Enhanced tooth bleaching with a hydrogen peroxide/titanium dioxide gel.

BACKGROUND: This study aimed to explore the effects of the titanium dioxide (TiO2) concentration and particle size in hydrogen peroxide (HP) on tooth bleaching effectiveness and enamel surface properties. METHODS: TiO2 at different concentrations and particle sizes was incorporated into 40% HP gel to form an HP/TiO2 gel. The specimens were randomly divided into 8 groups: C1P20: HP + 1% TiO2 (20 nm); C3P20: HP + 3% TiO2 (20 nm); C5P20: HP + 5% TiO2 (20 nm); C1P100: HP + 1% TiO2 (100 nm); C3P100: HP + 3% TiO2 (100 nm); C5P100: HP + 5% TiO2 (100 nm); C0: HP with LED; and C0-woL: HP without LED. Bleaching was conducted over 2 sessions, each lasting 40 min with a 7-day interval. The color differences (ΔE00), whiteness index for dentistry (WID), surface microhardness, roughness, microstructure, and composition were assessed. RESULTS: The concentration and particle size of TiO2 significantly affected ΔE00 and ΔWID values, with the C1P100 group showing the greatest ΔE00 values and C1P100, C3P100, and C5P100 groups showing the greatest ΔWID values (p < 0.05). No significant changes were observed in surface microhardness, roughness, microstructure or composition (p > 0.05). CONCLUSIONS: Incorporating 1% TiO2 with a particle size of 100 nm into HP constitutes an effective bleaching strategy to achieve desirable outcomes.

Efficacy of a buccal and lingual at-home bleaching protocol-A randomized, split-mouth, single-blind controlled trial.

OBJECTIVE: To compare the color change, the risk and intensity of tooth sensitivity (TS), and gingival irritation (GI) of at-home bleaching applied on the buccal surface only or the buccal and lingual surfaces. MATERIALS AND METHODS: Sixty patients with canines A2 or darker were selected and their superior arches were randomized in two groups: at-home bleaching on the buccal-only or on the buccal and lingual surfaces, with 7.5% hydrogen peroxide, for 1 h daily/2 weeks. The color change was evaluated at baseline, 7, 14 days, and 1 month after bleaching using shade guides scales (ΔSGU) and a spectrophotometer (ΔEAB, ΔE00, and ΔWID). Risk and intensity of TS and GI were recorded daily using visual analogic scale (0-10). Patient satisfaction was evaluated with the orofacial esthetics. Paired t-test, McNemar's, and Wilcoxon signed-rank test were used for data analysis (α = 5%). RESULTS: Neither the color change nor the risk/intensity of TS was statistically different between groups (p > 0.05). Patient satisfaction increased after bleaching for both groups (p < 0.05). CONCLUSION: The addition of one contact surface does not result in an increased whitening degree compared to bleaching applied solely on the buccal surface. CLINICAL SIGNIFICANCE: Understanding the influence of surfaces interacting with the bleaching agent is crucial for comprehending the bleaching mechanism and avoiding unnecessary material expenses. Notably, employing the buccal-only technique is sufficient to achieve the desired efficacy.

Peróxido de carbamida 37% no clareamento dentário e sua atuação na efetividade clareadora e eliminação de sensibilidade: relato de caso / The usage of 37% carbamide peroxide in tooth bleaching and its effect on bleaching effectiveness and elimination of sensitivity: a case report / Peróxido de carbamida al 37% en el blanqueamiento dental y su efecto sobre la eficacia del blanqueamiento y la eliminación de la sensibilidad: informe de un caso

Introdução:A sensibilidade dentária é o efeito adverso mais comum relacionado ao clareamento dentário. Na técnica de consultório, o peróxido de carbamida a 37%, surgiu como possibilidade de clarear e não causar sensibilidade.Objetivo:trata-se deum relato de caso, que avaliou a eficácia (mudança de cor) e a presença ou não de sensibilidade dentária quando se fezo uso de um produto àbase de peróxido de hidrogênio a35% e outro de peróxido de carbamida a 37%, na técnica de clareamento dentário de consultório.Relato de caso:Paciente de25 anos, sexo masculino, submetido a estudo de boca dividida, onde no hemiarco esquerdo foi aplicado peróxido de hidrogênio a 35% e no hemiarco direito, peróxido de carbamida a 37%. Foram feitas 3 sessões, sendo Peróxido de Carbamidacom aplicação única de 45 minutos, e Peróxido de Hidrogêniocom 3 aplicações de 15 minutos, em seu respectivo lado de aplicação e intervalo de sete dias entre cada sessão. Os valores de sensibilidade foram analisados antes e depois de cada sessão por meio da escala visual analógica de dor, e a alteração de cor foi avaliada através da Escala Vita, analisando incisivos e caninos superiores, antes de cada sessão.Conclusões:O clareamento dental com o Peróxido de Hidrogênio apresentou melhor eficácia clareadora e o Peróxido de Carbamida apresentou ausência de sensibilidade durante o procedimento clareador. Sugerem-se mais estudos do tipo ensaio clínico, com o Peróxido de Carbamida, para que se possa, com uma amostra maior de pacientes, verificar suas vantagens no quesito sensibilidade, bem como sua efetividade clareadora (AU).

Introduction:Tooth sensitivity is the most common adverse effect related to tooth bleaching. In the in-office technique, 37% carbamide peroxide has emerged as a way of tooth bleaching which does not cause sensitivity.Objective:This paper consists of a case report that evaluated the efficacy (color change) and the presence or absence of tooth sensitivity when using a product based on 35% hydrogen peroxide and another product based on 37% carbamide peroxide in the in-office tooth bleaching technique.Case report:A 25-year-old male patient underwent a split-mouth study in which 35% hydrogen peroxide was applied to the left hemi-arch and 37% carbamide peroxide to the right hemi-arch. Three sessions were carried out, carbamide peroxide with a single 45-minute application, and hydrogen peroxide with three 15-minute applications, on their respective application side and with a seven-day interval between each session. Sensitivity values were analyzed before and after each session using the visual analogue pain scale, and color change was assessed using the Vita Scale, analyzing upper incisors andcanines before each session. Conclusions:Teeth bleaching with hydrogen peroxide showed better bleaching efficacy and carbamide peroxide showed no sensitivity during the bleaching procedure. Further clinical trials with carbamide peroxide are suggested inorder to verify, with a larger sample of patients, its advantages in terms of sensitivity, as well asits bleaching effectiveness (AU).

Introducción: La sensibilidad de la dentina es el efecto adverso más común relacionado con el blanqueamiento dental. En la técnica en clínica, el peróxido de carbamida al 37% ha surgido como una posibilidad de blanqueamiento sin causar sensibilidad.Objetivo: Se tratade un informe de caso que evaluó la eficacia (cambio de color) y la presencia o ausencia de sensibilidad de la denina al utilizar un producto a base de peróxido de hidrógeno al 35% y otro a base de peróxido de carbamida al 37% en la técnica de blanqueamiento dental en clínica.Informe de caso:Un paciente del sexo maculino de 25 años fue sometido a un estudio de boca dividida en el que se aplicó peróxido de hidrógeno al 35% en la hemiarcada izquierda y peróxido de carbamida al 37% en la hemiarcada derecha.Se realizaron tres sesiones, la peróxido de carbamida con una única aplicación de 45 minutos, y la peróxido de hidrógeno con tres aplicaciones de 15 minutos, en sus respectivos lados de aplicación y con un intervalo de siete días entre cada sesión. Se analizaron los valores de sensibilidad antes y después de cada sesión mediante la escala analógica visual del dolor, y se evaluó el cambio de color mediante la Escala Vita, analizando los incisivos superiores y los caninos antes de cada sesión. Conclusiones: El blanqueamiento dental con peróxido de hidrógeno demostró una mayor eficacia blanqueadora y el peróxido de carbamida no manifestó sensibilidad durante el procedimiento de blanqueamiento. Se sugiere realizar más ensayos clínicos con peróxido de carbamidaparapoder utilizar una muestra mayor de pacientes y verificar sus ventajas en términos de sensibilidad, así como su eficacia blanqueadora (AU).

Effect of hydrogen peroxide and hyaluronic acid in mouth rinse after third molar extraction: a triple-blind parallel randomized controlled clinical trial.

OBJECTIVE: The study aimed to investigate the potential beneficial role of hydrogen peroxide (H2O2) and hyaluronic acid (HA) combination formulation in socket healing after third molar surgery. Biomaterials, including mouthwash formulations, were hypothesized to contribute to improved socket healing and reduced post-operative complications. PATIENTS AND METHODS: A triple-blinded parallel randomized controlled clinical trial was conducted at a single-center dental hospital in Milan, Italy. The trial included 114 patients who underwent extraction of impacted, partially erupted, and completely erupted third molars. Patients were randomly assigned to three parallel groups: Group 1 (H2O2 and HA), Group 2 (placebo), and Group 3 (0.2% chlorhexidine). The trial was registered at ClinicalTrial.gov (registration number NCT04438434). The main outcome measures included various parameters related to socket healing, such as pain, inflammation, swelling, plaque index, bleeding index, granulation tissue, suppuration, re-epithelialization, bleeding upon palpation, odor, and taste alteration. Patients were followed up for 7 days. RESULTS: All 114 enrolled patients completed the study, with no dropouts or loss to follow-up. The mean age of patients in the three groups differed (H2O2 and HA: 30.9±14.9; placebo: 27.6±13.1; 0.2% chlorhexidine: 23.05±10.16). Significant reductions (p<0.001) in visual analog scale (VAS) pain levels and other outcome measures were observed in the H2O2 and HA group compared to the placebo group. These findings suggest a positive effect of the H2O2 and HA combination on socket healing after the third molar surgery. CONCLUSIONS: The study concludes that the combination of hydrogen peroxide and hyaluronic acid can be considered a potential mouthwash with beneficial effects on socket healing following third molar surgery. However, additional clinical trials are recommended to validate its effectiveness further and provide additional evidence supporting its use in clinical settings. CLINICALTRIAL: gov: NCT04438434.

Bleaching efficacy of in-office dental bleaching with different application protocols: a single-blind randomized controlled trial.

OBJECTIVE: This randomized controlled trial aimed to evaluate the equivalence in the color change, adverse effects, self-perception (AS) and the impact on oral condition (IO) of participants submitted to different application protocols of in-office dental bleaching. MATERIALS AND METHODS: 165 participants were bleached with a 35% hydrogen peroxide gel (Total Blanc Office One-Step, DFL), according to the following protocols: (1) 2 applications of 20-min each (2 × 20 min); (2) 1 × 40-min and; (3) 1 × 30-min. The color change was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The intensity and risk of tooth sensitivity (TS) and gingival irritation (GI) were recorded using a 0-10 visual analogue scale (VAS). AS and IO was assessed before and after the bleaching procedure using the Orofacial Aesthetic Scale and Oral Health Impact Profile-14, respectively. RESULTS: Equivalent color change were observed (p < 0.001), with no significant difference between groups. The group 2 × 20 min presented the highest risk of TS (76%, 95% CI 63 to 85), compared to the 1 × 30 min (p < 0.04). The intensity of TS and GI and the risk of GI was similar between groups (p > 0.31). Irrespectively of the group (p = 0.32), significant improvements were observed for all items of AS and IO after bleaching (p < 0.02). CONCLUSIONS: The 1 × 30 min protocol produced equivalent color change to the other bleaching protocols with reduced risk of TS and shorter application time. CLINICAL RELEVANCE: A more simplified application regimen of a single application of 30 min yields effective bleaching and patient satisfaction while minimizing undesirable side effects and improving patient satisfaction.

Hydrogen Peroxide May Reduce the Risk for Revision Surgery and Infection in Primary Shoulder Arthroplasty: Two-year Follow-up From a Prospective, Blinded, Controlled Trial.

BACKGROUND: The purpose of this study was to determine whether the addition of hydrogen peroxide to the preoperative skin preparation for primary total shoulder arthroplasty is associated with a difference in patient-reported outcomes, risk for postoperative infection, and risk for revision surgery at a minimum of 2-year follow-up. METHODS: This was a prospective, blinded, and controlled trial, which included a consecutive series of patients undergoing primary shoulder arthroplasty. The control group underwent standard sterile skin preparation using ethyl alcohol and ChloraPrep applicators, and the peroxide group had the same preparation with the addition of hydrogen peroxide between the alcohol and ChloraPrep applications. We then compared patient-reported outcome scores (American Shoulder and Elbow Surgeons Shoulder Score [ASES], simple shoulder test [SST], visual analog scale [VAS]), infections, and revision surgeries between the two groups at 2-year follow-up. RESULTS: Of the 61 patients included in the original study, 52 of 58 (85%) living patients agreed to participate in this study. No preoperative differences were observed between groups. No difference was observed in ASES, SST, or VAS scores at 2 years. More revision surgeries were done in the control group (7 versus 2, P = 0.268) and Cutibacterium acnes infections (2 versus 0, P = 0.168). CONCLUSION: The addition of hydrogen peroxide to the preoperative skin preparation before primary shoulder arthroplasty is safe, and additional research is warranted to investigate whether it may decrease the risk for revision surgery and postoperative C acnes infection. LEVEL OF EVIDENCE: III.

Does adding hydrogen peroxide to chlorhexidine gluconate increase the effectiveness of skin preparation in reducing cutaneous Cutibacterium levels? A randomized controlled trial.

BACKGROUND: Shoulder periprosthetic joint infection is most commonly caused by Cutibacterium. Effective removal of these bacteria from the skin is difficult because Cutibacterium live protected in the dermal sebaceous glands beneath the skin surface to which surgical preparation solutions, such as chlorhexidine gluconate (CHG), are applied. There is conflicting evidence on the additional benefit of using hydrogen peroxide (H2O2) as an adjunct to CHG in eliminating Cutibacterium from the skin. A previous study demonstrated that after CHG skin preparation, repopulation of Cutibacterium from sebaceous glands onto the skin surface occurs in 90% of shoulders by 60 minutes after application. The objective of this randomized controlled study was to determine the effectiveness of adding H2O2 to CHG in reducing skin Cutibacterium. METHODS: Eighteen male volunteers (36 shoulders) were recruited for this study. The 2 shoulders of each volunteer were randomized to receive the control preparation ("CHG-only" - 2% CHG in 70% isopropyl alcohol alone) or the study preparation ("H2O2+CHG" - 3% H2O2 followed by 2% CHG in 70% isopropyl alcohol). Skin swabs were taken from each shoulder prior to skin preparation and again at 60 minutes after preparation. Swabs were cultured for Cutibacterium and observed for 14 days. Cutibacterium skin load was reported using a semiquantitative system based on the number of quadrants growing on the culture plate. RESULTS: Prior to skin preparation, 100% of the CHG-only shoulders and 100% of the H2O2+CHG shoulders had positive skin surface cultures for Cutibacterium. Repopulation of Cutibacterium on the skin at 60 minutes occurred in 78% of CHG-only and 78% of H2O2+CHG shoulders (P = 1.00). Reduction of Cutibacterium skin levels occurred in 56% of CHG-only and 61% of H2O2+CHG shoulders (P = .735). Cutibacterium levels were significantly decreased from before skin preparation to 60 minutes after preparation in both the CHG-only (2.1 ± 0.8 to 1.3 ± 0.9, P = .003) and the H2O2+CHG groups (2.2 ± 0.7 to 1.4 ± 0.9, P < .001). Substantial skin surface levels of Cutibacterium were present at 60 minutes after both preparations. CONCLUSIONS: In this randomized controlled study, there was no additional benefit of using hydrogen peroxide as an adjunct to chlorhexidine gluconate skin preparation in the reduction of cutaneous Cutibacterium levels. Neither preparation was able to eliminate repopulation of Cutibacterium on the skin surface from the dermal sebaceous glands.

The value of sequential application of hydrogen peroxide, povidone-iodine and physiological saline in reducing postoperative infections after total knee arthroplasty: A prospective, randomized, controlled study.

BACKGROUND: Currently, in the field of total joint arthroplasty (TJA), there are no studies that have demonstrated the value of the sequential application of hydrogen peroxide, povidone-iodine, and physiological saline during the surgical procedure in decreasing postoperative infections in total knee arthroplasty (TKA), and in decreasing the incidence of periprosthetic joint infections (PJI) in particular. This study aimed to assess the efficacy of the sequential application of hydrogen peroxide, povidone-iodine, and physiological saline in reducing postoperative infections in TKA. METHODS: The study prospectively included 4743 patients, with Group A (2371, 49.9%) receiving sequential intraoperative application of hydrogen peroxide, povidone-iodine, and physiological saline irrigation of the incision, and Group B (2372, 50.1%) receiving intraoperative application of physiological saline irrigation of the incision only, to collect the patients' baseline data and clinical characteristics, and to statistically assess the incidence of superficial infections and the PJI during the follow up period to evaluate the clinical value of the study. RESULTS: The baseline levels of patients in Groups A and B were comparable. There were 132 (2.8%) lost visits during the study period. The incidence of superficial infections within 30 days after surgery was 0.22% in Group A and 1.17% in Group B, the difference between the two groups was statistically significant (P = 0.007). The incidence of PJI was 0.17% in Group A and 1.26% in Group B, the difference between the two groups was statistically significant (P = 0.0121). CONCLUSION: Sequential application of hydrogen peroxide, povidone-iodine, and physiological saline to irrigate incision in TKA can significantly reduce the incidence of postoperative superficial infections and PJI. The scientific and rational application of this therapy intraoperatively greatly reduces the incidence of PJI and postoperative superficial infections, which is of great benefit to the patient's prognosis.

Massive Subcutaneous Emphysema after Hydrogen Peroxide Irrigation of a Penetrating Facial Injury.

We present the case of a child impaled in the face by a meat thermometer who subsequently suffered a significant complication due to the administration of hydrogen peroxide to the wound. The soft tissues of the face rapidly expanded and blanched, the child experienced mental status changes, and imaging revealed massive subcutaneous emphysema, pneumomediastinum, and pneumo-orbit. Herein we review the literature on this rare complication and provide photodocumentation in the hopes that other practitioners, patients, and parents avoid administering hydrogen peroxide into or near any penetrating injury. Laryngoscope, 134:2954-2957, 2024.

Application Tip and Concentration of a Self-mixing Bleach: Hydrogen Peroxide Inside the Pulp Chamber, Color Change, and Amount of Bleaching Gel Used.

PURPOSE: The objective of this study was to evaluate if the application method (tip with brush or tip without brush) and hydrogen peroxide (HP) concentration (6% or 35% self-mixing) of in-office bleaching gel influences the penetration of HP into the pulp chamber, color change, and the amount of bleaching gel used. METHODS: Forty healthy premolars were randomly divided into the following five groups (n=8): no treatment; HP6% using a tip with a brush, HP6% using a tip without a brush, HP35% using a tip with a brush, and HP35% using a tip without a brush. After treatments, the HP concentration (µg/mL) within the pulp chamber was determined using UV-Vis spectrophotometry. The color change (ΔEab, ΔE00, and ΔWID) was evaluated using a digital spectrophotometer. The amount of gel used (g) in each group was measured using a precision analytical balance. Data from each test were submitted to parametric tests (α=0.05). RESULTS: The tip with a brush resulted in a lower amount of HP inside the pulp chamber and less gel used when compared with the tip without a brush, regardless of HP concentration (p<0.05). However, regarding the tip used, although no significant difference was observed when HP35% was used (p>0.05), a higher whitening effect was observed when the 6% HP was applied without a brush as opposed to with a tip brush (p<0.05). CONCLUSIONS: The use of a tip with a brush, regardless of the in-office bleaching gel concentration (6% or 35% self-mixing), presented a lower penetration and lower volume of spent gel when compared to a tip without brush. However, the whitening effect depended on the concentration of HP used.

ROS-Induced Oxidative Damage and Mitochondrial Dysfunction Mediated by Inhibition of SIRT3 in Cultured Cochlear Cells.

Sensorineural hearing loss (SNHL) is one of the most common causes of disability worldwide. Previous evidence suggests that reactive oxygen species (ROS) may play an important role in the occurrence and development of SNHL, while its mechanism remains unclear. We cultured dissected organs of Corti in medium containing different concentrations (0, 0.25, 0.5, 0.75, 1, and 1.25 mM) of hydrogen peroxide (H2O2) and established a four-concentration model of 0, 0.5, 0.75, and 1 mM to study different degrees of damage. We examined ROS-induced mitochondrial damage and the role of sirtuin 3 (SIRT3). Our results revealed that the number of ribbon synapses and hair cells appeared significantly concentration-dependent decrease with exposure to H2O2. Outer hair cells (OHCs) and inner hair cells (IHCs) began to be lost, and activation of apoptosis of hair cells (HCs) was observed at 0.75 mM and 1 mM H2O2, respectively. In contrast with the control group, the accumulation of ROS was significantly higher, and the mitochondrial membrane potential (MMP) was lower in the H2O2-treated groups. Furthermore, the expression of SIRT3, FOXO3A, and SOD2 proteins declined, except for an initial elevation of SIRT3 between 0 and 0.75 mM H2O2. Administration of the selective SIRT3 inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine resulted in increased damage to the cochlea, including loss of ribbon synapses and hair cells, apoptosis of hair cells, more production of ROS, and reduced mitochondrial membrane potential. Thoroughly, our results highlight that ROS-induced mitochondrial oxidative damage drives hair cell degeneration and apoptosis. Furthermore, SIRT3 is crucial for preserving mitochondrial function and protecting the cochlea from oxidative damage and may represent a possible therapeutic target for SNHL.

Antibacterial and antiplaque efficacy of a lactoperoxidase-thiocyanate-hydrogen-peroxide-system-containing lozenge.

BACKGROUND: Antimicrobial agents are considered valuable adjuncts to mechanical methods of plaque control. However, their long-term use can be limited because of side effects. Therefore, using physiological substances is promising due to no risk of development, for example, of microbial resistances, allergies or DNA damaging. The lactoperoxidase-thiocyanate-hydrogen peroxide system (LPO-system) is a highly effective antimicrobial system. This study aimed to evaluate in a randomized study with a four-replicate cross-over design the effectiveness of two oral hygiene lozenges containing LPO-system in oral hygiene. RESULTS: After using the mouth rinse as positive control (A) and allocated test lozenges (B) (0.083% H2O2) & (C) (0.04% H2O2) for 4 days instead of the normal oral hygiene procedures (tooth brushing etc.), Listerine rinse (A) was statistically significantly more effective than the LPO-system-lozenge with 0.083% H2O2, the LPO-system-lozenge with 0.04% H2O2, and the placebo lozenge (D) in inhibiting plaque. Lozenges B and C were statistically significantly more effective than the placebo lozenge, but no statistically significant differences could be observed between them. The LPO-system-lozenge (B) reduced statistically significantly more S. mutans than the LPO-system-lozenge with (C) and the placebo lozenge (D). The LPO-system-lozenge (C) reduced statistically significantly more Lactobacilli than Listerine (A), the LPO-system-lozenge (B) and the placebo lozenge (D). There were no statistically significant differences in the total CFUs between Listerine rinse, the LPO-system-lozenge with 0.083% H2O2 (B), the LPO-system-lozenge with 0.04% H2O2 (C), and the placebo lozenge (D). On day 5 there were no differences of the OSCN--values between all A, B, C, and D. However, the SCN--values increased over the days in both LPO-system-lozenges (B/C). The statistically significant differences between B/C and A/D on day 5 were as followed: A to B p = 0.0268; A to C p = 0.0035; B to D p = 0.0051; C to D p = 0.0007. Only in the group of Listerine (A) increased the NO3-/NO2--quotient over the test time, which indicates a reduction of nitrate-reducing bacteria. On Day 5 the statistically significant difference between A and B was p = 0.0123. CONCLUSIONS: The results indicate that lozenges containing a complete LPO-system, inhibiting plaque regrowth and reducing cariogenic bacteria, may be used in the daily oral hygiene.

Antimicrobial Effect of Calcium Hydroxide Combined with Electrolyzed Superoxidized Solution at Neutral pH on Enterococcus faecalis Growth.

OBJECTIVE: To evaluate the effect of the combination of calcium hydroxide (Ca(OH)2) and a novel electrolyzed superoxidized solution at neutral pH, known as OxOral® on Enterococcus faecalis growth in root canals. METHODS: Sixty human teeth were used, from which root canals were infected and randomly divided into the following treatment groups: saline solution, saline solution plus Ca(OH)2, OxOral®, and OxOral® plus Ca(OH)2. RESULTS: A permanent reduction in bacterial growth was observed at days 1, 6, 12, and 18 after OxOral® plus Ca(OH)2 treatment from 4.4 ± 0.074 log10 CFU/mL to 0.0 ± 0.001 log10 CFU/mL. In addition, alkaline conditions maintenance was observed from application time (pH = 12.2 ± 0.033) to 18 d posttreatment (pH = 12.6 ± 0.083). CONCLUSION: The combination of OxOral® and Ca(OH)2 provides an alkaline pH and inhibits E. faecalis growth into the root canals. Our study opens the possibility for further research on the use of OxOral® in endodontic therapy.

Cell survival after DNA damage in the comet assay.

The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H2O2) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H2O2 or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided.

A meta-analysis of ozone effect on tooth bleaching.

This systematic review assessed the effectiveness of ozone (O3) in the color change of in-office tooth bleaching in vital teeth (TB) and the sensitivity control. Only randomized controlled clinical trials were included. Seven databases were used as primary search sources, and three additional sources were searched to capture the "grey literature" partially. The JBI tool was used to assess the risk of bias. TB was assessed using the ΔELab color change metric comparing tooth color pre- and post-bleaching. We meta-analyzed the ΔELab estimates per method and calculated the absolute standardized mean difference using random-effect models. The GRADE approach assessed the certainty of the evidence. The ΔELab estimates ranged from 1.28 when the O3 was used alone to 6.93 when combined with hydrogen peroxide (HP). Two studies compared O3 and HP alone, but their TB was similar (SMD = - 0.02; 95%CI: - 0.54; 0.49). The bleaching effectiveness for the combination of O3 + HP compared to HP was similar (SMD = 0.38; 95%CI: - 0.04; 0.81). Thus, based on the available literature, our findings suggest that O3 is not superior to the conventional technique using HP on the change of tooth color. The O3 did not present sensitivity when used alone. When O3 was used in combination with HP, patients reported hypersensitivity only when O3 was applied before HP, i.e., no sensitivity was perceived when O3 was applied after HP.

Effectiveness of hydrogen peroxide as auxiliary treatment for hospitalized COVID-19 patients in Brazil: preliminary results of a randomized double-blind clinical trial.

OBJECTIVES: To evaluate the effectiveness of hydrogen peroxide (H2O2) in the form of mouthwash and nasal spray as an auxiliary treatment for coronavirus disease 2019 (COVID-19). METHODS: Forty hospitalized patients who tested positive for severe acute respiratory syndrome coronavirus 2 using a reverse-transcription polymerase chain reaction test were evaluated. They were randomly divided into an experimental group (n= 20; gargling with 1.0% H2O2 and nasal wash with 0.5% H2O2) or a control group (n= 20). The solutions were used for 7 days and the patients were monitored every 2 days, for a total of 8 days. At check-ups, patients were asked about their symptoms and possible adverse effects of the solutions. The presence and severity (mild, moderate, or severe) of symptoms were recorded. Data were compared using the Student test and the Fisher exact test (α= 0.05). RESULTS: There was no significant difference between the 2 groups in the length of hospital stay (p= 0.65). The most frequent symptom on day 0 was coughing (72.0% in the experimental group and 76.5% in the control group), which abated over time. There was no significant difference between the groups in the evaluated symptoms. Most (75.0%) of the patients in the experimental group presented a reduction in dyspnea between days 0 and 2. Few patients reported adverse effects from the use of the solutions. CONCLUSIONS: H2O2 as a mouthwash and nasal spray is safe to use. There is insufficient evidence to demonstrate that H2O2 is effective as an auxiliary treatment for hospitalized COVID-19 patients.

H2O2 enhances the anticancer activity of TMPyP4 by ROS-mediated mitochondrial dysfunction and DNA damage.

Cancer is one of the diseases that threatens human health and is a leading cause of mortality worldwide. High levels of reactive oxygen species (ROS) have been observed in cancer tissues compared with normal tissues in vivo, and it is not yet known how this influences chemotherapeutic drug action. Cationic porphyrin 5,10,15,20-tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) is a photosensitizer used in photodynamic therapy (PDT) and a telomerase inhibitor used in the treatment of telomerase-positive cancer. Here, we investigated the anticancer activity of TMPyP4 in A549 and PANC cells cultured in H2O2. The results showed that compared to TMPyP4 alone, the combination of TMPyP4 and H2O2 exhibited sensitization effects on cell viability and colony formation inhibition and apoptosis in A549 and PANC cells, but had no effect in human normal MIHA cells. Mechanistically, the combination of TMPyP4 and H2O2 activates high ROS and mitochondrial membrane potential in A549 and PANC cells, resulting in intense DNA damage and DNA damage responses. Consequently, compared to TMPyP4 alone, TMPyP4 and H2O2 combined treatment upregulates the expression of BAX, cleaved caspase 3, and p-JNK and downregulates the expression of Bcl-2 in A549 and PANC cells. Taken together, these data suggested that H2O2 enhanced the anticancer activity of TMPyP4-mediated ROS-dependent DNA damage and related apoptotic protein regulation, revealing that the high ROS tumor microenvironment plays an important role in chemotherapeutic drug action.

Evaluation of hydrogen peroxide-assisted endoscopic ultrasonography-guided necrosectomy in walled-off pancreatic necrosis: A single-center experience.

ABSTRACT: Hydrogen peroxide is a liquid that functions in mechanical removal of the necrotic tissue via the elimination of tissue debris.In this study, we aimed to evaluate the effectiveness of the use of hydrogen peroxide in necrosectomy treatment of walled-off pancreatic necrosis.Records of 24 patients who were diagnosed with pancreatic necrosis or walled-off pancreatic necrosis and underwent endoscopic necrosectomy (EN) were retrospectively assessed. Patients were divided into 2 groups; hydrogen peroxide used for treatment or not used, and these 2 groups were compared.A total of 24 patients underwent endoscopic intervention for walled-off pancreatic necrosis. Procedural success was comparable between the 2 groups. During the post-procedural follow-up, the duration of the hospital stay, recurrence, and complication rates were found to be similar in both groups. The mean number of the endoscopic interventions was significantly lower in the hydrogen peroxide group (4.2 ±â€Š1.4 vs 6.1 ±â€Š4.2; P = .01).The use of hydrogen peroxide for EN in walled-off pancreatic necrosis patients seems to have similar efficiency and safety. However, it can be said that the use of hydrogen peroxide could reduce the number of endoscopic procedures.