In this research, the application of walnut shell ash, as an adsorbent for soybean oil bleaching, has been investigated. Therefore, neutralized soybean oil was bleached with 1 and 2% of walnut shell ash as well as commercial bleaching earth. Then, a series of chemical tests such as amounts of carotenoids, chlorophylls, peroxide value, and free fatty acid content of bleached oils and oil retenti...

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OBJECTIVES The aim of this study was to determine an appropriate application duration of sodium ascorbate (SA) antioxidant gel in reducing microleakage of bonded composite restoration in intracoronally-bleached teeth. MATERIALS AND METHODS Eighty endodontically-treated human incisors were randomly divided into eight groups: control, no bleaching; IB and DB, immediate and delayed bonding after...

Psychophysical experiments have shown an equivalence between sensitivity reduction by background light and by bleaches for the human scotopic system. We have compared the effects of backgrounds and bleaches on the light-sensitive membrane-current responses of isolated rod photoreceptors from the salamander Ambystoma tigrinum. The quantum catch loss was factored out from the desensitization due ...

AIM To investigate the effect of nonthermal atmospheric pressure plasma on intracoronal tooth bleaching in blood stained human teeth. METHODOLOGY Forty extracted single-root and blood stained human teeth were used. The teeth were randomly divided into two groups (n=20): group 1 received 30% HP activated by nonthermal atmospheric pressure plasma in the pulp chamber for 30 min, whilst group 2 r...

The aim of this study is to evaluate the flexural resistance of three types of restorative materials: compomer (Freedom), resin-modified glass-ionomer (Vitremer) and composite resin (Esthet-X), observing whether the application of bleaching agent can cause alterations of their flexural properties. Sixty samples were made using a 10 x 1 x 1 mm brass mold, and divided into three groups: G1- Freed...

OBJECTIVES The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. STUDY DESIGN Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces...

BACKGROUND To determine the susceptibility of teeth for repigmentation after bleaching. MATERIALS AND METHODS Forty premolars were assigned to three groups (n = 12). Group 1 was bleached using 30% w/v hydrogen peroxide 15 min 3 times a day every other day for 4 days. In Group 2 was bleached using 16% carbamide peroxide (Polanight), 90 min a day for 15 days. 2 days later, the shades of the ble...

INTRODUCTION Tooth bleaching is based on hydrogen peroxide application. The Objective of this study was to determine whether dental bleaching agents affect metalloproteinases-mediated dentin collagen degradation. METHODS Human dentin specimens were subjected to different treatments: (1) untreated dentin; (2) demineralization by 37% phosphoric acid (PA); (3) demineralization by 37% PA, followe...

Aim: This randomizes clinical trial evaluated of color change, rebound effect and tooth sensitivity associated with power and at-home bleaching techniques. Methods and Materials: Anterior teeth of twenty volunteers were randomized into two balanced groups (n=20) ; Power and at-home bleaching. Color was recorded before bleaching ,immediately after bleaching, at two weeks, one, three and six mont...