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PubMed1975

A chlorhexidine-containing methacrylic gel as a periodontal dressing.

The modification of a methacrylic gel for use as a periodontal dressing was attempted. The increased adhesion and rigidity of the resultant material appeared consistent with the clinical findings. Satisfactory retention of the dressing was found in 85% of those placed on a group of patients attending for periodontal surgery. The potential value of the methacrylic gel for carrying and releasing pharmacological agents useful in the management of lesions of the oral mucosa was assessed by incorporating chlorhexidine acetate into the dressing. In vitro and in vivo studies demonstrated effective release of the chlorhexidine from the dressing throughout the period of time a periodontal dressing is normally in situ. In conclusion the results suggested that the modified methacrylic gel fulfills the requirements of a periodontal dressing. Study to assess further the potential for this material to carry other pharmacological agents used in the topical treatment of lesions of the oral mucosa is indicated.

Acrylates↗
PubMed1984

Spontaneous autoradiographic grain activation associated with mast cells in methacrylate plastic embedded tissue sections.

Autoradiographic tracing using tritium labeled compounds or cells is a common laboratory technique for light and electron microscopy. This report describes a chemographic effect associated with certain cells in sections from tissues embedded in the new methacrylate plastic embedding compounds. When tissue sections from rats and rhesus monkeys that received no radioisotope were coated with nuclear track emulsion and subsequently developed, cells with morphologic characteristics of mast cells showed significant grain formation over the entire cell. Three different types of methacrylate plastics were tested using rat and monkey tissues and all three were found to promote grain formation over mast cells; however, this phenomenon was not seen in similar tissue sections from paraffin or epoxy embedded material. The properties of methacrylate plastics which promote positive chemography by mast cells may reflect the greater permeability of this class of plastics. Due to their wide tissue distribution, the presence of such chemographically active cells could cause false estimates of the distribution of either exogenous radiolabeled cells or radioisotopes within many tissues.

Animals↗
PubMed1989

Lymphocyte membrane antigens in glycol methacrylate embedded tissue.

The use of formalin or Michel's solution either alone or in combination with acetone, and acetone, methanol or ethanol alone as fixatives, and glycol methacrylate as embedding medium were evaluated for their suitability in procedures to detect lymphocyte membrane antigens by OKT and Leu monoclonal antibodies in human tonsils. No staining was detected in sections fixed in 70% or absolute ethanol and embedded in glycol methacrylate with either the direct immunofluorescence or avidin-biotin methods. Fixation in Michel's solutions plus acetone at room temperature revealed staining by both. Neither method resulted in staining after fixation in Michel's solution plus acetone at 4 C presumably due to the slow action of the fixative. Staining was enhanced using a combination of primary and secondary biotinylated antibodies. Dual staining allowed concurrent detection of two antigens in the same section. Glycol methacrylate embedding is a possible replacement for ultracold storage in the preservation of tissue for immunofluorescent staining.

Acrylates↗
PubMed1990

Changes in NMR chemical shifts of methacrylates induced by their interactions with the phospholipid and the phospholipid/cholesterol liposome system.

The interaction of methyl methacrylate (MMA), ethylene dimethacrylate (EDMA) and triethyleneglycol dimethacrylate (TEGDMA), which are widely used in dentistry, with the dipalmitoyl phosphatidylcholine (DPPC) and the DPPC/cholesterol (CS) liposome system was studied by 1H and 13C nuclear magnetic resonance spectroscopy (NMR). EDMA and TEGDMA have a larger interaction with the DPPC liposome system compared to MMA, resulting in changes in chemical shifts. The 13C chemical shift differences of C = C-C-O were larger than those of other carbon portions in methacrylate, indicating that double bonds interact predominantly with DPPC liposomes due to the hydrophobicity of methacrylates. At 37 degrees C, 1H signals from TEGDMA appeared in the DPPC/CS/TEGDMA liposome system, while signals due to H2C = C-C-OCH2CH2 did not appear in the DPPC/TEGDMA liposome system.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

Influence of water on bonding of various methacrylates to dentin treated with 10% citric acid-3% ferric chloride solution.

The bond strength of resins (MMA-TBB resin system), containing 2-hydroxyethyl methacrylate (2-HEMA), 3-methacryloyloxypropionic acid (3MPA), 2-phenylethyl methacrylate (Py1EM) and 2-(1-naphthyl) ethyl methacrylate (NEM), to dentin treated with a solution of 10% citric acid and 3% ferric chloride was measured after being immersed in water at 37 degree C for a long period of time to investigate the influence of water on bonding, and the relationship between the monomer structure and the decrease in bond strength in water. The bond strength of the resins did not change with the time spent immersed in water up to 6 months, but decreased with any further increase in time. The decrease in bond strength of all the resins tested was caused by either the degeneration and swelling of collagen or a difference in the degradation of the resin inside and outside the acid-proof dentin layer. There was no significant relationship between the decrease in bond strength in water and the monomer structure.

Acid Etching, Dental↗
PubMed1976

Effect of the methyl methacrylate-tributylborane sealant in preventing occlusal caries.

A newly developed pit and fissure sealant, named Enamite, was studied technologically and clinically. Major ingredients of the sealant are a solution of 3% 2-hydroxy-3-beta-naphthoxypropyl methacrylate in methyl methacrylate and poly (methyl methacrylate) powder, using tributylborane as an initiator. In comparison with other commercially available sealants, Enamite showed much greater adhesiveness to enamel, which was confirmed by scanning electron micrographic observations. The sealant was applied to 161 first molars in 99 children, aged 6-8 years, to determine the caries preventive as well as the caries retardation effect. Among the treated teeth, 98 were intact and the remaining had incipient caries. The right side teeth of each subject was assigned to the test side and the other side served as a control. Each child was evaluated every 6 months by clinical exploration and bite-wing X-ray survey. At the final examination, the electric conductivity test was also used for the caries detection. After 2 years the sealant was effective in preventing 57.1% of the occlusal caries on treated compared with control teeth. When evaluation was made by including the caries retardation effect--teeth initially carious but remaining sealed after 2 years were counted as effective--, the sealant was effective in preventing or retarding 96.3% of the occlusal caries.

Adhesiveness↗
PubMed1992

Comparative lectinhistochemical studies on paraffin- and glycol methacrylate-embedded CNS tissue specimens from AIDS autopsies. Mistletoe lectin I (ML I) as cell-marker.

Brain tissue and spinal cord tissue from 12 patients who had died of AIDS was fixed in neutral formalin; then after the embedment of some of it in paraffin and some of it in glycol methacrylate, it was analyzed lectinhistochemically with mistletoe lectin I (ML I). Mistletoe lectin (ML I) is a reliable marker for microglia cells and macrophages and for special cell forms (polynuclear giant cells, so-called pericytes) belonging to this cell system. In both the embedding procedures used, the representation of the cells is very clear and subtly differentiated so that the preparations are very well suited to the study of AIDS-associated tissue damage in the CNS. Whereas the immunological macrophage markers (CD 68 markers) KPI, PG-M1 produce good results on paraffin-embedded material but are completely useless on material embedded in glycol methacrylate, the cells of the monocyte-macrophage system can be represented very well and reliably after being embedded in glycol methacrylate with mistletoe lectin I (ML I).

AIDS Dementia Complex↗
PubMed2003

Adhesion of 4-META/MMA-TBB resin to ground enamel treated with self-etching primer containing amino acid methacrylate.

PURPOSE: The effect of self-etching primer on the adhesion of tri-n-butylborane (TBB)-initiated resin to enamel has not been fully determined. We prepared a self-etching primer containing amino acid methacrylate, and evaluated the effectiveness of the self-etching primer for the adhesion of TBB-initiated 4-methacryloxyethyl trimellitate anhydride (4-META)/methyl methacrylate (MMA) resin to ground enamel. MATERIALS AND METHODS: Methacryloyloxy tyrosine (MTY) was prepared by reacting methacryloyl chloride and L-tyrosine in trifluoroacetic acid. An original self-etching primer containing an aqueous mixture of MTY, 35 wt% 2-hydroxyethyl methacrylate (HEMA), and 3 wt% ferric chloride was designed. Three strengths of MTY (5%, 10%, and 20%) were tested. The bovine enamel surface was treated with the self-etching primer for 30 s. After drying, a stainless steel rod was bonded to the enamel using TBB-initiated 4-META/MMA resin. The tensile bond strength was measured after 1-day immersion in water at 37 degrees C. RESULTS: The self-etching primer containing 20 wt% MTY (20MTY) yielded a significantly higher bond strength of 13.2 +/- 2.8 MPa than the self-etching primer containing 5 wt% and 10 wt% MTY. This value was not significantly different from that with phosphoric acid etching. Field-emission scanning electron microscopy revealed that 20MTY treatment produced no distinct dissolution pattern on enamel. Tight bonding between the resin and enamel was clearly observed. CONCLUSION: Our original self-etching primer containing 20 wt% MTY, 35 wt% HEMA, and 3 wt% ferric chloride was effective for obtaining strong adhesion of 4-META/MMA-TBB resin to enamel compatible with phosphoric acid etching.

Acid Etching, Dental↗
PubMed1977

[Studies of the dental methacrylic resins. (V) Effects of molecular weight and temperature on the plasticity (author's transl)].

The plasticity, the douing time, and the working time, of the mixture of powder-liquid type methacrylic resin were measured under the various circumstances of the elapsed time and the certain temperature. Six polymethyl methacrylates, whose molecular weight was prepared by mean of gamma-ray irradiation, were used as the polymer of resin, again methyl methacrylate being used as the monomer of resin. The results obtained are as follows: (1) The plasticity is reduced with the increase of the molecular weight of the polymer. (2) The plasticity, generally, is reduced with the time elapsed, but its values appear at 10 min. and 5 min. elapsed at 16 degrees C and 23 degrees C respectively. (3) The plasticities of the mixtures of polymers with 6 X 10(4), 8 X 10(4), 20 X 10(4) and 34 X 10(4) molecular weights are increased with the increase of temperature. The plasticities of the mixtures of polymers with 60 X 10(4) and 74 X 10(4) molecular weights at 0 min. time elapsed, indicate their maximum value at 30 degrees C. At 5 min. time elapsed plasticities of all mixtures indicate their maximum value at 23 degrees C. Over 5 min. time elapsed, however, the plasticity is reduced with the increase of temperature. (4) The doughing time and the working time are reduced with the increase of molecular weight of the polymer and the temperature.

Acrylates↗
PubMed1988

[Immuno- and enzymehistochemical studies of methacrylate-embedded biopsy material, especially iliac crest biopsies].

Immunohistochemical and histochemical methods are increasingly used and their application in surgical pathology is obvious. Especially we used these methods on bone marrow core biopsies. Optimal and comparable results have been obtained by using different methods after halving the biopsy cores longitudinally and/or transversally. The two halves were used for cytologic imprints. Two parts of the biopsy cores were embedded in polymethacrylate at low temperature (-20 degrees C). The methacrylate-embedded biopsy part for routine histology was fixed in Schaffer's solution (methanol-formalin-fixative). The methacrylate-embedded undecalcified section of 4 microns may be stained by most stains commonly employed in routine histopathology after removal of the plastic. The sections are virtually free of artefacts such as shrinkage and swelling in the light microscope. The second methacrylate-embedded part of biopsy cores was fixed in 2% paraformaldehyde with 5% sucrose in 0.02 M phosphate buffer (pH 7.4) and dehydrated in ethyleneglycolmonobutylether. All procedures were carried out at 4 degrees C. This method permits the use of immunohistochemical and histochemical procedures. The immunohistochemistry was carried out at sections of 4 microns after removal of the plastic with methoxide and use of proteolytic enzyme (0.1% alpha-chymotrypsin) to unmask antigens in sections. Surface and intracellular immunoglobulins were very well detected with the indirect FITC method. The histochemical procedures are carried out at sections of 7-8 microns after removal of plastic with xylene and toluol. The sections were incubated for specific esterase and nonspecific esterases, acid and alkaline phosphatase and then examined by light microscopy. A third part of biopsy cores may be immediately frozen, and cryostat sections are stained and evaluated for rapid diagnosis and used for immunohistologic analysis with mono- and polyclonal antibodies (FITC method) and/or histochemical investigations. Imprints of biopsy cores are evaluated for cytological, cytochemical and/or immunocytological analysis with mono- and polyclonal antibodies (FITC method). The cryostat sections and the imprints are fixed for all methods with 2% paraformaldehyde and 5% sucrose in PBS (0.02 M, pH 7.4) at 4 degrees C for 30 minutes. The best diagnostic results were obtained in the myelo- and lymphoproliferative disorders using the combination of methods described here. Examples were demonstrated.

Biopsy↗
PubMed1986

Separation of human lymphoid cells by affinity chromatography and cell surface labelling by hydroxyethyl methacrylate particles using monoclonal antibodies.

The hydroxyalkyl methacrylate gel Separon, Sepharose 6MB and polystyrene dishes with bound antibodies were used for affinity chromatography of cells isolated from human tonsils and peripheral blood. Enrichment of T cells by filtration through anti-human immunoglobulin Separon or Sepharose 6MB columns was comparable to that achieved by "panning" on dishes or by Nylon wool column fractionation. High enrichment of B cells was obtained when cells pretreated with monoclonal anti-T cell antibodies were fractionated on columns or dishes where anti-mouse antibody was bound. Hydroxyethyl methacrylate copolymer microspheres were conjugated with monoclonal antibodies directed against surface markers of human lymphocytes or with anti-mouse immunoglobulin antibodies and used for surface labelling of cells. The results obtained by immunofluorescence were in good correlation with labelling by hydroxyethyl methacrylate immunobeads.

Animals↗
PubMed1982

Sensitization capacity of polyester methacrylate in ultraviolet curing inks tested in the guinea pig.

One of the prepolymers used in Ultraviolet (UV) curing ink formulations is acrylated polyester. The prepolymer investigated is a dimethacrylated polyester, thus a saturated polyester terminated with methacrylic groups. In conventional UV-curing coatings the prepolymer commonly used is an unsaturated polyester. Three of six workers with dermatitis from UV-curing inks in printing plants had positive test results from the polyester methacrylate present in the inks used. The sensitizing capacity, performed with the "Guinea pig maximization test", shows polyester or methacrylate to be a moderate sensitizer.

Acrylates↗
PubMedDate not supplied

Proton nuclear magnetic resonance spectroscopic detection and determination of ethylene glycol dimethacrylate as a contaminant of methyl methacrylate raw material.

A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1-11% of dimer yielded a dimer recovery of 100.5 +/- 2.05% (mean +/- standard deviation). Correspondence (correlation coefficient, r = 0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.

Drug Contamination↗
PubMed1998

A methacrylate-based cement used as a root canal sealer.

In this study, a methacrylate-based orthopaedic bone cement was modified for use as a root canal sealer by changing the monomer from n-butyl methacrylate to tetrahydrofurfuryl methacrylate. The sealing and bonding capabilities, solubility and handling properties of the resin were evaluated. Seventy-three extracted mature human teeth with single canals were used. The teeth were randomly divided into two experimental groups each of 30 teeth; three control teeth were set aside for the leakage tests. Ten teeth were reserved for the scanning electron microscope studies. All the experimental teeth were root filled with gutta-percha and the resin sealer. The particle size of the polymer was limited in Group 1 to 75 microns or less and in Group 2 to 45 microns or less. The controls were filled with gutta-percha only. Silver nitrate solution was used as the leakage indicator. In Group 1 the mean linear penetration of the indicator was 1.10 mm +/- 1.04; four roots showed no leakage. In Group 2 the mean linear penetration of the indicator was 0.57 mm +/- 0.65; 12 roots showed no leakage. The test bodies showed no weight change after 1 and 3 months' storage in saline at 37 degrees C. The scanning electron microscope examination revealed a bond both between the resin and the dentine and between the resin and the gutta-percha. The working time of the new resin composition was normally about 50 min, and handling was found to be easy.

Bone Cements↗
PubMedDate not supplied

Allergic contact dermatitis from 2-hydroxyethyl methacrylate in an adhesive on an electrosurgical earthing plate.

A highly (meth)acrylate-allergic patient underwent surgery because of nodular struma. Three days after her operation she developed an itching dermatitis on her left thigh. She came to our attention 18 days after the operation, because of an oozing, highly pruritic dermatitis, 8 x 19 cm in width on her left thigh, at the site where an electrosurgical earthing plate had been used during the surgery. It was revealed that the pressure-sensitive adhesive of the pad contained 2-hydroxyethyl methacrylate (2-HEMA) to which the patient earlier had had an allergic patch test reaction. The patient was negative on patch testing to other (meth)acrylates present in the pad. Patients should be questioned about possible methacrylate sensitivity before methacrylate-containing electrosurgical earthing plates are used during surgery. Allergic contact dermatitis caused by acrylic adhesives is briefly reviewed.

Adhesives↗
PubMed1975

Factors influencing the creep behavior of poly(methyl methacrylate) cements.

Room temperature compression creep and recovery tests have been performed using samples of pure poly(methyl methacrylate) (PMMA), three commercially available poly(methyl methacrylate) cements, and several experimental cements. From these tests the influence of density, mixing procedure, particle size, methyl methacrylate-styrene copolymer, barium sulfate, aquenous storage environments, residual monomer, molecular weight of the continuous phase, benzoyl peroxide, and N,N-dimethyl-paratoluidine, upon the creep behavior of PMMA cements has been determined. The important results is that lowering the porosity or residual monomer content, increasing the powder size, or adding an MMA-styrene copolymer tends to increase the creep resistance of PMMA cement.

Benzoyl Peroxide↗