Heloisa Forville de Andrade's research while affiliated with State University of Ponta Grossa and other places

Objective: Despite the availability of in-office bleaching gels with a 6% concentration of hydrogen peroxide (HP), these gels have not been evaluated in younger patients. They are commercially available with a tip, associated or not with a brush, where the tip with a brush spreads the gel over the entire surface to have a smaller thickness (thin layer) since the manufacturers indicate the application of a thin layer of gel. This randomized, split-mouth, double-blind clinical trial evaluated the efficacy of in-office bleaching with 6% HP in adolescents using different application tips, as well tooth sensitivity (TS) and aesthetic self-perception. Methodology: Sixty participants were randomized for 6% HP self-mixing bleaching gel tip design: without brush and with brush. In-office bleaching was performed in 3 sessions of 50 minutes. Color change was evaluated using a digital spectrophotometer (ΔE ab , ΔE 00 , and ΔWI D ) and color guide (ΔSGU), the absolute risk and intensity of TS with a visual analogue scale and aesthetic self-perception with the oral aesthetic scale (a=0.05). Results: The groups achieved similar bleaching regardless of the application tip (p>0.05). However, only for ΔWI D , a significant mean difference (MD) was observed in the third week (MD 2.3; 95% CI 1.2 to 3.3; p < 0.001) and at one month (MD 1.6; 95% CI 0.6 to 2.6; p < 0.03) favoring the tip without brush. Regarding TS, 45% in the tip-without-brush group and 33% in the tip-with-brush group reported TS (odds ratio 0.61; 95% CI 0.29 to 1.28; p<0.02), with low TS intensity (MD 0.05; 95% CI -0.06 to 0.17; p>0.36). All patients reported improved aesthetic self-perception after bleaching (MD -1.3; 95% -1.8 to -0.9; p<0.001). Conclusions: Regardless of the tip used bleaching with 6% HP achieved a bleaching efficacy and improved the aesthetic self-perception. However, a lower risk of TS for application using the tip with brush was observed.

This study aimed to evaluate the color stability of different temporary restorative materials in contact with staining solutions, as well as to verify which one presents the highest resistance to staining. In this laboratory study, five types of temporary restorative materials were evaluated: self-curing acrylic resin, bis-acrylic resin, light-curing acrylic resin, CAD/CAM machinable, and 3D printed resin. Thirty samples of each material were produced in a circular mold measuring 10 mm in diameter and 2 mm in thickness. The materials were divided into subgroups (n=10) and immersed in solutions: Coffee, Coca-cola®, and distilled water (control). Color measurements were carried out at baseline, 1, 7, and 14 days using a digital spectrophotometer and the color parameters were calculated according to the CIEDE00 system. The color change data were subjected to two-way ANOVA (temporary material vs time) and posthoc Tukey test (α = 0.05). The materials showed a color change only comparing baseline vs. one day, according to acceptability standard ΔE00 > 1.8. Thus, we concluded that there was a difference in color stability already on the first day of immersion. In ad-dition, the coffee solution showed the highest color variation when compared to the other solutions.

This study aimed to evaluate the color stability of different temporary restorative materials in contact with staining solutions, as well as to verify which one presents the highest resistance to staining. In this laboratory study, five types of temporary restorative materials were evaluated: self-curing acrylic resin, bis-acrylic resin, light-curing acrylic resin, CAD/CAM machinable, and 3D printed resin. Thirty samples of each material were produced in a circular mold measuring 10 mm diameter and 2 mm thickness. The materials were divided into subgroups (n=10) and immersed in solutions: Coffee, Coca-cola®, and distilled water (control). Color measurements were carried out at baseline, 1, 7, and 14 days using a digital spectrophotometer and the color parameters were calculated according to the CIEDE00 system. The color change data were subjected to two-way ANOVA (temporary material vs time) and post-hoc Tukey test (α = 0.05). The materials showed a color change only comparing baseline vs. one day, according to acceptability standard ΔE00 > 1.8. Thus, we concluded that there was a difference in color stability already on the first day of immersion. In addition, the coffee solution showed the highest color variation when compared to the other solutions. Clinical applicability: Temporary restorations are widely used in prosthetic treatments and can remain in the mouth for a considerable period. They are responsible for aesthetic and function maintenance along the rehabilitation process. In addition, they provide data for the definitive prosthesis and should assure comfort and confidence to the patient. Thus, it is necessary that these materials are resistant and present such color stability that does not compromise the aesthetics during the treatment phase.

Objective: Few studies evaluated low concentrations of hydrogen peroxide protocols. The aim of this paper was evaluated two application protocols using 4% hydrogen peroxide in at-home bleaching. Materials and methods: Eighty-six patients with upper canines' shade A2 or darker were randomly allocated under two experimental conditions: two daily applications of 1 h each or a 2-h single application. Color change was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer weekly and 1 month after the bleaching procedure through one-way ANOVA. The risk and intensity of tooth sensitivity (TS) was assessed through visual and numeric rating scale and measured by Fisher's exact test, Mann-Whitney test and one-way ANOVA respectively. Results: After 3 weeks, the mean difference for the ΔSGU Vita Classical (1.0; 95% CI -0.1 to 2.0), ΔEab (0.7; 95% CI -1.4 to 2.8), ΔE00 (0.1; 95% CI -1.4 to 1.6) and Wi (1.8; 95% CI -1.9 to 5.5) presented no difference (p > 0.08). The relative risk for TS was 0.91 (0.72 to 1.14) without significant difference neither in the risk (p = 0.6) nor in the TS intensity for both pain scales (p > 0.65). Conclusions: The application protocols evaluated (two daily applications of 1 h each or a 2-h single application) for at-home bleaching with 4% hydrogen peroxide did not showed differences in color change and tooth sensitivity. Clinical relevance: Higher amount of active hydrogen peroxide in two daily applications for at-home bleaching neither accelerate bleaching nor increase the risk or intensity of tooth sensibility.

Purpose: This study evaluated hydrogen peroxide (HP) diffusion within the pulp chamber, as well as color change and the surface morphology of teeth subjected to various microabrasion (MA) protocols associated or not with in-office (IO) bleaching. Methods: Forty sound premolars were randomly divided into the following four groups (n=10): no treatment (NC); IO bleaching only; IO immediately after MA (IMA), and IO seven days after MA (7MA). After treatments, the HP concentration (μg/mL) within the pulp chamber was determined using ultraviolet-visible (UV-Vis) spectrophotometry. The color change (ΔE*) was evaluated using the digital spectrophotometer before and 1 week after bleaching. The surface morphology was evaluated by scanning electron microscope (SEM). Data from each test were submitted to one-way ANOVA and Tukey tests (α=0.05). Results: All experimental groups exhibited higher HP concentrations compared to the NC group (p<0.00001). However, higher amounts of HP were observed for the IMA group compared to the IO and 7MA groups (p<0.00001). No significant difference in color change was observed among the groups (p<0.001). Pronounced grooves in enamel were found in the IMA and 7MA groups. However, enamel erosion areas were observed only in the 7MA group. Conclusions: The association between MA and IO bleaching could significantly affect the amount of HP inside the pulp chamber. Therefore, it is highly recommended to wait for 1 week after MA procedures before performing IO bleaching.

Objective: To evaluate the color change stability and patient satisfaction after one-year of at-home bleaching with 10% carbamide peroxide (CP) in trays with or without reservoirs. Materials and methods: Forty-six patients were subjected to bleaching with CP (3 h/daily; 21 days) with a bleaching tray with or without reservoirs. The color was measured one-month and one-year after the completion of bleaching using the spectrophotometer (ΔEab, Δ00 and ΔWi), and shade guide units (ΔSGU). Patients' satisfaction were assessed using a 5-point Likert Scale questionnaire. Data were submitted to paired t-test (α = 0.05). Results: No significant difference between color change after one-month and one-year was observed (VITA Classical shade guide unit and the ΔWi; p > 0.53). Significant differences were observed for the VITA Bleachedguide 3D-MASTER shade guide, ΔEab and ΔE00 (p < 0.03). The level of patient satisfaction was similar between groups (p = 1.00). Conclusions: Bleaching tray design did not have any influence on the bleaching stability for the 10% CP (Opalescence PF, Ultradent). Patients were very satisfied with the bleaching outcomes regardless of the bleaching tray design. Clinical relevance: Placement of reservoirs in bleaching trays does not increase longevity of dental bleaching. No clinically important color rebound was observed 1 year after bleaching with 10% CP.