ABSTRACT
The purpose of this study was to evaluate the effect of duration of finishing and polishing procedures on the surface roughness of two different types of composite resins. Forty samples of 6 mm in diameter and 2 mm in depth were prepared, 2 types of composite resins were used [nanocomposite and hybrid composite resin]. Twenty samples of each type of material were prepared and divided into two main groups and then each main group subdivided randomly into two subgroups of 10 samples for each subgroup [one]. Ten samples of each material were submitted to finishing by using a finishing kit. The available finishing kits used in this study containing discs, cups and points that were used with a slow-speed hand piece in a dry field and with a light intermittent pressure for about 15 seconds. While the other 10 samples of each material were finished for about 30 second; then the analysis of the surface roughness was carried out, three readings were made on each surface using a stylus tip and the extension of each reading was 2 mm stroke. There was non significant difference between the groups that were finished and polished for 15 second and the other groups that were finished and polished for 30 second for the two different types of composite resin. Increasing duration of finishing and polishing has no effect on the surface roughness of the two different types of composite resin