MECHANICAL-BEHAVIOR AND STRUCTURE OF LIGHT-CURED SPECIAL TRAY MATERIALS

Objectives: This study relates some structural characteristics of repr esentative special tray visible light cured (VLC) resin composites to their creep-recovery, hardness and flexural strength properties. VLC p rosthodontic materials have not yet achieved the same acceptance as th e VLC resin composites, perhaps because less is known of their structu ral and performance characteristics. Methods: The VLC resin composites used were Triad, Convertray and Palatray. The inorganic composition w as analysed quantitatively by heating known amounts of resin composite to 800 degrees C, and weighing the ash. Elemental composition was det ermined using X-ray microanalysis. Mechanical properties, including ha rdness, flexural behaviour and creep recovery, were obtained by standa rd methods. Results: The inorganic filler content for Palatray was hig her than that of Convertray or Triad, and the flexural modulus and fle xural strength of Palatray were superior to that of Triad or Convertra y. The mean maximum creep strain for the Palatray specimens was only 2 .45% after 5 h loading under 37 MPa and there was a permanent set of 1 .5% after 7 h recovery. Conclusions: Palatray exhibited superior overa ll properties and this evidently related primarily to the high volume fraction of filler.