maleic-acid and phosphoric-acid

Topics: Acid Etching, Dental; Composite Resins; Dental Enamel; Dental Leakage; Dental Restoration, Permanent; Humans; Maleates; Phosphoric Acids

Two hundred twenty permanent young molars in 60 children aged 8 to 13 years received only one application of a light-activated resinous sealant. The retention rate was assessed 6 and 12 months later. The teeth were divided into 2 groups of 110 each. In one of the groups the pits and fissures were etched with 37% phosphoric acid before being sealed (group 1); in the other (group 2) these areas were etched with 10% maleic acid. The retention rate of group 1 was 98.4% at 6 months, and 96.8% at 12 months. Group 2 had retention rates of 97.5% at 6 months and 95% at 12 months. There was no statistically significant difference between the two groups in the two test periods, nor were there differences in the same group at the different periods.

Topics: Acid Etching, Dental; Adolescent; Chi-Square Distribution; Child; Follow-Up Studies; Humans; Maleates; Phosphoric Acids; Pit and Fissure Sealants; Treatment Outcome

To evaluate the effect of distilled water, ethylenediaminetetraacetic acid (EDTA), phosphoric acid and maleic acid on Biodentine regarding surface topography, microhardness and push-out bond strength (POBS).. Fifty-two cylindrical shaped Biodentine specimens were divided into groups: control (distilled water); EDTA (17% EDTA); PA (37% phosphoric acid); and MA (7% maleic acid). Surfaces were evaluated by topographic analysis and Vickers microhardness test. Topographic changes were evaluated qualitatively and microhardness was statistically analyzed by Kruskal-Wallis test. Forty mandibular molars were used to simulate clinical conditions. The crowns were removed and a perforation was created at the furcal floor. The Biodentine was packed into the root perforations and the roots were divided into four groups (DW, EDTA, PA, MA). Samples were stored and subjected to interfacial analysis. POBS data were analyzed by Kruskal-Wallis and Dunn tests.. Ethylenediaminetetraacetic acid, MA and PA changed the morphology of the Biodentine surface. PA showed microhardness similar to distilled water (P > 0.05), while MA and EDTA demonstrated reduced values when compared with PA (P < 0.05). PA improved the POBS of Biodentine in comparison with the control.. Changes in the topography, microhardness and POBS of Biodentine are associated with irrigant agent used.

Topics: Calcium Compounds; Chelating Agents; Crowns; Dental Stress Analysis; Dentin; Edetic Acid; Hardness; Humans; Maleates; Materials Testing; Phosphoric Acids; Silicates

A key evolutionary development facilitating land colonization in terrestrial isopods (Isopoda: Oniscidea) is the intermittent liberation of waste nitrogen as volatile ammonia. Intermittent ammonia release exploits glutamine (Gln) as an intermediary nitrogen store. Here, we explore the relationship between temporal patterns of ammonia release and Gln accumulation in three littoral oniscideans from Southern California. Results are interpreted in terms of water availability, habitat, activity patterns, and ancestry. A two-way experimental design was used to test whether ammonia excretion and Gln accumulation follow a tidal or diel periodicity. Ammonia excretion was studied in the laboratory using chambers with or without available seawater and using an acid trap to collect volatile ammonia. Ligia occidentalis releases ammonia directly into seawater and accumulates Gln during low tide (48.9 ± 6.5 μmol g⁻¹ at low tide, 24.1 ± 3.0 μmol g⁻¹ at high tide), indicating that excretion is tidally constrained. Alloniscus perconvexus and Tylos punctatus can excrete ammonia directly into seawater or utilize volatilization. Both species burrow in sand by day and show a diel excretory pattern, accumulating Gln nocturnally (31.8 ± 2.7 μmol g⁻¹ at dawn and 21.8 ± 2.3 μmol g⁻¹ at dusk for A. perconvexus; 85.7 ± 15.1 μmol g⁻¹ at dawn and 25.4 ± 2.9 μmol g⁻¹ at dusk for T. punctatus) and liberating ammonia diurnally. Glutaminase shows higher activity in terrestrial (0.54-0.86 U g⁻¹) compared to intertidal (0.25-0.31 U g⁻¹) species, consistent with the need to generate high PNH₃ for volatilization. The predominant isoform in Armadillidium vulgare is phosphate dependent and maleate independent; phosphate is a plausible regulator in vivo.

Topics: Ammonia; Animals; Arthropod Proteins; Behavior, Animal; California; Circadian Rhythm; Ecosystem; Enzyme Activation; Glutaminase; Glutamine; Isopoda; Kinetics; Maleates; Models, Biological; Pacific Ocean; Phosphoric Acids; Phylogeny; Species Specificity; Tidal Waves; Trees

To test and describe the use of various combinations of mechanical and chemical techniques for enamel reduction to obtain a smooth surface.. Bovine teeth (2 surfaces on each of 32 teeth) were used. The teeth were mounted in blocks of dental plaster, which were then mounted in a vise. The mesiodistal enamel contact areas were reduced by various combinations of mechanical and chemical aids. The mesiodistal width of each tooth was measured with a digital caliper after initial reduction of the enamel surface and again after polishing. The teeth were subsequently prepared and mounted for scanning electron microscopy.. All combinations yielded statistically significant enamel reduction (p < 0.05). The use of acid stripping in conjunction with mechanical procedures produced especially smooth enamel surfaces.. Steps must be taken to ensure that a smooth enamel surface remains after enamel reduction and polishing. It is recommended that conventional enamel etchants be added to the polishing procedure. Enamel reduction can increase available space, but the quantity of enamel that can be removed without adverse consequences should be carefully evaluated.

Topics: Acid Etching, Dental; Animals; Cattle; Dental Enamel; Dental High-Speed Technique; Dental Instruments; Diamond; Hydrochloric Acid; Maleates; Microscopy, Electron, Scanning; Odontometry; Phosphoric Acids; Pilot Projects; Surface Properties; Tungsten Compounds

This study examined the shear bond strength of bonding agents to normal or fluoridated enamel following use of weak or strong acids to prepare enamel surfaces and after contamination with a measured amount of saliva at various stages of the bonding procedure.. One hundred extracted human third molar teeth were randomly separated into 2 basic groups (normal or fluoridated teeth), then divided into 5 subgroups. Group A specimens were not contaminated. After etching, enamel surfaces were dry and clean. Group B was left with wet surfaces after etching. Group C specimens were contaminated with artificial saliva and then dried. Group D specimens were contaminated with artificial saliva, rinsed, and then dried. In group E, all enamel surfaces were left contaminated with saliva after the etching procedures (with maleic acid or phosphoric acids). Adhesive resins were applied to all enamel surfaces according to the manufacturer's instructions. The specimens were then mounted and tested to determine shear bond strength.. If normal enamel surfaces were rinsed and dried immediately after contamination, there was no significant reduction of shear bond strength of adhesive to enamel. Specimens in group E and group C had significantly lower bond strengths than did control specimens (group A). In the fluoridated groups etched with the phosphoric acid, statistically significant reductions in bond strengths were obtained in all contamination groups and in the control group. In the fluoridated specimens, there were no statistically significant differences between any of the contamination groups and the control group when maleic acid was used.. Saliva contamination may not be a risk factor for successful bonding between bonding agent and dental tissues for normal or fluoridated enamel surfaces if they are rinsed and dried immediately after contamination. Etching of normal enamel surfaces with phosphoric acid in the presence of contamination may provide higher shear bond strength than etching with maleic acid.

Topics: Acid Etching, Dental; Composite Resins; Dental Bonding; Dental Enamel; Dentin-Bonding Agents; Desiccation; Fluorides; Humans; Maleates; Materials Testing; Molar; Phosphoric Acids; Random Allocation; Resin Cements; Saliva, Artificial; Silicon Dioxide; Statistics, Nonparametric; Tensile Strength; Water; Zirconium

A unique characteristic of some new etching systems is that they combine the conditioning and priming agents into a single acidic primer solution. The purpose of this study was to determine the effects on the shear bond strength and the bracket/adhesive failure mode when an acidic primer and other enamel etchants were used to condition the enamel surface before bonding. The brackets were bonded to extracted human teeth according to one of four protocols following the manufacturers instructions. Group I, teeth were etched with 37% phosphoric acid, the brackets were then bonded with System 1+ adhesive (Ormco Corporation. Orange, Calif.); group II, teeth were etched with 10% maleic acid, the brackets were also bonded with System 1+ adhesive; group III, an acidic primer that contains both the acid (phenyl-P) and the primer (hema and dimethacrylate) were placed on the enamel for 30 seconds. The adhesive used on this group was a lightly filled resin that contains Bis-GMA and HEMA. (Clearfil Liner Bond 2. J.C. Moritta, Kuraway, Japan); Group IV, the same acidic primer was used as in group II, the adhesive used was highly filled (Panavia 21. J.C. Moritta) and contains Bis-GMA. The present in vitro findings indicated that the use of acidic primers to bond orthodontic brackets to the enamel surface could provide clinically acceptable shear bond forces (x = 10.4 +/- 4.4 MPa) when used with a highly (77%) filled adhesive (Panavia 21). These debonding forces were comparable to those obtained when the enamel was conditioned with either Phosphoric (x = 11.8 +/- 4.1 MPa) or Maleic (x = 10.9 +/- 4.4 MPa) acids. With the use of a lightly (10%) filled adhesive (Clearfil Liner Bond 2), the shear bond strength was significantly lower (x = 5.9 +/- 5.6 MPa). It is of interest to note that there was a tendency to have less residual adhesive remaining on the tooth when an acid primer was used than when phosphoric and maleic acids were used. This might be of advantage to the clinician because it will require less time to clean the teeth after debonding.

Topics: Acid Etching, Dental; Adhesiveness; Analysis of Variance; Bisphenol A-Glycidyl Methacrylate; Dental Bonding; Dental Debonding; Dental Enamel; Dentin-Bonding Agents; Humans; Maleates; Materials Testing; Methacrylates; Orthodontic Brackets; Phosphates; Phosphoric Acids; Resin Cements; Statistics, Nonparametric; Tensile Strength

Composite materials have become an integral part of the wide range of filling materials currently available. Conditioning is necessary to achieve adequate bonding of the composite material to enamel and dentin. Normally, this is done by applying acid preparations to the dental surfaces. These acids have an etching effect that causes surface roughening. The increasing application of lasers in dentistry has introduced another possibility. Laser irradiation can cause roughening of enamel and dentin surfaces. Another interesting alternative is the so-called kinetic cavity preparation technique. This method also results in distinct surface roughening. The purpose of the present study, was to compare the described methods. Tensile bond strength tests and shear bond tests were carried out to examine the adhesion of a composite material to surfaces treated with these methods. Laser irradiation with certain devices and the air-abrasive technique yielded results similar to those with acid etching.

Topics: Acid Etching, Dental; Air Pressure; Carbon Dioxide; Composite Resins; Dental Bonding; Dental Cavity Preparation; Dental Enamel; Dentin; Erbium; Humans; Lasers; Maleates; Materials Testing; Neodymium; Phosphoric Acids; Potassium; Semiconductors; Silicon Dioxide; Surface Properties; Tensile Strength; Zirconium

To investigate the effect of dentin treatment with mixed solutions of citric acid and ferric chloride on the tensile bond strength of resin-modified glass ionomers.. 120 freshly extracted bovine incisors were ground to expose dentin surface. Vitremer and Fuji II LC were bonded to dentin surfaces that were (1) rinsed with distilled water and dried with oil-free compressed air, (2) treated with Super Bond Dentin Activator for 30 seconds, (3) treated with Bondwell LC Conditioner for 20 seconds, (4) treated with Scotchbond Multi-purpose Etchant for 15 seconds, (5) treated with Dentin Conditioner for 20 seconds, or (6) treated with K-etchant for 40 seconds following manufacturers' recommendations. Specimens were stored in water at 37 degrees C for 24 hours. The tensile bond strength was measured at a crosshead speed of 0.5 mm/minute. The data were statistically analyzed by a one-way ANOVA and Dunnett's Post-hoc Procedure (P < 0.05).. Super Bond Dentin Activator and Bondwell LC Conditioner increased the tensile bond strength of Vitremer and Fuji II LC. Scotchbond Multi-purpose Etchant, Dentin Conditioner, and K-etchant did not improve the tensile bond strength of Vitremer and Fuji II LC.

Topics: Acid Etching, Dental; Acrylic Resins; Analysis of Variance; Animals; Cattle; Chlorides; Citric Acid; Composite Resins; Dental Bonding; Dentin; Ferric Compounds; Glass Ionomer Cements; Maleates; Materials Testing; Phosphoric Acids; Resins, Synthetic; Tensile Strength

Thirty-six noncarious human molars were extracted and stored in saline. The buccal surfaces were ground wet on 400-grit silicon carbide paper to create a flat surface. The enamel and dentin surfaces were treated with 35% phosphoric acid gel, 10% phosphoric acid gel and 10% maleic acid gel for 15 and 60 seconds. Scanning electron microscope analysis showed that all the acid etchants modified the micromorphological appearance of enamel and dentin surfaces independent of the type of acid, the etching time and the concentration. On the enamel surface, the 35% and 10% phosphoric acid gels and the 10% maleic acid gel applied for 15 or 60 seconds preferentially removed the prism core material. In the specimens treated for 15 seconds with 10% maleic acid the prism core material was partially removed. On the dentin surface, the phosphoric acid gels (35% and 10%) and the 10% maleic acid gel applied for 15 and 60 seconds removed the smear layer and opened the dentinal tubule orifices; however, the dentinal surface etched for 15 or 60 seconds with 10% maleic acid gel showed residues of the smear layer.

Topics: Acid Etching, Dental; Dental Enamel; Dentin; Gels; Humans; Maleates; Microscopy, Electron, Scanning; Phosphoric Acids; Time Factors

The aim of the study was to evaluate the effect of some acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ.. Smear layer-covered dentin specimens prepared from third molars immediately after extraction were imaged by tapping made AFM and analyzed by MIR-FTIR spectroscopy. The same specimens were subjected to conditioning treatments with CA Agent (Kuraray), Scotchbond Etchant (3M Dental Products) and Scotchbond MP Etchant (3M Dental Products) gels and then imaged and analyzed again. The extent of dentin decalcification at the uppermost 2 microns region was calculated from the percentage reduction in the-PO4/amide I peak area ratio of conditioned specimens relative to their individual smear layer-covered references. These results were compared by ANOVA and Scheffé statistical analyses. The conformational changes of dentin type I collagen at the region were studied qualitatively by deconvoluting the amide I bands of MIR-FTIR spectra and assigning the band components to carbonyl hydrogen bonding states related to the alpha-helix structure.. All the conditioners removed the smear layer, funneled the tubules, increased the intertubular roughness and contaminated the dentin surfaces with residues from irreversibly adsorbed thickening agents. Conditioned dentin surfaces showed a reduction in orthophosphates and carbonates and an increase in amide I, II and III groups. CA Agent manifested a significantly lower extent of dentin decalcification than Scotchbond etchants (p < 0.05). Collagen conformational changes involved a decrease in intermolecular hydrogen bonded amide I carbonyls associated with the alpha-helix structure and enhancement of imide carbonyls hydrogen bonded to water, which suggest collagen denaturation.. Apart from dentin decalcification, the acidic conditioners induced considerable changes on dentin collagen conformation mostly associated with denaturation processes. In addition, irreversibly adsorbed residual thickeners substantially modified the morphology and composition of dentin surfaces. These findings show the complex interaction pathways between conditioners and dentin surfaces and the great potential of modern in situ imaging and analysis techniques in probing these interactions.

Topics: Acid Etching, Dental; Amides; Analysis of Variance; Citric Acid; Collagen; Dentin; Hydrogen-Ion Concentration; Maleates; Phosphoric Acids; Protein Conformation; Regression Analysis; Smear Layer; Spectroscopy, Fourier Transform Infrared; Surface Properties; Tooth Demineralization

The aim of this in vitro study was to evaluate, using scanning electron microscopy (SEM), the effects of acid solutions on dentin surface, and to analyze the depth of demineralization that the acid solutions cause on dentin, using different acids. Fifteen 3-mm thick dentin discs were prepared from the middle third of human molars. Standard smear layer was prepared on the dentin surface using 600 grit sandpaper, for 1 minute. The acids used were 10%, 35% and 37.5% phosphoric acid and 10% maleic acid, for 15 seconds, washed and dried. The control group received no treatment. Dentin discs were fractured, observed on the horizontal surface and also on the fractured surface to evaluate the depth of demineralization. Specimens were immersed in 4% glutaraldehyde in phosphonate buffer, and prepared for SEM examination at 2000X and 4000X magnification. Acid etching of dentin, regardless of the concentration of phosphoric acid, caused removal of the smear layer, exposing the apertures of dentinal tubules. This was not observed when 10% maleic acid was used. At the fractured surface, one could observe an increase in demineralization of the width of dentinal tubules, to a specific depth of about 8.19 to 11 mm, except for 10% maleic acid.

Topics: Acid Etching, Dental; Dentin; Humans; In Vitro Techniques; Maleates; Microscopy, Electron, Scanning; Osmolar Concentration; Phosphoric Acids; Smear Layer; Surface Properties

To assess the microleakage of Class V preparations restored with three bonding agents using wet and dry bonding.. Cavities were prepared in the buccal and lingual surfaces of extracted human premolar teeth and restored with resin composite after application of the dentin bonding agents, using a wet or dry bonding technique. The teeth were stored for 2 weeks at 37 degrees C, thermocycled, and the restorations examined for leakage using buffered methylene blue as the marker. The teeth were sectioned bucco-lingually through the restorations and the degree of microleakage assessed microscopically.. All groups showed leakage at both the dentin and enamel margins. There was no significant difference in leakage at the enamel margins between groups (p > 0.05) and no significant differences in leakage between the wet bonding (P > 0.05) or dry bonding (P > 0.05) procedures. However, when comparing the effects of wet and dry bonding, there was less leakage at the gingival margin in the groups where the bonding agent was acetone-based and wet bonding was used (P < 0.03). There was no significant difference in leakage for Scotchbond Multi-Purpose Plus when either maleic acid or phosphoric acid was used as the etchant (P > 0.05).

Topics: Acid Etching, Dental; Bisphenol A-Glycidyl Methacrylate; Composite Resins; Dental Bonding; Dental Leakage; Dental Restoration, Permanent; Dentin-Bonding Agents; Humans; Maleates; Materials Testing; Methacrylates; Phosphoric Acids; Polymethacrylic Acids; Resin Cements; Silicon Dioxide; Statistics, Nonparametric; Water; Zirconium

The preparation of enamel surfaces before etching by removing 0.5 mm of surface tooth structure is common-place in modern restorative dentistry. This study was designed to measure and compare the shear bond strength of composite resin bonded to prepared and unprepared enamel using various proprietary bonding systems. The analysed results failed to show significant differences between the shear bond strengths of the prepared and unprepared enamel specimens. Conditioning enamel surfaces for 60 seconds using 2.5% nitric acid where the solution was allowed to desiccate, resulted in significantly lower bond strengths compared to the other regimes. A correlation of the etchant pH with the mean shear bond strength of the adhesive systems to enamel was observed. The surface topography of the etched enamel surfaces correlated moderately well with the bond strengths obtained.

Topics: Acid Etching, Dental; Analysis of Variance; Composite Resins; Dental Bonding; Dental Enamel; Humans; Hydrogen-Ion Concentration; Maleates; Materials Testing; Microscopy, Electron, Scanning; Nitric Acid; Phosphoric Acids

The clinical requirements of dentin bonds are that they should be non-permeable to oral fluids, seal dentinal tubules, protect the pulp, and be long lasting and durable. Dentin bonding systems that use acidic agents to remove the smear layer are currently being used. Acid conditioning not only removes the smear layer, but also demineralizes the surface of the intertubular dentin and produces intratubular demineralization and funnelling. A dentin bond is produced when hydrophillic resin monomers infiltrate the dentinal tubules and collagen of the demineralized intertubular zone, producing a hybrid layer. The use of a critical point drying technique and SEM allows a clear visualization of the structure of the hybrid layer. This study showed that currently used hydrophillic resin monomers are unable to completely infiltrate the demineralized zone, and it is speculated that this failure could contribute to microleakage and influence the long-term durability of the bond. It is also apparent that these bonds depend on the mechanical investment of collagen by the infiltrating monomer. Since none of the unfilled resins tested seem capable of completely infiltrating the demineralized collagenous zone, the degree of demineralization produced by the commercial acid concentrations in current use is questioned. More dilute acids than those available commercially are shown to reduce both the degree and depth of demineralization, and we suggest that the resultant thinner layer may lend itself to more complete resin infiltration of the collagen.

Topics: Acid Etching, Dental; Animals; Cattle; Collagen; Composite Resins; Dental Bonding; Dentin; Dentin Permeability; Dentin-Bonding Agents; Desiccation; Humans; Maleates; Methacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Surface Properties; Tooth Demineralization

To investigate the effects of different acid etchants' ability to condition enamel as gently as possible to remove a minimum of substance only, to produce a highly retentive pattern, and finally to ensure frosty appearance of the etched enamel for clinical control of the procedure.. Two commercial uni-etch gels, Gluma 2000-1 and Scotchbond Multi-Purpose Etchant, were studied together with gels of 5, 10, 20 and 35% phosphoric acid and varying amounts of thickening agents in the 20% gel. Enamel loss was measured with a contact-free method by materials and etch duration, and the shortest etching times for dull frosty enamel appearance were determined. Shear bond strength (SBS) was measured after 24 hours' storage in water.. Enamel loss was very low with the commercial agents and increased with H3PO4 concentrations and with etch duration. While the commercial compounds produced no frosty enamel even after 120-second etch duration, the phosphoric acids produced frosted enamel after 15, 30, 60 and 120-second application of 35, 20, 10 and 5% acids, respectively. All etchants and etch durations tested produced effective retentive patterns. No differences in SBS were noted, and the failure modes were consistently cohesive in resin.

Topics: Acid Etching, Dental; Analysis of Variance; Composite Resins; Dental Bonding; Dental Enamel; Glutaral; Maleates; Materials Testing; Microscopy, Electron, Scanning; Oxalates; Oxalic Acid; Phosphoric Acids; Polymethacrylic Acids; Time Factors

Nine noncarious human molars were extracted and stored in saline solution. Three standard occlusal cavities with beveled enamel margins were prepared on each tooth and etched with the etching solutions of three dentinal adhesive systems: (1) 37% phosphoric acid solution, (2) 4.3% oxalic acid and 2.6% aluminum salts solution, and (3) 10% maleic acid solution. Scanning electron microscopic analysis revealed that all the etching solutions affected the enamel surface morphology. The solution of oxalic acid and aluminum salts removed primarily the prism core material and partially the periphery of the prisms, but did not affect the nonbeveled enamel surface. Phosphoric and maleic acids removed both prism core materials and prism periphery; these specimens also showed areas in which no prism morphology could be detected. These two acids also removed apatite crystals from the prism core of the intact enamel surface.

Topics: Acid Etching, Dental; Dental Enamel; Dentin; Humans; Maleates; Microscopy, Electron, Scanning; Molar; Oxalates; Oxalic Acid; Phosphoric Acids; Smear Layer

To examine in vitro the composition of resin tags in etched dentin by SEM and vital staining using Alcian Blue dye.. Bovine and human teeth were used. The dentin surface was exposed using water-irrigated #600 grit SiC paper and etched with varying dilutions of aquaeous solutions of phosphoric and maleic acid. Groups of 10 teeth per acid concentration were embedded in PMMA and Scotchbond Multi-Purpose (SMP) and cylinders of Z100 resin composite were bonded to their surfaces. These teeth were shear tested to failure and the failed surfaces subjected to SEM. Groups of three teeth per acid concentration had SMP and cylinders of Z100 bonded to their surfaces. These teeth were decalcified in concentrated HCL acid. The resultant cylinders and their attached resin tags were either subjected to SEM or stained with Alcian Blue dye. The latter specimens were embedded and prepared for light-microscopic examination. A further three human and three bovine teeth per acid concentration were etched and then prepared for SEM examination. All teeth for SEM were critical point dried.. Resin tags were shown to consist of both resin and the glycosaminoglycans (GAG) sheath lining of the dentin tubule. As a result of the SEM observations, three mechanisms are suggested for the formation of resin tags, two of which will probably be found in vivo.

Topics: Acid Etching, Dental; Animals; Cattle; Composite Resins; Dental Bonding; Dentin; Dentin Permeability; Dentin-Bonding Agents; Glycosaminoglycans; Humans; Maleates; Materials Testing; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Silicon Dioxide; Surface Properties; Zirconium

The purpose of this study was to evaluate the influence of six treatments on the dispersive, acid, and base components of the free surface energy of dentin.. Occlusal dentin surfaces were polished with 4000 grit abrasive paper, washed and air dried. Characteristics of the surface energy were calculated by measuring contact angles of the four following liquids:alpha-bromonaphtalene, glycerol, ethylene glycol, and water. The dentin was then treated with aqueous solutions containing: (1) oxalic acid and glycine (OX/GLY),(2) oxalic acid, glycine, and HEMA (OX/GLY/HEMA), (3) phosphoric acid (PA), (4) maleic acid (MA),(5) EDTA, or (6) NaCIO. After treatment, washing and air drying, the energy characteristics of the samples were evaluated again.. Three kinds of wetting behavior were observed: an increase (OX/GLY/HEMA), a stabilization (PA, NaCIO) or a decrease (OX/GLY, MA, EDTA) of the wettability of the dentin surface. The calculations demonstrated that dentin surfaces are basic.. This study of the evolution of the surface energy components gave information on adhesion mechanisms involving hydrophilic and hydrophobic interactions. The results may be helpful in the formulation of conditioners and primers.

Topics: Acid Etching, Dental; Analysis of Variance; Chemical Phenomena; Chemistry, Physical; Dentin; Edetic Acid; Glycine; Hydrogen-Ion Concentration; Maleates; Matched-Pair Analysis; Methacrylates; Oxalates; Oxalic Acid; Phosphoric Acids; Smear Layer; Sodium Hypochlorite; Statistics, Nonparametric; Surface Properties; Surface Tension; Thermodynamics; Wettability

The purpose of this study was to compare the structure of acid-conditioned dentin in its wet and dry state.. Using conventional and environmental scanning electron microscopy, conditioned dentin was examined in a wet, air-dried and critical point-dried state. Six different treatments were used including citric, maleic, nitric, oxalic and phosphoric acids in their commercial formulations and applied in accordance with manufacturer's instructions.. Loss of moisture from acid-conditioned dentin through simple air drying and drying under controlled conditions of environmental scanning microscopy resulted in morphological alteration of the fibrous, collagenous structure. Critical point drying preserved the fibrous integrity of the outer mineral-depleted zone. This observation was true for all the acids used.. While the ultrastructure of dentinal collagen may be chemically stabilized or relatively unaltered by acid conditioning, it is nonetheless subject to morphological degradation and collapse during water loss. Only critical point drying can control the interfacial stress accompanying water transport and loss at the fiber boundary. Confirming previous observations, this study supports the concept of maintaining the moist state of dentin and the morphological integrity of the collagen so as to facilitate optimal resin infiltration in the bonding procedure.

Topics: Acid Etching, Dental; Citrates; Citric Acid; Collagen; Dental Bonding; Dentin; Dentin Permeability; Desiccation; Maleates; Microscopy, Electron, Scanning; Nitric Acid; Oxalates; Oxalic Acid; Phosphoric Acids; Smear Layer; Surface Properties; Water

To measure the shear bond strength of resin composite to dentin using three fourth generation bonding agents in combination with three different acid treatments. One such treatment was followed by sodium hypochlorite. The purpose was to determine the contribution which the collagen rich, demineralized zone made to bond strength.. Three groups, representing (1) All Bond 2/BisFil, (2) Optibond Dual Cure/XRV and (3) Scotchbond Multi-Purpose/Z100, contained four sub-groups each comprised of 10 caries-free molar teeth whose dentin was exposed in a transverse mid-coronal plane. Dressed with 320 grit, wet silicon carbide paper, the dentin surface in each sub-group was conditioned with 10% maleic acid (15 seconds), 10% phosphoric acid (20 seconds), 2.5% nitric acid (60 seconds) and 10% phosphoric acid (20 seconds) followed by 5% sodium hypochlorite (120 seconds). The bonded resin composite assemblies were stored in water at 37 degrees C for 24 hours and then subjected to shear force at a crosshead speed of 5 mm/minute until failure.. The mean and standard deviation values derived for the groups were not statistically different from each other (P < 0.05). It was concluded that the type of conditioning agent was not a factor in achieving optimal bond strength for the system tested. Furthermore, it was tentatively concluded that the collagen-rich zone offered no direct, quantitative contribution to the interfacial bond strength which is probably derived from complete resin diffusion into the porous, partially demineralized dentin below.

Topics: Acid Etching, Dental; Analysis of Variance; Bisphenol A-Glycidyl Methacrylate; Collagen; Composite Resins; Dental Bonding; Dentin; Dentin Permeability; Dentin-Bonding Agents; Humans; Maleates; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Nitric Acid; Phosphoric Acids; Resin Cements; Silicon Dioxide; Sodium Hypochlorite; Surface Properties; Tensile Strength; Zirconium

This study critically examined the surface and subsurface effects of selected dentin priming agents. Various dentin priming agents were used and specimens were prepared for SEM examination by conventional air drying or by a freeze fracture and critical point drying technique. The results showed that in specimens prepared by freeze fracture and critical point drying technique the demineralization of the dentin surface and subsurface by priming agents leaves a visible network of collagen fibrils. This technique allows better evaluation of the adaptation of bonding resins to the collagen network of the demineralized layer.

Topics: Acid Etching, Dental; Animals; Cattle; Collagen; Composite Resins; Dentin; Dentin Permeability; Dentin-Bonding Agents; Freeze Fracturing; Humans; Maleates; Methacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Surface Properties; Wettability

This study compared the shear bond strength of resin composite bonded to porcelain with six commercial porcelain repair adhesive systems. The porcelain repair systems tested were: All-Bond 2, Clearfil Porcelain Bond, Ceram-Etch, C&B Metabond with Etch-Free Primer, Scotchprime, and Ultradent Porcelain Etch. Resin composite cylinders were bonded to primed porcelain surfaces and the specimens were thermocycled and stored in distilled water at 37 degrees C for 36 days. After storage, a testing machine was used to deliver a shear force parallel to the porcelain/composite interface. Mean load to failure was calculated for each group and the fracture location was noted. Results demonstrated cohesive porcelain failures and high bond strengths for All-Bond 2, Clearfil, Metabond, Scotchprime, and Ultradent. Statistical analysis revealed significantly lower bond strengths for the group that failed at the porcelain/composite interface.

Topics: Analysis of Variance; Boron Compounds; Composite Resins; Dental Alloys; Dental Bonding; Dental Cements; Dental Porcelain; Dentin-Bonding Agents; Denture Repair; Hydrofluoric Acid; Maleates; Materials Testing; Methacrylates; Methylmethacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Silanes; Surface Properties; Tensile Strength

This study evaluated the effects of etching time on bond strengths of composite to enamel. Proximal surfaces of extracted molars were etched with either a conventional etchant (35% phosphoric acid) or one of two dentin/enamel conditioners, 10% maleic acid (Scotchbond Multi-Purpose Etchant), or a solution of oxalic acid, aluminum nitrate, and glycine (Gluma 1 & 2 Conditioner). Each agent was applied for 15, 30, or 60 seconds. Specimens etched with 35% phosphoric acid had the highest mean bond strengths at each etching time. At the manufacturer's recommended application times, the other two agents gave significantly lower shear bond strengths than phosphoric acid.

Topics: Acid Etching, Dental; Analysis of Variance; Composite Resins; Dentin-Bonding Agents; Glutaral; Humans; Maleates; Materials Testing; Oxalates; Phosphoric Acids; Polymethacrylic Acids; Resin Cements; Silicon Dioxide; Tensile Strength; Time Factors; Zirconium

In this study, the effect of enamel etching resulting in permanently lost enamel was investigated. Phosphoric acid and maleic acid were used as etchants. Also the etch duration was varied. The results of the study show that phosphoric acid removed significantly more enamel than maleic acid. The relationship found between the loss of enamel and the etch duration suggested that a diffusion controlled mechanism plays a role in the case of both acids. Morphological information obtained by scanning electron microscopy indicated that the surface structure resulting from etching with phosphoric acid and maleic acid is similar.

Topics: Acid Etching, Dental; Dental Enamel; Humans; Maleates; Microscopy, Electron, Scanning; Phosphoric Acids; Regression Analysis; Time Factors

The aim of the present study was to evaluate the surface morphology and the permeability of dentine after different acid treatments: polyacrylic acid, maleic acid, phosphoric acid and saline solution as control. Dentine permeability was expressed as hydraulic conductance. All the acid treatments removed the smear layer and increased the dentine permeability.

Topics: Acid Etching, Dental; Acids; Acrylic Resins; Adult; Dental Cavity Lining; Dentin Permeability; Humans; Maleates; Microscopy, Electron, Scanning; Phosphoric Acids; Smear Layer

A light-cured bonding agent consisted of 50 wt% BisGMA and 50 wt% 2 HEMA was prepared in order to investigate the effect of light curing system on the bonding to etched dentin treated with 37 wt% phosphoric acid (PA), 10 wt% citric acid (CA), 10 wt% maleic acid (MA), 10 wt% citric acid-3 wt% ferric chloride (10-3) and 0.5 M EDTA.2 Na (EDTA) solutions. The bond strength to dentin treated with 10-3 solution was statistically higher than to dentin treated with the other etchant. The acid-proof dentin layers with about 1-2 microns thickness at the interface between resin and dentin treated with CA, MA, and 10-3 solutions were visible with SEM. The presence of Ca, P, and Br elements in the layers was confirmed by EPMA analysis. The bond strength was greatly dependent upon the physical property of the layer because difference in Knoop hardness of the etched dentin surfaces and the dentin surface after bond testing was greatest when used 10-3 solution.

Topics: Acid Etching, Dental; Bisphenol A-Glycidyl Methacrylate; Citrates; Citric Acid; Dental Bonding; Dentin; Electron Probe Microanalysis; Hardness; Light; Maleates; Methacrylates; Phosphoric Acids; Surface Properties

Phosphate-activated glutaminase (EC 3.5.1.2) in synaptosomal preparations is inhibited 40-60% by the sulphydryl group reagent N-ethylmaleimide (NEM), forming the basis for distinction between NEM-sensitive and NEM-insensitive glutaminases. The NEM effect cannot be explained by differential effects on distinct glutaminases because other glutaminases have not been detected, and the synaptosomal glutaminase activity can be fully accounted for by the activity of phosphate-activated glutaminase. By fractionation of mitochondria isolated from synaptosomal preparations, which are preincubated with and without NEM, both NEM-sensitive and NEM-insensitive glutaminases are found to be localized to the inner mitochondrial membrane. Variations in pH (7.0-7.6) and the phosphate concentration (5-10 mM) affect chiefly NEM-sensitive glutaminase, demonstrating that this glutaminase may be subject to regulation by compounds in the cytosol having restricted permeability to the inner mitochondrial membrane. Since p-hydroxymercuribenzoate, which is known to be impermeable to the inner mitochondrial membrane, inhibits glutaminase similarly to NEM, phosphate-activated glutaminase is assumed to be compartmentalized within the inner mitochondrial membrane. Thus, NEM-sensitive glutaminase is localized to the outer face and NEM-insensitive glutaminase to the inner region of this membrane and probably also to the matrix region.

Topics: Animals; Enzyme Activation; Ethylmaleimide; gamma-Glutamyltransferase; Glutaminase; Hot Temperature; Hydrogen-Ion Concentration; Hydroxymercuribenzoates; Intracellular Membranes; Maleates; Phosphoric Acids; Rats; Synaptosomes