IADR Abstract Archives
Effect of Toothbrushing on Optical Properties of Stained Monolithic Ceramics
Objectives: This study investigated the effect of toothbrushing with different dentifrices on optical properties of extrinsically stained monolithic ceramics.
Methods: Bar specimens (12x10x1.5 mm) were obtained (N=60) from CAD/CAM blocks of feldspathic (VITABLOCS Mark II), leucite-based (IPS Empress CAD), lithium disilicate glass-ceramic (IPS e.max CAD), zirconia-reinforced lithium silicate (VITA Suprinity) and zirconia (VIPI Block Zirconn) ceramic materials. After sintering/crystallizing, specimens were roughened in a standardized manner using abrasive papers, stained and subsequently glazed following the manufacturer’s recommendation. After 24 h, CIELab shade parameters (L, a, b) of the specimens were measured (VITA Easyshade V spectrophotometer). Then, the specimens of each material were randomly divided into two groups (n=6) and submitted to brushing (36,500 cycles; 2.0 N; 95 strokes/min) using a soft toothbrush (Oral-B Indicator #35) and two different dentifrices in a 2:1 distilled water slurry: conventional (Colgate Total 12-Clean Mint) or whitening (Colgate Total 12 Professional Whitening). After brushing, specimens were cleaned, stored in a stove at 37°C for 24 h, and submitted to new recordings of the optical parameters. Color change (ΔE) and lightness (ΔL) were calculated according to CIELab formulae. Data were submitted to normality and homoscedasticity tests. The effect of the independent variables on the ΔE and ΔL was individually evaluated by t-tests (α=.05).
Results: Ceramic materials did not show statistically significant differences (p>.05) among their ΔE and ΔL results when the dentifrices were individually evaluated. When the ceramics were individually analyzed, VITABLOCS and IPS Empress showed higher ΔE (p<.05) after toothbrushing with whitening dentifrice. No differences were observed among the other materials (p>.05). Only the lightness of VITABLOCS was significantly affected (p<.05) by toothbrushing with whitening dentifrice.
Conclusions: Toothbrushing with whitening dentifrice influenced the optical properties of the stained feldspathic (VITABLOCS) and glass-ceramic (IPS Empress) materials. Color changes (ΔE) were always below the adopted clinical perceptible threshold (ΔE<2.6).
Methods: Bar specimens (12x10x1.5 mm) were obtained (N=60) from CAD/CAM blocks of feldspathic (VITABLOCS Mark II), leucite-based (IPS Empress CAD), lithium disilicate glass-ceramic (IPS e.max CAD), zirconia-reinforced lithium silicate (VITA Suprinity) and zirconia (VIPI Block Zirconn) ceramic materials. After sintering/crystallizing, specimens were roughened in a standardized manner using abrasive papers, stained and subsequently glazed following the manufacturer’s recommendation. After 24 h, CIELab shade parameters (L, a, b) of the specimens were measured (VITA Easyshade V spectrophotometer). Then, the specimens of each material were randomly divided into two groups (n=6) and submitted to brushing (36,500 cycles; 2.0 N; 95 strokes/min) using a soft toothbrush (Oral-B Indicator #35) and two different dentifrices in a 2:1 distilled water slurry: conventional (Colgate Total 12-Clean Mint) or whitening (Colgate Total 12 Professional Whitening). After brushing, specimens were cleaned, stored in a stove at 37°C for 24 h, and submitted to new recordings of the optical parameters. Color change (ΔE) and lightness (ΔL) were calculated according to CIELab formulae. Data were submitted to normality and homoscedasticity tests. The effect of the independent variables on the ΔE and ΔL was individually evaluated by t-tests (α=.05).
Results: Ceramic materials did not show statistically significant differences (p>.05) among their ΔE and ΔL results when the dentifrices were individually evaluated. When the ceramics were individually analyzed, VITABLOCS and IPS Empress showed higher ΔE (p<.05) after toothbrushing with whitening dentifrice. No differences were observed among the other materials (p>.05). Only the lightness of VITABLOCS was significantly affected (p<.05) by toothbrushing with whitening dentifrice.
Conclusions: Toothbrushing with whitening dentifrice influenced the optical properties of the stained feldspathic (VITABLOCS) and glass-ceramic (IPS Empress) materials. Color changes (ΔE) were always below the adopted clinical perceptible threshold (ΔE<2.6).
