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Query: EC:2.3.1.177 (BIS)
 957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study two types of bioactive bone cement containing either MgO-CaO-SiO2-P2O5-CaF2 glass (type A) or glass-ceramic powder (type B) were made to evaluate the effect of the crystalline phases on their mechanical and biological properties. Type A bone cement was produced from glass powder and bisphenol-a-glycidyl methacrylate (BIS-GMA) resin, and type B from glass-ceramic powder containing apatite and wollastonite crystals and BIS-GMA resin. Glass or glass-ceramic powder (30, 50, 70, and 80 by wt %) was added to the cement. The compressive strength of type A (153-180 MPa) and B (167-194 MPa) cement were more than twice that of conventional polymethylmethacrylate (PMMA) cement (68 MPa). Histological examination of rat tibiae showed that all the bioactive cements formed direct contact with the bone. A reactive layer was seen at the bone-cement interface. In specimens with type A cement the reactive layer consisted of two layers, a radiopaque outer layer (Ca-P-rich layer) and a relatively radiolucent inner layer (low-calcium-level layer). With type B cement, although the Ca-P-rich layer was seen, the radiolucent inner layer was absent. Up to 26 weeks there was progressive bone formation around each cement (70 wt %) and no evidence of biodegradation. The mechanical and biological properties of the cements were compared with those of a previously reported bone cement containing MgO-free CaO-SiO2-P2O5-CaF2 glass powder (designated type C).
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PMID:Mechanical and biological properties of two types of bioactive bone cements containing MgO-CaO-SiO2-P2O5-CaF2 glass and glass-ceramic powder. 878 9

A patient presented with recurrent facial dermatitis associated with dental work. Dermatology referral identified the cause as allergic contact dermatitis to the epoxy acrylate BIS-GMA. Occupationally-induced allergic contact dermatitis to epoxy resin was also demonstrated. A structurally distinct aliphatic acrylate was successfully substituted. Contact sensitivity to BIS-GMA is reviewed and the potential for epoxy sensitive patients to cross-react to BIS-GMA is discussed.
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PMID:Allergic contact dermatitis to bisphenol-A-glycidyldimethacrylate (BIS-GMA) dental resin associated with sensitivity to epoxy resin. 937 44

This in-vitro investigation sought to identify the most effective softening agents for three commercial anterior resin composites (Prisma APH, Brilliant and Blend-a-Lux) from four potential agents (75% ethanol, polyacrylic acid, acetone and acetic acid), selected as having close solubility parameter values to BIS-GMA. The Vickers microhardness test was applied to samples before and following a 180 s application of each agent. In addition, the degree of cavity enlargement following removal of resin composite restorations, aged by thermocycling, was assessed by image analysis. Using the same method the influence of both colour match and the 180 s application of softening agents, in the optimum chemical/material combinations, upon this was determined. Analyses of variance revealed that significant (P < 0-01) reductions in surface microhardness occurred when 75% ethanol was applied to Prisma-APH and acetic acid to Blend-a-Lux. Removal of restorations of all materials resulted in highly significant (P < 0.001) increases in cavity size. Application of either 75% ethanol to Prisma-APH restorations or acetic acid to Blend-a-Lux did not alter this result. Thermocycling only produced a significant (P < 0.01) (McNemar Test) deterioration in shade match of the Prisma APH restorations but analyses of variance, for all materials, revealed that the observed changes in colour match had no significant (P < 0.05) effect upon the degree of cavity size enlargement. It is concluded that the application of softening agents to reduce cavity enlargement is not a viable clinical option.
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PMID:Can chemical softening agents minimize cavity enlargement during removal of failed anterior resin composite restorations? 957 22

Marginal adaptation to cylindrical dentin preparations of five commercially available dental composites--Charisma, Estelite, Herculite, Pertac, and Silux Plus--and seven experimental dental composites containing prepolymerized filler was evaluated by measurement of the wall-to-wall polymerization contraction gaps. The experimental composites were prepared with varying amounts of spherical inorganic filler particles, irregularly shaped prepolymerized filler particles, and a base resin matrix composed of BIS-GMA and TEGDMA. Cylindrical dentin preparations, approximately 3.0 mm in diameter and 1.5 mm deep, were prepared in the exposed approximal dentin surfaces of extracted human molars. These cavity preparations were pretreated with an experimental dentin bonding system consisting of 0.5 mol/L EDTA, 35% glyceryl methacrylate, and Clearfil Photo Bond, then restored with each composite. Complete marginal adaptation was observed in two composites (Silux Plux and Estelite). Wall-to-wall contraction gaps were significantly related to the amount of ashed inorganic component in the composites (0.01 < P < 0.05) and to the spherical inorganic filler content by volume (P < 0.01).
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PMID:Marginal adaptation of dental composites containing prepolymerized filler. 961 Mar 20

The relationships between filler type, filler content, matrix resin composition and viscosity and the flow characteristics of composite paste formulations have been investigated. BIS-GMA and 10 experimental BIS-GMA analogues were diluted as needed with TEGDMA to produce 1000 and 2000 cp solutions corresponding to the viscosity range of commercial composite matrices. All of these resins were mixed with a silanated hybrid-filler and a silanated micro-filler. For each combination the maximum filler content was determined, as well as the paste consistencies (plasticities) at a series of filler contents. Paste consistencies were measured by a modification of the ADA specification methods developed for determining standard test consistencies for zinc phosphate and silicate cements. For each monomer-filler combination increasing filler contents resulted in monotonically reduced plasticities. The maximum filler contents appeared to be an attribute of the particular filler rather than matrix resin characteristics. For the materials used, the maximum contents were approximately 86 wt% (83 vol%) filler for the hybrid filler, and 36% wt% (24 vol%) for the microfilled material. At lower filler contents, plasticity differences unexpectedly existed even at equal filler contents and matrix viscosities. Evidence was found that the plasticity varied both with the base monomer composition and the amount of TEGDMA present. The results imply that compositional interactions between the filler and matrix influence the results when all known mechanical factors are controlled.
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PMID:Relationship between filler and matrix resin characteristics and the properties of uncured composite pastes. 967 68

Two paste, self cured BIS-GMA based resin was developed and physicochemical and biological characterization carried out. Its suitability and safety for clinical use were evaluated. Clinical trials for direct bonding of Orthodontic brackets conducted at the College of Dental Surgery, Manipal showed a success rate of 83% against 85% with "Right On" adhesive used as control. Further research to improve shelf life of the material led to the development of light cure-BIS-GMA based resin. It was evaluated for physicochemical characteristics which included setting time, compressive strength, diametral tensile strength, microhardness, water sorption and exothermic reaction. Biological characterization studies on material toxicity and biocompatibility on animal models established the safety and suitability of this composite for clinical use in dentistry. Clinical evaluation for direct bonding of Orthodontic brackets in comparison to Ultralight (T.P Orthodontics, USA) showed its handling characteristics to be superior to control. Flash removal was easier around bracket bases bonded with Chitra light cure. However, bond strength of light cure composite was 66% as compared to 79% with Ultralight. Subsequent improvement of the material increased the bond strength significantly. Failure rate with the new material was 11% against 13% with control in the ongoing clinical trials.
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PMID:Development and clinical evaluation of Chitra visible light cure composite. 973 1

Synolite resin was analysed using FTIR, NMR and HPLC to determine its components and purity. The resin was found to be predominantly BIS-GMA containing traces of its two isomers. The analysis indicated that there was no unreacted methacrylic acid or other impurities.
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PMID:Synolite as a base resin for dental composites and related biomaterials. 1014 60

Decalcification and caries during orthodontic treatment still remains a problem. A method to protect the susceptible area beneath and adjacent to bonded attachments, independent of patient compliance, would be extremely beneficial. A clinical trial was performed using a dual-cured lightly filled BIS-GMA fluoride-releasing sealant. The barrier effect of this material on white spot formation, gingival irritation, and plaque accumulation during fixed orthodontic therapy was examined. Twenty patients with a total of 225 metal brackets placed on anterior teeth participated in this study. Brackets were placed in both arches in a conventional manner with a chemically cured, unfilled bonding resin; 112 teeth (every other tooth) received the barrier material after bracket placement, while the remaining 113 teeth served as controls. Intraoral photographic slides were taken before and after treatment and were evaluated blindly by 7 observers for white spot formation. Gingival and plaque indexes were recorded initially and consecutively every 6 months. Observation time ranged from 5 to 18 months. The results of this prospective clinical study indicated that there was no significant difference (P >.05) between the decalcification rates of the treatment or control groups. Likewise there was no added benefit with respect to plaque accumulation or gingival irritation.
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PMID:Effectiveness of a fluoride-releasing sealant in reducing decalcification during orthodontic treatment. 1058 96

Three light curing composite pastes with varying resin matrix ratios [bisphenol A-glycidyl methacrylate (BIS-GMA)/urethane tetramethacrylate (UTMA) 25:75, BIS-GMA/UTMA 50:50, and BIS-GMA/UTMA 75:25 w/w%] were prepared in combination with a radiopaque glass powder and camphorquinone photoinitiator. Cured samples were aged at 37 degrees C in three food simulating media such as citrate buffer (pH 4.0), PBS buffer (pH 7.4), and 75% ethyl alcohol. Samples were withdrawn at specific intervals of 1, 15, 30, 45, and 60 days and tested for changes in mechanical properties, sorption, and solubility characteristics. Statistical calculations revealed significant changes in compressive strength (CS) for composites depending on the resin matrix ratio and type of medium used for aging. While diametral tensile strength (DTS) was affected adversely in citrate medium for composites with higher urethane content, samples stored in alcohol medium showed deterioration of transverse strength (TS) and microhardness (VMH) for all composites studied. Increase in BIS-GMA content in the resin matrix and storage in alcohol medium resulted in higher sorption and solubility values and lower microhardness.
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PMID:Effect of resin matrix ratio, storage medium, and time upon the physical properties of a radiopaque dental composite. 1065 45

Occupational allergic contact dermatitis caused by (meth)acrylates is common in dental personnel, whereas dental acrylic fillings and crowns have rarely been reported to cause problems in dental patients. Here we report on a 48-year-old woman who developed gingivitis, stomatitis, and perioral dermatitis after a temporary crown made of restorative, two-component material had been inserted. The manufacturer stated that the temporary crown base paste and catalyst contained three (meth)acrylates, namely, a proacrylate, which is a modification of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BIS-GMA); a tricyclate, which is a saturated, aliphatic, tricyclic methacrylate; and urethane methacrylate. The manufacturer refused to give more exact information on the (meth)acrylates. Patch testing revealed that the patient was highly allergic to BIS-GMA, other epoxy diacrylates, and (meth)acrylates, as well as to the base paste and catalyst of the temporary crown. Accordingly, it was concluded that the allergic reaction was caused by BIS-GMA, or a cross-reacting (meth)acrylate, or other (meth)acrylates in the temporary crown.
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PMID:Allergic contact gingivostomatitis from a temporary crown made of methacrylates and epoxy diacrylates. 1068 37


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