expression of this phenotypic transformation. Soluble proteins extracted from rat incisor dentin matrix during demineralization with EDTA, and not precipitable with 1.0 M CaCl2, were active in the in vitro system. The active extract was fractionated by Sephacryl S-100 chromatography in 6 M guanidine HCl, isoelectric focusing in Immobilines, and by reverse phase high performance liquid chromatography. All fractions were assayed for activity at every stage. The final active fraction from the reverse phase chromatography on a Zorbax Poly-F column was purified to homogeneity, and yielded a single spot on two-dimensional gel electrophoresis. The component, RP-4, had pI 5.4-5.5, and an apparent Mr 6,000-10,000, based on globular protein standards. Maximal activity with respect to both sulfate incorporation into proteoglycan and production of type II collagen was in the 1.0-10 ng/ml range. The RP-4 had a unique amino-terminal amino sequence and was rich in Gly, Pro, Glx, and Ala residues. It was different from transforming growth factor-beta and the bone morphogenetic protein family of proteins in these essential features.

Amino Acid Sequence↗
PubMed1994

Degradation of insoluble bovine collagen and human dentine collagen pretreated in vitro with lactic acid, pH 4.0 and 5.5.

The purpose of the study was to test the hypothesis that both insoluble pure type I collagen from bovine Achilles tendon and dentine collagen in root dentine powder from human teeth required acid pretreatment for subsequent degradation by trypsin, a non-specific protease. Pure type I collagen or dentine powder was treated with lactic acid, at pH 4 or 5.5, or distilled, deionized water (pH 7) as a negative control. After incubation at 37 degrees C for 24 h, extracts of pure type I collagen solutions were analysed for soluble collagen with the hydroxyproline assay. Extracts of dentine powder solution were analysed for Ca2+, total protein, final pH, and hydroxyproline. Residual, undegraded pellets were washed and then treated with trypsin or collagenase. After 24 h of incubation, the soluble fractions from the enzyme-treated pure type I collagen and dentine powder solutions were analysed for hydroxyproline. Results showed that almost no pure type I collagen was degraded during acid pretreatment. Trypsin degraded significantly more pure type I collagen in the pH 4-treated group than in the other groups. Collagenase degraded about 70% of the pure type I collagen irrespective of acid pretreatment. While acid pretreatment at pH 4 did not degrade dentine collagen, data from Ca2+ analyses and collagen breakdown by trypsin suggested that pretreatment at pH 4 demineralized and denatured dentine collagen so that the collagen could be subsequently degraded by enzymes. After pretreatment at pH 4, about 27 and 57% of the dentine collagen was degraded by trypsin and collagenase, respectively, in contrast to minimal degradation of non-acid-treated dentine collagen by the same enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Achilles Tendon↗
PubMed2000

Novel priming and crosslinking systems for use with isocyanatomethacrylate dental adhesives.

OBJECTIVES: (a) to design, formulate and evaluate prototype primers and a crosslinking agent for use with isocyanatomethacrylate-based comonomer adhesives and (b) to establish correlations between bond strength and solubility parameter differences between the adhesives and etched dentin, and the permeability coefficients of the adhesives. METHODS: Equimolar mixtures of 2-isocyanatoethyl methacrylate (IEM) and a methacrylate comonomer were formulated with tri-n-butyl borane oxide (TBBO) as the free radical initiator to have cure times of 6-10 min. Shear bond strengths to dentin were determined for each adhesive mixture (n = 7) using standard testing protocols. Shear bond strengths for the three systems were also determined after application of "reactive primers" to the dentin surface. The "reactive primers" contained 10-20 parts by weight of the respective comonomer mixture and 3.5 parts by weight TBBO in acetone. Solubility parameters difference values (delta delta) and permeability coefficients (P) were approximated for each adhesive system and correlated with shear bond strength values. Additionally, a crosslinking agent was prepared by bulk reaction of an equimolar mixture containing IEM and a methacrylate comonomer. The effects of crosslinker addition on: (a) the setting time of IEM; and (b) the setting times and initiator requirements of selected IEM/comonomer mixtures were determined. RESULTS: Shear bond strength values (MPa): IEM/HEMA 13.6 +/- 2.0 (no primer), 20.1 +/- 2.0 (with primer); IEM/HETMA 9.3 +/- 3.3 (no primer), 20.8 +/- 8.1 (with primer); IEM/AAEMA 13.6 +/- 1.9 (no primer), 17.3 +/- 3.2 (with primer). Also, approximated permeability coefficients showed a significant correlation (r = +0.867, p < 0.001) with shear bond strength values. Crosslinker addition studies with IEM/4-META: (a) at 5-9 mol% reduced the setting time of IEM polymerization by 79%; and (b) at 6 mol% reduced initiator level requirements 60-70% to achieve a comparable setting time, and decreased setting times by ca. 75% for a given initiator level with selected IEM/methacrylate adhesive systems. SIGNIFICANCE: The shear bond strengths of isocyanatomethacrylate-based dental adhesives can be enhanced by using reactive primers; their setting times and initiator requirements can be improved using a dimethacrylate crosslinker. Approximated permeability coefficients may be useful as indicators of bonding performance for dentin adhesive systems.

Adhesives↗
PubMed1997

Comparative analysis of transforming growth factor-beta isoforms 1-3 in human and rabbit dentine matrices.

Previous studies have implicated transforming growth factor-beta (s)(TGF-beta) in both development. Here TGF-beta isoforms in dentine extracellular matrix were analysed because these molecules may participate in dental issue repair. EDTA-soluble and collagenase-released fractions were isolated from human crown and root and rabbit incisor dentine samples and analysed for TGF-beta isoforms. TGF-beta(1) was the major isoform detected in all samples and the only isoform detected in human dentine samples. TGF-beta(2) was detected only in the collagenase-released fraction of rabbit incisor dentine and was present at low levels. TGF-beta(3) was detected in both EDTA-soluble and collagenase-released fractions of rabbit dentine. Greater levels of the TGF-beta(1) isoform were detected in the rabbit than human dentine samples and some differences in distribution amongst the two tissue fractions were observed between these species. The presence of these isoforms of TGF-beta in dentine may provide a reservoir of growth factor in the matrix that could participate in processes leading to tissue repair after injury.

Animals↗
PubMed1999

Design, formulation, and evaluation of isocyanatoacrylate copolymer dental adhesives.

Experiments have recently been completed to explore the development of isocyanatoacrylate copolymers as new dental adhesives. A main goal of this work was to test the utility of solubility parameter differences between the candidate adhesives and etched dentin as a predictor of relative bond strength. All candidate adhesive mixtures contained 2-isocyanatoethyl methacrylate (IEM), a selected amount of tri-n-butylborane oxide (TBBO) initiator, and one of 13 methacrylate comonomers. Reactivity ratios were computed for comonomer pairs as indicators of relative reactivity. The concentration of TBBO was optimized for each comonomer mixture to obtain working times of 2-6 min and setting times of 6-10 min. The solubility parameter difference Deltadelta (J/cm(3))(1/2) was calculated for each test mixture with respect to an etched dentin substrate, as an approximation of wetting ability. Using standard techniques for shear bond strength evaluation, mean shear bond strength values ranging between 7-15.5 MPa were obtained for comonomer adhesives in bonding Z-100 composite to treated dentin. Shear bond strength values showed a good correlation (r = -0.612, P </= 0.05) with solubility parameter differences. This study illustrates the usefulness of reactivity ratios and solubility parameters in the design and development of effective dentin bonding agents.

Chemistry, Pharmaceutical↗
PubMed2001

Emerging methods used in the prevention and repair of carious tissues.

A systematic review was undertaken to investigate four emerging methodologies that might be used in the prevention of caries and/or repair of carious tissues. These included a partitioned dentifrice, laser technology, fluoride-releasing dental materials, and for deep carious lesions, bone morphogenic protein (BMP) therapy. The search strategy was to review articles written in English, indexed in MEDLINE and EMBASE databases and published since 1976. Over two hundred articles were read but because of the inclusion and exclusion criteria, only thirty-three were included in the evidence tables. The review of partitioned toothpaste showed either a greater remineralizing effect or a greater increase in the resistance to demineralization of both enamel and dentin, with the exception of its lack of effectiveness on coronal caries in the only clinical trial. Five of the six in vitro studies on enamel and the one study on dentin reported that lased tissue was less soluble than nonlased. Six clinical and four in situ studies were reviewed in answering the question as to whether fluoride-releasing restorative materials increase the remineralization or resistance to demineralization of human enamel and dentin. Eight of these reported positive findings. Six animal studies investigating BMP were reviewed, and all showed the ability of BMP to induce tubular dentin formation. Although the laboratory, animal, and limited clinical trials report encouraging results, independent, randomized, controlled clinical trials need to be carried out before these emerging technologies can be recommended for use in general practice.

Animals↗
PubMed2000

Angiogenic growth factors in human dentine matrix.

The importance of growth factors in mediating the cellular responses to injury in the dentine-pulp complex is well recognized and several growth factors are reportedly sequestered in dentine matrix from where they may be released during repair processes. Local angiogenesis at the injury site appears to be critical for successful pulpal repair. Here, soluble and insoluble matrix fractions were isolated from human dentine and the amounts of several important angiogenic growth factors in these fractions measured by enzyme-linked immunosorbent assay (ELISA). The EDTA-soluble matrix fraction contained high concentrations of platelet-derived growth factor (PDGF-AB), lower concentrations of vascular endothelial growth factor (VEGF), placenta growth factor (PlGF) and fibroblast growth factor (FGF2), and very low concentrations of epidermal growth factor (EGF). No FGF2 or PlGF could be detected in the insoluble matrix fractions, but these fractions contained some VEGF, lower concentrations of PDGF-AB and very low concentrations of EGF. It was concluded that dentine matrix contains angiogenic growth factors and that their release from the matrix after injury could make an important contribution to the overall reparative response of the dentine-pulp complex.

Angiogenesis Inducing Agents↗
PubMed1987

Effects of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) on the synthesis of dentin matrix proteins in the mouse.

The drug 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) is known to inhibit the mineralization of bone and dentin. Its mechanism of action, however, has not yet been elucidated. In order to study its effects on dentinogenesis, mice were supplied with either physiological saline or HEBP in a dose of 10 mg P/kg body weight. This dose is known to interfere with the deposition of mineral crystallites in dentin matrix. The animals were then given a combined injection of [3H]-serine and [14C]-proline (or [14C]-glycine) and killed 8-9 days thereafter. The dentin proteins were isolated and fractionated in soluble proteins among which phosphoproteins, CNBr-peptides of collagen and collagen-associated phosphoproteins. It was found that HEBP had a strong inhibitory effect on the synthesis of phosphoproteins and to a lesser extent on that of collagen. The inhibition of the formation of these proteins is supposed to be related to the impaired calcification of dentin under the influence of the bisphosphonate.

Animals↗
PubMed2004

AFM observation of collapse and expansion of phosphoric acid-demineralized dentin.

The objective of this study is to provide additional data regarding morphological changes that occur to dentin matrices following demineralization with etchants. Our understanding of the mechanism of diffusion of comonomers into the demineralized substrate is very limited. It has been hypothesized that certain water-soluble polyelectrolytes (acidic proteins) and neutral proteins in dentin can influence the collapse of demineralized dentin when it is air dried. Some of these solubilized substances are thought to aggregate by the action of Ca cations, which become dissolved during H(3)PO(4) etching, ultimately resulting in some degree of collapse. In the current study, dentin surfaces were examined by atomic force microscopy (AFM) before and after treatment by 10% H(3)PO(4)containing increasing concentrations of CaHPO(4). Reversal of matrix collapse by aqueous 30% 2-hydroxyethyl methacrylate (HEMA) was evaluated by AMF for 60 min. The results demonstrate two forms of matrix collapse; we speculate that one form is induced by acidic noncollagenous polyelectrolytes and the other by neutral peptides. Our data indicate that further evaluation of the influence of endogenous noncollagenous proteins must be studied to understand the mechanism of the collapse and reexpansion dynamics of demineralized dentin networks.

Animals↗
PubMed1994

Comparative efficacy of two dentifrices containing 5% potassium nitrate on dentinal sensitivity: a twelve-week clinical study.

The effect of a dentifrice containing 5.0% potassium nitrate, 1.3% soluble pyrophosphate, 1.5% PVM/MA copolymer, and 0.243% sodium fluoride in a silica base (Sensitive/Tartar Control) on dentinal hypersensitivity over a twelve-week period was compared to a commercially available dentifrice containing 5% potassium nitrate and 0.76% sodium monofluorophosphate in a dicalcium phosphate dihydrate base (Sensodyne-F). A total of ninety-seven subjects were entered into the study, and stratified into two balanced groups according to their baseline mean air sensitivity score and baseline mean tactile (Yeaple Probe) sensitivity score. The two groups were randomly assigned to use either the Sensitive/Tartar Control dentifrice or the commercially available hypersensitivity control dentifrice with potassium nitrate. The two groups were balanced with regard to their mean baseline air and tactile sensitivity scores, sex and age. Subjects were instructed to brush their teeth twice daily (morning and evening) for one minute with their assigned dentifrice and a commercially available soft-bristled toothbrush. Dentinal hypersensitivity examinations, which included tactile sensitivity, cold air blast, and a visual analog scale were conducted at baseline, six weeks, and twelve weeks. All examinations were conducted by the same dental examiner. After six weeks' use of the assigned dentifrices, there were no statistically significant differences between dentifrice groups in any of the parameters assessed (tactile, cold air blast and visual analog scale). After twelve weeks' use of the assigned products, there were no statistically significant differences between dentifrice groups in any of the parameters assessed (tactile, cold air blast and visual analog scale). Thus it can be concluded from this study that the use of a dentifrice containing 5.0% potassium nitrate, 1.3% soluble pyrophosphate, 1.5% PVM/MA copolymer, and 0.243% sodium fluoride in a silica base provides a clinically effective method of reducing dentinal hypersensitivity which is comparable in efficacy to a commercially available hypersensitivity control dentifrice containing 5% potassium nitrate and 0.76% sodium monofluorophosphate in a dicalcium phosphate dihydrate base.

Adult↗
PubMed2005

Development of self-etching primer adhesive in all-in-one bonding system.

The self-etching primer adhesives examined in the present study were aqueous mixtures of 5 wt% MDP, 35 wt% HEMA, 3 wt% 2-hydroxyl-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride (QTX), 0.5 wt% ethyl-p-(N,N-dimethylamino)benzoate (EDM), and 30 wt% water-soluble dimethacrylate (i.e., 2,2-bis(4-methacryloxy polyethoxypheny)propane (BPE), Glycerol dimethacrylate (GMR), or Glycerol methacrylate acrylate (GAM)). Self-etching primer adhesive was directly applied to polished bovine teeth. Tensile bond strength of composite resin to bovine teeth was measured after one-day immersion in water at 37 degrees C. Differences in water-soluble dimethacrylate monomer did not produce any significant differences in tensile bond strength to dentin or enamel. The use of N-phenyliminodiacetic acid (PIDAA) instead of EDM showed significantly higher bond strength to dentin and enamel. In conclusion, GMR and GAM were useful as water-soluble dimethacrylates while the combination of PIDAA and QTX was effective in improving the bond strength of composite resin to teeth in an all-in-one bonding system.

Acid Etching, Dental↗
PubMed1984

Isolation of phosphophoryn from human dentin organic matrix.

Normal human dentin was demineralized in 0.6 N HCl and then extracted in 1.0 M NaCl, 0.5 M Tris/HCl, pH 7.6 in the presence of neutral protease inhibitors. All of the soluble phosphorus-containing proteins were extracted directly in the 0.6 N HCl demineralizing solution; none were collected in the 1.0 M NaCl neutral pH extraction. The principal phosphoprotein was precipitated from solution by 1.0 M CaCl2 and subjected to further chromatographic purification. This fraction proved to be a typical phosphophoryn with Asp and Ser + PSer, in near equimolar amounts, accounting for approximately 75 residue percent of the protein. The second major organic phosphate-containing component was a peptide, Mr approximately 2,000. It was calcium precipitable and its amino acid composition showed a relationship to phosphophoryn. The residual collagenous matrix, which also contained organic phosphate, was digested with CNBr and the phosphate-containing moiety isolated. This had a composition indicative of a complex of collagen and phosphophoryn. Thus, in spite of the reports by Leaver and colleagues that human dentin contains neither soluble nor matrix-bound phosphophoryns, these data show that human dentin, like rat, hamster, rabbit, porcine, and bovine dentins, does contain a phosphophoryn as a major noncollagenous protein.

Amino Acids↗
PubMed1983

The amino-acid composition of the non-collagenous organic matrix of human cementum.

Human cementum was demineralized and exhaustively extracted with EDTA and then digested with collagenase. The insoluble residue after digestion was extracted successively with 8M urea and with 8M urea containing 0.1M mercaptoethanol. The non-collagenous fraction accounted for a larger proportion of the total organic matrix than previously found in bone and dentine, largely due to the presence of more collagenase-insoluble material. Fractionation of the EDTA-soluble material resulted in less-acidic fractions, showing similarities to the corresponding fractions of bone and dentine, and anionic fractions with lower levels of acidic amino acids than those from other hard tissues. Fractions obtained from the soluble collagenase-released material after ion-exchange chromatography and gel filtration, although more heterogeneous than those of bone and dentine, showed many similarities, thus confirming the close homology within this fraction from the various hard tissues. The insoluble residue after collagenase digestion appeared to be of the acid-structural protein type found also in bone, dentine and a wide range of connective tissues.

Amino Acids↗
PubMed2002

Solvation of dried dentin matrix by water and other polar solvents.

PURPOSE: To develop a simple method for measuring the degree of solvation of dried, demineralized dentin matrix by water and other polar solvents. The null hypothesis was that there are no differences in expansion forces produced by different polar solvents. MATERIALS AND METHODS: Midcoronal dentin discs were prepared from extracted, unerupted human third molars. The discs were cut into square specimens with surface areas of 2 x 2, 3 x 3 and 4 x 4 mm and thicknesses of 0.5, 1.0 and 1.5 mm. After demineralization in 0.5 M EDTA (pH 7), the dimensions of the specimens were measured both wet and dry. Dry specimens were held between two parallel steel plates connected to a 50 N load cell which measured the solvation force when water or other polar solvents were added. After measuring the expansion force induced by water, the specimens were fixed in glutaraldehyde and the trials repeated. On additional specimens, repeated measures of expansion forces were obtained using water, methanol, ethanol, n-propanol, n-butanol, ethylene glycol, formamide, hydroxyethylmethacrylate, N,N-dimethyl formamide and acetone in unfixed specimens. RESULTS: Water produced hydration forces as high as 204 g before, and 428 g after glutaraldehyde treatment. The hydration force correlated better with specimen thickness than with surface area. Water solvated the matrix faster than methanol > ethanol > formamide > ethylene glycol. Hydroxyethylmethacrylate, N,N-dimethyl formamide and acetone were unable to solvate the dried matrix. Regression analysis of solvation force vs. Hansen's solubility parameters for dispersive, polar and hydrogen bonding forces demonstrated that solvation force correlations were highest with hydrogen bonding solubility parameters. Measurements of solvation forces provides a simple method for determining solvent-collagen matrix interactions.

1-Butanol↗
PubMed1992

Effects of surface-active resins on dentin/composite bonds.

Effective dentin bonding systems based on para-PMDM diadduct of pyromellitic dianhydride and 2-hydroxyethyl methacrylate (HEMA) have been developed (Bowen et al., 1982). Para-PMDM, a solid of limited solubility, is usually applied from an acetone solution to dentin that has been preconditioned with acid and N-phenylglycine. The feasibility of using a liquid, surface-active bonding resin to substitute for or to supplement para-PMDM was explored. Mono(2-methacryloyloxy)ethyl phthalate (MMEP), a liquid, monofunctional homolog of para-PMDM (derived from the reaction of phthalic anhydride with HEMA) was used to formulate several bonding resin systems and solutions. Dentin surfaces were pretreated according to several variations of a three-step bonding protocol involving sequential application of 6.8 w/o ferric oxalate in 2.5 w/o HNO3, N-phenylglycine in acetone, and an experimental bonding resin before placement of a chemically cured composite restorative material. Tensile bond strengths were tested after 24 h storage in distilled water at 23 degrees C. The results suggest that solutions based on MMEP and/or para-PMDM in acetone or in other monomers, especially those containing HEMA, can effectively promote bonding to dentin. A new mechanism for the observed self-polymerization of MMEP or para-PMDM with N-phenylglycine is proposed.

Acetone↗