At low concentrations used for in-office bleaching gels, such as 6% HP, gingival barrier continues to be performed. If we take into account that, in the at-home bleaching technique, no barrier is ...indicated, it seems that the use of a gingival barrier fails to make much sense when bleaching gel in low concentration is used for in-office bleaching.
This double-blind, split-mouth, randomized clinical trial evaluated the gingival irritation (GI) of in-office bleaching using 6% hydrogen peroxide (HP) with and without a gingival barrier in adolescents, as well as color change and the impact of oral condition on quality of life.
Overall, 60 participants were randomized into which side would or would not receive the gingival barrier. In-office bleaching was performed for 50 minutes with 6% HP in three sessions. The absolute risk and intensity of GI were assessed with a visual analogue scale. Color change was assessed using a digital spectrophotometer and color guides. The impact of oral condition on quality of life was assessed using the Brazilian version of the Oral Health Impact Profile (α=0.05).
The proportion of patients who presented GI for the "with barrier" group was 31.6% and for the "without barrier" group, 30% (p=1.0). There is an equivalence for the evaluated groups regarding GI intensity (p<0.01). Color change was detected with no statistical differences (p>0.29). There was a significant impact of oral condition on quality of life after bleaching (p<0.001).
The use or not of the gingival barrier for in-office bleaching with 6% HP was equivalent for GI, as well as for bleaching efficacy, with improvement in the impact of oral condition on quality of life.
Objectives
To evaluate the bleaching efficacy and permeability of hydrogen peroxide (HP) in the pulp chamber of human teeth bleached with lower concentrations of carbamide peroxide gel (4%, 5% and 7% ...CP).
Materials and methods
Bleaching gels with lower concentrations were formulated and a commercial standard gel, 10% CP, was used as a reference. Fifty-six human premolars were randomly divided into four groups. Applications of the bleaching gel were made for 3 h for 21 days. The bleaching efficacy was evaluated by digital spectrophotometry on 1, 7, 14 and 21 days, with analysis in the ∆E
ab
, ∆E
00
and WI
D
color spaces. The concentration of HP in the pulp chamber was measured in the same periods by UV-Vis spectrophotometry (µg/mL). Two-way repeated analysis of variance (ANOVA) examined bleaching efficacy and HP permeability, followed by Tukey’s post-hoc test (α = 0.05).
Results
All groups showed significant color changes, with no statistical differences after the second and third week of bleaching (
p
> 0.05). The ‘time’ factor was statistically different (
p
< 0.05), increasing the bleaching efficacy throughout the treatment. The 4% CP group had lower HP levels in the pulp chamber (
p
< 0.05).
Conclusions
The results seem promising, revealing that low concentration gels are as effective as 10% CP with the benefit of reducing the amount of HP in the pulp chamber.
Clinical relevance
Low concentration 4% PC and 5% PC maintains bleaching efficacy, reduces the penetration of HP peroxide into the pulp chamber, and may reduce tooth sensitivity.
Objective
This in vitro study aims to evaluate of hydrogen peroxide (HP) diffusion into the pulp chamber, bleaching efficacy (BE), and pH stability (pH) of single-application high concentrated ...in-office bleaching gels.
Materials and methods
Eighty-eight healthy premolars were randomly into eleven groups (
n
= 8) according to the in-office dental bleaching: DSP White Clinic 35% calcium (DW), Nano White 35% (NW), Opalescence XTra Boost 40% (OB), Pola Office + 37.5% (PO), Potenza Bianco Pro SS 38% (PB), Total Blanc 35% (TB), Total Blanc One-Step 35% (TO), Whiteness Automixx 35% (WA), Whiteness Automixx Plus 35% (WP), and Whiteness HP Blue 35% (WB). A group not exposed to bleaching agents was the control group (CG). All bleaching agents were applied in one session with a single application. After the bleaching procedure, the concentration of HP diffusion (μg/mL) into the pulp chamber was assessed using UV-Vis spectrophotometry. The BE (Δ
E
ab
and Δ
E
00
) was evaluated before and 1 week after the bleaching procedure using a digital spectrophotometer. The pH of each bleaching gel was evaluated by digital pHmeter. The one-way ANOVA and Tukey’s was used for a statistical analysis (
α
= 0.05).
Results
The concentration of HP diffusion into the pulp chamber was higher in all in-office bleaching gels when compared to CG (
p
< 0.0000001). However, there are a significant difference between them (
p
= 0.0001). A significant BE was observed in all in-office bleaching gels (
p
< 0.0001 for Δ
E
ab
and Δ
E
00
), with a significant difference between them (
p
< 0.0001). PO, OB, TB, WP, and WB showed a higher BE when compared to DW, PB, and WA (
p
< 0.0001). Most bleaching gels were slightly acidic or alkaline during the total application time, while DW, PB, TB, and WA showed a high acidic behavior after 30 min of application.
Conclusions
A single application was able to produce a bleaching efficacy. However, usually, gels with slightly acidic or alkaline pH during the application time reduces the HP diffusion into the pulp chamber.
Clinical relevance
The single-application of bleaching gels with slightly acidic or alkaline and stable pH decreased the penetration of hydrogen peroxide into the pulp chamber in in-office bleaching and maintained the bleaching efficacy.
The prevalence of cervical dentin hypersensitivity in patients after corrective orthodontic treatment has been poorly studied, although such hypersensitivity is very common. This study aimed to ...assess the prevalence of dentin hypersensitivity in patients who received corrective orthodontic treatment, the impact of general oral problems on quality of life, and the impact of hypersensitivity on the quality of life of this population.
This observational, cross-sectional study evaluated 232 patients who finished orthodontic treatment between 2000 and 2020 for self-reported hypersensitivity and clinically diagnosed hypersensitivity. The following tests were used: tactile, evaporative (bellows), evaporative (triple syringe), and thermal. The patients were also evaluated regarding their quality of life using questionnaires (Oral Health Impact Profile-14 and Dentine Hypersensitivity Experience Questionnaire). We evaluated data with nonparametric statistics.
The prevalence of hypersensitivity was higher in women and in those aged <30 years; the most affected teeth were the mandibular incisors and premolars; different diagnostic tests for hypersensitivity may indicate different prevalence values; patients with hypersensitivity had a lower quality of life in most of the domains of both of the tests that were used.
The prevalence of hypersensitivity among patients after orthodontic treatment may be higher than in the general population. Further investigation is needed to indicate the possible factors associated with orthodontic tooth movement.
•Dentin hypersensitivity and quality of life after using braces have been poorly studied.•The prevalence of dentin hypersensitivity after using braces is higher among women.•Gingival recession is associated with dentin hypersensitivity after using braces.•Desensitizing toothpaste may decrease dentin hypersensitivity after using braces.•Dentin hypersensitivity negatively impacts the quality of life after using braces.
Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times.
Thirty healthy human premolars ...and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05).
All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05).
A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth.
This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.
