Abstract
A new composite resin“TC”has recently developed by joint efforts of Tani and Fujisawa Research Laboratory, Tokuyama Soda Co.Ltd..One of special features of TC is to be filled with submicronsized spherical silica particles which lie between conventional composites and microfilled resins in size of fillers.The ability to take a good polish and to maintain the polish are important clinical properties of dental restorative materials.The purpose of the present study was to evaluate the surface characteristics of TC in comparison with a conventional composite resin(Clearfil F II)and a microfilled resin(Superlux).Six specimens(11×11×1.5mm)in each material were cured at room temperature for 20minutes sandwiching with strips and stored in 37℃ water for 24hours.One group of specimens were polished with silicon carbide papers(#320 and #600)and buffed with alumina suspension using a polishing machine.Another group of specimens were polished with Sof-lex Discs(Medium, Fine and Super Fine)under dry condition by hands.On each step, the surface gloss and the surface roughness of the specimen were measured with a gloss meter(Nippon Denshoku Co.)and a surface roughness analyzer(Surfcom 304B, Tokyo Seimitsu Co.).The surface gloss was expressed as a percentage(GS)relative to the standard black board(GS 89%).1.With all materials, the value of the gloss of the unpolished surface, i.e.the matrixed surface, was best(GS 82〜90%).The gloss diminished steeply after coarse polishing and recovered in some degree as polishing progressed.However, it was impossible that the conventional composite could recover the surface smoothness lost by polishing.2.Both the gloss and the surface roughness of TC showed higher than those of the microfilled resin and much higher than those of the conventional composite resin in every polishing stage.
