Effect of a New Bleaching Gel on Tooth Whitening

Comparison of mechanical and optical properties of a newly marketed universal composite resin with contemporary universal composite resins: An in vitro study

The purpose of this study was to evaluate the surface roughness, microhardness, color change, and translucency of a newly marketed universal nanohybrid composite resin (CR) (G-aenial A'CHORD) comparing with four contemporary universal CRs including two nanofilled (Filtek and Estelite Asteria) and two nanohybrid CRs (Charisma Dimond and Neo Spectra ST HV in vitro). Sixty-five specimens (8.0 mm × 2.0 mm) were fabricated (n = 13, per group). After finishing and polishing, specimens were subjected to surface roughness and microhardness tests. Color and translucency of the specimens were evaluated at baseline and after darkening with coffee solution at day 1 and day 7. A representative specimen from each group was investigated under scanning electron microscopy (SEM). Data was analyzed statistically (p < .05). There were significant differences among the groups in terms of surface roughness, microhardness, color, and translucency. The surface roughness was recorded as: Charisma Diamond > Neo Spectra ST HV, Filtek > Estelite Asteria, G-aenial A'CHORD, whereas Vickers Hardness number was as: Filtek, Charisma Diamond > Neo Spectra ST HV > G-aenial A'CHORD, Estelite Asteria. Color change was as: Charisma Diamond > Neo Spectra ST HV, Filtek, G-aenial A'CHORD > Estelite Asteria and the translucency was as: Neo Spectra ST HV > G-aenial A'CHORD, Filtek > Estelite Asteria, Charisma Diamond. SEM examinations revealed smooth surfaces for G-aenial A'CHORD, Neo Spectra ST HV and Estelite Asteria. Mechanical and optical properties of universal composite resins with different compositions show variations.

Effects of preoperative air-powder polishing and rubber-cup prophylaxis on tooth bleaching: randomized controlled split-mouth clinical study

OBJECTIVE

This clinical study aimed to compare the effects of preoperative air-powder polishing and rubber-cup prophylaxis on tooth bleaching.

MATERIALS AND METHODS

Twenty-three patients with tooth discoloration were enrolled in this randomized controlled split-mouth experimental study. Before bleaching, air-powder polishing (APP) and rubber-cup polishing (RCP) techniques were applied on either side of the mouth. A 40% hydrogen peroxide bleaching agent was applied twice for 15 min for the in-office bleaching treatment. The tooth bleaching effects were assessed immediately and 1 week after bleaching.

RESULTS

There were no significant differences between the prophylaxis groups with respect to all color parameters (ΔL, Δa, Δb, ΔSGU, and ΔE00) immediately after bleaching (p > 0.05). At 1-week assessment period, there were no significant differences between the prophylaxis groups with respect to all color parameters (p > 0.05), except ΔE00 (p < 0.05).

CONCLUSION

Immediately after the bleaching treatment, the two prophylactic techniques produced similar efficacy. One week after the bleaching treatment, the APP technique produced higher levels of color changes.

CLINICAL RELEVANCE

APP prophylaxis before bleaching treatment may reduce the application time and the number of sessions to achieve the desired color.

TRIAL REGISTRATION

ClinicalTrial.gov ID: NCT04407910.

Nitrogen-Doped Titanium Dioxide Mixed with Calcium Peroxide and Methylcellulose for Dental Bleaching under Visible Light Activation

The available tooth whitening products in the market contain high concentrations of hydrogen peroxide (H₂O₂) as an active ingredient. Therefore, in order to curb the high H₂O₂ concentration and instability of liquid H₂O₂, this study evaluated the efficacy and cytotoxicity of the bleaching gel composed of 10% calcium peroxide (CaO₂) and visible-light-activating nitrogen-doped titanium dioxide (N-TiO₂) with methyl cellulose as a thickener. Extracted bovine teeth were discolored using coffee and black tea stain solution and were divided into two groups (n = 6). Bleaching was performed thrice on each tooth specimen in both the groups, with one minute of visible light irradiation during each bleaching time. The CIELAB L*a*b* values were measured pre- and post-bleaching. The N-TiO₂ calcinated at 350 °C demonstrated a shift towards the visible light region by narrowing the band gap energy from 3.23 eV to 2.85 eV. The brightness (ΔL) and color difference (ΔE) increased as bleaching progressed each time in both the groups. ANOVA results showed that the number of bleaching significantly affected ΔE (p < 0.05). The formulated bleaching gel exhibits good biocompatibility and non-toxicity upon exposure to 3T3 cells. Our findings showed that CaO₂-based bleaching gel at neutral pH could be a stable, safe, and effective substitute for tooth whitening products currently available in the market.

Effectiveness and SEM-EDX analysis following bleaching with an experimental bleaching gel containing titanium dioxide and/or chitosan

The aim of this study was to evaluate the bleaching effectiveness and mineral alterations following the use of experimental bleaching gels that included 6% hydrogen peroxide (HP), titanium dioxide (TiO₂) and/or chitosan in comparison with the routinely used 35% HP bleaching gel. Thirty-six maxillary anterior teeth were divided into three groups according to bleaching agent as follows: Group 1: 6% HP + TiO₂, Group 2: 6% HP + TiO₂ + chitosan, Group 3: 35% HP. Tooth colour was measured with a spectrophotometer before bleaching and after sessions one and two on days 14 and 30, respectively. Colour changes were assessed with the CIEDE2000 and CIELab formulas. Mineral analysis was performed with a scanning electron microscopy-energy dispersive X-ray (SEM-EDX) device before and 14 days after application. The enamel surfaces of randomly selected samples from each group were analysed by SEM. Two-way ANOVA was used to compare differences between groups. All tested materials resulted in significantly increased bleaching compared to the initial colour values (p < 0.05). Group 3 showed significantly more whitening compared to the other groups after the first and second sessions (p < 0.05). However, Group 2 presented prolonged whitening efficiency and reached a bleaching level similar to the 35% HP treatment after 14 and 30 days. The results of the CIEDE2000 and CIELab formulas were found to be correlated (r > 0.6). The increases in Ca were similar in Groups 2 and 3 (p > 0.05) and were significantly higher than that in Group 1 (p < 0.05). p was similarly decreased among all groups (p > 0.05). The combination of 6% HP, chitosan and TiO₂ appears to constitute a promising material for tooth whitening, showing good bleaching efficiency and acceptable mineral alterations.

Color Masking White Fluorotic Spots by Resin Infiltration and Its Quantitation by Computerized Photographic Analysis: A 12-month Follow-up Study

OBJECTIVE

To manage three cases of mild to moderate fluorosis by resin infiltration technique and to quantify the tooth color changes by measuring CIE L*a*b* values of digital photographs and calculating ΔE₀₀ based on the CIEDE2000 formula using Adobe Photoshop software.

METHODS AND MATERIALS

Three cases of mild to moderate fluorosis were treated with a combination of bleaching and a resin infiltration technique. CIE L*a*b* values of 18 fluorosed spots were measured from digital photographs of these cases at four different stages-preoperative, postbleaching, postinfiltration and at 12-month follow-up-using Adobe Photoshop software, and ΔE₀₀ was calculated based on the CIEDE2000 formula. The ΔE₀₀ values of all 18 points obtained at different stages were submitted to statistical analysis (α=0.05).

RESULTS

In all the cases reported, clinically as well as by the photographic color analysis, it was found that the technique masked the lesions, improving the patients' esthetics, which was maintained even at 12-month recall. Statistically significant difference in ΔE₀₀ values was present between comparison of all stages (p<0.001) except between postinfiltration and the 12-month follow-up stage (p=0.642).

CONCLUSION

A resin infiltration technique helped in the satisfactory management of white spot lesions of fluorosis, which were stable even at 12-month follow up. Quantitation of the changes was achieved using Adobe Photoshop software.