maleic-acid and silicon-carbide

The aim of this in vitro study was to evaluate the effect of 7% maleic acid and 17% EDTA solutions on the microhardness and the surface roughness of human root canal dentin.. Forty-five extracted human maxillary central incisors were sectioned longitudinally into a total of 90 segments, were embedded in auto polymerizing acrylic resin, and were grounded flat with silicon carbide abrasive papers. Based on the test solutions used, samples were divided randomly into three groups: (1) the EDTA group, 1 mL of 17% EDTA for 1 minute (n = 30), (2) the maleic acid group, 1 mL of 7% maleic acid for 1 minute (n = 30), and (3) the control group, 1 mL of 0.9% saline for 1 minute (n = 30). Every group was then divided into two subgroups of 15 specimens each. In group 1a, 2a, and 3a, specimens were used to determine the microhardness of the root canal dentine in the coronal, middle, and apical third using Vicker's hardness tester. In groups 1b, 2b, and 3b, specimens were used for the determination of surface roughness of the root canal dentine using a roughness tester (Surtronic, Leicester, England). The data were statistically analyzed using the Kruskall Wallis and Mann Whitney U tests.. There was no significant difference between EDTA and maleic acid in the reduction of microhardness. The increase in roughness was significantly greater with maleic acid when compared with EDTA.. Maleic acid reduced the microhardness of root dentin similar to EDTA but increased the surface roughness significantly more than EDTA.

Topics: Aluminum Oxide; Carbon Compounds, Inorganic; Chelating Agents; Dental Pulp Cavity; Dentin; Edetic Acid; Hardness; Humans; Maleates; Materials Testing; Root Canal Irrigants; Silicon Compounds; Surface Properties; Time Factors; Tooth Apex

The use of disinfectants on the dentin surface contributes to superficial cleaning and removal of remaining microorganisms of the carious process. However, the effect of these agents on the adhesion of resin materials to the dentin surface of primary teeth has not been established. This study evaluated the dentin micromorphological effects due to the use of antimicrobial agents in the different depths of dentin. Twenty-five buccal surfaces of primary molars were prepared from the sectioned teeth, ground flat and polished with silicon carbide paper of different grits. The surfaces were treated with 32% phosphoric acid with benzalkonium chloride (Bisco), 35% phosphoric acid gel (3 M), 3% benzalkonium chloride solution by itself or 10% maleic acid. All agents were applied for 15 seconds on the dentin surface. The samples were washed with distilled water, dried and coated with gold for observation of the dentin surface with the scanning electron microscope. The samples were subdivided according to the dentin depth in upper, middle and lower areas. The following was observed: presence of smear layer, opening of the dentin tubules, and inter and intratubular dentin morphology. The effects of the antimicrobial agents were compared in the different depths of the dentin. The results demonstrated that the surface conditioned with 3% benzalkonium chloride solution presented few disclosed dentin tubules. The use of the 32% phosphoric acid with benzalkonium chloride completely removed the smear layer and increased the diameter of the dentin tubule openings. The 35% phosphoric acid totally exposed the tubules in the upper area of the analyzed surface but partially exposed them in the middle and lower areas. The 10% maleic acid totally removed the smear layer, left all the tubules opened and conditioned the intertubular dentin. It was concluded that in the different depths of the dentin surface, conditioning with 10% maleic acid in primary teeth showed the most consistent micromorphological characteristics compared to the other agents used in this study.

Topics: Acid Etching, Dental; Anti-Infective Agents, Local; Benzalkonium Compounds; Carbon Compounds, Inorganic; Child; Dental Bonding; Dental Polishing; Dentin; Humans; Maleates; Microscopy, Electron, Scanning; Microtomy; Phosphoric Acids; Resins, Synthetic; Silicon Compounds; Smear Layer; Surface-Active Agents; Tooth, Deciduous

The purpose of this study was to evaluate the short-(24 h) and long-(180 day) term shear bond strengths of resin to bovine dentine etched with varying dilutions of aqueous solutions of phosphoric and maleic acids.. Bovine dentine surfaces were prepared using water irrigated #600 grit SiC paper. The dentine surfaces were etched in groups of 10 teeth using various dilutions of phosphoric or maleic acid. Using the Scotchbond Multipurpose System (SBMP; 3M Co., MN, USA) and a wet technique the etched surfaces were primed and unfilled bonding resin (UBR) was applied to the dentine surface within the confines of a gelatin cylinder. A cylinder of filled resin (Z 100; 3M Co., MN, USA) was then photocured and the specimens were then stored in water for 24 h or 180 days prior to shear bond testing to failure.. The results showed that high bond strengths were recorded using acids which were more dilute than those commercially available. There were also indications that phosphoric acid is not the etching acid of choice for the SBMP system.. The results of this study showed that high bond strengths can be achieved in dentine using etching acids which are more dilute than those commercially available. Maleic acid appears to be the etchant of choice for the SBMP system.

Topics: Acid Etching, Dental; Animals; Carbon; Carbon Compounds, Inorganic; Cattle; Composite Resins; Dental Bonding; Dentin; Dentin-Bonding Agents; Hydrogen-Ion Concentration; Maleates; Methylmethacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Silicon Compounds; Silicon Dioxide; Surface Properties; Tensile Strength; Time Factors; Zirconium