3D-Surface Roughness of a Novel vs. Conventional Nanofilled Composites

Methods: One-hundred-twenty disk-shaped specimens (diameter:10-mm;thickness:2-mm) were prepared from three different resin composites (Filtek Z550 [filled with nano-silica particles]; Tetric N-Ceram and Clearfil Majesty Esthetic [filled with nano-hybrid particles]). Each specimen was cured under the mylar strips for 20 seconds from each of top and bottom surfaces. All the specimens were stored in distilled water for 24 h at 37°C. Baseline measurements of surface roughness (Ra) values were performed with a 3D-optical-profilometer (NewView^TM 7200, Zygo). For each composite, specimens were immersed in two different soft-beverages (Coca-Cola, and Dimes-Lemonade) 3 minutes daily for a period of 30 days. Control groups were stored in distilled water only. Surface rouhnesses were measured after the immersion period. For each group 30 measurements were performed. Data were statistically analyzed using one way ANOVA and Tukey’s post-hoc test (SPSS18.0) (p=0.05), as well as a multivariate analysis (General Linear Model) to evaluate the influence of the study parameters on the surface roughness.

Results: Significant differences were observed between the Ra values of study groups (p<0.05). Baseline measurement of Majesty exhibited the lowest Ra values (0.338±0.14). Filtek Z550 (0.429±0.11) showed higher Ra values than Majesty (p>0.05), whereas exhibited lower Ra values than Tetric N-Ceram (p<0.05). Tetric N-Ceram expressed the highest Ra values when immersed in Coca-Cola for 30 days (0.505±0.17). Both structure of resin composite and type of soft-bevarage affected the Ra values of nanofilled composites (p<0.05).  

Conclusions: The tested soft-beverages caused alterations in 3D-surface roughnesses of nanofilled composites for a 30-day evaluation period. Composite structure was more effective than type of beverage on surface roughness of nanofilled resin composites.