Bleaching Research Articles

Effect of the reduction in the exposure time to at-home bleaching gel on color change and tooth sensitivity: A systematic review and meta-analysis.

To investigate the effect of reducing exposure time to at-home bleaching gel on color change and tooth sensitivity. The search was carried out using PubMed, Scopus, Web of Science, EMBASE, LILACS, Cochrane. Randomized clinical trials (RCTs) were included involving adult patients who have never undergonebleaching treatment before (P), subjected to bleaching with a reduced exposure time to the at-home bleaching agent (I) compared to those who used it for the time indicated by the manufacturer (C), to evaluate the effects on color change and tooth sensitivity (O). The Cochrane guidelines for the Risk of Bias Assessment Tool (RoB 2.0) and GRADE were used to assess risk of bias and quality of evidence, respectively. Using at-home bleaching gel for the period recommended by the manufacturer resulted in significantly higher ΔEab and ΔWID values and better subjective color change (ΔSGU-Classical), regardless of the evaluation time. Regarding the post-bleaching evaluation, no significant differences were found for ΔE00 immediately after bleaching or ΔSGU (Bleached) at any time. Reducing the time of use significantly decreased tooth sensitivity events. Reducing exposure time to at-home bleaching gel reduces tooth sensitivity events; however, most of the parameters that assess color change indicate using at-home bleaching gel for the time recommended by the manufacturer. Reducing exposure time to at-home bleaching gel should be applied with caution in clinical practice. Although the evidence suggests a reduction in tooth sensitivity events, bleaching effectiveness was significantly higher after using the bleaching gel for the time indicated by the manufacturer.

Characterization of heat- and alkali-resistant feruloyl esterase from Humicola insolens and application in the production of high-strength kraft straws.

The application of feruloyl esterase (FAE) in biobleaching can effectively hydrolyze the feruloyl ester bond between hemicellulose and lignin, thereby partially disrupting the dense structure of the fiber, reducing the use of chemical reagents, and obtaining high-performance pulp fibers. Here, we successfully expressed the thermostable alkaline feruloyl esterase from Humicola insolens (H. insolens) in Pichia pastoris GS115, with an enzyme activity yield of 2.36 ± 0.21U/mL. The highest activity of FAE for the hydrolysis of ethyl ferulate was observed at pH7.5 and 70°C. It retained about 56% of its maximum activity in the pH range of 11.0. After being incubated at 50-55°C for 1h, it retained 70.05% of its maximum activity. The addition of bio-enzyme pretreatment before chemical bleaching can reduce chemical reagents by 20%, result in a 10.64% reduction in kappa value, and increase the delignification rate of the pulp by 6.36%. In addition, the surface of the enzyme-treated pulp showed rougher broom-like fiber filaments, and the viscosity of the enzyme-pretreated pulp (ECP) before chemical treatment increased by 131.51% compared to the chemically treated pulp (CP), further indicating that the enzyme-pretreated pulp had higher pulp strength.

Regulatory issues related to the use of sodium hypochlorite solutions in endodontics.

To assess the regulation of sodium hypochlorite (NaOCl) solutions for endodontic usage in some of the world's main dental markets, in view of the European Union's recent move to classify antimicrobial root canal irrigants as high-risk devices under their Medical Device Regulation (MDR). The authors consulted legal texts available online and communicated with local health authorities wherever necessary to assess into which medical device category NaOCl solutions intended for endodontic application were subsumed. Furthermore, it was investigated whether there were sources outside the dental market to obtain NaOCl solutions for root canal treatments. Upon completion of this text (mid 2024), NaOCl solutions for root canal irrigation had not been classified in the US and Canada, whilst in the European Union, they had just been upgraded to high-risk medical devices, with all the consequences for the dental supply market. This MDR rule was adopted by the EU's close trading partners, the United Kingdom, Switzerland and Turkey. In Japan, the legal hurdles were already high for manufacturers and importers of endodontic NaOCl solutions. Conversely, in China, these solutions were down-graded from a high-risk to a medium-risk status in 2017. A low-medium risk category was applied in the other countries under investigation, that is, Australia, India and Brazil. In some countries there was a possibility for dentists to procure plain NaOCl solutions from pharmacies. An alternative route to avoid buying NaOCl from dental suppliers was to use (household) bleach solutions for root canal irrigation wherever this practice was not prohibited explicitly. The legal situation to produce, import and use NaOCl solutions for root canal irrigation differs vastly around the globe. A sensible approach to regulate (yet not over-regulate) endodontic NaOCl solutions appears to be timely and necessary.

Oxalic Acid from Averrhoa bilimbi L. as a Bleaching Agent

Oxalic Acid from Averrhoa bilimbi L. as a Bleaching Agent

Bleaching Agents: A Review of Their Utilization and Management

Exposure to disinfectants, cleansers, and bleaching chemicals irritates the eyes, respiratory systems, and skin, triggering asthma and allergic rhinitis symptoms. Bleach, as the major constituent of cleansers, when used improperly or mixed with other indoor cleaning agents, produces harmful halogenated volatile organic compounds. This manuscript assesses the influence of excessive exposure to disinfectants, including bleaching agents, when used against infectious conditions related to SARS-COVID-19 and its management. The use and impact of different bleaching agents in cleansing and their associated problems have been analyzed and presented in this review. This analysis focuses on the conventional and post-pandemic approach towards bleaches. Usage of bleaching agents increased by a staggering 20.4% and 16.4% from January to March 2020 compared to the same period in 2018 and 2019. Mounting use of bleaching agents during the COVID-19 pandemic resulted in negative health effects like asthma, eye irritation, and skin allergies. An approximately 42% rise in poisoning cases, including a few deaths, has been associated with exposure to harmful chemicals involving bleaches during the recent pandemic. Bleaching agents are the primary sources of hazardous indoor pollutants; therefore, despite their importance in disinfection, their utility must be substantiated based on legal guidelines, disposal, and remedial measures. Thus, conducting future occupational exposure assessment studies for bleach hazard management is crucial.

Penetration of Intracoronal Bleaching Agents Across a Calcium Silicate-Based Coronal Barrier in Pulpless Immature Permanent Teeth: An In Vitro Study.

Tooth bleaching procedures on nonvital teeth have been performed for crown discoloration caused by regenerative endodontic therapy (RET). However, leakage of bleaching agents across the root canal can be detrimental. This study aimed to assess and compare the penetration levels of hydrogen peroxide (HP) from different bleaching agents across calcium silicate-based coronal barriers in immature permanent teeth. Fifty extracted single-rooted human teeth were randomly divided into four groups (n = 10): Group I (HH)-35% hydrogen peroxide (HP); Group II (SS)-a mixture of sodium perborate (SP) powder and saline; Group III (SH)-a mixture of SP powder and 30% HP liquid; Group IV (CP)-10% carbamide peroxide gel. The control group (Group V, CC) was treated with distilled water. The bleaching agent was replaced on the 4th day, and penetration analysis was performed on the 7th day using ferro thiocyanate (FTC) method and a UV-spectrophotometer at a wavelength of 480 nm. Compared with the control group, the SH group (SP mixed with HP) showed a significant difference, indicating substantial HP penetration across the root canal space (p value < 0.0001). Intergroup comparisons also revealed a significant difference between the SS and SH groups (p value < 0.0001), suggesting that the SS group had less penetration. Compared with other bleaching agents, SP mixed with saline/water resulted in the lowest HP penetration in the pulp canals of the RET-simulated tooth models. This study is the first to investigate HP penetration from different bleaching agents in teeth that have undergone RET, identifying the safest bleaching agent for use in these cases. This study also provides a foundation for further research to develop precise guidelines for nonvital tooth bleaching protocols in RET-treated teeth.

Oxidative Release of Natural Glycans: Unraveling the Mechanism for Rapid N-Glycan Glycomics Analysis.

N-glycosylation is a critical post-translational modification involved in various biosynthetic pathways and disease mechanisms. In this study, we present an optimized oxidative release of natural glycans (ORNG) method using household bleach that enables the rapid and efficient release of N-glycans from biological samples. We thoroughly investigated the ORNG mechanism, identifying key intermediates and side products and providing valuable insights into the oxidative release process. The method is highly efficient, releasing a wide range of N-glycans, including high-mannose, hybrid, and complex structures, with minimal sample processing. Our ORNG-based specific N-glycan profiling approach has demonstrated high sensitivity and efficiency, particularly in releasing N-glycans resistant to enzymatic digestion, such as core α3-fucosylated N-glycans from soy protein. Validation through mass spectrometry confirmed the method's ability to accurately profile N-glycans from complex biological samples, including human serum, with results comparable to traditional PNGase F digestion. The ORNG-based method's scalability, versatility, and use of low-cost reagents make it especially suited for large-scale glycomics studies. Furthermore, the mass spectrometry data revealed that the ORNG-based method achieves high sensitivity and specificity, positioning it as a robust alternative for comprehensive glycan profiling and functional studies. Our findings highlight ORNG's potential to advance N-glycomics, offering promising improvements in speed, efficiency, and breadth of glycan analysis.

Surface Properties of Enamel after Using Different Bleaching Agents

Surface Properties of Enamel after Using Different Bleaching Agents

Assessment of Dyeing Time on Color Change of Dyed Cotton Fabrics using Household Bleach

Assessment of Dyeing Time on Color Change of Dyed Cotton Fabrics using Household Bleach

Effect of Hydrogen Peroxide-Based Bleaching Agents on the Color Dimensions and Surface Roughness of Different Milled Restorative Dental Materials.

To compare the color dimensions, color discrepancies (ΔE00), and surface roughness of milled materials before and after application of a bleaching agent. A total of 10 extracted molars were obtained. Each tooth was cut in transverse sections to create disks (3-mm thick, 10-mm diameter; control group). Disk specimens of eight materials (n &#61; 10 per group) were fabricated: polymethyl methacrylate (PMMA) interim material (PMMA-Telio group), two resin nanoceramics (RNC-Ultimate group and RNC-Cerasmart group), two hybrid ceramics (HC-Shofu group and HC-Enamic group), lithium disilicate (LD-Emax group), zirconia-reinforced glass ceramic (ZGC-Suprinity group), and zirconia (Zr-InCeram group). Color measurements were obtained using a spectrophotometer before and after applying 35% hydrogen peroxide-based bleaching agent. Pre- and postbleaching surface roughness (Sa) analyses were completed using a profilometer. Significant L*, a*, b*, and ΔE00 value differences were found (P < .05). Color discrepancies (ΔE00) ranged from 0.30 ± 0.14 to 4.82 ± 0.10. The highest color discrepancies were measured on the PMMA-Telio group, while the lowest color discrepancies were computed for ZGC-Suprinity, RNCUltimate, and RNC-Cerasmart. Significant surface roughness differences were found (P < .05). The largest increase of surface roughness values between the pre- and postbleaching measurements was obtained in the PMMA-Telio group with a mean ΔSa value of 4.73 ± 3.02, while the largest decrease of surface roughness values between the pre- and postbleaching measurements was obtained in the Zr-InCeram group with a mean ΔSa value of -1.58 ± 0.10. The milled materials showed significant pre- and postbleaching color and surface roughness discrepancies.

Effect of immune-boosting beverage, energy beverage, hydrogen peroxide superior, polishing methods and fine-grained dental prophylaxis paste on color of CAD-CAM restorative materials

BackgroundThe effect of an immune-boosting beverage (SAM) containing Sambucus Nigra, an energy beverage (ENE), an in-office bleaching (BLE) agent with 25% hydrogen peroxide superior, glazing (GLA) or polishing (POL) methods, and professional dental prophylaxis (PDP) on the color of CAD-CAM restorative materials is unknown.MethodsIn total 210 specimens were prepared, consisting of CAD-CAM feldspathic (FC), zirconia-reinforced lithium disilicate ceramic (ZLS) and hybrid ceramic (HC). The ceramic specimens were divided according to the polishing methods of glazing (GLA) and mechanical polishing (POL). All materials were divided into two groups: with and without BLE. A 25% hydrogen peroxide superior (HPS) gel was used for BLE. After the baseline (BAS) measurement, the specimens were immersed in 3 different beverages (distilled water (DIS), SAM, ENE). After 28 days, a fine-grained (RDA 7) prophylaxis paste was applied. Statistical analysis of ∆E00 color difference values was performed by 3-way ANOVA and Bonferroni test (α = 0.05).ResultsThe effect of all other actions except material-BLE-beverage on color for BAS-Day 28 was statistically different (p < 0.05). The effect of material, material-BLE, beverage on color for Day 28-PDP was statistically different (p < 0.05). After 28 days, the lowest color change was found in FC-GLA and HC immersed in DIS (p = 0.0001) and the highest in FC-POL immersed in ENE (p = 0.0002). PDP was efficient in color recovery in HC immersed to DIS, ENE and SAM (p = 0.0010). For FC, HC and ZLS, BLE caused a higher color change (p < 0.0001). Regardless of the material, the highest color change for BLE-beverage was found in BLE-treated specimens immersed in ENE (p = 0.0496) and the lowest color change was found in non-BLE-treated specimens immersed in SAM (p = 0.0074).ConclusionsIn materials pre-exposed to 25% HPS, the effect of PDP on color recovery was lower than in unexposed materials. After 28 days, mechanical polishing produced higher color change in FC than glazing, however, in ZLS effects of glazing and mechanical polishing on color were similar. For material/polishing method, HC was the most effective. ENE caused higher color change than DIS and SAM. PDP was more effective than ENE in restoring color to DIS- and SAM-immersed specimens.

An ionic liquid crystal functionalized nanocellulose lubricant additives

Cellulose, one of nature's most abundant, clean, and sustainable resources, has often shown unsatisfactory results when used as bio-lubricant additives. Herein, nanocellulose (NC) from amorphous waste natural poplar was extracted using deep eutectic solvent encapsulation treatment and chlorine bleaching process. Subsequently, 1-hexadecyl-3-methylimidazolium bromide was integrated onto NC using a one-step hydrothermal treatment (high-temperature and high-pressure environment) to obtain ionic liquid crystal (ILC) functionalized products (named as ILC-NC). After ball-milling process and solid phase separation step, ILC-NC exhibits excellent dispersion stability and lubrication properties in the liquid phase (including water and vegetable oil). Based on the polar and colloidal activity properties of ILC, it can form an ordered molecular layer on NC surface and form a lubricating film-like structure, making NC smoother and sliding well. Compared to ILC/NC aqueous dispersion, ILC-NC reduces the coefficient of friction and wear rate on steel disk surface by 68.75 % and 74.07 %, respectively. The minimum coefficient of friction was further reduced to 0.032 as dispersing ILC-NC in sunflower oil, showing a reduction of 0.134 (77.91 %) compared to pure sunflower oil. Finally, the lubrication theoretical model calculation reveals the lubrication state of ILC-NC on the steel disk surface and proposes the lubrication mechanism.

Comparison of Surface Microhardness of Enamel after Bleaching with Two Commercially Available Hydrogen Peroxide-based Bleaching Agents -An In-vitro Study

Comparison of Surface Microhardness of Enamel after Bleaching with Two Commercially Available Hydrogen Peroxide-based Bleaching Agents -An In-vitro Study

Bio-Innovative Modification of Poly(Ethylene Terephthalate) Fabric Using Enzymes and Chitosan.

This article investigates the activation of surface groups of poly(ethylene terephthalate) (PET) fibers in woven fabric by hydrolysis and their functionalization with chitosan. Two types of hydrolysis were performed-alkaline and enzymatic. The alkaline hydrolysis was performed in a more sustainable process at reduced temperature and time (80 °C, 10 min) with the addition of the cationic surfactant hexadecyltrimethylammonium chloride as an accelerator. The enzymatic hydrolysis was performed using Amano Lipase A from Aspergillus niger (2 g/L enzyme, 60 °C, 60 min, pH 9). The surface of the PET fabric was functionalized with the homogenized gel of biopolymer chitosan using a pad-dry-cure process. The durability of functionalization was tested after the first and tenth washing cycle of a modified industrial washing process according to ISO 15797:2017, in which the temperature was lowered from 75 °C to 50 °C, and ε-(phthalimido) peroxyhexanoic acid (PAP) was used as an environmentally friendly agent for chemical bleaching and disinfection. The influence of the above treatments was analyzed by weight loss, tensile properties, horizontal wicking, the FTIR-ATR technique, zeta potential measurement and SEM micrographs. The results indicate better hydrophilicity and effectiveness of both types of hydrolysis, but enzymatic hydrolysis is more environmentally friendly and favorable. In addition, alkaline hydrolysis led to a 20% reduction in tensile properties, while the action of the enzyme resulted in a change of only 2%. The presence of chitosan on polyester fibers after repeated washing was confirmed on both fabrics by zeta potential and SEM micrographs. However, functionalization with chitosan on the enzymatically bioactivated surface showed better durability after 10 washing cycles than the alkaline-hydrolyzed one. The antibacterial activity of such a bio-innovative modified PET fabric is kept after the first and tenth washing cycles. In addition, applied processes can be easily introduced to any textile factory.

Comparative Evaluation of Impact of In-office Bleaching Agents on Shade and Gloss of Permanent Teeth -An In-vitro Study

Comparative Evaluation of Impact of In-office Bleaching Agents on Shade and Gloss of Permanent Teeth -An In-vitro Study

Quantitative Analysis of Tooth-Whitening Efficiency Using Natural Bleaching Agents: An In Vitro Spectrophotometric Evaluation

Abstract Aim: While conventional whitening agents provide effective color change, concerns linger regarding enamel health. This study explored the potential of natural alternatives for coffee stain removal on extracted teeth, aiming to identify safe and efficacious options for patients seeking noninvasive bleaching solutions. Materials and Methods: This study employed 50 extracted permanent anterior teeth divided into five groups (negative control, positive control, strawberry, pineapple, and honey). Standardized coffee staining was applied to all teeth followed by 3 weeks of twice-daily treatment with their respective solutions. Shade changes were measured objectively using a Konica Minolta Spectrophotometer CM-5 at baseline and after 1, 7, 14, and 21 days post-treatment. Statistical analysis was conducted with Kruskal–Wallis and Tukey post hoc tests (IBM® SPSS®). Results: Strawberry juice exhibited equivalent ΔE (color change) compared with 35% hydrogen peroxide (P &gt; 0.99), indicating similar stain removal efficacy. Both pineapple juice and honey solution displayed significantly lower ΔE values compared with the control and strawberry juice groups (P = 0.002 and &lt;0.001, respectively), suggesting limited bleaching capability. Conclusion: This study demonstrates the potential of strawberry juice as a viable alternative to conventional bleaching agents, offering comparable stain removal efficacy on coffee-stained teeth and further highlighting the need for further research on their effectiveness in clinical settings. Meanwhile, pineapple juice and honey solution exhibited limited bleaching potential. These findings contribute to the expansion of safe and potentially noninvasive teeth-whitening options.

Re-evaluation of shellac (E 904) as a food additive and a new application on the extension of use of shellac (E 904) in dietary foods for special medical purposes.

The present opinion deals with the re-evaluation of shellac (E 904) when used as a food additive and with the new application on the extension of use of shellac (E 904) in dietary foods for special medical purposes. The Panel derived an acceptable daily intake (ADI) of 4 mg/kg body weight (bw) per day for wax-free shellac (E 904) produced by physical decolouring, based on a NOAEL of 400 mg/kg bw per day and applying an uncertainty factor of 100. The Panel concluded that the ADI of 4 mg/kg bw per day should be considered temporary for wax-free shellac (E 904) produced by chemical bleaching, while new data are generated on the identity and levels of the organochlorine impurities in E 904. This ADI is not applicable for wax-containing shellac as a food additive. For several age groups, the ADI was exceeded at the 95th percentile in the non-brand-loyal exposure assessment scenario and maximum level exposure assessment scenario. Considering the low exceedance and the fact that both the exposure estimation and the toxicological evaluation of shellac were conservative, the panel concluded that the calculated exceedance of the ADI does not indicate a safety concern. The Panel recommended to the European Commission separating specifications for E 904 depending on the manufacturing process, chemical bleaching and physical decolouring, because they result in different impurities; revising the definition of the food additive to include a description of each manufacturing process; deleting information on wax-containing shellac from the EU specifications; revising the acid value for wax-free shellac produced by chemical bleaching; lowering the maximum limit for lead; to consider introducing limits for other toxic elements potentially present in shellac; including a maximum limit for chloroform and total inorganic chloride in the EU specification for shellac produced by chemical bleaching.

Exploring the Potential of Invasive Species Sargassum muticum: Microwave-Assisted Extraction Optimization and Bioactivity Profiling.

Sargassum muticum (SM) poses a serious environmental issue since it is a fast-expanding invasive species occupying key areas of the European shoreline, disrupting the autochthonous algae species, and disturbing the ecosystem. This problem has concerned the general population and the scientific community. Nevertheless, as macroalgae are recognized as a source of bioactive molecules, the abundance of SM presents an opportunity as a raw material. In this work, response surface methodology (RSM) was applied as a tool for the optimization of the extraction of bioactive compounds from SM by microwave-assisted extraction (MAE). Five different parameters were used as target functions: yield, total phenolic content (TPC); and the antioxidant measurements of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and β-carotene bleaching (BC). After the optimal extraction conditions were determined (time = 14.00 min; pressure = 11.03 bar; ethanol = 33.31%), the chemical composition and bioactivity of the optimum extract was evaluated to appraise its antioxidant capability to scavenge reactive species and as a potential antibacterial, antidiabetic, antiproliferation, and neuroprotective agent. The results lead to the conclusion that MAE crude extract has bioactive properties, being especially active as an antiproliferation agent and as a nitric oxide and superoxide radical scavenger.

Determination of Optical Properties of Ovangkol (Guibourtia ehie) Wood Treated with Oxalic Acid and Hydrogen Peroxide

Ovangkol wood is a valuable species in woodworking industries, especially in the furniture sector. Bleaching processes alter the color of the wood. In this research, changes in certain surface properties [whiteness index (WI*), glossiness, and color parameters (lightness (L*), red (a*) color tone, yellow (b*) color tone, chroma (C*) value, and hue (ho) angle)] were investigated upon the application of two different bleaching chemicals [oxalic acid (C2H2O4) and hydrogen peroxide (H2O2) + sodium hydroxide (NaOH)] on the surfaces of ovangkol (Guibourtia ehie) wood. With the chemical C2H2O4, increases were observed in the WI* ║ direction and in all color parameters. In addition, with the NaOH + H2O2 solution, increases were obtained in the L* and ho values, while decreases were observed in the a*, C*, and b* parameters. When employing the C2H2O4 chemical, the ∆E* value measured at 4.25, whereas treatments involving solutions prepared with H2O2 + NaOH yielded a ∆E* value of 13.14. Positive ∆L* values were observed with the use of both chemicals. Conversely, while the ∆a*, ∆b*, and ∆C* values showed positivity with the C2H2O4 chemical, they exhibited negativity when using the NaOH + H2O2 solution. Glossiness values decreased at both 60 and 85 degrees, irrespective of whether they were measured parallel or perpendicular to the fibers, following the application of both bleaching agents on the wooden surfaces.

Comparative Evaluation of Activated and Nonactivated Microbubbles on the Efficacy of Bleaching Agents.

Intracoronal bleaching serves as a conservative option for nonvital teeth that exhibit discoloration.Hydrogen peroxide (H2O2) is frequently utilized in bleaching processes owing to its capability to produce free radicals.The main drawbacks of the currently available bleaching agents are the occurrence of cervical resorption and the multiple dental visits to achieve the desired result. Therefore, in our study, to address the limitations associated with cervical resorption and extended treatment duration for badly stained teeth, an attempt was made to incorporate a whitening agent (35% H2O2) with microbubbles. This study aimed tocompareandevaluatetheeffect ofactivated and nonactivated microbubbles on the efficacy of bleaching agents. Forty-five human central incisors were collected and divided into three groups:Group I (HP), H2O2 plain(n= 15) (Control); Group II (HPM), H2O2-infused microbubbles without ultrasonic activation (n= 15) (experimental group); and Group III (HPMU), H2O2-infused microbubbles with ultrasonic activation (n= 15) (experimental group).The crowns were artificially stained. Microbubbles containing 35% H2O2were generated using the probe sonication method.The bleaching agent H2O2 plain (0.04 mL) was syringed into the pulp chamber in group I, while H2O2-infused microbubbles (0.04 mL) were syringed into group II and group III. Group III was further activated ultrasonically. The evaluation of color shade differences was conducted using the Vita Lumin shade guide at three time points: baseline, day 7, and day 14. Data regarding color change using Vita shade were investigated for normality using theKolmogorov Smirnov test and assessed a non-normal distribution.Intergroup comparisons at each particular time interval (baseline, day 7, and day 14) were analyzed using the Kruskal-Wallis H test followed by multiple pairwise comparisons using the Adjusted Bonferroni post hoc test. Intragroup comparisons between different time intervals were analyzed using related samples from Friedman's test followed by multiple pairwise comparisons using the post hoc Dunn test. The level of statistical significance was determined at P< 0.05. There was no statistical difference in the baseline values of all three groups. Group I (HP) exhibited an average increase of three Vita Lumin shade tabs on day 7 and day 14, respectively, whereasGroup II (HPM)exhibited an average increase of six and four Vita Lumin shade tabs on day 7 and day 14, respectively, and Group III (HPMU)exhibited an average increase of 10 and 3 Vita Lumin shade tabs on day 7 and day 14, respectively. Microbubbles containing H2O2 were more efficient and faster than plain H2O2 for bleaching, and the efficacy of bleaching was enhanced when activated using ultrasonic technology.