RESUMO
OBJECTIVES: This study evaluated the efficacy of simulated brushing with toothpastes containing different concentrations of hydrogen peroxide (HP) in pulp chamber penetration and color change. Also, physical-chemical properties (concentration, pH and viscosity) were evaluated. METHODS: Forty-nine premolars were divided into seven groups (nâ¯=â¯7): untreated (control); whitening gel (White Class 6â¯%, 6â¯%BG) with one 90⯠min application (6â¯%BG 90⯠min) and 14 applications of 90⯠min (6â¯%BG 14×90â¯min); toothpastes (Colgate Luminous White Glow 3â¯%, 3â¯%TP; Crest 3D White Brilliance 4â¯%, 4â¯%TP; Colgate Optic White Pro-Series 5â¯%, 5â¯%TP) and 6â¯%BG toothbrushing for 14 applications of 90â¯s. HP penetration into the pulp chamber was measured through UV-Vis spectrophotometry and color change with a spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through Titration, Digital pH-meter, and Rheometer, respectively. Statistical analysis used one-way ANOVA and Tukey's test (αâ¯=â¯0.05). RESULTS: 6â¯%BG (14×90â¯min) and 4â¯%TP groups showed acidic pH and higher concentrations of HP in the pulp chamber compared to the other groups (pâ¯<â¯0.05). On the other side, 3â¯%TP and 5â¯%TP groups showed alkaline pH, higher viscosity between the toothpastes and lower HP penetration (pâ¯<â¯0.05). The 6â¯%BG AH (14×90â¯min) group exhibited the most significant color change (ΔEab, ΔE00, and ΔWID) (pâ¯<â¯0.05). CONCLUSIONS: Brushing with whitening toothpaste with an acidic pH leads to greater HP penetration into pulp chamber; but, even when a high concentrated HP whitening toothpaste was used, a lower whitening effect was observed when compared to a two-week at-home bleaching. CLINICAL SIGNIFICANCE: Whitening toothpastes containing up to 5â¯% HP produced lower whitening effect than two-week at-home bleaching. Additionally, HP was detected within the pulp chamber which can potentially impact in tooth sensitivity.
