IADR Abstract Archives
Effect of Double-Layer Technique on Peroxide Penetration and Tooth-Whitening Efficacy
Objectives: To measure the amount of hydrogen peroxide (HP) penetration into the pulp chamber and to assess whitening efficacy when treated with an innovative double-layer of potassium nitrate (PN) desensitizer and HP whitening gel.
Methods: Extracted human molar teeth (n=24) were collected and stained with tea solution. Roots were trimmed 3mm apical to the cemento-enamel junction, pulp removed and a cavity prepared, leaving a standardized wall of 2mm thickness, which retained 100μL of acetate buffer solution. A standardized whitening area of 6mm in diameter was established by painting the rest of the tooth with grey nail varnish and teeth randomly distributed into four groups. Group 1: no treatment (negative control); Group 2: double-layer of 20μL 5% PN (Relief ACP, Philips Oral Healthcare, LA, CA) and 100μL 25% HP (Zoom Chairside Whitening Gel, Philips Oral Healthcare); Group 3: double-layer of 40μL 5% PN and 100μL 25% HP; and Group 4: 100μL 25% HP (positive control). All groups received three 45-minute sessions of in-office whitening with light activation at 3-day intervals. HP penetration was evaluated spectrophotometrically using leucocrystal violet and horseradish peroxidase. Color measurements were assessed with VITA Easyshade prior to staining, after staining, 1-day, and 1-week post-whitening. Tooth color change was measured per Commission Internationale de l'Eclairage methodology. One-way ANOVA with Tukey multiple comparisons adjustment was performed to compare group differences in overall tooth color change (△E*) and HP penetration (α=0.05).
Results: No significant differences were observed in the quantification of HP penetration among 4 groups (p=0.24). ΔE* for the negative control was not significantly different from baseline (after staining). Groups 2 to 4 had significant tooth color change compared to baseline and significant whitening effect compared to negative control (p<0.05).
Conclusions: Whitening efficacy and penetration of hydrogen peroxide was not adversely affected when preceded by potassium nitrate as a desensitizer.
Methods: Extracted human molar teeth (n=24) were collected and stained with tea solution. Roots were trimmed 3mm apical to the cemento-enamel junction, pulp removed and a cavity prepared, leaving a standardized wall of 2mm thickness, which retained 100μL of acetate buffer solution. A standardized whitening area of 6mm in diameter was established by painting the rest of the tooth with grey nail varnish and teeth randomly distributed into four groups. Group 1: no treatment (negative control); Group 2: double-layer of 20μL 5% PN (Relief ACP, Philips Oral Healthcare, LA, CA) and 100μL 25% HP (Zoom Chairside Whitening Gel, Philips Oral Healthcare); Group 3: double-layer of 40μL 5% PN and 100μL 25% HP; and Group 4: 100μL 25% HP (positive control). All groups received three 45-minute sessions of in-office whitening with light activation at 3-day intervals. HP penetration was evaluated spectrophotometrically using leucocrystal violet and horseradish peroxidase. Color measurements were assessed with VITA Easyshade prior to staining, after staining, 1-day, and 1-week post-whitening. Tooth color change was measured per Commission Internationale de l'Eclairage methodology. One-way ANOVA with Tukey multiple comparisons adjustment was performed to compare group differences in overall tooth color change (△E*) and HP penetration (α=0.05).
Results: No significant differences were observed in the quantification of HP penetration among 4 groups (p=0.24). ΔE* for the negative control was not significantly different from baseline (after staining). Groups 2 to 4 had significant tooth color change compared to baseline and significant whitening effect compared to negative control (p<0.05).
Conclusions: Whitening efficacy and penetration of hydrogen peroxide was not adversely affected when preceded by potassium nitrate as a desensitizer.