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AIMS: The utilization of micro‐organisms in pulp and paper industries has proved biobleaching technology as an environmentally friendly alternative to the conventional approach. In this paper, the effect of actinobacterial fermentation broth on pulp biobleaching has been investigated. METHODS AND RESULTS: Actinobacterial colonies were isolated from lignocellulose‐rich soil samples and screened for xylanase production and bleaching activity. The most efficient isolate in bleaching activity showed 100% similarity to Streptomyces rutgersensis. Pulp treatment with 5‐day fermentation broth of this strain showed up to 7% increase in brightness (30°C for 6 h, pH (5–7)) compared to untreated (control) pulp. Also, after 60 min biotreatment, significant reduction (12·5%) in consumption of bleaching chemicals was achieved to obtain final brightness of 55%. CONCLUSION: Actinobacterial fermentation broth can be considered as a rich source of effective biobleaching agents which may be considered as environmental friendly and cost‐effective technique in comparison with traditional method. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings showed ability of S. rutgersensis UTMC 2445 in bleaching chemomechanical paper pulp. Also, two strains of Saccharothrix, a rare actinobacterium, with biobleaching activity were introduced. In the proposed method, there is no need to use purified enzymes, and biobleaching process can be done using the fermentation broth.

Background Tooth hypersensitivity and pain are undesirable side effects of bleaching agents in humans. The aim of this study is to implement strategies to counter such side effects, and to demonstrate the efficacy and mechanisms of action of N-acetyl cysteine (NAC) in countering the side effects of clinically used bleaching agents. Methods In a series of in vitro experiments, animal model studies, and human clinical trials, we demonstrate that NAC protects oral mucosa and teeth from damage induced by bleaching agents. Results The addition of NAC along with clinically used bleaching agents to dental pulp stromal/stem cells (DPSCs), stem-cells of apical papillae (SCAP) and oral epithelial cells, inhibited cell death mediated by bleaching agents in several in vitro assays. In addition, rat teeth, when treated with chair-side or over-the-counter bleaching agents, exerted adverse side effects to pulpal and gingival tissues as evidenced by the white lesions of gingivae as well as decreased survival and function of DPSCs. These side effects of bleaching agents were greatly mitigated by the application of NAC to the surfaces of the teeth and to the oral mucosa. NAC protected the surface topography and the appearance of the tissues after bleaching using scanning electron microscopic (SEM) analysis. Finally, application of NAC prior to the bleaching demonstrated significant translational benefit for the patients since it ameliorated pain and hypersensitivity and protected gingivae from bleaching induced white lesions and improved inflammatory index in the oral mucosa in human clinical trials. Conclusions Therefore, application of NAC to the surfaces of the teeth and oral mucosa prior to the use of bleaching materials is beneficial for countering adverse side effects of bleaching in patients and decreases pain, sensitivity, and potential damage to the dentition and oral mucosa associated with bleaching. Trial registration NCT03534115 (NAC Prevents Side-Effects of Teeth Bleaching). Registration 4 December 2014.

Summary Bleach disinfectant wipes are corrosive to hospital surfaces and equipment. This study measured the effect of two widely used bleach wipes, with and without Highlight® colour additive, on stainless steel to quantify the rate of corrosion and to determine the effect of Highlight® on reducing surface damage caused by bleach wipes. The two bleach wipes alone caused severe corrosion [>5 mils per year (mpy), where 1 mil = 0.001 inch], while the addition of Highlight® reduced the rate of corrosion significantly (

Background: The diagnosis of heavily pigmented melanocytic lesions is problematic. This is often compounded by lack of visibility of nuclear detail of tumour cells due to physical masking by melanin pigment. Similarly, there can be colour merging of chromogenic final reaction products with melanin, making an evidence of antigenic localisation problematic. There are a number of melanin bleaching techniques available for immunohistochemical assessments.Material and methods: All methods to date have involved the bleaching of melanin as a manually performed primary step before loading subsequently bleached slides onto automated immunohistochemical platforms. Here we define a semi-automated bleaching procedure that allows full integration on one of the most widely employed automated IHC staining platforms (Roche Ventana BenchMark Ultra). The bleaching protocol was defined on the BenchMark Ultra and involved the assessment of 24 histological cases of heavily pigmented malignant melanoma lesions (13 cutaneous and 11 metastatic) routinely fixed processed and paraffin wax embedded.Results: Completion of the bleaching was assessed on H&E preparations performed following the semi-automated bleaching step and employing the Roche Ventana BenchMark Ultra machine for 60 min at 42°C. Complete immunohistochemical staining was achieved on the automated platform within 5-6 h including the bleaching step. Results were consistent across all tissue evaluated.Discussion: This data provides evidence that the hydrogen peroxide bleaching procedure can be adapted for integration on one of the most widely employed automated IHC staining platforms and as a result, improve the efficiency and reproducibility of the technique.

Melanin plays an important role in protecting human skin, while excessive synthesis of melanin can cause abnormal pigmentation and induce skin diseases. Long-term use of commercial whitening agents in managing skin melanin such as kojic acid and arbutin can lead to some negative effects such as dermatitis and liver cancer. Although past studies have researched the melanin inhibitory effect of plant extracts, the effective dose and mechanisms are not well summarized and discussed. This study aims to explore the melanin inhibitory property of phytochemicals and tries to answer the following research questions: (1) Which plant extracts and phytochemicals could inhibit melanin biosynthesis in the skin? what is the mechanism of action? (2) Have human trials been conducted to confirm their melanin inhibitory effect? (3) If not, which phytochemicals are recommended for further human trials? This article would provide information for future research to develop natural and safe skin whitening products.A preferred reporting items for systematic reviews and meta-analyses (PRISMA) systematic review method and OHAT risk-of-bias tool were applied to screen literature from 2000 to 2021 and 50 research articles met the selection criteria.Flavonoids, phenolic acids, stilbenes and terpenes are main classes of phytochemicals responsible for the melanin inhibitory effects. The in vitro/in vivo melanin inhibitory effects of these plant extracts/phytochemicals are achieved via three main mechanisms: (1) the ethyl acetate extract of Oryza sativa Indica cv., and phytochemicals such as galangin and origanoside could manage melanin biosynthesis through competitive inhibition, non-competitive inhibition or mixed-type inhibition of tyrosinase; (2) phytochemicals such as ginsenoside F1, ginsenoside Rb1 and 4‑hydroxy-3-methoxycinnamaldehyde could inhibit melanogenesis through down-regulating microphthalmia-related transcription factor (MITF) gene expression via different signalling pathways; (3) the ethanolic extracts of Dimorphandra gardneriana, Dimorphandra gardneriana, Lippia microphylla and Schinus terebinthifolius have a good ultraviolet absorption ability and high sun protective factor (SPF) values, thereby inhibiting UV induced melanogenesis in the skin.Although many plant extracts and phytochemicals have been found to inhibit melanin production, most of the results were only proved in cellular and/or animal models. Only the ethyl acetate extract of Oryza sativa Indica cv. panicle, and ginsenoside F1 were proved effective in human trials. Animal studies proved the effectiveness of galangin, origanoside, ginsenoside Rb1 and 4‑hydroxy-3-methoxycinnamaldehyde with effective dose below 3 mM, and therefore recommended for future human trial. In addition, cellular studies have demonstrated the effectiveness of oxyresveratrol, mulberroside A, kurarinol, kuraridinol, plumbagin, (6aR,11aR)-3,8-dihydroxy-9‑methoxy pterocarpan, ginsenoside Rh4, cardamonin, nobiletin, curcumin, β-mangostin and emodin in inhibiting melanin synthesis at low concentrations of 20 µM and proved the low SPF values of Dimorphandra gardneriana, Dimorphandra gardneriana, Lippia microphylla and Schinus terebinthifolius extracts, and therefore recommended for further animal and human trials.

This study evaluated the effects of four over-the-counter (OTC) bleaching products on the properties of enamel. Extracted human molars were randomly assigned into four groups (n = 5): PD: Poladay (SDI), WG: White Teeth Global (White Teeth Global), CW: Crest3DWhite (Procter & Gamble), and HS: HiSmile (HiSmile). The hydrogen peroxide (H2 O2 ) content in each product was analyzed via titration. Twenty teeth were sectioned into quarters, embedded in epoxy resin, and polished. Each quarter-tooth surface was treated with one of the four beaching times: T0: control/no-bleaching, T14: 14 days, T28: 28 days, and T56: 56 days. Materials were applied to enamel surfaces as recommended. Enamel surfaces were examined for ultramicrohardness (UMH), elastic modulus (EM), superficial roughness (Sa), and scanning electron microscopy (SEM). Ten additional teeth were used to evaluate color and degree of demineralization (DD) (n = 5). Data were statistically tested by two-way ANOVA and Tukey's tests (α = 5%). Enamel surfaces treated with PD and WG presented UMH values significantly lower than the controls (p

To evaluate whether adding calcium and phosphorus-containing salts to 35% hydrogen peroxide at saturation concentrations with respect to hydroxyapatite would reduce its deleterious effects on bleached enamel or affect bleaching efficacy.The saturation concentrations of elemental calcium and phosphorus in a 35% hydrogen peroxide solution were determined after equilibration with powdered enamel. The solubility limit of the salts in 35% hydrogen peroxide was then experimentally determined. Polished bovine enamel-dentin specimens (n=120) with known baseline enamel Knoop microhardness (KHN), surface roughness (Ra), and color were bleached with hydrogen peroxide containing different concentrations of calcium and phosphorus-containing salts as follows: Negative Control - water without any addition; Positive Control - 35% hydrogen peroxide without any addition; 50% of Ca and P - hydrogen peroxide with calcium and phosphorus-containing salt additions of 50% of the saturation concentration; 100% of Ca and P - hydrogen peroxide with calcium and phosphorus-containing salt additions of 100% of the saturation concentration; Ca limit - hydrogen peroxide with addition of calcium-containing salt at the solubility limit, and P limit - hydrogen peroxide with addition of phosphate-containing salt at the solubility limit. The prepared bleaching solutions were applied on the surface of the specimens for 60 minutes. The microhardness and surface roughness were measured immediately after bleaching, and the color change (ΔE*00) was evaluated after 7 days.One-way ANOVA showed significant differences among the groups for all evaluations (P0.05). The groups saturated with elemental calcium and/or phosphorus with respect to hydroxyapatite did not show significant changes in microhardness and roughness in relation to the negative control, while the positive control without mineral supplementation and the 50% saturated group showed reduced microhardness and increased roughness. The addition of calcium and/or phosphorus-containing salts in sufficient concentrations to create a saturated hydrogen peroxide solution with respect to hydroxyapatite was able to completely prevent surface changes without affecting the bleaching effect.The addition of ions at saturation concentrations or higher with respect to hydroxyapatite can prevent enamel demineralization without compromising the efficacy of bleaching gels.

Fluorescent whitening agents (FWAs) are very important chemical additives that are widely applied in the industrial production field. The history of global FWA production and use spans more than 60 years, but the environmental fate of FWAs has been less reported in the public literature and most studies predate 2000; in addition, the studied FWAs were still limited to FWA71 and FWA351. In this study, the occurrence and distribution of 9 commonly used FWAs in a lake in North China were reported for the first time. We found that 6 target FWAs were prevalent in the lake, and the concentration levels were usually at the ng L−1 level. Decreasing FWA levels with increasing distance from the estuary area were observed in summer. FWA135, FWA185, and FWA367, the most detected 3 FWAs, with the ecological risk at high levels, and ΣRQ >10 were obtained from all the investigated samples, suggesting that all the sampling sites could be considered with certain ecological risk for aquatic life. As a category of heavily and widely used dyes, FWAs in environmental media have been ignored for a long time. Substantial additional research needs to be conducted to determine the environmental behavior and ecological toxicology of FWAs.

Plant-derived protein hydrolysates have potential applications in nutrition. Rice protein hydrolysates (RPHs), an excellent source of proteins, have attracted attention for the development of cosmeceuticals. However, few studies have reported the potential application of RPH in analysis, and this study examined their antioxidant activities and the inhibitory activities of skin aging enzymes. The results indicated that the total phenolic and flavonoid concentrations were 2.06 ± 0.13 mg gallic acid equivalent/g RPHs and 25.96 ± 0.52 µg quercetin equivalent/g RPHs, respectively. RPHs demonstrated dose-dependent activity for scavenging free radicals from 1,1-diphenyl-2-picrylhydrazyl [half-maximal inhibitory concentration (IC50) = 42.58 ± 2.1 mg/g RPHs] and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (IC50 = 2.11 ± 0.88 mg/g RPHs), dose-dependent reduction capacity (6.95 ± 1.40 mg vitamin C equivalent/g RPHs) and oxygen radical absorbance capacity (473 µmol Trolox equivalent/g RPHs). The concentrations of the RPH solution required to achieve 50% inhibition of hyaluronidase and tyrosinase activities were determined to be 8.91 and 107.6 mg/mL, respectively. This study demonstrated that RPHs have antioxidant, antihyaluronidase, and antityrosinase activities for future cosmetic applications.

The aim - to study the efficiency of correction of hard tooth tissues discoloration. The study was conducted on 135 patients with tooth discoloration. Clinical - complex examination of patients with determination of hard tooth tissues color (Vіta scale), indexes of individual oral hygiene, intensity and prevalence of gums inflammation for the study of efficiency of the applied medical and preventive complexes of correction of hard tooth tissues discoloration depending on a clinical situation; statistical - for determination of authenticity of differences of the results. Patients of O-1 group, who used abrasive bleaching toothpastes, during the initial examination, had a poor oral hygiene. In patients O-2 group, who used peroxide containing bleaching toothpastes, during examination of 420 teeth hard tooth tissues discoloration were noted in 187 (44.53%) patients teeth. Patients O-3 group, who used enzyme containing bleaching toothpastes, during the initial examination had hard tooth tissues discoloration in 198 (47.14%) tooth. The proposed algorithms for whitening with usage of oral hygiene facilities tested positive. However, obtained in the long-term observation results showed that the most pronounced bleaching effect with enzyme containing toothpaste. Studies had shown the most pronounced efficacy of enzyme containing whitening toothpaste in the complex treatment and prevention of correction of hard tooth tissues discoloration compared to other whitening toothpastes.

To compare the bleaching efficacy of in-office (Opalescence), professional home (LumiBrite), over the counter (WhiteLight) and natural (strawberry extract) bleaching agents.80 teeth were selected and divided into two groups which were stained with black coffee and red wine respectively. The stained specimens were subdivided into four subgroups to be bleached with Opalescence, LumiBrite, WhiteLight and strawberry extract. Color measurements were made using spectrophotometer at baseline level, after staining, after bleaching and 1 week after bleaching. The ΔE₀₀ was calculated post bleaching (ΔE₀₀1), after 1-week follow up (ΔE₀₀2) and color changes between 1-week follow up and baseline (ΔE₀₀3). Data were analyzed by paired t-test and ANOVA with a significant difference of P0.05.Paired t-test showed significant differences in ΔE₀₀1 and ΔE₀₀2 for both stained specimens (P0.001). For black coffee stained specimens, Whitelight had significantly higher ΔE₀₀2 compared to the other bleaching agents (P0.05). For red wine stain, Whitelight also showed the significantly lowest ΔE₀₀1 (P0.001) and the highest ΔE₀₀2 (P0.001) compared to other groups. LumiBrite showed the significantly lowest ΔE₀₀3 for red wine stained specimens (P0.05). Whitelight had the poorest bleaching efficacy with deterioration effect after 1-week follow up. Opalescence, LumiBrite and strawberry extract had clinically perceptible and comparable bleaching efficacy. Strawberry extract appeared to be a potential natural bleaching agent with a desirable effect.Commercial tooth bleaching agents can cause several undesirable side effects such as damage to enamel, hypersensitivity and even affecting the pulp. Strawberry extract is a natural, effective bleaching agent that may have reduced side effects.

Resumen Introducción: El oscurecimiento de un diente anterior interfiere negativamente en el aspecto de la sonrisa, y varias son las causas que pueden ser responsables por este oscurecimiento. Objetivo: Describir las técnicas de blanqueamiento mixto e inmediato a través del reporte de dos casos clínicos. Caso 1: Individuo de sexo masculino, con Síndrome de Treacher Collins, se quejó sobre alteración cromática del diente 33, verificada mediante examen clínico, radiográficamente presencia de tratamiento endodóntico satisfactorio. Por lo que fue planeado el blanqueamiento interno mediante técnica mixta. Caso 2: Individuo de sexo masculino, con Síndrome de Apert reportó cambio cromático en el diente 22, observado en el examen clínico, radiográficamente presentando tratamiento endodóntico insatisfactorio. Se realizó retratamiento endodóntico y a los 6 meses se realizó blanqueamiento interno mediante técnica inmediata. Conclusión: El blanqueamiento dental ejecutado con las técnicas mixtas e inmediatas, devuelve la armonía de la sonrisa, recuperando el color ideal y elevando la autoestima a los pacientes. Resumo Introdução: O escurecimento de um dente anterior interfere negativamente na aparência do sorriso, e várias são as causas que podem ser responsáveis por esse escurecimento. Objetivo: Descrever as técnicas clareadoras mista e imediata através do relato de dois casos clínicos. Caso 1: Indivíduo do gênero masculino com Síndrome de Treacher Collins, queixou-se de alteração cromática no dente 33, constatado no exame clínico, radiograficamente apresentando tratamento endodôntico satisfatório. O clareamento interno foi planejado e realizado pela técnica mista. Caso 2: Indivíduo do gênero masculino, com Síndrome de Apert, relatou alteração cromática no dente 22, constatado ao exame clínico, apresentando tratamento endodôntico insatisfatório. Foi realizada a reintervenção endodôntica e após 6 meses, foi realizado clareamento interno pela técnica imediata. Conclusão: O uso das técnicas clareadoras mista e imediata, resulta na devolução da harmonia do sorriso, recuperando a coloração ideal e devolvendo a autoestima aos pacientes. Abstract Introduction: The darkening of a single anterior tooth negatively affects the smile's appearance, and several factors may cause this darkening. Objective: To describe the mixed and immediate bleaching techniques by reporting two clinical cases. Case 1: A male individual with Treacher Collins Syndrome. He complained of chromatic alteration in tooth 33, which was verified on clinical examination. X-ray imaging showed satisfactory endodontic treatment. Internal bleaching was performed with the mixed technique. Case 2: A male individual with Apert Syndrome reported chromatic alteration in tooth 22, observed on clinical examination. X-ray imaging showed unsatisfactory endodontic treatment. Endodontic retreatment was performed. Six months later, internal whitening was performed immediately. Conclusion: The use of mixed and immediate whitening techniques restores the smile’s harmony, the tooth’s ideal color, and patients’ self-esteem.

Introduction The use of light sources during the application of bleaching can reduce the time and improve the results, but at the same time this can increase the dental temperature. The objective of this study was to evaluate the performance of two bleaching agents and the increase in dental temperature with the use of light emitted by diodes (LED)-unit. Materials and methods Forty third molars were obtained and randomized: the whiteness without lamp (WHN) and Pola office without lamp (PON) groups, two bleaching systems based on 35% hydrogen peroxide were used, according to manufacturer specifications. For the whiteness with lamp (WHL) and Pola office with lamp (POL) groups the same bleaching agents were light boosted. A spectrophotometer and ∆WID equation was used to record and analyzed teeth color. An infrared thermometer was used to record the external and internal temperature. A ∆T was obtained by the difference of the temperature of the groups with and without LED (WHN-WHL and PON-POL). For statistical analysis Kruskal-Wallis test and Anova test were performed. Results The WHN, PON, WHL, and POL groups reported ∆WID values of 4.88 ± 1.08, 9.26 ± 3.27, 5.70 ± 2.48, 12.08 ± 5.44, respectively. The dates of internal temperature were 1.01 and 1.07°C, and for external temperature were 1.61 and 1.15°C respectively. Conclusions With the limitations of this study, both bleaching agents reported a significant increase in ∆WID with and without association of light. Significant temperature increases were also observed. The highest average temperature increase was approximately 1.61°C. Clinical significance Bleaching agents boosted with LED may improve the results of bleaching, but it is not essential to obtain good results.

Objectives This clinical study aimed to evaluate the effect of incorporating bioactive nanoparticles (n-Bm) inside an in-office bleaching gel on the risk and intensity of tooth sensitivity (TS) and on bleaching effectiveness. Materials and methods Sixty-six participants were selected and randomly assigned into two groups: control-only in-office gel and experimental-in-office gel with n-Bm. Teeth were bleached in two sessions (3 × 15-min). TS was recorded using a VAS and NRS. The color change was evaluated by subjective (VITA Classical and VITA Bleachedguide) and objective (Easyshade spectrophotometer) methods at baseline and 30 days after the end of treatment. The TS was evaluated by McNemar, Wilcoxon Signed Rank, and paired t test. The color changes between groups were compared using paired t test (α = 0.05). Results No significant differences between the groups were observed in the risk (control = 27% [95%IC 18-39]; experimental = 21% [95%IC 13-32]) and intensity of TS, as well as in the color change (p >0.05) for any color measurement. Conclusion The inclusion of n-Bm into the bleaching agents did not affect the whitening effectiveness, as well as the risk and intensity of TS between groups. However, the results of the absolute risk of TS were low for both in-office gels used. Clinical significance Despite no significant differences between groups, both experimental bleaching agents present suitable results with low values for TS.

BACKGROUND The antimelanogenesis effect of topical and oral glutathione has been shown in several in vitro and clinical studies. However, whether combination of topical and oral glutathione is superior to topical or oral monotherapy is unknown. This study aimed to compare the skin-whitening effect of topical and oral glutathione combination therapy against topical and oral monotherapy. METHODS This double-blind randomized controlled study was done on 46 participants who were divided into two equal groups. Each group received oral placebo and oral glutathione, respectively. All participants were also instructed to apply topical placebo and glutathione to each facial side, respectively. Colorimeter examination was done biweekly using mexameter and chromameter for 8 weeks. One-way ANOVA test was used to compare the results of all groups. RESULTS The combination group showed significantly lower melanin index (MI) and L* score to placebo (P

Made available in DSpace on 2021-06-25T10:18:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 ASCRS Research Foundation Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This study evaluated the effects of calcium gluconate (CaGlu), sodium fluoride (NaF), sodium trimetaphosphate (TMP), and NaF/TMP when added to a 35% hydrogen peroxide (H2O2) bleaching gel on the color change, enamel hardness, penetration and cytotoxicity trans-amelodentinal. Bovine enamel/dentin disks (n = 288) were divided according to the bleaching gel: 35% H2O2; 35% H2O2 + 0.05% NaF; 35% H2O2 + 0.25% TMP; 35% H2O2 + 0.05% NaF + 0.25% TMP; 35% H2O2 + 0.1% NaF + 1% TMP and 35% H2O2 + 2% CaGlu. The bleaching gels were applied thrice (40 min/session) at 7-day intervals between each application. Then, the color change, percentage of surface hardness loss (%SH), cross-sectional hardness (ΔKHN), trans-amelodentinal penetration of H2O2, cell viability and morphology (MDPC-23 odontoblast-like cells), alkaline phosphatase activity (ALP) and deposition of mineralization nodules were determined. The data were submitted to ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). All bleaching gels showed significant color changes after treatment (p < 0.001). Mineral loss (%SH and ΔKHN) and H2O2 penetration were lower for 35% H2O2/0.1% NaF/1% TMP; 35% H2O2/2% CaGlu, meanwhile, showed higher values, compared to the other groups (p < 0.001). Cell viability was around 9%, except for the bleaching gel containing 35% H2O2/0.1% NaF/1% TMP with 12.8% (p < 0.05). ALP was higher for groups containing TMP compared to other whitening gels (p < 0.05). The formation of mineralization nodules was greater for gels containing NaF/TMP or CaGlu (p < 0.05). The alterations of cell morphology were intense for all bleaching gels. It was concluded that the addition of NaF/TMP in-office bleaching did not interfere in bleaching efficacy, reduced enamel demineralization, H2O2 penetration and cytotoxicity. São Paulo State University (UNESP) School of Dentistry Department of Preventive and Restorative Dentistry School of Dentistry University of Ribeirão Preto - UNAERP, Ribeirão Preto São Paulo State University (UNESP) School of Dentistry Department of Physiology and Pathology São Paulo State University (UNESP) School of Dentistry Department of Dental Materials and Prosthodontics São Paulo State University (UNESP) School of Dentistry Department of Preventive and Restorative Dentistry São Paulo State University (UNESP) School of Dentistry Department of Physiology and Pathology São Paulo State University (UNESP) School of Dentistry Department of Dental Materials and Prosthodontics FAPESP: 2018/08769–5 CAPES: 88881.068437/2014–01

This study investigated the effect of pH of bleaching agent, photo-irradiation time or application times on bleaching action using hematoporphyrin-stained papers (HSPs) and artificially stained bovine-teeth (BT). 23% H2O2 with pH 5.5, 6.0, 7.0, 8.0 and 9.0 were applied on the specimens. HSP was photo-irradiated for 1, 3 and 5 min. BT were photo-irradiated for 10 min and the bleaching was repeated ten times (n=10). CIE L*a*b* of the specimens were measured before and after the procedure. Data were analyzed by repeated-measures ANOVA followed by multiple comparisons with Bonferroni correction. For the HSP, longer irradiation time and higher pH yielded significantly higher color difference (ΔE). As for BT, increasing application times and higher pH resulted in higher ΔE. It was concluded that the pH of the bleaching agent significantly improved the bleaching effect with increased photo-irradiation time for HSP and with an increase of repeated application times for BT.

Made available in DSpace on 2021-06-25T11:04:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Alginate only finds industrial applicability after undergoing a bleaching process to improve its visual appearance. Box-Behnken Design was used to optimize bleaching parameters (time, oxygen flow and temperature) for sodium alginate (SA) extracted from seaweeds using ozone as the bleaching agent. The optimal conditions (oxygen flow 2 L/min for 35 min at 25 °C) resulted in an ozone-bleached SA with a mannuronic/guluronic acids ratio of 0.70, viscosity-average molecular weight of 66.30 kDa and dynamic viscosity of 1.39 mPa.s, aligned to strong and brittle gels formation, which are potentially suitable for hydrogels and bioink application. Results indicated that ozonation caused depolymerization of the SA chain. Colorimetric parameters showed that ozone has a great bleaching efficacy. The bleached sample presented high antioxidant capacity, highlighting that discoloration by ozone might have minimal effects on the bioactive compounds which are valuable ingredients for food-based products. São Paulo State University (UNESP) Biological Sciences Department University of São Paulo (USP) Food Engineering Department Federal University of Sao Carlos (UFSCAR) Chemistry Department São Paulo State University (UNESP) Biological Sciences Department FAPESP: 2014/22952-6

BACKGROUND: In the current pandemic situation, glove disinfection is a process that can be used to care for the same patient or when removing personal protective equipment. For this reason, it is necessary to check compatibility data of the glove with the disinfectant product in glove disinfection. AIM: To test the resistance of nitrile gloves to different disinfectant solutions. METHODS: To analyze the resistance of nitrile gloves, firstly, the gloves were exposed to the disinfectant. The exposure to the disinfectant was analyzed comparing the control group (untreated glove) with the others. For the tensile test, the thickness of each test specimen was measured with a micrometer .100% powder-free nitrile gloves, composed of nitrile Butadiene rubber (NBR) compounds, were used. The 7 most commonly used disinfectant solutions in the healthcare field were selected. FINDINGS: A bleach solution did decrease breaking load, although to a lesser extent than disinfectants that contain ethanol in their composition. CONCLUSION: With the methods used, we have determined the influence that various disinfectants have on nitrile gloves, finding that those which contain alcohol cause a decrease in breaking load.

To evaluate the bleaching efficacy and shear bond strength (SBS) of composite restorations performed immediately after bleaching with a newly developed experimental bleaching agent, including 6% hydrogen peroxide (HP), titanium dioxide (TiO2), and/or chitosan (CS).We randomly divided 132 maxillary anterior teeth into 2 study groups, 60 teeth for color analysis and 72 teeth for the SBS test. For color analysis, teeth were divided into 5 subgroups. For SBS analysis, teeth were divided into 6 subgroups according to bleaching agent: group C (control): no bleaching; group 35HP: whiteness 35% HP; group 6HP: 6% HP; group HPC: 6% HP+CS; group HPT: 6% HP+TiO2; group HPTC: 6% HP+ TiO2+CS. The teeth were measured with a spectrophotometer before and 24 h after the bleaching, and calculated with the CIEDE2000 formula. SBS test was evaluated in composite restorations immediately after bleaching, using a universal testing machine. Statistical analysis was performed using ANOVA.The highest ∆E00 values were observed in group 35HP (4.2 ± 1.2); the lowest value was observed in group 6HP (1.7 ± 0.6) (p0.05). The values for groups HPC and HPT were similar to each other and significantly lower than the value for 35HP (p0.05 and p0.05, respectively). Group HPTC was similar to 35 HP (p0.05). For SBS, all groups except those containing chitosan showed significantly decreased bond strength compared to the control (p0.05), while groups HPC and HPTC had values similar to the control (p0.05). Group C (28.02 ± 6.81) had the highest value, while group 35HP (17.02 ± 7.79) had the lowest SBS value.With the newly developed agent, the bond strength immediately after bleaching was found to be similar to the control group. Its bleaching efficacy was similar to that of routinely used bleaching agents.

Made available in DSpace on 2020-12-12T01:36:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 This study evaluated the effect on enamel demineralization of 10% hydrogen peroxide (H2O2) gels containing different concentrations of sodium trimetaphosphate (TMP) and sodium fluoride (NaF) combined with the daily use of fluoridated or placebo dentifrice. Bovine enamel blocks were selected by surface hardness (n = 72) and randomly assigned to one of the following experimental treatments: 10% H2O2; 10% H2O2 + 3% TMP + 0.1% NaF; and 10% H2O2 + 0.3% TMP + 0.05% NaF, each with or without fluoridated dentifrice. H2O2-based gels were applied for 30 min d−1 followed by treatment with dentifrice (1 min). Enamels blocks were stored in artificial saliva at 37°C between sessions during the 14 days of experiment. Percentage of surface hardness loss (%SH) was calculated, and the blocks were cut into halves to analyze cross-sectional hardness (ΔKHN). Polarized light microscopy images were obtained of the longitudinal sections of the samples. Enamel treated with fluoridated dentifrice presented lower hardness loss than those treated with placebo dentifrice (%SH and ΔKHN). Use of TMP- and NaF-based gels, regardless of concentration, led to the lowest %SH values. Specimens treated with 10% H2O2 gel had the highest %SH and ΔKHN values. Gels with 10% H2O2 + 3% TMP + 0.1% NaF showed the lowest ΔKHN values. Microscopy images clearly showed that the addition of TMP and NaF to the H2O2-based gels was effective in reducing the loss of hardness, and the fluoridated dentifrice helped minimize it in all treatments. School of Dentistry São Paulo State University (Unesp) School of Dentistry São Paulo State University (Unesp)

To investigate the effect of a tooth whitening agent on surface roughness, surface hardness, and force delivery properties of polyethylene terephthalate glycol (PETG) thermoplastic retainer materials of two different thicknesses.PETG sheets (1 mm and 1.5 mm) were thermoformed over a 30 × 60 × 10 mmExposure of PETG specimens to the bleaching agent for 14 days significantly reduced surface hardness and increased surface roughness of samples of both thicknesses. The magnitude of force at different deflection points decreased significantly in the 1.5 mm thickness specimens treated with the bleaching agent, but no significant change was observed in the specimens with 1 mm thickness.Use of a home bleaching agent could have adverse effects on surface roughness and hardness of PETG materials leading to reduced survival time of thermoplastic orthodontic retainers.ZIELSETZUNG: Untersucht werden sollte der Einfluss einer zahnaufhellenden Substanz auf die Oberflächenrauigkeit, die Oberflächenhärte und die Kraftübertragungseigenschaften von thermoplastischen PETG(Polyethylenterephthalat-Glykol)-Retainermaterialien in 2 Stärken.Zwei unterschiedlich dicke PETG-Platten (1 und 1,5 mm) wurden über ein 30 × 60 × 10 mmDie Exposition der PETG-Proben gegenüber der zahnaufhellenden Substanz über den Zeitraum von 14 Tagen führte zu einer signifikanten Verringerung der Oberflächenhärte und zu einer Erhöhung der Oberflächenrauigkeit der Proben beider Stärken. Die Größe der Kraft an verschiedenen Durchbiegungspunkten nahm bei den mit dem Aufheller behandelten Proben mit einer Dicke von 1,5 mm signifikant ab, während bei den Proben mit einer Dicke von 1 mm keine signifikante Veränderung beobachtet wurde.Die Verwendung eines Home-Bleaching-Mittels könnte negative Auswirkungen auf die Oberflächenrauigkeit und -härte von PETG-Materialien haben und so zu einer verringerten Überlebenszeit thermoplastischer kieferorthopädischer Retainer führen.

This study developed experimental gels containing titanium tetrafluoride (TiF4) combined with commercial 35% hydrogen peroxide (HP), and evaluated bleaching efficacy and pH of the gels, and mineral content and morphology of enamel submitted to these treatments. In phase-1, different stock gels mixed with TiF4 were combined with HP. In phase-2, the selected gels were tested on enamel/dentin specimens (n=8): HP; HP and Natrosol+TiF4 (HPnT); HP and Natrosol+Chemygel+TiF4 (HPncT); HP and Aristoflex+TiF4 (HPaT). Bleaching was performed in four sessions (3x15min-application/session). Color (CIEL*a*b*) and whiteness index (WID) were measured after each session, whereas whiteness index differences (ΔWID), color alteration (CIELab–ΔE, CIEDE2000-ΔE00), enamel morphology and pH, at end of bleaching therapy. The change in Knoop microhardness (ΔKHN) was compared before and after bleaching. Data were analyzed by two-way repeated measures ANOVA and Bonferroni (CIEL*, a*, b*), one-way ANOVA and Tukey (ΔWID, ΔE, ΔE00), and LSD (ΔKHN) tests (α=5%). SEM and pH measurements were submitted to descriptive analysis. No differences were observed in lightness (L*) or WID among the groups (p > 0.05), but HP exhibited lower b* values (p 0.05), and HPncT showed higher ΔKHN than HP (p < 0.05). HP presented pH values closer to neutral (6.9), whereas experimental agents showed acidic pH values (2.3–3.9). No morphological changes were observed in HP or HPncT groups. HPncT was able to bleach the enamel and maintain enamel microhardness and surface integrity, even at low pH.

Objective This study evaluated the influence of carbamide peroxide, 10% and 16%, on the surface roughness and gloss of a pressable ceramic. Materials and methods Carbamide peroxide (10% or 16%) was applied for 4 hours or 3 hours per day for 14 days, respectively, in pressable ceramic discs (14 mm × 2 mm). Specimens were stored in distilled water at 37°C. Surface roughness and gloss were determined before carbamide peroxide application (T0 ), 7 days (T7 ) and 14 days (T14 ) after the initial treatment. ANOVA was used with repeated measures and multiple comparisons with a Bonferroni adjustment (P Results Significant increase in surface roughness was observed over time (P T7 > T14 . Conclusions The surface roughness of pressable ceramics increased, while their gloss significantly decreased when 10% or 16% carbamide peroxide was applied. The specimens treated with 16% carbamide peroxide exhibited higher surface roughness and less gloss than the specimens treated with 10% carbamide peroxide. Clinical significance This study found that carbamide peroxide gels commonly used in at-home procedures influenced the surface roughness and gloss of a pressable ceramic that is often used for rehabilitation esthetics.

Bleaching agents may affect surface properties of mineral trioxide aggregate (MTA) as a coronal barrier. The purpose of this study was to investigate surface properties of MTA after exposure to intracoronal bleaching agents. MTA was set in acrylic molds with a 4 mm high central hole and a 6 mm diameter. Specimens were divided into four groups (n = 10); three groups were exposed to bleaching agents three times on every fourth day (carbamide peroxide—CP, hydrogen peroxide—HP, sodium perborate—SP) and a control group—C. The surface roughness and Vickers surface microhardness were measured. Differences between groups were analyzed using a Kruskal–Wallis test and intergroup comparisons were assessed with a Mann–Whitney U test with a Bonferroni correction (p

FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais Objetivos: Avaliar (1) a influência de diferentes sistemas de polimento na estabilidade de cor e rugosidade da superfície da resina composta e (2) a capacidade de diferentes tratamentos de superfície em reduzir a alteração de cor sem afetar a rugosidade da superfície após o manchamento. Métodos e materiais: Um total de cento e sessenta amostras em forma de disco (8 x 2 mm) foram preparadas usando uma resina composta. As amostras foram divididas de acordo com os sistemas de polimento: controle negativo (NC), sistema 3M (3S), sistema DhPro (DS) e sistema FGM (FS). Depois disso, os espécimes foram imersos em café por 48 horas. Uma nova subdivisão foi realizada de acordo com o tratamento de superfície (n = 10): gel ozonizado (OG), peróxido de hidrogênio (HP), jato de bicarbonato (BJ) e repolimento (R). Mudança de cor (ΔE00), índice de clareamento (WI), opacidade e rugosidade da superfície (Ra) foram avaliadas após o polimento, após o manchamento com café e após o tratamento da superfície. Os dados de ΔE00, WI e opacidade não apresentaram distribuição normal e foram submetidos ao teste de Kruskal-Wallis. Comparações múltiplas foram realizadas pelo teste de Tukey. Teste ANOVA two-way de medidas repetidas foi utilizado para analisar os dados de rugosidade da superfície em diferentes tempos de avaliação. Todos os procedimentos de comparação múltipla aos pares foram conduzidos usando o teste de Tukey. (α = nível de significância 0,05). Resultados: A maior coloração apresentada foi em NC e DS. 3S e FS obtiveram resultados semelhantes para alteração de cor, o que significa maior estabilidade de cor. Os tratamentos de superfície reduziram significativamente a alteração de cor e afetaram a rugosidade da superfície (p

We present a study «in vitro» of the effect of bleaching agents on dental surfaces using the «Walking bleaching technique». We found that hydrogen peroxide bleached more quickly than carbamide although, after a period of six weeks, the results were the same as far as wheitening was concerned. In the scanning electron microscope we observed significantly different changes in each case. Carbamide caused a regular and uniform opening of the enamel prisms of the surface while hydrogen peroxide produced more severe superficial destructuration with the appearance of patterning similar to the acid etching, and the presence of some crystalline areas emerging from the body of the prisms., Nous présentons une étude in vitro de l’effet sur la surface dentaire de deux agents de blanchiment utilisés par la technique «Walking bleaching». Nous observons que le peroxyde d’hydrogène blanchit plus vite que le peroxyde de carbamide même si dans un délai de 6 semaines les résultats sont les mêmes en ce qui concerne le blanchiment. Au MEB, nous observons des changements significativement différents dans l’un et l’autre cas. Le peroxyde de carbamide provoque une ouverture des prismes sur la surface de l’émail de manière régulière et uniforme, alors que le peroxyde d’hydrogène produit des destructurations superficielles plus importantes avec l’apparition d’un maître-modèle comme celui de mordançage acide avec la présence sur certaines zones de cristaux qui émergent du corps des prismes.

Aim To evaluate the extraradicular peroxide release from sodium percarbonate compared to sodium perborate as an intracoronal bleaching agent. Methodology Sixty mandibular single-rooted premolars with intact CEJ were selected. After root filling, gutta-percha was removed 4 mm apical to CEJ and 2 mm of GIC was condensed over the root filling. Intracoronal bleaching agents were placed into six groups of teeth (n = 10): sodium perborate with distilled water (SPW); sodium percarbonate with distilled water (SPCW); sodium perborate with 30% hydrogen peroxide (SPHP); sodium percarbonate with 30% hydrogen peroxide (SPCHP); 30% hydrogen peroxide as positive control (HP) and distilled water as negative control (CL). The teeth were then mounted in vials filled with distilled water, kept in an incubator and taken out at 1, 3 and 6 days for spectrophotometric analysis. Extraradicular peroxide release was quantified by the ferrothiocyanate method. Statistical analysis was undertaken with one-way anova and Scheffe post hoc tests. Results The greatest peroxide release occurred in the HP group, followed by the SPCHP and SPHP groups, and then by the SPCW and SPW groups. Intergroup comparison revealed that there was no significant difference in peroxide release among the groups SPCW and SPW on days 1, 3 and 6 (P > 0.05). Similarly, no significant difference was found between the SPCHP and SPHP treated groups on days 1, 3 and 6 (P > 0.05). Conclusion Extraradicular peroxide release from sodium percarbonate was comparable to that of sodium perborate, as the differences were not significant.

Intraorifice barriers (IOBs) are usually used before internal bleaching for coronal sealing and the prevention of cervical resorption. The aim of this study was to investigate the effect of different IOBs on the fracture resistance (FR) of endodontically treated anterior teeth bleached with various bleaching agents (BAs).After performing root canal treatment for 72 extracted bovine upper incisors, the coronal 3 mm of gutta-percha was removed, and samples were classified into 3 based on the type of IOB: calcium-enriched mixture, mineral trioxide aggregate, and resin-modified glass ionomer. After applying IOBs, samples of each group were subdivided into 4 based on the BA: carbamide peroxide 45% (CP), hydrogen peroxide 35% (HP), sodium perborate (PB), and distilled water as the control. At the end of bleaching, the access cavities were restored with composite resin. The FR was measured with a universal testing machine at a crosshead speed of 5 mm/min. The data were analyzed using 2-way analysis of variance and least significant difference post hoc tests (P .05).The effect of BAs on the FR was significant (P .05); however, the effect of the IOB and the interactive effect of these variables were not significant (P .05). The FR in the HP and PB groups was significantly different from the control (P .05) but that of CP was not significantly different from the control (P .05).Mineral trioxide aggregate and calcium-enriched mixture act similarly to resin-modified glass ionomer as an IOB. CP, unlike HP and PB, did not significantly decrease the FR.

There is great concern about decreasing the amounts of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) that are formed and emitted during the chlorine bleaching of pulp. The formation of PCDD/Fs during non-woodpulp chlorine bleaching was investigated in the study described here. Wheat straw was separated into three components, cellulose, hemicellulose, and lignin. Chlorination experiments were performed, and lignin and hemicellulose contributed more than cellulose to PCDD/F formation when the pulp was bleached using chlorine. The chemical components of lignin were identified by gas chromatography mass spectrometry, and nine possible PCDD/F precursors were quantified by gas chromatography tandem mass spectrometry. Spiked chlorination experiments were performed to investigate the effects of these compounds on PCDD/F formation. 4-Ethyl-2-methoxyphenol had the strongest effect on PCDD/F formation, followed by p-chlorophenol, and guaiacol. All the test compounds promoted polychlorinated dibenzofuran formation but had limited effects on polychlorinated dibenzo-p-dioxin formation. The results allowed mechanisms for the formation of PCDD/Fs from phenol, chlorophenol, catechol, and guaiacol to be proposed.

PubMed: 30338618 The present study aimed to evaluate the effect of sodium perborate on the compressive strength of calcium silicate-based materials. ProRoot wMTA, MTA Plus, NeoMTA Plus and Biodentine discs with 5 mm thickness and 4 mm diameter were prepared. Thirty discs from each material were used for compressive strength testing and divided into two groups: control and bleaching (n = 15). The sodium perborate was mixed with 30% hydrogen peroxide in a creamy consistency and placed on the surface of the specimens. Specimens were tested in an Instron machine, and compressive strength values were recorded and compared. The data were analysed using one-way anova and post hoc Tukey tests. Compressive strength of all tested materials significantly decreased after bleaching (P

Background: Cellulose is an insoluble plant polysaccharide produced from soft-wood pulp. Although chronic respiratory effects associated with high cellulose-based dust levels have been previously described, occupational asthma has not. A 37 year old machine operator in a sanitary pad production factory presented with new-onset work-related asthma symptoms for two years. Methods: The worker underwent clinical, pulmonological and immunological (skin prick tests, serum specific IgE determinations) evaluation using standardised procedures. The cellulose product was subjected to scanning electron microscopy (SEM) examination. A specific inhalation challenge test performed with the cellulose product ensured that dust concentrations were kept below 5mg/m(3). Results: The subject was not atopic and did not have elevated IgE to pine wood or xylanase. The cellulose product appeared to be free of protein contaminants on SEM. The Work Effect Index computed on serial PEF recordings was elevated (WEI = 3.8). Specific inhalational challenge with the cellulose product dust revealed a late bronchial response (39% drop in FEV1 at 3 hours post challenge). Conclusion: This is the first reported case of occupational asthma to a cellulose fibre product. A non-specific immune reaction or irritant response seems likely. These fibres may therefore not be biologically inert. The occupational exposure limit of 10mg/m(3) generally used for cellulose dust appears to be non-protective.

Objectives: To evaluate the effect of bleaching on colour, gloss, translucency, and microhardness of two types of resin composites (Charisma Classic and Filtek Z350 XT), previously aged. Materials and methods: Forty specimens of each material were artificially aged for 300 hours (UV-accelerated aging). Specimens were then treated with 35% hydrogen peroxide (Whiteness HP) in four 15-minutes sessions, totaling one hour of bleaching. Colour coordinates CIE L*a*b* and parameters of translucency (PT) were measured using a spectrophotometer (CM2600d – Konica Minolta), surface gloss readings were performed with a glossmeter (Novo-Curve – Rhopoint TM), and microhardness was assessed using a hardness device (FM-700, Future-Tech). Measurements have been performed after artificial aging as well as after the first and last bleaching protocol. Data were analyzed by two-way ANOVA and two-way repeated measures ANOVA, followed by Tukey’s test (5%). Results: The bleaching procedures of aged resin composites decreased the gloss and increased the translucency, but did not alter colour and microhardness. Conclusion: Bleaching procedures should be used carefully when resin composite restorations are present.

Background:Dental bleaching has been increasingly sought out to improve dental aesthetics, but it may cause changes in dental enamel.Objective:To assess the influence of different time intervals on bleaching gel applications with regard to the Microhardness (MH) and Surface Roughness (SR) on dental enamel.Material and Methods:Forty bovine incisors were randomly divided into two groups (G1 and G2) and both were bleached with 35% Hydrogen Peroxide (HP35) (n=20; G1: seven-day interval and G2: two-day interval). The MH and SR tests were performed before bleaching (T0) and after the first (T1), second (T2), and third (T3) bleaching gel applications. The specimens were stored in artificial saliva between each application (37°C). The data were analyzed using the student’s t-test (p≤ 0.05) for dependent samples.Results:The reduced time interval (two days) led to a significant reduction in MH, while MH was not affected during the seven-day interval. The SR results increased regardless of the bleaching gel application time interval.Conclusion:The decreased time interval of two days between bleaching gel applications caused changes in MH but did not influence the SR of dental enamel.