The effect of whitening toothpastes on the color stability and surface roughness of stained resin composite.

BACKGROUND: This study aimed to investigate the effect of whitening toothpastes on the color stability and surface roughness of resin composites stained with coffee and cigarette smoke. METHODS: Seventy-two disk-shaped specimens (6 × 2 mm) of suprananohybrid resin composite were randomly divided into two groups and exposed to coffee and cigarette smoke (n = 36). After staining, the samples randomly divided into four groups according to whitening toothpastes and were brushed for 4 min: Opalescence Whitening (OW); Colgate Optic White (COW); Curaprox Black is White (CPX) and, distilled water (control) (n = 9). Color was measured with spectrophotometer at the initial, after staining, and after brushing, and surface roughness was measured with profilometer at the initial and after brushing. A surface morphology analysis was examined using scanning electron microscopy and atomic force microscopy. The obtained data were statistically analyzed. (p < 0.05). RESULTS: Cigarette smoke caused a significantly higher color change than coffee in the resin composite (p < 0.05). Brushing with hydrogen peroxide and silica-containing whitening toothpaste showed significant differences in color change (p < 0.05). The lowest whitening effect was found in activated charcoal-containing toothpaste. While all toothpastes increased the degree of surface roughness of resin composites, the highest roughness was caused by whitening toothpastes containing activated charcoal. (p < 0.05). CONCLUSIONS: The color stability and surface properties of resin composites can be affected by brushing them with whitening toothpaste. The utilization of whitening toothpaste containing hydrogen peroxide can be considered a safe method for increasing the whiteness of discolored resin composites.

The effect of contemporary finishing and polishing systems on the surface roughness of bulk fill resin composite and nanocomposites.

OBJECTIVE: To evaluate the effects of various finishing and polishing (F/P) systems regarding the surface roughness (Ra ) value of two nanocomposites and a bulk fill resin composite. METHODS AND MATERIALS: Three resin composites (Filtek Z550, Filtek Ultimate Body, Filtek Bulk Fill Posterior) were tested. Forty disk-shaped specimens of each material were cured under Mylar strip and then randomly divided into four subgroups according to the F/P method (n = 10): Control, Sof-Lex Spiral Wheels, Astropol, and Clearfil Twist Dia. Ra values was measured and the surfaces were examined under scanning electron microscope. The data were analyzed by generalized linear models (p < 0.05). RESULTS: The Filtek Bulk Fill Posterior had the highest Ra value while Filtek Ultimate Body was the resin composite with the lowest roughness (p < 0.05). Considering the average Ra values after polishing, while the lowest Ra in all groups was obtained with the control group, the Clearfil Twist Dia showed similar Ra to the control group (p > 0.05). The samples polished with Sof-Lex Spiral Wheels had the highest Ra (p < 0.05). CONCLUSIONS: In addition to the resin composite type, the F/P technique greatly affected the Ra value of resin composite. The nanocomposites exhibited with the lowest Ra compared to the bulk fill resin composite after F/P. It was observed that the diamond containing-polishing system created smoother surfaces than the aluminum oxide containing- and silicon carbide containing-polishing systems. CLINICAL SIGNIFICANCE: In terms of Ra , the nanocomposites exhibited better performance than the bulk fill resin composites. Nowadays, newly developed polishing systems containing diamonds can be successful at a comparable level to existing polishing systems. For this reason, these systems are preferable for polishing both nanocomposites and bulk fill resin composites.