G.M. Brauer

Effect of Diluent Monomer on the Physical Properties of Bis-GMA-based Composites

packets for IADRs 1982 meeting in New Orleans are now available, from the Central Office and from the office of your Dean. Vol. 60 No. 6 989

Bonding of Bovine Enamel to Restorative Resin: Effect of Pretreatment of Enamel

The efficiency of simple treatments of the enamel surface with various polyfunctional acids and chelating agents was studied to obtain adequate adhesion between tooth surfaces and commercially available acrylic resins. Many water soluble acids induced bonding to enamel. Two ten-second treatments at three minute intervals with acid solutions such as 20% lactic acid may be useful in the clinical treatment of precarious lesions.

New Amine Accelerators for Composite Restorative Resins

The overall characteristics of the composites cured with a number of newly synthesized, tertiary aromatic amines compare favorably to those of resins polymerized with commonly used accelerators. Maximum compressive and tensile strength for the composites are obtained only over a narrow concentration range of accelerator used.

Isocyanato Urethane Methacrylates Derived from Hydroxyethyl Methacrylate

Isocyanato urethane methacrylates were synthesized from five diisocyanates and hydroxyethyl methacrylate. They may be homopolymerized or copolymerized with other methacrylates by the usual free radical methods of initiation and have potential as adhesion-promoting agents for dentin.

The Reaction of Metal Oxides with o-Ethoxybenzoic Acid and other Chelating Agents

Z INC oxide-eugenol mixtures form a hard, coherent mass that has been useful in a number of dental applications. The hardened mass consists of zinc oxide embedded. in a matrix of a zinc eugenolate chelate with the empirical formula (C10H1102) 2Zn.1 Mixtures of zinc oxide with ortho substituted phenols such as isoeugenol, guaiaeol, and 4-methylguaiacol also harden. As would be expected from the reaction mechanism, phenols that do not contain ortho substituents or that contain substituents that are incapable of chelation do not undergo this reaction. The presently available commercial zinc oxide-eugenol mixtures harden rapidly only in the presence of accelerators. The products have low compressive strength. The materials inhibit the polymerization of acrylic monomers. Hence, acrylic resins will not polymerize in direct contact with these materials. It therefore appeared of interest to study the reaction of zinc oxide with a number of commercially available chelating agents. A large portion of this report deals with the products obtained from mixtures of zinc oxide with o-ethoxybenzoic acid (EBA) because they appeared to be the most promising.

4-N,N-Dialkylaminophenethanols,-Alkanoic Acids and Esters: New Accelerators for Dental Composites:

The newly synthesized 4-N,N-dialkylaminophenethanol, 4-N,N-dialkylaminophenalkanoic acid and ester are highly reactive accelerators for the polymerization of composites. With low amine concentration, nearly colorless restorations having good color stability are obtained.

Characterization of Components of Dental Materials and Components of Tooth Structure by Differential Thermal Analysis

Differential thermal analysis (DTA) has been used to characterize a variety of dental materials and the components of tocth structure. The technic is useful for the rapid comparison of similar materials, quality control, measurement of melting ranges, and the study of reactions occurring at elevated temperatures.

Oligomers with Pendant Isocyanate Groups as Adhesives for Dentin and Other Tissues

Oligomers containing pendant isocyanate groups were synthesized from various vinyl monomers, m-isopropenyldimethylbenzyl isocyanate (TMI), and 2-isocyanatoethyl methacrylate (IEM). The liquids were characterized by their refractive indices, infrared spectra, and percentage of isocyanate groups in the molecule. Adhesive properties of these compounds were compared with those of oligomers prepared from methacrylate esters, IEM, and/or TMI which had been synthesized previously. Bond strengths of the sodium salt of ethylenediaminetetraacetic acid (Na2EDTA adjusted to pH 7.4) and glutaraldehyde-treated dentin cemented to composite resin with dilute solutions of the oligomers and then stored in water were determined by the procedure of Kemper and Kilian (1975). These adhesive compositions, especially formulations synthesized from vinyl monomers, adhered at least as well to dentin as did other dentin bonding agents. Oligomers synthesized with methacrylate esters bonded more strongly to bone than did other hard-tissue adhesives. These oligomeric compositions are also excellent soft-tissue adhesives. For example, they provide a strong bond between a collagenous substrate (such as calfskin) and cured denture-base resin. Provided that their biological properties prove satisfactory, these compositions could find many applications as hard-and soft-tissue adhesives in clinical dentistry.

Bonding of Acrylic Resins to Dentin with 2-Cyanoacrylate Esters

Strength and durability of the dentin-acrylic resin joint cemented with 2-cyanoacrylate esters were studied. Maximum adhesion is obtained with isobutyl 2-cyanoacrylate after 1% acid pretreatment of the dentin. Hydrolytic stability is somewhat improved by addition of polymer to the adhesive or coating around the joint.

Effect of Hydrophilic Diluents on the Properties of Cured Composites

Hydrophilic diluents in composite formulations slightly increase water sorption of cured resin. This increased water uptake does not result in a significant improvement in the marginal adaptation, although other properties of the resulting composites are very satisfactory.