Influence of Bleaching Agents on Color and Translucency of Aged Resin Composites.
OBJECTIVE
Evaluate the influence of two bleaching agents (16% carbamide peroxide-CP and 35% hydrogen peroxide-HP) on color and translucency of one resin composite (Filtek Z350 XT) in two opacities (enamel and dentin) previously aged in deionized water or red wine.


METHODS
Sixty specimens of each material were divided in two groups (n = 30): aged in water or red wine for 14 days. Then the specimens were divided in three subgroups (n = 10): control/no treatment, treated with 16% carbamide peroxide (Mix Night), treated with 35% hydrogen peroxide (Mix One). Color readings were performed 24 hours after polishing (baseline); after the 14 days of aging; and after bleaching treatment. Color coordinates CIE L*a*b* were measured using a spectrophotometer (SP60 X-Rite). Color change (CIEDE2000) and translucency parameter were calculated. Data were analyzed with repeated measures two-way ANOVA, and Student-Newman-Keuls tests (5%).


RESULTS
Bleaching decreased color change in stained resin composites (aged in red wine), whereas increased it in non-stained enamel resin composites (aged in water). CP had better bleaching results with stained resin composites than HP. Translucency of non-stained dentin resin composite decreased with aging, but did not change with bleaching. For stained resin composites, aging caused reduced translucency, whereas bleaching increased it.


CONCLUSIONS
Effective bleaching of discolored resin composites aged in an acidic and alcoholic media rich in staining agents was achieved, improving color and translucency. Carbamide peroxide showed better performance than hydrogen peroxide for the bleaching of stained resin composites. (J Esthet Restor Dent 29:368-377, 2017).
Private practice, Santa Maria, Brazil.
Maristela
M
Lago
Private practice, Santa Maria, Brazil.
Lisandra R
LR
Mozzaquatro
School of Dentistry, Federal University of Santa Maria, Santa Maria, Brazil.
Camila
C
Rodrigues
School of Materials Science and Engineering, Federal University of Pelotas, Pelotas, Brazil.
Marina R
MR
Kaizer
School of Dentistry, Federal University of Santa Maria, Santa Maria, Brazil.
André
A
Mallmann
School of Dentistry, Federal University of Santa Maria, Santa Maria, Brazil.
Letícia B
LB
Jacques
D000180:Acrylic Resins / Q000737:chemistry*; D000077463:Carbamide Peroxide / Q000737:chemistry*; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008422:Materials Testing; D011140:Polyurethanes / Q000737:chemistry*; D013053:Spectrophotometry; D013499:Surface Properties; D058205:Tooth Bleaching Agents / Q000737:chemistry*; D014867:Water; D014920:Wine
D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes; D058205:Tooth Bleaching Agents; D014867:Water; D000077463:Carbamide Peroxide; D006861:Hydrogen Peroxide