The effect of different fluoridation methods on the red wine staining potential on intensively bleached enamel in vitro

Purpose : To study the effect in vitro of different fluoridation methods after intensive bleaching on the color of enamel slabs during a severe staining challenge with red wine. Methods: 75 specimens were equally divided among five groups. Group I (no bleaching, no wine) served as control. Groups 2, 3 and 4 underwent bleaching with 35% H2O2 for 10 minutes followed by home-bleaching for 8 hours/day with 10% carbamide peroxide on 14 consecutive days. Groups 2 and 3 were fluoridated for I hour with either Elmex gelee or Duraphat, respectively whereas Group 4 remained without fluoridation. Group 5 (no bleaching, no fluoride, wine) served as control for the influence of red wine on the color of untreated enamel. Color determination was accomplished using the CIE-Lab System. Results: Nine successive cycles of wine saliva treatment (10 minutes wine, 23 hours 50 minutes saliva) for Groups 2-5 revealed the highest changes of a-values (Delta a= 4.17) (towards red) for the Duraphat-treated group (bleaching, Duraphat, wine) with significantly higher Delta a-values compared with Group 4 (bleaching, no fluoride, wine) (Delta a= 2.97). After final cleaning no differences were found between the three bleached groups (Groups 2, 3 and 4) for Delta L, Delta a, Delta b and Delta E, respectively. Exposure to red wine led to an increase in a-values (Delta a= 0.44) of the intrinsic tooth color in Group 5 (no bleaching, no fluoride, wine) that was significantly different from baseline.