The porosity and roughness of four direct filling resins

Abstract

Four direct filling resins were examined in order to compare the roughness and porosity of different materials, mixed by different methods. From each material six specimens were prepared. Each specimen was formed against a Mylar sheet and the Mylar-formed surface was examined. Subsequently it was trimmed and polished and re-examined. Each specimen was examined with a microscope using incident light and employing an automatic point-counting attachment in order to assess the percentage surface (apparent) porosity. Each specimen was also examined with a stylus-type profile meter. Rt (total roughness height) was recorded for all specimens and Ra (roughness average) was recorded for all polished specimens. The findings support the conclusion that a capsulated resin without an inorganic filler yields a better surface than other resins.

Effect of Thermo-mechanical Cyclic Stresses on Flexural Strength of Two Aesthetic Restoratives with Modified Filler Systems

“…The single paste is directly packed into the Teflon mold without mixing and minimum handling, accordingly no opportunity for air incorporation. This could be also extrapolated from earlier studies, where the incorporation of air during spatulation and insertion of hand-mixed chemically cured materials contributed significantly to higher level of porosity in comparison to the minimum handling of the single-paste light-activated materials during specimen preparation [37][38][39][40].…”

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“…Both mixing methods result in air inclusion into the cement mixture. Conventional glass ionomer cement porosity studies report the percent of air ranges from six to nine surface area percent (Mitchell & Douglas, 1997;Bertenshaw & Piddock, 1993 (Gjerdet & Hegdahl, 1978;Jörgensen & Hisamitsu, 1983;Ogden, 1985;Valcke & Duggan, 1981) and polymethylmethacrylate powder and liquid monomer when used to produce bone cement (five to 12 surface area percent) (Jasty & others, 1990;Lindén & Gillquist, 1989;Wixson, Lautenschlager & Novak, 1987). Researchers found that air inclusion has a detrimental effect on the mechanical properties of composite resin (Nakayama & others, 1974;de Gee, 1979) and bone cement (Jasty & others, 1990;Wixson, 1992;Topoleski, Ducheyne & Cuckler, 1990;Burke, Gates & Harris, 1984).…”

Porosity in posterior composite resins

“…Pores caused by entrapped air are common in deotal restorations of composite resins. Previous studies of anterior composite resins demonstrated porosities ranging from 0.03 to 28.3% (1)(2)(3)(4)(5)(6).…”