The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram, Heliomolar and Esthet-X), being 20 for each shade. In each group, 10 specimens were light-cured ...

AIM This study was designed to determine the type and amount of the monomers leached from the different particle sizes of the composite materials. MATERIALS AND METHODS Three different disk sizes (2, 4, 6 mm) prepared for each material group (Filtek Flow, Filtek A110, Filtek P60 and Filtek Supreme) were polymerised by LED and halogen light; the specimens were then placed in artificial saliva....

OBJECTIVE To measure the irradiance in humidified incubator under three different overhead phototherapy devices. DESIGN/METHODS The effective irradiance of three phototherapy devices was assessed by taking a series of irradiance measurements in the illuminated field. Measurements were made with a fixed bandwidth broadband radiometer (380-530 nm). The distance between the light source and the ...

The interactions between the two CX3 groups in perhalogenated ethanes, X3C–CX3 are studied, with X3C–CX3 = H3C–CH3, F3C–CF3, F3C–CCl3, and Cl3C–CCl3. Utilising the recently developed method for revealing non-covalent interactions in molecular systems by Johnson et al. [1], a previously overlooked non-covalent interaction between halogens attached to opposite carbon atoms is unearthed. Further i...

A new approach towards highly enantioselective halogen-bonding catalysis has been developed. In order to circumvent the intrinsic issues of halogen-bond (XB) nature and consequent unresolved limitations in asymmetric catalysis, fine-tuned halogen--halogen interactions between substrate XB-donor were designed pre-organize catalyst’s cavity boost enantiocontrol. The present strategy exploits both...

This study evaluated the influence of 3 different photopolymerization sources on enamel shear bond strength after bleaching with 10% carbamide peroxide. Seventy-two incisive bovine teeth were randomly divided into 6 groups (n=12) according to bleaching treatment and photopolymerization source used: G1 -- Bleached / Halogen lamp; G2 -- Not bleached / Halogen lamp (control); G3 -- Bleached / Ligh...

Two bistable halogen and hydrogen bonding-naphthalene diimide [2]rotaxanes have been prepared and the system incorporating a halogen bond donor anion recognition site is demonstrated to exhibit superior anion induced translational motion of the macrocyclic wheel component relative to the hydrogen bonding analogue. Proton NMR spectroscopy is used to estimate the percentage occupancies of the mac...

The formation of a halogen bonded self-assembled co-crystal physisorbed monolayer containing N···Br interactions is reported for the first time. The co-crystal monolayer is identified experimentally by synchrotron X-ray diffraction and the structure determined. Density functional theory (DFT) calculations are also employed to assess the magnitudes of the different interactions in the layer. Sig...

The influence of halogen substituents on the catalytic oxidation of 2,4,6-trihalogenated phenols (TrXPs) by iron(III)-porphyrin/KHSO₅ catalytic systems was investigated. Iron(III)-5,10,15,20-tetrakis(p-hydroxyphenyl)porphyrin (FeTHP) and its supported variants were employed, where the supported catalysts were synthesized by introducing FeTHP into hydroquinone-derived humic acids via formaldehyd...

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is n...