Bleaching effect on surface roughness and micro hardeness of composite

This book gives a look on the effect of in office bleaching material on surface roughness and micro-hardness of four composite material ,and which of these materials did not altered by bleaching. To evaluate the effect of in office bleaching (SDI pola office +, 37.5% hydrogen peroxide) on the surface roughness and micro-hardness of four newly developed composite materials that are different in their filler type, load and resin matrix. These four materials are: ¿ Filtek Z350XT (noanofilled, nanoclusters), 3M /ESPE, St. Paul, MN, USA. ¿ Filtek Z250XT (nanohybrid), 3M /ESPE, St. Paul, MN, USA. ¿ Filtek Z250 (microhybrid), 3M /ESPE, St. Paul, MN, USA. ¿ Filtek P90 (Silorane ¿based composite), 3M /ESPE, St. Paul, MN, USA.