Surface detail reproduction of elastomeric impression materials related to rheological properties.

Objectives: The purpose of this work was to discern, for elastomeric impression materials, the important rheological properties and importance of hydrophilicity for detail reproduction.

Methods: Viscosity, modulus and tan delta were measured using a controlled-stress rheometer in cone/plate configuration. The flow of the materials, immediately after mixing and at the manufacturer's stated working time, was measured using a shark fin test and the interaction with moist surfaces was determined by taking impressions from two different sized grooves in moist gypsum casts.

A method for producing controlled fluoride release from an orthodontic bracket.

The aim of this study was to manufacture and test, in vitro, a novel modification to provide fluoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.

Dentin decontamination using chloramine T prior to experiments involving bacteria.

Objectives: This study aims to investigate the importance of ISO11405 recommended storage regime for extracted teeth in surface disinfectant chloramine T (chlT) prior to use in biofilm or in vitro caries studies involving microorganisms. ChlT may be absorbed into dentin and undergoes breakdown with organic material.

Methods: Extracted roots were stored in chlT (2 days), rinsed and transferred to distilled deionised water.

Response to thermal stimuli of glass ionomer cements.

Objectives: This study was designed to determine the dimensional changes of glass ionomers caused by thermal stimuli under both dry and wet conditions.

Methods: Eight cylindrical specimens (6 mm x 4 mm) were made (using a stainless steel mold) of each of the following materials: a conventional luting glass ionomer, two high viscosity restorative glass ionomers, a resin-modified glass ionomer and a resin composite which was used as a control. The thermal expansion characteristics were determined by a thermal mechanical analyzer (TMA) under wet and dry conditions by heating the samples from 25 to 70 degrees C at 10 degrees C min (-1).

Fluoride release and neutralizing effect by resin-based materials.

This study evaluated the fluoride-releasing and neutralizing abilities of resin-based materials containing fluoride in water and aqueous lactic acid. Two composites, containing a low-solubility fluoride component (Heliomolar) and a fluoroalumino-silicate glass (UniFil S), and two giomers, containing surface reaction type prereacted glass-ionomer filler (Beautifil) and full reaction type glass-ionomer filler (Reactmer paste), were used. Resin-modified glass-ionomer cement (Fuji II LC) was used as a control.

Fluoride release from aged resin composites containing fluoridated glass filler.

Objectives: The aim of this study was to evaluate the fluoride release from aged resin composites containing different types of fluoridated glass filler into both deionized distilled water and lactic acid solution.

Methods: Three resin composites, UniFil S (containing fluoro-alumino-silicate glass filler), Reactmer (containing pre-reacted glass-ionomer filler) and Beautifil (containing both types of fillers) were used. A conventional glass-ionomer cement, Ketac-Fil, was used as a control.

Effect of the applied load on surface contact fatigue of dental filling materials.

Objective: The purpose of this study was to investigate the effect of the applied load in a rolling-ball device on the surface contact fatigue of two dental filling materials: a microfilled composite (FA) and a glass ionomer (GFII).

Methods: Disk specimens 10 mm diameter by 1.5 mm thick were set into cavities cut in plates of PMMA.

Fluoride release and recharge in giomer, compomer and resin composite.

Objectives: The aim of this study was to examine the fluoride recharging and releasing abilities of resin-based materials containing fluoridated glass filler to determine whether the extent of the glass-ionomer matrix of the material affects these properties.

Methods: Three materials having a different proportion of the hydrogel matrix surrounding the glass filler, namely: Reactmer paste, Dyract AP and Xeno CF, were used for this study. Five disk specimens of each material were placed into distilled/deionized water and the fluoride release measured during 38 days.

Temperature mediated coefficient of dimensional change of dental tooth-colored restorative materials.

Objectives: Restorative materials are constantly subjected to thermal challenges in the oral environment. Such challenges, if significant, can have unfavorable effects on the margins of restorations in terms of the seal between the material and the tooth structure. This study aimed to assess the Coefficient of Dimensional Change (CDC) of tooth-colored restorative materials.

Determination of fluoride ions released from resin-based dental materials using ion-selective electrode and ion chromatograph.

Objectives: The aim of this study was to investigate the quantities of total and free fluoride ions released from four resin-based composites containing fluoride (Heliomolar (HE), UniFil S (UF), Beautifil (BE) and Reactmer paste (RP)) and one glass ionomer cement (Ketac-Fil Plus Aplicap (KF)).

Methods: Five disk specimens of each material were prepared and the fluoride release was measured at 1, 2, 4, 7, 14, 21 and 28 days. The amounts of total and free fluoride ions released from materials were measured by using an ion-selective electrode (ISE) and ion chromatography (IC).

Determining low levels of fluoride released from resin based dental materials.

Fluoride release determinations were made on two resin matrix dentine bonding systems using an ion-selective electrode and ion chromatography. Calibrations were made on serially diluted samples of standard fluoride solutions. The electrode method consistently gave higher values than the chromatographic method for one of the materials, and this was considered to be due to the use of total ionic strength adjustment buffer in electrode determinations.

Adhesive bond strength and compliance for denture soft lining materials.

Peel bond strength and tensile bond strength between three polyvinylsiloxane denture soft liners and a heat-cured acrylic resin denture base were measured using two adhesive systems. The soft lining materials differed only in regard of their filler content and compliance. The values of bond strength and mode of failure were explained in terms of the inherent strength of the bond and varying compliance and tear strength of the soft material.