The present study investigated the effects on enamel of a toothpaste containing bioactive glasses added
at different time periods of in-office bleaching with 40 % hydrogen peroxide (HP) gel by evaluating the effectiveness
of bleaching and staining susceptibility, using a spectrophotometer, non-contact profilometer and scanning electron
microscope (SEM). At baseline, luminosity (L1) and surface roughness (Ra0) of enamel were measured. Samples
(n=48) were allocated into four groups according to the treatments: 1) bleached with 40 % HP gel (Control); 2)
applied toothpaste containing bioactive glasses for 5 min prior to bleaching with 40 % HP gel (Bio_Bleach); 3)
bleached with a mixture of 40 % HP gel and the toothpaste in a 1:1 proportion (Mix); 4) bleached with 40 % HP gel
and immediately applied the toothpaste for 5 min (Bleach_Bio). After treatment, luminosity (L2) and roughness
(Ra1) measurements and also SEM examination were performed. Samples were immersed in the staining solution
(red wine) every day for 14 days. Luminosity was measured on day 7 (L3) and day 14 (L4). At baseline, L1 values of
all groups were not significantly different. After bleaching, L values (L2) in all groups increased significantly and Mix
group significantly showed the lowest L values comparing to the others. After 7-day staining, L values (L3) in all
groups decreased but only the control and Bio_Bleach groups showed significant differences compared to the after
bleached values. After 14 days of staining, all groups, except the Mix group, significantly demonstrated lower L
values relatively to the values at 7-day staining. Despite the fact that surface roughness in all groups increased
after the completion of the bleaching process, only Bio_Bleach and Bleach_Bio groups were statistically significant
relatively to the baseline. SEM analysis presented morphological alterations characterized by depressions, porosities
and superficial irregularities in different degrees. A treated enamel surface with toothpaste containing bioactive glass
either during or after 40 % HP in-office bleaching process reduced red wine staining.