BACKGROUND Non vital bleaching is simple, conservative procedure for esthetic correction of discolored endodontically treated teeth. The aim of this study was to determine and compare the amount of peroxide leakage from four different bleaching agents i.e superoxol, sodium perborate, combination of superoxol & sodium perborate and carbamide peroxide during intracoronal bleaching, as the safe an...

AIM To measure the time course hydrogen peroxide penetration into the pulp cavity and evaluate short-term tooth color changes after bleaching. MATERIALS AND METHODS Twenty extracted human canines were sectioned, pulp tissue removed and the cavity enlarged. Teeth were painted with nail varnish to leave a 6-mm diameter circle on the buccal surface. Baseline color was measured spectrophotometric...

Hydrogen peroxide (H2O2) has been observed in significant concentrations in many natural waters. Because hydrogen peroxide can act as an oxidant and reductant, it participates in an extensive suite of reactions in surface waters. Hydrogen peroxide is produced as a secondary photochemical product of chromophoric dissolved organic matter (CDOM) photolysis. Apparent quantum yields for the photoche...

In the trend of the use of antimicrobial compounds from natural and renewable resources, natural antimicrobial compounds, particularly found in food and with potential biomedical applications, are of highest interest. In this context, the contribution by Brudzynski et al. to our special issue on “antimicrobial compounds from natural sources” deserves a special attention not only for giving insi...

Among those writing on the mechanism of photosynthesis, which include WARBURG (7), WILLSTATTER (9), and FRANCK (3), the opinion is widely held that the Blackman reaction, which limits the rate of assimilation at high light intensities and carbon dioxide concentrations, involves the decomposition of a peroxide, formed in a preceding photochemical reaction, by the enzyme catalase. The best experi...

Our previous proteomic study demonstrated that oxidative stress and antioxidant delphinidin regulated the cellular level of p27(kip1) (referred to as p27) as well as some heat shock proteins in human colon cancer HT 29 cells. Current study was conducted to validate and confirm the regulation of these proteins using both in vitro and in vivo systems. The level of p27 was decreased by hydrogen pe...

Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n = 27) according to the bleaching materials used. Each main group was divid...

The rate of decomposition of hydrogen peroxide has been measured in aqueous, concentrated (0.1–1M) reagent-grade sodium carbonate liquors and compared with that in sodium hydroxide liquors at the same pH, temperature, and ionic strength. Over the ranges of temperature (303–323 K), pH (10.0–10.6), and ionic strength (1.5–3.0M), and without peroxide-stabilizing additives, hydrogen peroxide decomp...

The microwave enhanced advanced oxidation process (MW/H2O2-AOP) aided with dilute sulfuric acid was applied in a two-stage treatment of dairy manure for nutrient release, solids reduction, and reducing sugar production. A much higher hydrogen peroxide dosage (1.2 g H2O2/g TS) was used in Stage 2 than that in Stage 1 (0.38 g H2O2/g TS). Most of the reducing sugar was produced in Stage 1, and onl...

There has been recent concern about the inadvertent exposure of dentin with patent tubules as well as gingiva to bleaching systems containing 10-15% carbamide peroxide or 2-10% hydrogen peroxide for more than a few minutes. The aims of the present study were: (1) to determine the cytotoxicity of dilutions of hydrogen peroxide in cell culture; (2) to measure hydrogen peroxide diffusion from blea...