The main objective of this study is to evaluate the effectiveness and longevity of color and Tooth sensitivity of patients undergoing home whitening peroxide 10% carbamide ( Whiteness Perfect , FGM , Joinville , Santa Catarina , Brazil) , and the relationship with the cigarette use for tooth whitening. They will be selected 120 patients with incisors darker than A2, higher plants will be divided into 2 groups per center (n = 30 ) , GE - Group Experimental ( smoking) and GC - Group Control ( non-smoking) . For the two groups will be used Carbamide peroxide 10% for 3 hours daily for a period of 3 weeks. Color will evaluated through the Vita Classical scale and Vita Easyshade Spectrophotometer in the periods: Home , for tooth whitening (1st , 2nd and 3rd week) and post- whitening ( 1 week and 1 month , 2 and 3 months). Patients recorded the perceived sensitivity through Numerical Analogue Scale (NRS ) with values from 0 to 4, where 0 = no sensation, 1 = mild, 2 = moderate, 3 = severe and 4 = significant , also in the Visual Analogue Scale (VAS ), with values from 0 to 10 where 0 = 10 = severe tenderness and sensitivity. for color analysis will be made two-way ANOVA (group vs. treatment time ), being Over time the repeated measure ( α = 0.05). Test will be held on Tukey to contrast the average ( α = 0.05). The sensitivity will be evaluated by the Fisher exact test . It is expected that there is no difference on the effectiveness of home whitening and tooth sensitivity between smokers and nonsmokers.