To reduce variability, all specimen preparation and finishing/polishing procedures were performed by the same operator. The specimens were randomly separated into three treatment groups (n = 7). The Mylar strip groups were selected, and others were wet ground with 1200 grit silicon carbide paper to provide a base line before using the polishing systems. A slow-speed handpiece rotating at a maximum 12,000 rpm was used with a constant moving repetitive stroking action to prevent heat build up and the formation of grooves. A new polishing disc was used for each specimen and was discarded after each use.
The groups were divided as follows for each composite:
Group I: (Control) – Mylar strip
Group II: Super snap discs
Group III: PoGo discs
Table 2 reflects the details of the finishing and polishing sequence that were based on the manufacturer's instructions. The polished resin composite discs were washed, allowed to dry and kept again in 100% humidity for 24 h before measuring the average surface roughness values (Ra). The surface roughness test was performed using a profilometer (Surftest-211, Mitutoyo; Kanagava, Japan). Readings were taken at the centre of each specimen, and four sampling lengths of 0.25 mm each were used, giving a total evaluation length of 1 mm. The data were analysed using student's t test at a significance level of 0.05.
To reduce variability, all specimen preparation and finishing/polishing procedures were performed by the same operator. The specimens were randomly separated into three treatment groups (n = 7). The Mylar strip groups were selected, and others were wet ground with 1200 grit silicon carbide paper to provide a base line before using the polishing systems. A slow-speed handpiece rotating at a maximum 12,000 rpm was used with a constant moving repetitive stroking action to prevent heat build up and the formation of grooves. A new polishing disc was used for each specimen and was discarded after each use.The groups were divided as follows for each composite:Group I: (Control) – Mylar stripGroup II: Super snap discsGroup III: PoGo discsTable 2 reflects the details of the finishing and polishing sequence that were based on the manufacturer's instructions. The polished resin composite discs were washed, allowed to dry and kept again in 100% humidity for 24 h before measuring the average surface roughness values (Ra). The surface roughness test was performed using a profilometer (Surftest-211, Mitutoyo; Kanagava, Japan). Readings were taken at the centre of each specimen, and four sampling lengths of 0.25 mm each were used, giving a total evaluation length of 1 mm. The data were analysed using student's t test at a significance level of 0.05.
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