maleic-acid and hydroxyethyl-methacrylate

The aqueous phase of glass ionomer cements enables fluoride ions to diffuse and to be released from the material. The matrix of resin composites is much less hydrophilic, and fluoride incorporated in the material is only released in small amounts. It was the purpose of the present work to study the influence of resin matrix formulation on the fluoride release from experimental, fluoride-containing resin composites. The resin composites were based on methacrylate monomers and the adduct of maleic anhydride and HEMA (2-hydroxyethyl methacrylate). The resin composites contained 1 w% or 5 w% of AlF3*3H2O. A glass ionomer cement and a compomer were used as controls. Five disks of each material were stored in distilled water at room temperature. By means of a fluoride sensitive electrode, the fluoride release from disk-shaped specimens was determined periodically over 3 years. The glass ionomer cement released the most fluoride (1.54 +/- 4 microg/cm2 after 1 year and 248 +/- 7 microg/cm2 after 3 years). The compomer released relatively little fluoride during the 1st year (30 +/- 1 microg/cm2) but after this time the rate of fluoride release became equal to that of the glass ionomer cement, resulting in a release of 122 +/- 8 microg/cm2 after 3 years. Regarding the resin composites, the fluoride release increased with the hydrophilicity and the acid character of the polymer matrix. The release, however, was significantly lower than that from the glass ionomer cement and the compomer and ranged from 1.2 +/- 0.07 to 42 +/- 3.9 microg/cm2 at 1 year and from 2.3 +/- 0.16 to 79 +/- 6 microg/cm2 at 3 years.

Topics: Aluminum Compounds; Analysis of Variance; Cariostatic Agents; Chemistry, Pharmaceutical; Compomers; Composite Resins; Diffusion; Fluorides; Glass; Glass Ionomer Cements; Humans; Ion-Selective Electrodes; Maleates; Materials Testing; Methacrylates; Polyethylene Glycols; Polymethacrylic Acids; Polyurethanes; Regression Analysis; Resin Cements; Silanes; Silicates; Statistics as Topic; Statistics, Nonparametric; Temperature; Time Factors; Water

The effect of experimental dentin primers containing N-methylolacrylamide (MEAA) or N-methylolmethacrylamide (MEMA) on bond durability of a resin composite (Photo Clearfil A) with a bonding agent (Clearfil Photo Bond) to bovine dentin was investigated.. The etching agents were 10% maleic acid (10% MA), 10% phosphoric acid (10% PA) and 10% citric acid-3% ferric chloride (10-3 solution). Water solutions of 35% hydroxyethyl methacrylate (HEMA), 50% MEAA or 30% MEMA were used as dentin primers. The etched dentin was pre-treated with the dentin primers for 30s. The resin composite systems were applied in a Teflon tube positioned onto pre-treated dentin surfaces. After water immersion for 1 day and 5 years, the shear bond strengths were measured. The amounts of calcium dissolved with etching agents were measured using atomic absorption spectrometry. The thicknesses of hybrid layers at the dentin-resin interfaces treated with 6 mol/l HCl and 1% NaOCl were measured using scanning electron microscopy.. The bond strengths of the specimens (Controls) without primers to dentin etched with 10% MA and 10-3 solution significantly decreased after immersion in water for 5 years (p<0.05) while other bond strengths did not decrease. The bond strengths of the composites to MEMA- and MEAA-primed dentin were significantly higher than that of the control after 1 day, regardless of the types of etching agents (p<0.05). The 5 year bond strengths of the composites to HEMA-, MEMA- and MEAA-primed dentin were significantly higher than that of the control, regardless of the types of etching agents (p<0.05). The 1 day and 5 year bond strengths of the composite to MEAA-primed dentin were significantly higher than those of the composites to HEMA-primed dentin, regardless of the types of etching agents (p<0.05). The highest amount (182.3+/-8.0 microg/cm(2)) of dissolved calcium was determined for the pre-treatment with 10% PA, followed by that (152.0+/-6.9 microg/cm(2)) with 10% MA and that (140.1+/-2.8 microg/cm(2)) with 10-3 solution (p<0.05). The hybrid layer thicknesses (approximately 1 microm) for 10-3 solution were thinner than those (approximately 2 microm) for others after HCl immersion. For the controls, the hybrid layers after NaOCl immersion become narrower or disappeared. The main fracture pattern of specimens was a mixture of resin-dentin interface failure and dentin cohesive fracture after the bond test.. MEAA solution was more effective in improving the bond strength of the controls to etched dentin than was HEMA after 1 day and 5 years. Clearfil Photo Bond created good hybrid dentin layers which could resist NaOCl-attack and showed good dentin bond durability when dentin primers were used, regardless of the type of etching agent.

Topics: Acid Etching, Dental; Acrylamides; Analysis of Variance; Animals; Calcium; Cattle; Chlorides; Citric Acid; Composite Resins; Dental Bonding; Dentin; Dentin-Bonding Agents; Ferric Compounds; Hydrochloric Acid; Immersion; Maleates; Methacrylates; Microscopy, Electron, Scanning; Oxidants; Phosphoric Acids; Resin Cements; Sodium Hypochlorite; Spectrophotometry, Atomic; Stress, Mechanical; Surface Properties; Time Factors; Water

The adherence of resin cements depends upon, among other factors, the polar interactions across the interface: resin cement/restorative material. The polar interactions may be augmented by inclusion of polar additives such as maleic anhydride to the cement monomer. However, maleic anhydride is slowly converted to maleic acid when exposed to an aqueous environment. This may affect mechanical properties of such a cement in a negative way. It was the aim of the present investigation to analyze the role of maleic anhydride dissolved in the monomer of resin cements. The resin cement monomers used were common methacrylates, to which maleic anhydride in amounts of up to 30 mol% was added. Polymerization initiators were included to make the materials dual curing. Finally, the preparations were mixed with silanated fillers. The adherence energy of the cements bonded to a chromium-cobalt alloy was assessed by means of the double cantilever beam test. The strength and stiffness of the resin cements were recorded at base line and after two months storage in water. The initial adherence energy increased by a factor of about two as a result of addition of maleic anhydride. However, resin cements containing maleic anhydride suffered significant reductions in long-term adherence, strength and stiffness. These reductions were particularly pronounced in non-irradiated specimens. The use of resin cements containing maleic anhydride is not a viable means of conveying adhesiveness to resin cements.

Topics: Adhesiveness; Adhesives; Aldehydes; Chemical Phenomena; Chemistry, Physical; Chromium Alloys; Composite Resins; Dental Bonding; Elasticity; Humans; Maleates; Maleic Anhydrides; Materials Testing; Methacrylates; Polyethylene Glycols; Polymers; Polymethacrylic Acids; Polyurethanes; Resin Cements; Silanes; Stress, Mechanical; Time Factors; Water

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

The goal of this study was to illustrate the micromorphological spectrum along the resin-dentin interface when a water-based, dentin adhesive (Scotchbond Multi-purpose) was applied to acid-conditioned dentin under different dry and wet bonding conditions.. Twenty-eight 1 mm dentin discs were each conditioned with 10% maleic acid for 15 s. Twenty-four of these discs were randomly divided into four groups, based upon the status of the remaining surface moisture: Group I (30 s dry); Group II (3 s dry); Group III (visibly moist) and Group IV (overwet). They were bonded using Scotchbond Multi-purpose. The remaining four discs were bonded using an experimental water-based primer containing 35 vol.% HEMA (Group V). Laminated dentin disc pairs were prepared for transmission electron microscopic examination.. In all groups, diffusion of the polyalkenoic acid copolymer component of the primer into acid-conditioned dentin was localized to the surface region of the hybrid layer. The remaining part of the hybrid layer (the subsurface region) appeared variable. In Group I (30 s dry), collagen fibrils were collapsed. In Group II (3 s dry) and Group III (visibly moist), stained collagen fibrils were surrounded by wide electron-lucent interfibrillar spaces. In Group IV (overwet), a marked diffusion gradient was observed representing dilution of part of the primer components. In addition, an electron-dense primer phase, containing electron-lucent globular domains was invariably observed, irrespective of the hydration status of the demineralized collagen matrix. This electron dense phase was absent when HEMA alone was used as the primer (Group V).. With the use of a water-based adhesive, one could briefly air-dry the acid-conditioned dentin and allow the water in the primer to rehydrate the collapsed collagen matrix, without the risk of incomplete hybridization or tubular seal along the resin-dentin interface. However, care should be exercised to minimize dilution of the water-soluble primer component.

Topics: Acid Etching, Dental; Collagen; Dental Bonding; Dentin; Dentin-Bonding Agents; Diffusion; Humans; Maleates; Methacrylates; Microscopy, Electron; Resin Cements; Water

In an attempt to compare the morphology of the resin-dentin interface in areas where the dentinal tubules run perpendicularly or at an angle to the cavity surface with that of areas where they run parallel to it, we studied a dentin adhesive system using transmission electron microscopy and fluorescence confocal laser scanning microscopy. The design of the study included the simulation of the normal hydrostatic pressure within the pulp and the dentinal tubules. Following acid etching of the dentinal surface with maleic acid/HEMA, the smear layer was removed, and a superficial zone was demineralized in such a way that the exposed collagenous dentin matrix retained its integrity. Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred not only vertically via surface porosities, but mainly laterally, via the dentinal tubules. The adhesive resin labeled with fluorescein completely infiltrated the demineralized layer, thereby forming a hybrid layer. The orientation of the dentinal tubules had a profound effect on the formation of the hybrid layer. In areas with perpendicular tubule orientation, the layer was 3.2 +/- 0.8 microns thick, showing solid 27.2 +/- 0.8 microns long resin tags in the dentinal tubules, and a network of tiny tags in their side-branches. In areas with parallel tubule orientation the layer was significantly thinner (1.3 +/- 0.6 microns) and resin tags were absent.

Topics: Acid Etching, Dental; Adhesives; Collagen; Dental Bonding; Dental Cavity Preparation; Dental Pulp; Dentin; Dentin-Bonding Agents; Fluorescein; Fluorescent Dyes; Humans; Hydrostatic Pressure; Maleates; Methacrylates; Microscopy, Confocal; Microscopy, Electron; Microscopy, Fluorescence; Porosity; Resin Cements; Rhodamines; Smear Layer; Surface Properties

The purpose of this study was to investigate the relationship between dentine shear bond strength, using data from experiments performed according to a standard protocol, and the absolute humidity for a new, fourth generation dentine adhesive system.. Results of seven recently performed adhesion experiments using the same protocol and product were analysed. Groups of 10 human molars were each bonded in a humidity chamber. The temperature and relative humidity conditions varied from 23 to 37 degrees C and 30 to 95%. After bonding of the composite resin a shear bond test at a crosshead speed of 2.0 mm/min was performed.. The bond strength levels of the dentine adhesive system were influenced significantly by extreme temperature and humidity differences. Adhesion levels varied from 27.8 (SD 8.5) MPA to 12.8 (SD 1.4) MPA. Isobond strength curves are a good method to gain insight into the humidity sensitivity of adhesive systems.. Results of in vitro adhesive bonding procedures for a dentine adhesive can be significantly influenced by the absolute humidity levels at which the procedures are performed. Consequently "Materials and Methods" sections of publications should refer to absolute humidity or temperature and relative humidity levels as a relevant parameter.

Topics: Acid Etching, Dental; Adhesiveness; Bisphenol A-Glycidyl Methacrylate; Composite Resins; Dental Bonding; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Humans; Humidity; Linear Models; Maleates; Methacrylates; Molar; Resin Cements; Stress, Mechanical; Temperature; Tensile Strength

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

The shear bond strengths of a dental bonding system used in conjunction with a composite resin bonded to dentin were determined 1 minute after irradiation and after storage in saline at 37 degrees C for 24 hours, 1 week without and with temperature cycling, and 4 weeks without and with temperature cycling. The quantitative microleakage of class V preparations in cementum (dentin) restored with the system was determined by a spectrophotometric dye-recovery method. Excellent shear bond strengths ranging from 13.9 MPa (1 minute) to 19.5 MPa (1 week) were obtained. The shear bond strengths and quantitative microleakage of the multipurpose dental adhesive system compared favorably with the data obtained from other dental bonding systems under similar experimental conditions.

Topics: Analysis of Variance; Dental Bonding; Dental Leakage; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Humans; Least-Squares Analysis; Maleates; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Resin Cements; Smear Layer; Tensile Strength; Wettability

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 local detail of the geometry of the adhesive interface can have a significant effect on the measurement of dentin bond strengths and may be a contributory factor in the discrepancies among data in the published literature. The potential effect on the dentin bond strength due to modifications of the local stress distribution at the adhesive/dentin interface has been assessed. Tensile bond strength measurements for specimens with and without an adhesive flash were carried out and compared with the stress distribution at the adhesive interface determined by finite element stress analysis. The results showed that when the adhesive was constrained to the interface only, the tensile bond strength was 3.10 MPa, which increased to 6.90 MPa when a flash of adhesive was present. For a realistic measurement of dentin bond strength, the adhesive should be constrained to the interface only. Extension of the adhesive beyond the interface will result in an artificially high value for the dentin bond strength. A standardized method for the measurement of dentin bond strength is urgently needed, but must take these as well as all other known factors into account if results from different testing centers are to be directly comparable.

Topics: Adhesives; Bisphenol A-Glycidyl Methacrylate; Composite Resins; Dental Bonding; Dental Cements; Dentin; Humans; Maleates; Methacrylates; Microscopy, Electron, Scanning; Models, Biological; Resin Cements; Surface Properties; Tensile Strength; Viscosity

Standardized cylindrical Class V preparations, 3 mm in diameter and 1.5 mm deep, were made on the roots of 60 extracted human maxillary permanent canines. The teeth were restored with Scotchbond 2/Silux (S); Gluma/Lumifor (G); and Tenure/Perfection (T), respectively. The root apices were sealed with Copalite/amalgam and two coats of nail varnish applied to the teeth except for 1 mm around the restorations. For the qualitative microleakage evaluation the teeth were thermocycled x500 in 0.5% basic fuchsin between 8 degrees C and 50 degrees C and for the quantitative microleakage evaluation in 2% methylene blue solution. The marginal gap dimensions were measured on cylindrical restorations placed on the facial surfaces of ground root surfaces of 30 teeth. Epoxy replicas were made of the restorations, coated with gold/palladium and examined with the SEM. The maximum marginal gap dimensions were measured. The data were analyzed by ANOVA, Duncan's and their nonparametric analogues. In the qualitative microleakage evaluation the total microleakage was: S: 16; G: 50; T: 18. The quantitative microleakage (micrograms) was: S: 3.1 +/- 2.9; G: 16.1 +/- 5.3; T: 4.4 +/- 4.1. The maximum marginal gap dimensions (microns) were: S: 4.1 +/- 3.6; G: 9.3 +/- 3.4; T: 16.4 +/- 7.0.

Topics: Analysis of Variance; Composite Resins; Cuspid; Dental Bonding; Dental Cements; Dental Leakage; Dentin; Glutaral; Humans; In Vitro Techniques; Maleates; Methacrylates; Microscopy, Electron, Scanning; Nitrates; Nitric Acid; Oxalates; Polymethacrylic Acids; Resin Cements; Surface Properties

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

A recently released dentine adhesion promoter, based on a HEMA/maleic acid primer, was found to bond exceptionally well to dentine (14.1 MPa) if the adhesion promoter layer was applied thickly enough. Air inhibition of the promoter layer during its initial cure was seen to reduce the bond strength by a half if the promoter layer was air-thinned prior to curing. The adhesion promoter was found to greatly enhance the bond strength of composite to glass ionomer, removing the necessity to acid etch the glass ionomer prior to applying the composite. The failure of the composite/glass ionomer bond was always within the glass-ionomer cement itself, with the higher bond strengths resulting in a greater incidence of oblique cracks at 45 degrees to the bond surface than had been previously observed.

Topics: Acid Etching, Dental; Acrylates; Adhesives; Composite Resins; Dental Bonding; Dental Cements; Dentin; Glass Ionomer Cements; Humans; Maleates; Materials Testing; Methacrylates; Resin Cements; Stress, Mechanical; Surface Properties