Aims The aim of this project was to evaluate the effects of 2 different whitening strips on color, microstructure and roughness of tea stained porcelain and composite surfaces. Methods 54 porcelain and 72 composite chips served as samples for timed application of over-the-counter (OTC) test or control dental whitening strips. Chips were divided randomly into three groups of 18 porcelain and 2...

Abrasive flow machining (AFM) is an advance machining process which is used to machine complex shape and is used to deburr, remove recast layer and radius surfaces. This research uses a developed abrasive flow machine and an experiment employing abrasive flow machining was conducted on plunger body fabricated on stainless steel SS 446. In this research AFM parameters such as abrasive particle s...

The tribological behavior of new green friction materials with rice husk (RH) and ash (RHA) is discussed in the current paper. Two formulations developed, one 6% RH RHA, were compared a reference formulation alumina under AK Master test, through braking tribometer. Formulation RHA showed performance equal to or better than material, especially high temperature applications where particles assis...

PURPOSE Our study aimed to test the null hypothesis that whitening and non-whitening dentifrices affect similarly the surface roughness of commercial microhybrid composites, independent of the brushing time. MATERIALS AND METHODS One hundred and ninety-two disc-shaped specimens of Filtek Z250 (3 M/ESPE, St. Paul, MN, USA) and Rok (SDI, Australia) were built up and randomly assigned to 24 grou...

OBJECTIVES To investigate the loss of enamel and dentin surface caused by the interaction between abrasives in toothpaste and toothbrush filament stiffness. METHODS The study followed a 2 (high-level or low-level abrasive; silica) × 3 (filament stiffness; soft, medium or hard) × 2 (cycling time; 3 or 5 days) factorial design. Polished bovine enamel and dentin specimens (n = 8 each per group) ...

introduction: whitening toothpastes which have been accepted in populations may affect properties of enamel and restorative materials. the aim of this study was to compare the microhardness of human enamel and z250 microhybrid composite resin after brushing with two whitening toothpastes. materials and methods: in this experimental study of enamel specimens, forty five freshly extracted human i...

When cutting thick material with an abrasive wateriet, the surface area can be characterized by two texture types. At the top of the cut, the surface texture is smooth. At the bottom, the slurry jet exiting the workpiece forms large striations in the surface. An investigation was conducted to experimentafly determine the influence of the abrasive waterjet cutting parameters on surface texture. ...

OBJECTIVE The goal of this study was to evaluate the enamel whitening effects of 2 new test formulations, one of which was a rinse, and the other a whitening strip. MATERIALS AND METHODS Forty enamel chips were prepared from 20 healthy extracted teeth (2 from each tooth). After pre-staining and colorimetry to measure L* and b* values, 20 matched samples were immersed in either test or control...

A multicomponent evaluation of the oxidative consumption of salivary biomolecules by a hydrogen peroxide (H2O2)containing tooth-whitening formulation has been performed using high-resolution proton (H) nuclear magnetic resonance (NMR) spectroscopy. Unstimulated human saliva samples (n = 10) were treated with aliquots of supernatants derived from 1) the H2O2-containing whitening gel, 2) the corr...