Comparative clinical study of the effectiveness of different dental bleaching methods - two year follow-up

this study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques. material and methods: in this study, 48 patients were divided into five groups. a half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): g1: 35% hydrogen peroxide (hp) (lase peroxide - dmc equipments, s？o carlos, sp, brazil) + hybrid light (hl) (led/diode laser, whitening lase ii dmc equipments, s？o carlos, sp, brazil); g2: 35% hp; g3: 38% hp (x-traboost - ultradent, south jordan ut, usa) + hl; g4: 38% hp; and g5: 15% carbamide peroxide (cp) (opalescence pf - ultradent, south jordan ut, usa). for g1 and g3, hp was applied on the enamel surface for 3 consecutive applications activated by hl. each application included 3x3' hl activations with 1' between each interval; for g2 and g4, hp was applied 3x15' with 15' between intervals; and for g5, 15% cp was applied for 120'/10 days at home. a spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. a vas questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after. results: statistical analysis did not reveal any significant differences between in-office bleaching with or without hl activation related to effectiveness; nevertheless the time required was less with hl. statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup). immediately, in-office bleaching increased tooth sensitivity. the groups activated with hl required less application time with gel. conclusion: all techniques and bleaching agents used were effective and demonstrated similar behaviors.