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A tungsten (VI) complex, [WO(O2)L(CH3OH)], L = (E)-N'-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide has been synthesized by the action of WO3 with a ONO donor tridentate Schiff base using H2O2. The tungsten(VI) complex has been characterized by CHN, FT-IR, multinuclear (1H & 13C) NMR, and UV-Vis. spectroscopic methods. Theoretical calculations, using DFT at the B3LYP level of theory at the Def2-TZVP basis set, for the estimation of geometrical parameters like natural bond orbital (NBO), molecular electrostatic potential (MEP), and frontier molecular orbitals (FMOs) analysis of the synthesised compounds showed that the numerical results correspond to the actual findings. The catalytic activity of WO(O2)L(CH3OH) for the selective oxidation of benzylic alcohols to the corresponding aryl aldehydes was studied utilizing various factors, like the nature of the oxidant, the effect of solvent, and the amount of catalyst. The best results were obtained by using 2 mmol of urea hydrogen peroxide (UHP) as an oxidant in the presence of 1 mol% of the catalyst in CH3CN under reflux conditions. [ABSTRACT FROM AUTHOR]

The present work revealed a novel one-pot synthesis of 2-oxo-1,2,3,4-tetrahydropyrimidines. It involved the use of methyl arenes as a surrogate of aldehydes, in situ generation of urea, and eco-friendly lactic acid as a green catalyst for the synthesis of the desired product in solvent-free conditions via the Biginelli reaction. The appealing characteristics of the proposed protocol include; environmentally benign mild reaction conditions, readily available and cost-effective chemicals as starting material, invaluable bio-based green catalyst, aerobic conditions, shorter reaction time, tolerance to distinct functional groups, and easy isolation of final product with high yield value even without the use of chromatographic separation technique. [ABSTRACT FROM AUTHOR]

Tooth color change is an alteration that varies in cause, location and severity, which may be related to extrinsic factors, intrinsic factors or a combination of both; For this reason, dental whitening is one of the procedures most requested from dentists; more and more patients are looking for a better image and smile without considering the possible consequences. This is due to the constant advertising in the media; in addition, it has led to the appearance of certain products on the market that are used by consumers without any control from the dentist. Therefore, the objective of this review is to know the advantages and disadvantages of dental whitening with 35% hydrogen peroxide (PH) (ultradent) in the office and 10% carbamide peroxide (PC) (ultradent) for home use, with the aim of in order to guarantee the comfort of patients during use and to avoid possible adverse effects. The academic Google search engine was reviewed, as well as databases: PubMed, SciELO, Medigraphic and ScienceDirect, in the period 2002 to 2020, using as keywords "hydrogen peroxide", "carbamide peroxide", "whitening", "clarification", "ph" and their similar in English. Two hundred fifty-four articles were obtained, of which 50 were selected and analyzed because they were related to the topic raised. It is concluded that, according to the instructions specified by the manufacturer, PH 35% and PC 10% are reliable agents for dentistry. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the correlation between the dental crown's color and the pulse oximeter result in healthy teeth before and after 30 days of the end bleaching procedures. Material and methods: The dental crown's color of 70 healthy maxillary central incisors were evaluated using a spectrophotometer and the oxygen saturation level of the pulp was recorded using a pulse oximeter. The bleaching was performed using the combined technique, with 35% hydrogen peroxide bleaching gel, in the office stage, and 10% carbamide peroxide, in the at-home, for 16 days. The variables symmetry was verified by the Kolmogorov Smirnov test, and the quantitative variables described by mean and standard deviation. The correlation between quantitative variables was established using Pearson's correlation coefficient. The significance level considered was 5%. Results: A significant change was observed between values recorded by the pulse oximeter before (85.0% ± 4.1) and after (86.4% ± 2.3) 30 days of the end. Thirty days after the end of the bleaching procedures, the dental crowns were lighter with the difference between L*s equal to 1.4, more greenish with a difference between a*s equal to 1.3, and more bluish with a difference between b*s equal to -7.2. There was no correlation between the values of coordinates L*, a* and b* and the results recorded by the pulse oximeter in the initial period, respectively, or 30 days after the bleaching procedures, respectively. Conclusion: Changes in pulse oximeter recordings did not correlate with the change in the dental crown's color promoted by bleaching procedures. [ABSTRACT FROM AUTHOR]

Background: Dental aesthetic procedures aim to rectify flaws in dental elements' shape, alignment, or overly dark color. One of the most common dental aesthetic procedures is tooth whitening. This study attempts to introduce key aspects of bleaching and describe the different techniques and the mechanism of action of bleaching agents, focusing on the clinical implications in orthodontic and on composite restorations. Methods: The research was performed on PubMed, Web of Science, and Science Direct databases for articles on our topic published between 2017 and 2023, and we found a total of 1512 studies. In total, 57 papers were considered for the qualitative analysis in the review. Results: This study found that both carbamide peroxide and hydrogen peroxide were clinically effective, although patients' level of tooth sensitivity seemed to be lessened by the latter. However, the latter appears to be more effective at reducing patient-experienced tooth sensitivity. Conclusion: Carbamide and hydrogen peroxide based whitening techniques were shown to be equally successful at treating tooth discoloration after bracket composite removal, with no discernible differences between them. To increase the effectiveness of whitening on composites, more research is needed. To achieve the desired results and avoid the negative effects of whitening gels on teeth and soft tissue, a patient-specific approach is advised. [ABSTRACT FROM AUTHOR]

Introduction. Bleach-shade composite resins were recently introduced to the market due to the high demand of patients for whiter teeth. This study sought to compare four stain removal methods for bleach-shade composite resins. Materials and Methods. Seventy-two discs were fabricated from each of the Filtek Z350 XT and Gradia XBW composite resins and immersed in coffee or sour cherry juice staining solutions. Each group was then divided into four subgroups to assess the efficacy of four stain removal methods (finishing with soft-lex disk "brush with pumice" bleaching with carbamide peroxide 16%, bleaching with hydrogen peroxide 40%). The color of each specimen was measured by Easyshade spectrophotometer, and data were analyzed using SPSS 25 statistical package for social sciences. Results. The home-bleaching technique was more effective than the office-bleaching and pumice for the removal of sour cherry juice stain (ΔE = 1.93) and coffee stain (ΔE = 3.32) from Gradia composite discs, almost returning the baseline original color. The Sof-Lex discs were more effective than the pumice for the removal of sour cherry juice stain (ΔE = 4.11) and coffee stain (ΔE = 4.93) from Z350 composite discs but not return the baseline original color. Conclusions. Filtek Z350 had more discoloration than Gradia Direct. The different materials and solutions reacted differently to the four stain removal methods. In GCJ group after all stain removal methods, ΔE reduced to a clinically acceptable level. [ABSTRACT FROM AUTHOR]

The high aesthetic demands of patients have increased their requests to align their teeth using clear aligners, including Invisalign. Patients also want to have their teeth whitened for the same purpose; the use of Invisalign as a bleaching tray at night has been reported in few studies. However, whether 10% carbamide peroxide affects the physical properties of Invisalign is unknown. Therefore, the objective of this study was to evaluate the effect of 10% carbamide peroxide on the physical properties of Invisalign when used as a bleaching tray at night. Twenty-two unused Invisalign aligners (Santa Clara, CA, USA) were used to prepare 144 specimens to test their tensile strength, hardness, surface roughness, and translucency. The specimens were divided into four groups: a testing group at baseline (TG1), a testing group after application of bleaching material at 37 °C for 2 weeks (TG2), a control group at baseline (CG1), and a control group after immersion in distilled water at 37 °C for 2 weeks (CG2). Statistical analysis was conducted using a paired t-test, Wilcoxon signed rank test, independent samples t-test, and Mann–Whitney test to compare samples in CG2 to CG1, TG2 to TG1, and TG2 to CG2. Statistical analysis showed no statistically significant difference between the groups for all physical properties, except for hardness (p-value < 0.001) and surface roughness (p-value = 0.007 and p-value < 0.001 for the internal and external surface roughness, respectively), which revealed a reduction in hardness values (from 4.43 ± 0.86 N/mm2 to 2.2 ± 0.29 N/mm2) and an increase in surface roughness (from 1.6 ± 0.32 Ra to 1.93 ± 0.28 Ra and from 0.58 ± 0.12 Ra to 0.68 ± 0.13 Ra for the internal and external surface roughness, respectively) after 2 weeks of dental bleaching. Results showed that Invisalign can be used for dental bleaching without excessive distortion or degradation of the aligner material. However, future clinical trials are required to further assess the feasibility of using Invisalign for dental bleaching. [ABSTRACT FROM AUTHOR]

Recently, the use of antioxidants before the bonding of bleached enamel was considered effective for reversing the reduction in the bond strength. This article aimed to assess the influence of different sodium ascorbate (SA) presentations (liquid, gel, and semi-gel) on the composite resin–enamel bond strength after a bleaching protocol. Sound human anterior teeth were collected, cleaned, prepared for a bond strength test, and randomly allocated into groups according to the bonding procedure. Group 1 acted as a control, without bleaching treatment, and without applying an antioxidant agent. In groups 2–6, specimens were bleached using 10% carbamide peroxide. In groups 3, 4 and 5, 10% wt% SA was applied for 10 min as an antioxidant in the form of a liquid, gel, and semi-gel, respectively. In group 6, samples were bleached and immersed in fresh human saliva for 14 days. After the bleaching process, the materials were restored by means of an adhesive system and a resin composite material. The analysis revealed that the differences between the shear bond strength (SBS) between the different groups were statistically significant (p = 0.0469). The highest SBS was achieved for the group where the 10 wt% SA liquid was applied before the bonding procedures. The application of liquid 10 wt% SA might reverse the negative impact that bleaching has on the bond strength of a resin composite and enamel. [ABSTRACT FROM AUTHOR]

Background and Objectives: Tooth whitening is a relatively conservative and effective option to treat discolored teeth. However, questions remain whether in-office or at-home tooth whitening products with short treatment durations are as effective and stable as products with longer treatment durations. Materials and Methods: Forty human third molars with intact enamel surfaces were divided into four groups of ten each, subjected to discoloration challenges with coffee for 60 h, and they were treated with four professional tooth whitening systems: two for take-home use—6% hydrogen peroxide for 30 min/d for a total of 7 h in 14 days (HP6), 10% carbamide peroxide for 10 h/d for 140 h in 14 days (CP10), as well as two for in-office use—35% HP for 10 min × 3 (HP35) for a total of 30 min and 40% HP for 20 min × 3 (HP40) for a total of 60 min. Teeth colors were assessed in the CIE L*a*b* color space with a spectrophotometer immediately and six months after whitening treatments. Surface roughness (Sa) for the treated and untreated enamel surfaces of the teeth in all groups were evaluated with a three-dimensional laser scanning microscope after six months. Results: No significant differences were found between HP6 and CP10 groups immediately after whitening (∆E 10.6 ± 1.6 vs. 11.4 ± 1.7, p > 0.05) and at six months after treatments (∆E 9.0 ± 1.9 vs. 9.2 ± 2.5, p > 0.05), or between HP35 and HP40 groups immediately after whitening (∆E 5.9 ± 1.2 vs. 5.3 ± 1.7, p > 0.05) and at six months after treatments (∆E 7.2 ± 1.6 vs. 7.7 ± 1.3, p > 0.05). The two at-home whitening systems achieved significantly better whitening outcomes than the two in-office products immediately after whitening (p < 0.05). However, at six months after treatments, the differences between at-home and in-office treatments had narrowed significantly (p > 0.05). There were no statistically significant differences with respect to the Sa values between the treated and untreated surfaces (p > 0.05). Conclusions: Tooth whitening products in the same product category have similar whitening efficacies, despite significant differences in treatment durations (7 vs. 140 h, and 30 min vs. 60 min, respectively). Take-home products achieved better whitening outcomes than in-office products, but they needed 14 to 280 times longer treatment durations. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study aimed to evaluate the surface roughness evolution of several finished and polished composites when bleaching materials are applied. The research was conducted on four microhybrid or nanofilled composites that are used in dental restorations. Materials and Methods: For each composite type, 5 samples were selected for control, 5 samples were subjected to the bleaching protocol "office bleach" with 40% hydrogen peroxide, and 5 other samples were subjected to the "home bleach" protocol with 16% carbamide peroxide, resulting in a total number of 60 samples. The surfaces of all the samples were tested for roughness, and the values of the most relevant parameter (Ra), were collected. Comparisons between composites and samples were performed using one-way ANOVA (in Statistical Package for Social Sciences). Results: After the bleaching protocol with 40% hydrogen peroxide gel, it was found that the roughness of the group increased considerably compared to the control group, so the highest roughness was found at GC Gradia direct anterior group, and the lowest value was registered for the 3M ESPE Valux Plus group. Following the bleaching protocol with 16% carbamide peroxide (home bleach), it was noted that the sample surfaces were not as affected. In this case, the lowest roughness was found at 3M ESPE Valux Plus group, and the highest roughness was registered for the GC G-aenial anterior group. Following the interpretation of the results, all four types of dental composites tested showed significant surface roughness differences between the groups subjected to bleaching protocols and those kept as control (p < 0.05). Conclusions: The surfaces of the samples were affected by the bleaching protocols by increasing the roughness compared to the control samples. [ABSTRACT FROM AUTHOR]

Carbamide Peroxide, an adduct of Urea and Hydrogen Peroxide, is commonly used in the cosmetic and pharmaceutical industries as a solid source of hydrogen peroxide. However, it exhibits explosive properties and can be easily manufactured from readily available household chemicals, making it a potential emerging threat. We carried out a detailed performance assessment, combining experiments, thermochemical calculations and numerical simulations and highlighted a good level of agreement between experimental data from lab, field and underwater firings. A maximum detonation velocity of 3.65 km/s was recorded for unconfined 25 kg UHP charges at 0.85 g/cm3 (200 mm charge diameter). We determined in these conditions an infinite diameter detonation velocity of 3.94 km/s. These results are also consistent with previous results obtained at small scale under heavy confinement. Airblast measurements highlighted an average 40 % TNT equivalence for impulse and 55 % for peak overpressure at short distance, which are in good agreement with the 57 % (Power Index) calculated from Explo5, while 50 % for bubble energy (explosive power) and 20 % for shock pressure (brisance) were obtained from underwater experiments. The use of different experimental approaches has proven useful to characterise the performances parameters of a non‐ideal explosive for risk assessment purposes. [ABSTRACT FROM AUTHOR]

Background and Aim: Discoloration is an unfavorable side effect of regenerative endodontic procedures using mineral trioxide aggregate (MTA). The efficacy of home bleaching of discolored teeth with carbamide peroxide has not been well investigated, and the minimum required duration of home bleaching is still unclear. This study aimed to compare the effects of different durations of home bleaching on tooth discoloration caused by MTA. Materials and Methods: This in vitro, experimental study used 16 tooth blocks of bovine central incisors. To cause discoloration, white MTA was applied for 40 days in cavities drilled in blocks. The color parameters were measured at baseline and at 14, 28, and 42 days after the application of 20% carbamide peroxide using a spectrophotometer. Data were analyzed by repeated measures ANOVA and Tukey’s post-hoc test. Results: The color change (∆E) value was 22.9±10, 26.3±10.9, and 27.03±11 at 14, 28, and 42 days after bleaching, respectively. Significant color change occurred at 2, 4, and 6 weeks after the application of carbamide peroxide (P

Abstract Background The aim of this study was to evaluate the effect of bioactive glass (BAG) 45S5 paste on colour change and tooth sensitivity (TS) when used in combination with 20% carbamide peroxide (CP) during at-home vital tooth bleaching. Methods Twenty-four patients were selected and assigned into two experimental groups (n = 12) in a double-blind study design. Each patient received 20% CP followed by the application of either BAG paste or non-active placebo paste. The shade evaluation was performed using a digital spectrophotometer based on the CIE L*a*b* colour space system at different time points and the overall colour changes ΔE were calculated. TS was evaluated using visual analogue scale (VAS). The values of ΔE and TS were statistically analysed using paired t-test. The level of statistical significance was established at p = 0.05. Results The overall colour changes (ΔE) between baseline and each time point showed no significant differences between BAG and placebo groups (p > 0.05). The use of BAG paste significantly decreased TS reported by the participants. Conclusions The association of BAG paste with at-home bleaching treatment presents a promising method as it decreased TS and did not deteriorate bleaching efficacy. Trial registration This study was approved and registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under Registration number: ACTRN12621001334897.

The synthesis of N,N‐diphenylformamide from N‐benzylideneaniline and urea hydrogen peroxide is investigated using a zinc hydroxyapatite (ZnHAP) catalyst. It was found that the catalyst resulted in the highest activity of 91 % conversion and 40 % selectivity at 130 °C in 2 h. A kinetic model was validated by Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) at different temperatures and the absence of mass transfer resistance was proved by the Weisz Prater criterion. Effect of different catalysts, catalyst loading, temperature, mole‐ratio, and speed of stirring was studied. The as‐synthesized catalyst is characterized by FTIR, BET nitrogen adsorption‐desorption, TEM, EDX, TPD‐NH3, XPS, ICP‐MS and XRD. ZnHAP catalyst was found to be stable up to three recycles with no loss in activity. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study is to evaluate the effect of intracoronal bleaching agents (IBA) on discolored teeth with triple-antibiotic paste (TAP). Methods: Twenty-six extracted maxillary incisors were discolored for 3 weeks with TAP, containing metronidazole, ciprofloxacin, and doxycycline. Following CIE L*a*b* system, colors were measured at baseline and at 1, 2, and 3 weeks. Specimens, bleached intracoronally, were randomly divided into two groups (n = 13): 35% hydrogen peroxide (HP) and 37% carbamide peroxide (CP). Color changes (ΔE) were based on the spectrophotometric measurements at baseline, 3rd, 6th, and 9th days and analyzed using analysis of variance, Bonferroni, and Student t-tests (p < 0.05). Results: The discoloration increased from baseline to week 3 with significant difference (p < 0.05). The highest ΔE value was observed at week 3 (16.54 ± 5.90). In HP, there was no significant difference on the 6th day compared to the 3rd day (p > 0.05), but a significant difference on the 9th day (p < 0.05). In CP, ΔE was not statistically different among evaluated days. On day 9, HP had a significantly higher ΔE than CP (p = 0.032). Conclusion: TAP caused clinically unacceptable ΔE, increasing over time (ΔE ≥ 3.3). IBA was found effective on discolored teeth. 35% Hydrogen Peroxide was more effective than Carbamide Peroxide on the 9th days. [ABSTRACT FROM AUTHOR]

The most frequently used bleaching materials are hydrogen and carbamide peroxide materials with specific concentration and techniques. The disadvantages of these materials range of sensitivity to bone inflammation and resorption processes. Therefore, it is desirable to employ alternative natural materials with little to no negative effects on the enamel, pulp and oral mucosa. This article reviews recently developing materials like papain, bromelain, chlorine dioxide, sodium chloride and sodium bicarbonate and a combination of peroxide and natural substances. In studies employing bromelain and papain in comparison to peroxide bleaching materials, the peroxide materials evolved to show better stain removal than the natural alternatives. It is worth mentioning that the concentrations of natural materials used were 20 times lesser compared to the peroxide materials. Chlorine dioxide was found to improve bleaching efficacy by virtue of the warmth that was created on application of light, leading to dryness of teeth. This material needs further research and improvement to match its conventional alternatives in efficacy. The newer alternatives considered in this line-up are sodium chloride and sodium bicarbonate. There was no slod scientific support to back this material's efficacy to conclusively compare it against peroxide materials. Finally, combination materials including lactoperoxidase along with hydrogen and carbamide peroxide showed to increase after 8 hours of contact than the system without lactoperoxidase. It can be concluded by saying that further research is required to find better alternatives to peroxide materials with better efficacy. Nanoparticles, off late, have found extensive purpose in modern day dentistry. The application of nanoparticles in bleaching is through hydroxyapatite nanoparticles. These nanoparticles concentration dependent whitening in comparison with carbamide peroxide. Recent developments including reduced graphene oxide has also been tried as an alternative to conventional bleaching methods. This material provided significant results and prove to be promising alternatives to peroxide tooth bleaching materials. This article reviews the developments and efficacy of non-peroxide bleaching materials. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the tooth-whitening potential of five over-the-counter (OTC), peroxide-free dental bleaching methods as well as an experimental tooth-whitening solution containing 0.1% hydrogen peroxide complexed with doping agents with a gold standard (positive control) containing 16% carbamide peroxide. Material and Methods: Eighty permanent bovine incisor teeth were randomly allocated to eight different groups. Two teeth from each group were immerged into five staining solutions represented by coffee, tea, red wine, and curry mixed in warm oil or distilled water (control group) and stored at 37 °C for 28 days in an incubator. The teeth were then reallocated to the eight groups, resulting in ten samples per group, and each group was matched with a bleaching product. The bleaching procedures were executed following the manufacturer's recommendations. The color of each sample was assessed over a white and black background using a quantitative numerical measurement approach with a calibrated spectrophotometer. Spectrophotometric measurements were performed after exposing the teeth to the bleaching agent for 60 min (T2), 100 min (T3), and 200 min (T4), and ΔE00 was calculated. Results: When analyzed over a white background, the mean ΔE00 values ranged from 2.14 (placebo) to 6.32 (Opalescence PF). When analyzed over a black background, the mean ΔE00 values ranged from 2.31 (placebo) to 5.78 (Opalescence PF). Statistically significant ΔE00 color changes over time for the eight groups and five staining solutions at T1 and T4 were assessed for both backgrounds using repeated ANOVA followed by Fisher's LSD post hoc test (p-value < 0.01). Conclusions: All tested over-the-counter whitening kits except one exhibited positive color variation. However, the individual performance differed vastly from one brand to the other, and the overall performance was less effective compared to the conventional carbamide-peroxide-based positive control. [ABSTRACT FROM AUTHOR]

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The diffusion of odour caused by excavation disturbance during the restoration of pesticide sites adversely affects the surrounding environment. Therefore, it is essential to develop a new type of odour inhibitor that has both adsorption and oxidation functions and can effectively block odour. In this study, bentonite-modified cetyltrimethyl ammonium bromide (CTAB) was synthesised, and the structural changes of bentonite before and after modification were analysed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and other characterisation methods. Urea peroxide was loaded on modified bentonite (150C-Bent) by in situ synthesis method, and the preparation conditions were optimised. The effects of temperature, humidity and species on the adsorption behaviour and adsorption kinetics were studied by adsorption experiments. It is demonstrated that CTAB is embedded in bentonite through ion exchange, and the interlayer spacing expands from 1.42 to 3.11 nm. The optimal loading mass ratio of modified bentonite to urea peroxide was 1:1.5 and pH was 3. When the relative humidity is 54.3% and the temperature is 55 °C, the removal effect of paraxylene is the best; the optimal removal reached 82.4%. The adsorption behaviour of 1.5UHP-Bent conforms to the pseudo-second-order kinetic adsorption model. The adsorption pathway of paraxylene on UHP-Bent mainly includes partition effect and hydroxyl radical capture. [ABSTRACT FROM AUTHOR]

Over the past decades, the walking bleach technique using sodium perborate was considered a safe and effective method to bleach nonvital discolored teeth. However, sodium perborate has been classified as carcinogenic, mutagenic, and toxic for reproduction by European Union legislation. Its use is therefore prohibited since April 2015. The initially described inside/outside bleaching technique, combining internal and external application of 10% carbamide peroxide, is an alternative to the walking bleach technique using sodium perborate. While good esthetic results and low risks of external cervical resorptions have been associated with this technique, its main drawback is that the access cavity is left open. To overcome this disadvantage, the present authors propose to seal the bleaching agent in the access cavity instead of leaving the latter open. Through a clinical case, this paper presents and discusses several aspects of this protocol, including the clinical steps, the design of the bleaching tray, and the treatment of potential recurrences. The present authors believe that the protocol proposed in this article is easier to use for the patient. Moreover, it prevents the accumulation of food debris in the access cavity and avoids the colonization of coronary dentin by bacteria. [ABSTRACT FROM AUTHOR]

Composite resins are commonly used in dentistry for direct restorations. The color stability of these materials still represents a major concern for both the clinician and the patient. In recent years, ozone therapy has been extensively used in dentistry to manage wounds healing, dental caries, oral lichen planus, gingivitis and periodontitis, halitosis, osteonecrosis of the jaw, post-surgical pain, plaque and biofilms, root canal treatment, dentin hypersensitivity, temporomandibular joint disorders, and teeth whitening. To date, several studies have evaluated the bleaching effect exerted by ozone on natural teeth, but no studies have been conducted to determine the effect on the color of composite resins. The aim of the present study is to determine whether ozonized oils/gels could determine a color change on composite resin. A total of 40 discs of an A3 shade restorative composite were divided into two groups, respectively exposed to a pigmentation treatment consisting of 10 applications of 10 min each of a 1% chlorhexidine-based gel (trial group) and to storage into physiological solution (control group). The samples of both groups were respectively subdivided into four subgroups which underwent four different protocols, three of which were based on the exposure to different ozonized products and the latter representing the control. A colorimetric analysis with the CIELAB method was conducted with the following timing: after 24 h of storage in physiological solution (before the experimental procedures) (T0), after the subdivision into groups A and B (corresponding to the pigmentation for samples of group A and storage in physiological solution for samples of group B) (T1), and after subdivision into subgroups 1–4 (corresponding to the application of the ozonized products vs. control) (T2). No statistically significant difference was found between the samples at T0. The 20 samples of group A, exposed to the colorant agent, underwent a color change from T0 to T1, whereas the 20 samples exposed to the physiologic solution did not undergo any significant color change. A positive but moderate influence was assessed for E and L values, whereas no significant change occurred for A and B values. Therefore, dental ozonized oils/gels could be valuable in restorative dentistry as bleaching agents of resin composites exposed to discoloration, an alternative to the traditional hydrogen peroxide and carbamide peroxide, but further studies are required to confirm these findings. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of bleaching on surface roughness and gloss of different CAD/CAM ceramic materials. Methods: The ceramic materials included IPS e.max CAD (lithium disilicate), VITA ENAMIC (polymer infiltrated ceramic), and Celtra Duo CAD (zirconia reinforced lithium silicate). Samples of each material were randomly divided into four groups (n = 10); a control group immersed in distilled water, the second and third groups were treated with 20% carbamide peroxide (20% CP) and 35% carbamide peroxide (35% CP) bleaching agents for 4 h/day and 60 min/day respectively for 7 days. The fourth group was treated with 40% hydrogen peroxide (40% HP) applied twice, each turn for 20 min. After treatment, the surface roughness (using 3D non-contact profilometry) and surface gloss were assessed followed by imaging with a scanning electron microscope. The data were analyzed using multiple linear regression and Kruskal-Wallis one-way ANOVA tests (α = 0.05). Results: The surface roughness (p = 0.157) and gloss (p = 0.073) of IPS e.max CAD were not significantly affected by the different bleaching treatments. Similarly, no significant effect on surface roughness (p = 0.162) and gloss (p = 0.965) were shown for Celtra Duo CAD. On the other hand, VITA ENAMIC was significantly affected when treated with 20% CP and 35% CP showing increased roughness (p = 0.001) and gloss (p = 0.008). Conclusions: Home bleaching treatments (20% CP and 35% CP) significantly affected the surface roughness and gloss of VITA ENAMIC while IPS e.max CAD and Celtra Duo CAD were not affected by the different bleaching treatments. [ABSTRACT FROM AUTHOR]

To overcome the lack of dissolved oxygen in high-density aquaculture water, a hydrogen peroxide-acrylic resin inclusion complex with sustained oxygen releasing effect was designed and prepared. The resin was synthesized by emulsion polymerization of acrylic acid, methyl methacrylate and butyl acrylate in a mass ratio of 2: 3: 5, and neutralized with sodium hydroxide solution by 50%. The resin solution was mixed in a mixture of urea and 30% hydrogen peroxide solution (CO(NH2)2: H2O2, 1: 1, mol: mol), and dried at 40 °C for 4 h to obtain the hydrogen peroxide-acrylic resin inclusion complex. The product with 4.0% resin by mass of hydrogen oxygen solution, could release oxygen for 92 h in pond water. After optimization by adding a small amount of NaCl, Na2SO4, and EDTA, it was mixed with calcium carbonate and magnesium stearate in a mass ratio of 5: 4: 0.9, and pressed into tablets (1.2 × 0.6 cm, 0.99 g). One tablet in 50 L simulated micro ecosystem aquaculture water with 20 of Carassius auratus fish could release oxygen for 116 h and brought fish with 83.3% of survival rate higher than 51.7 and 70.0% of blank and sodium percarbonate groups. [ABSTRACT FROM AUTHOR]

The optical qualities of cutting-edge aesthetic dental ceramics are crucial for great aesthetics and may be impacted by various bleaching methods. The objectives of this study were to evaluate how home bleaching affected the translucency parameter (TP), contrast ratio (CR), total color difference (ΔE), and surface roughness (Ra) of various aesthetic dental ceramics, including innovative ultra-translucent zirconia. The three varieties of ceramics that were tested—IPS e.max-Press (IPS); classic zirconia with feldspathic layering (LZr); and translucent zirconia (TZr)—were each represented by seven samples. The samples were bleached at home using 15% carbamide peroxide for six hours a day for seven days. Each specimen's pre- and post-bleaching CIE L*a*b* values were measured using a spectrophotometer, and the TP, CR, and ΔE were determined. Ra values were measured via 3D profilometry. In comparison to the pre-stage results, statistical analysis showed a significant decrease in TP and increase in CR for LZr and TZr in the post-stage (p < 0.05), but not for IPS (p = 0.398). The results also showed substantial variations in ΔE for the three ceramics (p = 0.020). Ra readings during the post-stage were noticeably greater than those at the pre-stage (p = 0.018). Home bleaching had an impact on the optical characteristics and surface texture of the dental ceramics. Additionally, IPS had greater color stability than LZr and TZr. [ABSTRACT FROM AUTHOR]

Coupling dual-phase nickel selenides with N -doped carbon optimized number of catalytic active sites, reaction activation energy, electrical conductivity and improves the desorption of CO 2 , ultimately boosting UOR performance. [Display omitted] Electrochemical urea oxidation reaction (UOR) is urgently in demand for diverse energy conversion and storage device coupled with pollution treatment because of its favorable thermodynamic potential (0.37 V vs RHE) and wide distribution nature of urea, but simultaneously gravely limited by the sluggish reaction dynamics and poisoning of catalyst. Herein, dual-phased Ni 0.85 Se/NiSe 2 coupling with N doped carbon (Ni 0.85 Se/NiSe 2 @NC-2) in situ is prepared by a solvothermal-selenization pathway. Benefiting from the collective promotion of the dual-phased composition and the NC support, Ni 0.85 Se/NiSe 2 @NC provides abundant active sites, enhanced electrical conductivity. It delivers a current density of 252 mA cm−2 at 1.6 V vs RHE with a small Tafel slop of 64.4 mV dec-1 and gets a lower reaction barrier. Moreover, it requires a cell voltage of 1.46 V to approach 50 mA cm−2, about 250 mV less than that of water electrolysis, confirming the less energy consumption. Notably, the N doped carbon protects Ni 0.85 Se/NiSe 2 nanocrystals from aggregation leading to a faster CO 2 desorption from Ni sites, which endow the Ni 0.85 Se/NiSe 2 @NC-2 a much better working stability. The direct urea hydrogen peroxide fuel cell (DUHPFC) achieves a maximum power density of 9.09 mW cm−2 at 20 °C. This work extends highly efficient dual-phased structure loading in NC catalysts system for urea-assisted energy conversion. [ABSTRACT FROM AUTHOR]

Background: Activated charcoal is a nanocrystalline form of carbon with a large specific surface area and high porosity in the nanometer range, having consequently the capacity to absorb pigments, chromophores, and stains responsible for tooth color change, while carbamide peroxide is unstable and breaks down immediately upon contact with tissue and saliva, first dissociating into hydrogen peroxide and urea and subsequently into oxygen, water, and carbon dioxide. Therefore, the aim of the present study was to assess the effect of 16% carbamide peroxide and activated-charcoal-based whitening toothpaste on enamel surface roughness in bovine teeth. Materials and Methods: The present experimental in vitro, longitudinal, and prospective study consisted of 60 teeth randomly distributed in six groups: A: artificial saliva, B: conventional toothpaste (Colgate Maximum Protection), C: whitening toothpaste with activated charcoal (Oral-B 3D White Mineral Clear), D: 16% carbamide peroxide (Whiteness Perfect 16%), E: 16% carbamide peroxide plus conventional toothpaste (Whiteness Perfect 16% plus Colgate Maximum Protection), and F: 16% carbamide peroxide plus whitening toothpaste with activated charcoal (Whiteness Perfect 16% plus Oral-B 3D White Mineral Clear). Surface roughness was assessed with a digital roughness meter before and after each treatment. For the statistical analysis, Student's t test for related samples was used, in addition to the ANOVA test for one intergroup factor, considering a significance level of p < 0.05. Results: The surface roughness variation of bovine tooth enamel, before and after application of bleaching agent, was higher in groups of whitening toothpaste with activated charcoal (0.200 µm, Confidence Interval (CI): 0.105; 0.296 µm) and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (0.201 µm, (CI): 0.092; 0.309 µm). In addition, bovine teeth treated with conventional toothpaste (p = 0.041), whitening toothpaste with activated charcoal (p = 0.001), and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.002) significantly increased their surface roughness values. On the other hand, significant differences were observed when comparing the variation in surface roughness between the application of artificial saliva (control) and the whitening toothpaste with activated charcoal (p = 0.031), and the 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.030). Conclusion: The use of whitening toothpaste with activated charcoal and in combination with 16% carbamide peroxide significantly increased enamel surface roughness in bovine teeth. [ABSTRACT FROM AUTHOR]

Aim and Objective: The aim of the study was to evaluate and compare the surface microhardness of bleached enamel subjected to erosion after using Remin Pro and NovaMin. Methodology: Thirty human maxillary premolars were selected and decoronated. Enamel blocks were obtained from these teeth and subjected to three phases of treatment: bleaching phase, remineralizing phase, and erosive phase. Samples were divided into four groups with 15 samples each. Group I: subjected to erosion without application of bleaching and remineralizing agent, Group II: treatment with 35% carbamide peroxide without application of remineralizing agent, Group III: treatment with 35% carbamide peroxide, followed by application of Remin Pro, and Group IV: treatment with 35% carbamide peroxide followed by application of NovaMin. Initial and final surface microhardness was analyzed using Vickers microhardness. Results: There was a statistically significant difference between control and experimental groups. The percentage of surface hardness loss (%SHL) value was significantly higher in Group II in comparison with the other groups of treatment. However, Group IV and Group III showed the lowest %SHL compared to GI. Conclusion: Within the limitations of this present in vitro study, NovaMin has better-remineralizing potential than Remin Pro and demonstrated increased microhardness of bleached enamel. [ABSTRACT FROM AUTHOR]

Objectives The present experimental study aimed to assess the in vitro effect of sodium bicarbonate (SB) on tooth discolouration. Methods Forty-five extracted anterior teeth were decoronated 2 mm apical to the cementoenamel junction. The crowns were immersed in tea solution for 7.5 days. The teeth were divided into three groups (n = 15 per group) on a random basis. The groups were exposed to either SB paste 94%, hydrogen peroxide (HP) 40%, or carbamide peroxide (CP) 45%. Then, teeth were bleached according to the manufacturers' instructions. Next, all tooth samples were immersed again in tea solution for 10 min. The CIE L*a*b* colour parameters of the teeth were evaluated at baseline (T1), after primary staining (T2), after bleaching (T3), and after re-staining (T4) using a spectrophotometer. The enamel surface morphology of one sample from each group was evaluated preand post-bleaching using scanning electron microscopy (SEM). Within-group and between-group comparisons were made using repeated measures ANOVA and Tukey’s test. Results 94% of cases had color change(ΔE) more than 3.5 with no enamel surface wear after Applying SB. HP showed a maximum bleaching effect of ΔE = 8.77. After re-staining, the SB group showed minimal staining (ΔE = 3.77) compared to the HP and CP groups. Conclusion The present findings show that SB can chemically resolve tooth discolouration and prevent re-staining. Considering its low abrasiveness, optimal safety, low cost, antimicrobial activity, and availability, it seems to be ideal for use at home. [ABSTRACT FROM AUTHOR]

Objective. The causes of internal posteruptive discoloration of teeth are bleeding, necroses, infections, and endodontic filling materials. The aim of this study was to establish the results of bleaching endodontically treated teeth using walking bleach, in-office, and combined techniques, using 30% carbamide peroxide and 35% hydrogen peroxide, as well as the effect of etiological factors, and the time elapsed after endodontic treatment on the success of bleaching. Materials and Methods. The research involved 30 endodontically treated teeth in healthy patients. Retroalveolar X-rays were taken to check the quality of root canal obturation. Endodontic treatment and obturation were carried out on the discolored non-vital teeth without any previous endodontic treatment. Before bleaching, two millimeters of the filling were removed from the root canal and the very entry into the canal was protected with glass ionomer cement. The teeth were divided into three groups, depending on the bleaching technique: walking bleach technique (10 patients), in-office technique (10 patients), and combined technique (10 patients). The teeth were bleached with 30% carbamide peroxide and 35% hydrogen peroxide. The bleaching procedure was repeated in all the patients three times. The color of all teeth was determined based on the Vita Classic guide before and after bleaching. The Χ2 square and Kruskal–Wallis tests were used to identify differences in teeth bleaching results. Results. A statistically significant difference (p < 0.05) was established between bleaching success and the time elapsed after endodontic treatment. There were no statistically significant differences observed between the bleaching success and etiological factors, bleaching techniques, or bleaching agents. Conclusions. The effectiveness of non-vital tooth bleaching is affected by the time elapsed after endodontic treatment. [ABSTRACT FROM AUTHOR]

Objective: To assessed in vitro the effect of nanohydroxyapatite (n‐HA) to improve the aesthetic appearance and microhardness of white spot lesions (WSL) when associated with a low‐concentration bleaching agent (carbamide peroxide—CP10%). Material and methods: Enamel/dentin specimens (n = 60) of 5 × 5 × 2.2 mm were prepared, of these, 48 were submitted to pH‐cycling to create artificial WSL. Subsequently, these were allocated into five groups (n = 12): n‐HA; n‐HA + CP10%; CP10%; WSL control (WSLC); sound control (Sound). The color was assessed at baseline, pre‐treatment, and post‐treatment using a spectrophotometer, and the color (ΔE/ΔE00) and whiteness index (ΔWID) alterations were determined. The enamel cross‐sectional microhardness (CSMH) was evaluated (post‐treatment) with a Knoop indenter, 25gf/5 s, 20–200 μm. The data was analyzed through generalized linear models (α = 5%). Results: ΔE and ΔE00 were significantly higher for the bleached groups (n‐HA + CP10% and CP10%), and the n‐HA was higher than the WSLC group (p < 0.05). ΔWID was significantly higher for the bleached groups (p < 0.05). The CSMH values were significantly higher in the sound group than in the n‐HA, CP10%, and WSLC groups (p < 0.05). The WSLC had lower microhardness than the n‐HA + CP10% and sound groups (p < 0.05). Conclusion: n‐HA is suitable to remineralize and recover the color of the WSL. However, its association with CP10% maintains the esthetical outcome while increasing its in‐depth remineralizing effect. Clinical significance: Considering the aesthetic and functional repercussions of the WSL persistence, treatments that tend to improve its physical appearance and reinforce its weakened substructure in a non‐invasive way are ideal. For this associating low‐concentration, bleaching agents to the remineralizing treatments is promising to treat this type of lesions. [ABSTRACT FROM AUTHOR]

Discolouration resulting from regenerative endodontic procedures may have a negative impact on the quality of life of treated patients; therefore, it is recommended to minimize this risk by selecting appropriate scaffolds and barrier materials, and if discolouration occurs, the use of a simple, cost-effective and minimally invasive technique, such as whitening, should be considered. This in vitro study aimed to evaluate tooth discolouration after two- and single-visit regenerative endodontic procedures and the effectiveness of subsequent whitening procedures with carbamide peroxide. Two hundred bovine incisors were included in this study and divided into twenty groups based on the tested material combinations. Two groups were control groups, one with saline and the other group with blood. In the 12 groups, the experiment was designed to be consistent with the two-visit regenerative endodontic procedures. Triple antibiotic paste or calcium hydroxide were placed in the root canal, and then scaffolds (e.g., blood or platelet-rich fibrin) and barrier materials (Biodentine, OrthoMTA or MTA Repair HP) were applied after rinsing the disinfectant pastes. In the six groups that corresponded to the single-visit regenerative endodontic procedure, the use of a disinfectant paste was omitted. Subsequently, the specimens were bleached twice with carbamide peroxide at a 7-day interval. Colour change measurements were performed using a spectrophotometer (VITA Easyshade Compact 5.0, VITA Zahnfabrik, Bad Säckingen, Germany). Statistical analysis was performed with the Kruskal–Wallis H test, the independent t-test and t-test for related samples. Tooth discolouration was noticed after two- and single-visit regenerative endodontic procedures, except for the platelet-rich fibrin+MTA Repair HP group. After the first and second whitening procedures, all of the tested two- and single-visit regenerative endodontic procedures groups showed a change in the colour of the crown, which was noticeable to the naked eye (∆E > 3.3). When analysing the ∆E value between the first and second bleaching procedures, no changes in the colour of teeth were visually noticed in the calcium hydroxide and platelet-rich fibrin +MTA Repair HP groups (∆E < 3.3). Single-visit regenerative endodontic procedures are suggested if possible; however, if two-visit regenerative endodontic procedures are performed, it is recommended to use calcium hydroxide as the disinfectant paste because of the lower staining potential. In the context of discolouration, platelet-rich fibrin is advisable for use as a scaffold. The whitening procedure is worth considering, but does not guarantee a return to the original tooth colour, especially when triple antibiotic paste is used. [ABSTRACT FROM AUTHOR]

Objectives : To investigate the physical–chemical properties of home bleaching gels based on Carbamide Peroxide (CP) and Hydrogen Peroxide (HP) after accelerated stability (AS) and its effects on enamel. Materials and Methods: A total of 360 bovine teeth blocks were divided (n = 12): Control, CP10%-Whiteness Perfect, CP10%-Pola Night, HP7.5%-Pola Day, and HP7.5%-White Class Calcium. Microhardness (KHN), roughness (Ra), color (ΔE and ΔE00), hardness, compressibility, elasticity, cohesiveness, adhesiveness, weight, pH, and calcium (Ca) quantification in enamel were analyzed without storage of the bleaching gels and after AS at 1 and 3 months. Data of Ca, KHN, and Ra were analyzed through mixed models for repeated measurements and the Tukey–Kramer test. Values of weight, hardness, compressibility, and elasticity were analyzed with two-way ANOVA and Tukey's test. ΔE/ΔE00 data, cohesiveness, and adhesiveness were analyzed with Kruskal–Wallis and Dunn tests (α = 0.05). Results: Groups subject to AS had lower ΔE and ΔE00 compared to those without storage. Lower KHN and higher Ra values were found after bleaching treatment in all groups compared to controls. Higher amounts of Ca were found on the first day of evaluation in the gels subject to AS for 3 months, regardless of the bleaching agent used. Conclusions: Incorrectly stored bleaching gel accentuates adverse effects on enamel. Temperature and humidity interfere directly with the chemical stability of bleaching agents, reducing their properties. Clinical relevance: HP is an unstable oxidizing agent when stored at high temperatures. Therefore, pH becomes more acidic and potentiates the demineralizing effect on enamel. [ABSTRACT FROM AUTHOR]

Objectives : To evaluate bleaching efficacy and oral health-related quality of life (ORHQoL) of three bleaching systems with similar hydrogen peroxide (HP) concentration for up to 6 months post-treatment. Materials and methods: A randomized controlled trial was designed with three parallel groups: group A — in-office 6% HP paint-on varnish; group B — at-home 6% HP with adaptable tray; group C — at-home 16% carbamide peroxide with custom tray. At three different stages (baseline, after bleaching, and 6-month follow-up), ORHQoL was evaluated by the OHIP-14 questionnaire and tooth color of the upper canines and central incisors were measured by two shade guides and a spectrophotometer (measuring CIE L*a*b* with respective color/whiteness differences − ΔE00/ΔWID). Results were presented as mean and 95% confidence intervals and statistical tests were performed appropriately, considering a significance level of α = 0.05. Results: All groups presented significant color differences (P < 0.05) between all stages, with ΔE00/ΔWID surpassing the perceptibility threshold in 98% cases, with group C's results being significantly (P < 0.05) higher when compared to other groups, although with significantly (P < 0.05) higher values of color relapse. Significative ORHQoL improvements (P < 0.05) were detected after bleaching in a global analysis with no differences between techniques. Conclusions: All techniques presented bleaching efficacy, color stability, and improvements in ORHQoL up to 6 months post-treatment. Clinical significance: Clinicians may consider both at-home and in-office bleaching techniques with 6% HP to attain long-lasting satisfactory clinical results while producing positive changes in ORHQoL. [ABSTRACT FROM AUTHOR]

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Objective: The objective of the present study was to assess the progress and efficiency of at-home bleaching protocols with 10% carbamide peroxide using a new methodology based on dental photography. Materials and methods: A 4-week overnight at-home bleaching protocol using whitening trays and 10% carbamide peroxide was performed on 52 patients. The tooth color was analyzed using standardized photographs taken every week for 4 weeks and at 4 months posttreatment. The values of the color evolution (AE00), L*, a*, and b* were also measured and used to assess the evolution of the chroma, luminosity, and hue using the CIEDE2000 formula. The statistical analyses were conducted at a significance level of P < 0.05 by means of a repeated measures analysis of variance (ANOVA). Results: The tooth color changed the most, and thus the highest AE00 was observed, after the first week of treatment. The color continued to change but to a lesser degree during the following weeks. After 4 weeks, the treatment proved to be very effective. Four months after the end of treatment, a color relapse was observed, though it was hardly perceptible to the human eye. The luminosity (L') changed significantly between the beginning and the end of treatment, affecting the maxilla to a greater extent. The chroma evolution showed a high variance and a low; elapse for both jaws. The hue was not affected significantly during the treatment and the stabilization. Conclusions: Within the limitations of the present study, the authors were able to assess the progress and efficiency of at-home bleaching with 10% carbamide peroxide in terms of chroma, luminosity, and hue using a new methodology based on dental photography. Clinical significance: This new method is effective and enables a reliable analysis of the evolution of a dental bleaching treatment, turning dental photography into an even more powerful tool for analysis and communication. It can also be used as a proof-of-concept, paving the way for further research on objective monitoring and evaluation of dental treatments using dental photography. (Int J Esthet Dent 2022;17:2-20) [ABSTRACT FROM AUTHOR]

Aim: This study aimed to investigate the effects of the repeated usage of a home-bleaching agent (16% carbamide peroxide) on the surface roughness of commonly used computer-aided design-computer-aided manufacture (CAD-CAM) restoration materials. Methodology: Five different CAD-CAM restoration materials were used in this study: feldspathic ceramic (Vita Mark II-Group VM II), leucite-reinforced glass ceramic (IPS Empress CAD-Group EMP), lithium disilicate-reinforced glass ceramic (IPS e.max CAD-Group EMAX), polymer infiltrated network hybrid ceramic (Vita Enamic-Group VE), and resin nanoceramic (Lava Ultimate-Group LU). A home-bleaching agent containing 16% carbamide peroxide was applied in three repeated periods (10 days, 20 days, and 30 days of exposure). A surface profilometer was used to determine the roughness average (Ra) values of the specimens. The data obtained were statistically analyzed using repeated measures of the analysis of variance (ANOVA) and Bonferroni post-hoc test at a 5% level of significance. Results: All materials exhibited a rougher surface after the first treatment period (10 days of exposure). The roughness of Group VM II continued to increase for up to 20 days. With the exception of Group LU, all groups exhibited a significantly rougher surface after 30 days of exposure compared to the baseline values (p < 0.05). The greatest variation in surface roughness was observed for the ceramic-based groups (VM II, EMP, and EMAX) rather than the hybrid groups (LU and VE). Conclusion: Patients with ceramic-based CAD-CAM restorations should be careful during home-bleaching treatment, especially when repeated applications are involved. Hybrid materials, particularly Lava Ultimate, seem more resistant to the effects of repeated bleaching cycles than ceramic-based materials. [ABSTRACT FROM AUTHOR]

The article focuses on Coltene's Brilliant Lumina product, designed to provide a comfortable and effective teeth-brightening treatment without causing tooth sensitivity.

Aim: The present in vitro study was designed to determine the effect of different access cavity designs on intracoronal bleaching of endodontically treated teeth with two different agents. Materials and Methods: Fifty selected permanent maxillary central incisors were stained. Traditional and contracted access cavity designs and two types of bleaching agents, i.e., 35% carbamide peroxide and 35 percent hydrogen peroxide were used for the study. Color measurements were performed with a spectrophotometer: before staining (T1), after staining (T2), at 7 and 14 days (T3 and T4) post bleaching. The values were calculated and subjected to the statistical analysis. Results: The results of our study showed that teeth in which traditional access cavity (TAC) was prepared had statistically significant better bleaching results with both 35% carbamide peroxide and 35% hydrogen peroxide than contracted access cavity design. Carbamide peroxide showed better results than hydrogen peroxide irrespective of the access cavity design, but difference was statistically nonsignificant. Conclusion: The present study concluded that TAC design showed better results than contracted access with both carbamide peroxide and hydrogen peroxide. Whereas, when bleaching agents were compared 35% carbamide peroxide is better than 35% hydrogen peroxide irrespective of access cavity design used.

This study aimed to evaluate the effects of 22% carbamide peroxide combined with an erosive challenge and simulated brushing on enamel. Bovine incisor teeth were divided into G1, tooth bleaching; G2, tooth bleaching + erosive challenge; and G3, tooth bleaching + erosive challenge + simulated brushing, and evaluated at T0, before any intervention; T1, 14 days after the proposed treatments; and T2, 28 days after the proposed treatments. Tooth bleaching was performed daily for 1 h for 28 days. The microhardness, surface roughness, mass variation, and ultrastructure were analyzed at T0, T1, and T2. Two-way analysis of variance for repeated measures was performed and Tukey's post hoc test (α = 5%) was used. The surface roughness increased in groups G2 and G3 as a function of time, whereas microhardness and mass measurements demonstrated a significant reduction for groups associated with challenges. Ultrastructural evaluation indicated a loss of the aprismatic layer and exposure of the enamel prisms in all groups after 14 days of bleaching, with more pronounced results in G2 and G3 after 28 days. In conclusion, abrasive and erosive challenges potentiated the deleterious effects of tooth whitening on microhardness, ultramorphology, and mass, without affecting the roughness of dental enamel. [ABSTRACT FROM AUTHOR]

The objective of this article was to systematically review the literature to determine how effective tooth whitening procedures are when carried out in tandem with orthodontic clear aligners. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Online searches of PubMed, Medline via Ovid, Science Direct, the Cochrane database of systematic reviews via Ovid, Scopus, and Google Scholar as well as manual searches of the references of the selected articles were conducted. Clinical studies which assessed the efficacy of dental bleaching using orthodontic clear aligners were included in the present study. Data from the included studies were extracted and assessed for risk of bias using the Cochrane risk of bias tool. Three studies met the inclusion and exclusion criteria and were included in this study. One study compared the efficiency of tooth bleaching between clear aligners and conventional bleaching trays. One study evaluated the effectiveness of dental bleaching using clear aligners by comparing the tooth shade of those patients to a control group of patients who did not receive dental bleaching during orthodontic clear aligner treatment. One study evaluated the effectiveness of different concentrations of different bleaching agents using clear aligners. All the included studies showed an improved tooth shade when using clear aligners as bleaching trays. [ABSTRACT FROM AUTHOR]

Infectious disease outbreaks are a primary contributor to coral reef decline worldwide. A particularly lethal disease, black band disease (BBD), was one of the first coral diseases reported and has since been documented on reefs worldwide. BBD is described as a microbial consortium of photosynthetic cyanobacteria, sulfate-reducing and sulfide-oxidizing bacteria, and heterotrophic bacteria and archaea. The disease is visually identified by a characteristic dark band that moves across apparently healthy coral tissue leaving behind bare skeleton. Despite its virulence, attempts to effectively treat corals with BBD in the field have been limited. Here, we developed and tested several different therapeutic agents on Pseudodiploria spp. corals with signs of active BBD at Buck Island Reef National Monument in St. Croix, USVI. A variety of therapies were tested, including hydrogen peroxide-based treatments, ointment containing antibiotics, and antiviral/antimicrobial-based ointments (referred to as CoralCure). The CoralCure ointments, created by Ocean Alchemists LLC, focused on the dosing regimen and delivery mechanisms of the different active ingredients. Active ingredients included carbamide peroxide, Lugol's iodine solution, along with several proprietary essential oil and natural product blends. Additionally, the active ingredients had different release times based on treatment: CoralCure A-C had a release time of 24 hours, CoralCure D-F had a release time of 72 hours. The ointments were applied directly to the BBD lesion. Also, jute rope was saturated with a subset of these CoralCure ointment formulations to assist with adhesion. These ropes were then applied to the leading edge of the BBD lesion for one week to ensure sufficient exposure. Corals were revisited approximately three to five months after treatment application to assess disease progression rates and the presence/absence of lesions—the metrics used to quantify the efficacy of each treatment. Although most of the treatments were unsuccessful, two CoralCure rope formulations—CoralCure D rope and CoralCure E rope, eliminated the appearance of BBD in 100% of the corals treated. As such, these treatments significantly reduced the likelihood of BBD occurrence compared to the untreated controls. Additionally, lesions treated with these formulations lost significantly less tissue compared with controls. These results provide the mechanisms for an easily employable method to effectively treat a worldwide coral disease. [ABSTRACT FROM AUTHOR]

Aim -This study is to evaluate the preferences of general dentists regarding the vital and nonvital tooth bleaching therapies and investigate whether the time of clinical practice and post-graduate training has influenced these options or not. Introduction The dental practice in today's time is a combination of treatment and maintenance of esthetics. People consider whiteness of teeth as an important component for achieving self -esteem and confidence; discolored teeth significantly impacts on physical, psychological, and social aspects of individuals' quality of life. Materials and methods A cross-sectional study was conducted using a questionnaire with closed questions applied to dentists. The Information was collected regarding the sociodemographic variab les, and level of specialization In addition the options regarding bleaching therapies including the first choice of material, technique and clinical practice for vital and nonvital tooth bleaching therapies are also included. The Data were submitted to descriptive analysis and the associations were evaluated using chi-square and Fisher exact tests. Results The response rate was 68%. At-home bleaching therapy was broadly preferred over in-office bleaching. For at-home bleaching, most dentists answered to use 10% carbamide peroxide (CP) and >30% hydrogen peroxide (HP) for nonvital therapies. The majority of dentists with training preferred at-home bleaching techniques. At-home bleaching therapy was also more indicated by younger dentists. No association was found between the choice for nonvital bleaching therapies and time since graduation or continuous education. The P value = 0.392 (> 0.05) hence not statistically significant. Conclusion It is found that carbamide peroxide is the most effective material for non vital bleaching. The discoloration of pulp chamber origin is an indication of internal bleaching in females than in males. Also dental practitioners and specialists prefer carbamide peroxide for non vital bleaching. [ABSTRACT FROM AUTHOR]