Color and translucency changes during and after curing of esthetic restorative materials.

Objectives: This study was conducted to evaluate various types of contemporary resin composites and glass ionomer restorative materials for color differences that occur during light curing and after submersion in water. Additionally, translucency was evaluated through the use of a translucency parameter for each of these materials at these times.

Methods: A translucency parameter was calculated from observed colors of 2 mm thick layers of light, medium and dark shades of popular restorative materials on black and white backings.

Irreversible hydrocolloid and gypsum interactions.

This study examined the compatibility of nine popular gypsum products with three more recently developed irreversible hydrocolloid impression materials, some of which were disinfected before pouring. A test die and evaluation procedure conforming to ANSI/ADA specification no. 18 standards were used to evaluate detail reproduction of the impression materials and detail transfer and roughness of the resultant die.

Mechanical property and microstructural variations for recast low-gold alloy.

Using polystyrene plastic patterns meeting the dimensional requirements of ANSI/ADA specification no. 5, tension test specimens were recast multiple times from a popular Type III gold (46%) alloy. The alloy was melted by electrical heating in a graphite crucible and four conditions were compared: new alloy and alloy cast two, three, and four times (n = 4).

A comparison of an accelerated technique for casting post-and-core restorations with conventional techniques.

Purpose: This project compares an accelerated technique for the casting of post-and-core restorations with four traditional techniques. The accelerated technique uses two phosphate-bonded investments and the traditional techniques use a gypsum- and a phosphate-bonded investment. The study measures and compares the differences between the seating of the casting and the seating of the acrylic resin pattern.

Cement luting thickness beneath porcelain veneers made on platinum foil.

Porcelain laminate veneers were made using a platinum foil matrix and were subsequently cemented to mandibular anterior Cymel teeth. Cement film thickness was measured in six predetermined locations. Repeated measures analysis of variance and single degree of freedom contrasts delineated a significant difference between marginal openings at the incisal edge where foil is folded and in four of the other vertical areas (132 versus 74.