The resistance of three silicone and one polyvinyl chloride maxillofacial materials to staining by tea, lipstick, and disclosing solution was measured by reflectance spectrophotometry. Changes in color caused by staining were larger than changes caused by color instability of the base elastomers or pigments under conditions of accelerated aging.

OBJECTIVE The purpose of this laboratory study was to evaluate extrinsic stain removal from teeth by a specially engineered sonic powered toothbrush with unique sensing and control technologies, using the Triple Clean and the Sensitive refill brush heads, in comparison to a manual flat-trim toothbrush. METHODS Twelve (12) artificially stained bovine teeth were tested with each product. The pe...

OBJECTIVE Two randomized, six-week, double-blind, parallel group, clinical trials were independently conducted to compare the extrinsic stain removal efficacy of a novel whitening therapeutic dentifrice containing 0.454% stannous fluoride and sodium hexametaphosphate in a formulation with high cleaning silica, relative to a positive control whitening dentifrice. METHODOLOGY Generally healthy ...

The color in the pigment of the stain is caused when molecules absorb light in the visible wavelength range (400-780 nm) [10]. The wavelengths that are not absorbed will be reflected instead and are visible to the human eye. For example, red wine stains are red because the molecules absorb every wavelength that is not in the red range, and the red wavelengths (500-600 nm) are then reflected to ...

Step in procedure Supernatant haemoglobin (g) After thawing 0 45 First wash 1 6 Second wash 0-45 Third wash 0-12 Final product 0-023 After incubation 0-05 stability of the red cell preparation after incubation at 37°C for 30 minutes. Recovery was calculated from the supernatant haemoglobin in relation to the initial total haemo-globin after thawing (table 2). Mean (SD) recovery was 70% (13 3), ...

Nyka9) employed the Gomori-Grocott's chromic acid-methenamine silver method for demonstrating tubercle bacilli in tissue sections after sublimate fixative with added hydrogen peroxide or periodic acid. He described that this procedure could demonstrate mycobacteria that had lost their acidfastness by the usual carbol fuchsin stain. Harada5) also employed the periodic acid-methenamine silver sta...

Helicobacter pylori (Hp) gastritis is a worldwide problem significantly associated with duodenal and gastric peptic ulcer disease, gastric carcinomas, and MALT-type lymphomas. A simple, rapid, reproducible, reliable, and inexpensive stain to detect the organism in gastric biopsy specimens is thus of great value. To assess the reliability and cost-effectiveness of a novel Alcian yellow-toluidine...

In this paper, the optimal Fresnel lenses are designed by Zemax software.The fundamental problem of the Fresnel lenses is the beam divergence, which wasresolved by decreeing the output stain diameter on the image plane. For this purpose,two types of radial and cylindrical Fresnel lenses are simulated with different groovesusing Global and Hammer optimization methods. The minimum output stain di...

In recent years there has been renewed interest in the immunology of syphilis and the possibility of developing a vaccine against this disease. The rabbit is the animal most frequently used for preliminary evaluation of vaccines. For this reason, we felt that a critical re-appraisal of the fate of Treponema pallidum when inoculated into the skin of normal rabbits was necessary. Early attempts t...