OBJECTIVES To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. STUDY DESIGN Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X∘Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX...

BACKGROUND There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. MATERIAL AND METHODS Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot ...

The aim of this in vitro study was to evaluate enamel microhardness following bleaching treatments using either high- or low-concentration hydrogen peroxide (HP) agents containing calcium and/or fluoride. Sixty enamel blocks were bleached with 1 of 6 different bleaching agents (n = 10). The high-concentration HP agents were Whiteness HP Maxx (35% HP), Whiteness HP Blue (35% HP, 2% calcium gluco...

The purpose of this study was to evaluate the polymerization effectiveness of a composite resin (Z-250) utilizing microhardness testing. In total, 80 samples with thicknesses of 2 and 4 mm were made, which were photoactivated by a conventional halogen light-curing unit, and light-curing units based on LED. The samples were stored in water distilled for 24 h at 37 ° C. The Vickers microhardness ...

The aim of this study was to evaluate the influence of different light-curing units on the tensile bond strength and microhardness of a composite resin (Filtek Z250 - 3M/ESPE). Conventional halogen (Curing Light 2500 - 3M/ESPE; CL) and two blue light emitting diode curing units (Ultraled - Dabi/Atlante; UL; Ultrablue IS - DMC; UB3 and UB6) were selected for this study. Different light intensiti...

OBJECTIVE Tooth bleaching tends to increase enamel roughness and porosity, in addition to reducing surface microhardness. The aim of this in vitro study was to evaluate the effects of bleaching treatments using different hydrogen peroxide (HP) concentrations, with and without light activation on bovine enamel microhardness. MATERIALS AND METHODS The buccal surfaces of sixty bovine incisors we...

This study aimed to evaluate the effect of beers on the bovine enamel microhardness. Fifty rectangular (1 x 3 x 1 mm-height x width x thickness) enamel specimens were obtained from permanent bovine incisors, and divided into five groups (n = 10) according to the treatment employed: Saliva, Coke, Brahma, Heineken, and Budweiser. Microhardness (Knoop) were obtained before; after 5, 30 and 60 min ...

The microhardness, H, of carbon black–polycarbonate and carbon black– low-density polyethylene composites was investigated. Two types of microadditives with different average particle sizes were employed. It has been shown that the morphology of the polymeric matrix conspicuously influences the hardness dependence of the composites with volume concentration of filler, f. The microhardness of th...

OBJECTIVE The aim of this study was to analyze the impact of green tea on dentin erosion. MATERIALS AND METHODS Twelve extracted sound human premolars were immersed in Coca Cola with a pH of 2.8 for 5 minutes. The surface microhardness was measured with a Knoop diamond under a load of 50gr/10s. The teeth were immersed in green tea (Camellia sinensis) solution for one minute. The microhardness...

The dissimilar joint between aluminum/titanium alloys (Al 6082 and Ti G2) were successfully achieved by CO2 laser welding with a single pass and without filler material using the overlap joint design. Laser welding parameters ranges combinations were experimentally determined using Taguchi approach with the objective of producing welded joint with acceptable welding profile and high quality of ...