Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry

A total of 120 specimens of resin composite were prepared. They were divided into two equal groups, according to the type of resin composites, 60 specimens for nanofilled resin composite and 60 specimens for microhybrid resin composite. Each group was then divided into two equal subgroups, according to the type of polishing system 30 specimens for one-step polishing system and 30 specimens for multi-step polishing system. Each subgroup was further subdivided into three classes, according to the type of food simulating liquid, 10 specimens for water as set storage medium (control), 10 specimens for heptane and 10 specimens for ethanol. The specimens were transferred immediately after preparation to labeled air tight containers containing 20 ml deionized water, stored at 37{u00B0}C for seven days in dark environment. The top surface of the specimens of each main half were tested immediately after being finished and polished for surface roughness and surface gloss before storage. After testing the specimens, they were stored into 3 different media; distilled water, heptane and 75% ethanol in air tight containers for 3 months at room temperature. After aging periods for 3 months, the specimens were removed from their media, lightly rinsed with water and gently dapped dry with absorbent paper, for reassessment of surface roughness and gloss. The results of current study showed a non statistical significant difference in changes in surface roughness with different resin composite restorations and with different storage conditions. There was no difference between different resin composite restorations in changes in surface gloss

Issued also as CD