Effects of different discoloration challenges and whitening treatments on dental hard tissues and composite resin restorations

Objectives: To compare the relative effects of cigarette smoke (CS), electronic cigarette (EC), red wine, coffee, and soy sauce on the color of enamel, dentin, and composite resin restorations, as well as the effects of whitening treatments. Methods: Seventy premolars with composite restorations were exposed to CS, EC aerosol (a novel EC device with MESHT technology [P4M3 version 1.0, Philip Morris International]), red wine, coffee, and soy sauce for 56 min/day for 15 days. Two whitening sessions with 6% and 35% hydrogen peroxide (H2O2) were performed on the exposed samples. Teeth exposed to CS and EC aerosol were also brushed with whitening toothpaste for 3 weeks. Color match of resin restorations was assessed, and color changes were compared after exposure and after whitening treatments. Results: Discolorations in enamel, dentin, and composite resin were observed in the order of red wine > CS > soy sauce > coffee > EC. Color mismatch between enamel and resin restorations occurred only in red wine and CS groups. Brushing with whitening toothpaste removed discoloration caused by EC aerosol; H2O2 treatments were necessary to eliminate discolorations caused by coffee and soy sauce. Discolorations of dentin and resin restorations could not be completely removed by whitening treatments, and color mismatch remained in teeth exposed to red wine and CS. Conclusion: Red wine and CS cause significant tooth discoloration and color mismatch in enamel and resin restorations that are not reversible by whitening treatments. Tooth discoloration associated with EC aerosol was minimal and could be removed by brushing with whitening toothpaste. Clinical significance: Red wine drinkers and cigarette smokers have increased risks for tooth discoloration and color mismatch between enamel and composite resin restorations. Whitening treatments may not be effective in correcting the color mismatch. Tooth discoloration associated with EC aerosol is minimal.