Effectiveness of Three Bleaching Techniques for Endodontically Treated Teeth: A Randomized Clinical Trial.

BACKGROUND: Various techniques, products, and protocols are used for the bleaching of non-vital teeth. The walking bleach technique involves sealing the bleaching agent in the pulp chamber. In the inside/outside technique, a low-concentration bleaching agent is applied at home using a custom tray. In the in-office technique, a high-concentration bleaching agent is applied by a dental professional. Limited research has compared the effectiveness of these techniques. OBJECTIVE: This clinical trial aimed to evaluate the effectiveness of the walking bleach, the inside/outside, and the in-office bleaching techniques. METHODS AND MATERIALS: Fifty-four discolored teeth were selected according to eligibility criteria, randomized, and assigned to three treatment groups (n=18): walking bleach (sodium perborate - SP), inside/outside bleaching (7.5% hydrogen peroxide -HP7.5), and in-office bleaching (35% hydrogen peroxide - HP35). A cervical seal was placed in all the teeth, and nonvital bleaching was performed according to each technique. The CIELab color coordinates were measured using a clinical spectrophotometer at baseline, weekly, and at the 1-week follow-up. ΔE00 and ΔWID were calculated between the baseline and each evaluation time point. The ANOVA, Fisher exact, and Kruskal-Wallis tests were used to compare the quantitative variables, and the Fisher exact test, to determine the association among categorical variables. Bleaching effectiveness was interpreted by 50:50% perceptibility and acceptability thresholds. RESULTS: As the treatment progressed, all techniques presented a significant increase in L* and WID (p<0.001), and a significant decrease in a* and b* (p<0.001). HP7.5 and HP35 presented greater increases in WID mean values, in comparison with SP (p=0.006). No significant differences were observed among the techniques for ΔE00 after treatment completion (p=0.383). There were no statistical differences in bleaching effectiveness among the techniques after treatment completion (p=0.098). CONCLUSION: All techniques presented excellent effectiveness after treatment completion. However, HP7.5 and HP35 techniques provided a more rapid whitening response.

Development of PHBV electrospun fibers containing a borate bioactive glass doped with Co, Cu, and Zn for wound dressings.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers embedded with borate glasses of 45B5 composition doped with Co2+, Cu2+, and Zn2 +(46.1 B2O326.9-X CaO24.4 Na2O2.6 P2O5, X CoO/CuO/ZnO mol % (X = 0-5)) were produced by electrospinning for wound healing applications. Prior to their addition, the glasses exhibited two broad halos typical of a vitreous borate network, which were mainly composed of ring-type metaborate structural units. The particle distribution in the PHBV nanofibers embedded with 45B5 borate bioactive glasses is present in isolated and agglomerated states, being partially coated by a polymeric layer-except for the cobalt-doped glass, which resulted in a successful encapsulation with 100% embedding efficiency. The incorporation of the glasses reduced the PHBV crystallinity degree and its decomposition temperature, as well as its mechanical properties, including Young's modulus, tensile strength, and elongation at break. The neat PHBV fibers and those containing the cobalt-doped glasses demonstrated great cytocompatibility with human keratinocytes (HaCat), as suggested by the high cell viability after 7 days of exposure. Further studies are needed to fully understand the wound healing potential of these fibers, but our results significantly contribute to the area.

Structural and thermoluminescence properties of lithium borate glass matrices under UV and beta radiation.

In the present work, glass samples in the (100 - x)B2O3-xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV-visible region (UV-vis absorbance), Fourier transform infrared spectroscopy on the medium region, X-ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50-250°C. Samples were also exposed to beta radiation in the temperature range 25-275°C, also showing single peaks with a maximum temperature of ~150°C.

Assessing the bleaching effect of an experimental stabilized chlorine dioxide agent used for internal bleaching purposes

Aim Assessing the intracoronal bleaching effectiveness of an experimental chlorine dioxide product, based on the walking bleach technique. Methods Extracted bovine incisors were artificially stained with bovine blood and filled with zinc phosphate cement at cementoenamel junction level. Teeth were divided into 3 groups (n=10): (SP) sodium perborate added with distilled water, (CD) chlorine dioxide and (C) control - dry cotton inserted into the pulp chamber. Bleaching agents were used at 0, 7 and 14 days. VITA Easyshadetm (∆Eab) was used to analyze tooth color at the 7th, 14th and 21st days, based on the CIE2000 system. Data were analyzed through ANOVA and Tukey's test. Results There were no statistically significant differences in Δb, ΔE, ΔE00 and ΔWID between CD and the control group. These parameters have shown significant differences between CD and SP, which differed from the control. However, they did not show significant differences either in the control group or in CD at the 7th, 14th and 21st days. Values recorded for SP at the 7th day differed from those recorded at the 14th and 21st days. Δa has shown differences within the same group at the 7th, 14th and 21st days. There was no difference between groups, when they were compared at the same day (7th and 14th). The control group differed from SP at the 21st day. CD did not differ from the other two groups. ΔL did not show differences between groups and times. Conclusion Stabilized chlorine dioxide (0.07%, at pH 3.5) should not be used as intracoronal bleaching agent along with the walking bleach technique.

Effects of glycerol and sodium pentaborate containing new formulation on sleeve gastrectomy model in rats.

PURPOSE: The development of cutting surface leakage and postoperative peritoneal adhesions (PPA) after sleeve gastrectomy (SG) are the most serious operative complications. We investigated the effectiveness of the newly developed glycerol and sodium pentaborate containing formulation on the prevention of these complications. METHODS: Sixteen Sprague Dawley rats (mean weight 310 ± 50 g, mean age 3 months old) were divided into two groups, consisting of eight rats in each. SG and a double-layer suture technique were performed for each group. In study group, there was the mixture of 2 mL 3% glycerol plus 3% sodium pentaborate formulation, and in the control group 2 mL 0.9% NaCl was injected into the peritoneal cavity. Rats were sacrificed after 30 days, then macroscopic adhesion grade scoring and histopathological evaluations were assessed. RESULTS: Macroscopic PPA scores in the control and study groups were 2.75 ± 0.16 and 1.50 ± 0.327, respectively (p = 0.004). Histopatologic fibrosis scores in the control and study groups were 0.87 ± 0.125 and 2.00 ± 0.26, respectively (p = 0.002). CONCLUSIONS: In SG operation model, glycerol plus sodium pentaborate compound decreased PPA formation and also increased stomach cut surface line fibrosis. This new formulation is hopeful for more safe SG operations.

Addition of Ammonium Acetate to Protein-Borax Baited Traps Does Not Improve Attraction of Anastrepha obliqua or Anastrepha serpentina (Diptera: Tephritidae).

Ammonia is considered a key component in the attraction of tephritid flies to protein-based lures. The addition of ammonium acetate to improve hydrolyzed protein-borax mixtures used to monitor tephritids has not been evaluated, although it has improved attraction to toxic baits. The presence of ammonium acetate crystals in a ventilated tube inside a trap containing hydrolyzed protein + borax, did not improve the capture of Anastrepha obliqua or Anastrepha serpentina flies in field experiments when compared with hydrolyzed protein + borax alone. In contrast, the addition of 1% ammonium acetate into the drowning solution of a hydrolyzed protein + borax mixture resulted in significantly reduced captures of both pests. Laboratory tests indicated that the emission of ammonia gas was increased 1.6-4.5-fold from traps that included ammonium acetate. These results confirm the hypothesis that a higher release of ammonia does not improve the attraction of tephritids when protein-derived odors are also present.

Sodium carbonate versus borate buffer for lactase quenching, laboratory work.

A laboratory exercise for undergraduate advanced students of enzymology and biocatalysis is presented. Since enzyme assays can be quenched or continuous, this experiment compares the performance of two quenching agents for lactase, in a continuous setup. Enzymatic activity of ß-galactosidase (Aspergillus oryzae) was determined based on the release of 4-nitrophenol from 4-nitrophenyl ß-D-galactopyranoside using a microplate reader. Sodium carbonate and borate buffer were tested as quenching agents, and experimental control was the unstopped assay. Based on released 4-nitrophenol, enzyme activity, and rate constant k, the students could assess the performance of each termination agent. The experiment promotes disciplinary and transversal competencies, including research-based learning, critical thinking, and introduce the students to high-throughput techniques that are common in the research and development environment.

Metabolic activity of hydro-carbon-oxo-borate on a multispecies subgingival periodontal biofilm: a short communication.

OBJECTIVE: This study evaluated the metabolic activity of hydro-carbon-oxo-borate complex (HCOBc) on a multispecies subgingival biofilm as well as its effects on cytotoxicity. MATERIALS AND METHODS: The subgingival biofilm with 32 species related to periodontitis was formed in the Calgary Biofilm Device (CBD) for 7 days. Two different therapeutic schemes were adopted: (1) treatment with HCOBc, 0.12% chlorhexidine (CHX), and negative control group (without treatment) from day 3 until day 6, two times a day for 1 min each time, totaling 8 treatments and (2) a 24-h treatment on a biofilm grown for 6 days. After 7 days of formation, biofilm metabolic activity was determined by colorimetry assay, and bacterial counts and proportions of complexes were determined by DNA-DNA hybridization. Both substances' cytotoxicity was evaluated by cell viability (XTT assay) and clonogenic survival assay on ovary epithelial CHO-K1 cells and an osteoblast precursor from calvaria MC3T3-E1 cells. RESULTS: The first treatment scheme resulted in a significant reduction in biofilm's metabolic activity by means of 77% by HCOBc and CHX treatments versus negative control. The total count of 11 and 25 species were decreased by treatment with hydro-carbon-oxo-borate complex and CHX, respectively, compared with the group without treatment (p < 0.05), highlighting a reduction in the levels of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Fusobacterium periodontium. CHX significantly reduced the count of 10 microorganisms compared to the group treated with HCOBc (p < 0.05). HCOBc and CHX significantly decreased the pathogenic red-complex proportion compared with control-treated biofilm, and HCOBc had even a more significant effect on the red complex than CHX had (p ≤ 0.05). For the second treatment scheme, HCOBc complex and CHX significantly decreased 61 and 72% of control biofilms' metabolic activity and the counts of 27 and 26 species, respectively. HCOBc complex did not significantly affect the proportions of formed biofilms, while CHX significantly reduced red, orange, and yellow complexes. Both substances exhibited similar cytotoxicity results. CONCLUSIONS: This short communication suggested that the HCOBc complex reduced a smaller number of bacterial species when compared to chlorhexidine during subgingival biofilm formation, but it was better than chlorhexidine in reducing red-complex bacterial proportions. Although HCOBc reduced the mature 6-day-old subgingival multispecies biofilms, it did not modify bacterial complexes' ratios as chlorhexidine did on the biofilms mentioned above. Future in vivo studies are needed to validate these results. CLINICAL RELEVANCE: HCOBc complex could be used to reduce red-complex periodontal bacterial proportions.

Effects of glycerol and sodium pentaborate containing new formulation on sleeve gastrectomy model in rats

ABSTRACT Purpose: The development of cutting surface leakage and postoperative peritoneal adhesions (PPA) after sleeve gastrectomy (SG) are the most serious operative complications. We investigated the effectiveness of the newly developed glycerol and sodium pentaborate containing formulation on the prevention of these complications. Methods: Sixteen Sprague Dawley rats (mean weight 310 ± 50 g, mean age 3 months old) were divided into two groups, consisting of eight rats in each. SG and a double-layer suture technique were performed for each group. In study group, there was the mixture of 2 mL 3% glycerol plus 3% sodium pentaborate formulation, and in the control group 2 mL 0.9% NaCl was injected into the peritoneal cavity. Rats were sacrificed after 30 days, then macroscopic adhesion grade scoring and histopathological evaluations were assessed. Results: Macroscopic PPA scores in the control and study groups were 2.75 ± 0.16 and 1.50 ± 0.327, respectively (p = 0.004). Histopatologic fibrosis scores in the control and study groups were 0.87 ± 0.125 and 2.00 ± 0.26, respectively (p = 0.002). Conclusions: In SG operation model, glycerol plus sodium pentaborate compound decreased PPA formation and also increased stomach cut surface line fibrosis. This new formulation is hopeful for more safe SG operations.

Role of sodium tetraborate as a cardioprotective or competitive agent: Modulation of hypertrophic intracellular signals.

Boron is an essential trace element in cellular metabolism; however, the molecular mechanism of boron in the heart is unclear. In this study, we examined the effect of sodium tetraborate (as boron source) as a possible protective agent or competitive inhibitor of cardiac hypertrophy in an in vitro murine model. We evaluated different previously reported sodium tetraborate concentrations and it was found that 13 µM improves viability without affecting the cellular structure. We demonstrated that cardiomyocytes pretreated with sodium tetraborate prevents cellular damage induced by isoproterenol (cardioprotective effect) by increasing proliferation rate and inhibiting apoptosis. In addition, the reduction of the expression of the α1AR and ß1AR adrenergic receptors as well as Erk1/2 was notable. Consequently, the expression of the early response genes c-myc, c-fos and c-jun was delayed. Also, the expression of GATA-4, NFAT, NKx2.5 and myogenin transcription factors involved in sarcomere synthesis declined. In contrast, cardiomyocytes, when treated simultaneously with sodium tetraborate and isoproterenol, did not increase their size (cytoplasmic gain), but an increase in apoptosis levels was observed; therefore, the proliferation rate was reduced. Although the mRNA levels of α1AR and ß1AR as well as Erk1/2 and Akt1 were low at 24 h, their expression increased to 48 h. Notably, the mRNA of expression levels of c-myc, c-fos and c-jun were lower than those determined in the control, while the transcription factors GATA-4, MEF2c, Nkx2.5, NFAT and CDk9 were determined in most cells. These results suggest that pretreatment with sodium tetraborate in cardiomyocytes inhibits the hypertrophic effect. However, sodium tetraborate attenuates isoproterenol induced hypertrophy damage in cardiomyocytes when these two compounds are added simultaneously.

Synthesis of calcium borate nanoparticles and its use as a potential foliar fertilizer in lettuce (Lactuca sativa) and zucchini (Cucurbita pepo).

This study was carried out to evaluate the effects of foliar sprays containing boron (B) nano-fertilizer (NF) on the growth and physiology of lettuce (Lactuca sativa) and zucchini (Cucurbita pepo). Plants were grown under greenhouse conditions for 60 days on a modified Hoagland solution with the presence and absence of boron (+B or -B). A synthesized B-NF foliar spray and a commercial B foliar fertilizer (Bortrac™ 150, BT) was applied at a concentration of 30 mg B L-1 at 10-d intervals throughout the experiment. The B-NF treatment increased the growth of lettuce 2.7- and 1.9-fold for shoots and roots, respectively, with an average production of lettuce biomass by ~58%. Similarly, the NF increased the growth of zucchini by 18 and 66% compared with Control-B (the absence of B), and 13 and 36% compared with BT, both for shoots and roots, respectively. Nevertheless, NF + B mostly decreased lettuce growth with symptoms of B toxicity in leaves. In lettuce, addition of B did not affect concentrations of phenols; however, in zucchini, Control-B induced a higher production of phenolic compounds possibly related to B deficiency. The B addition in lettuce reduced the DPPH activity by 32 and 21% in NF and BT, respectively, compared to Control-B. These responses were similar in zucchini; however, the effect of B was product of its presence in mineral solution rather than due the foliar product applied. This suggests that a NF-based delivery system for B may be highly effective at boosting plant productivity on B-limited soils.

Thermoluminescence emission on lead oxychloroborate glasses under UV exposure.

Glassy materials were prepared using two different systems: 50B2 O3 - (50 - x)PbO - xPbCl2, with x = 0, 2 and 5 in mol % (System BPCl-I) and 50BO1.5 - (50 - x)PbO - xPbCl2 with x = 0, 2, 5 and 7 in cationic % (System BPCl-II). Structural and optical characterization showed that PbCl when substituted for PbO changed the structure of the glass network by replacing nonbridging oxygens for chlorine ions. This substitution also caused a change in the number of defects responsible for thermoluminescence (TL) emission (electrons and hole trap centres). Thermoluminescence emissions were observed for the first time in lead oxychloroborate glasses after exposure to UV radiation. Sample BPCl-I-2 (x = 2 from System I) demonstrated better TL emission compared with other glass samples. One intense peak in the glow curve, centred at ~122°C followed by a shoulder at ~180°C, was highly sensitive to UV radiation. There were also good linear responses at dose range ~0.4 to ~2 J/cm2 for the first peak (low temperature) and ~0.4 to ~4 J/cm2 for the second peak (high temperature).

Baseline separation of α and ß-acids homologues and isomers in hop (Humulus lupulus L.) by CD-MEKC-UV.

An alternative method for simultaneous baseline separation of α and ß-acids homologues and isomers in hop by CD-MEKC with UV detection was proposed. The optimized background electrolyte was composed of 30 mmol/L sodium tetraborate solution, 45 mmol/L sodium dodecyl sulfate, 20 mmol/L ß-cyclodextrin and 10% v/v acetonitrile. The instrumental conditions were evaluated by using a 33 Box-Benhken experimental design. In order to demonstrate the applicability of the method, 21 hop samples from different varieties were analyzed. The repeatability intra- and interday tests were performed and relative standard deviations lower than 7% for area and migration times were observed. The present method comprehended 8 min analysis time and revealed to be faster and more efficient when compared to previous reports from literature.

Development of a rapid HPLC method for quantification of the copper tetramibi tetraflourborate in a kit for preparation of Technetium 99 m Sestamibi Injection.

Radiopharmaceuticals are radioactive compounds that can be used for diagnostic and therapeutic purposes. Technetium (99mTc) Sestamibi is the most commercialized radiopharmaceutical in the world. It includes a coordination complex consisting of the radioisotope 99 m technetium bound to six copper tetramibi tetrafluorborate ligands, and is mainly used to image the myocardium via scintigraphy. As radiopharmaceuticals are regarded as drugs, they are subject to the same regulations; therefore, the objective of this study was to develop a quantification method for the active pharmaceutical ingredient before their complexation with the radioisotope by employing high-performance liquid chromatography (HPLC) methodology. A simple and efficient method (retention time = 2.5 min) was developed and validated for copper tetramibi tetrafluorborate in the final product using a buffer and organic solvent mixtures (ACN-methanol-ammonium sulfate buffer) and a C18 column. The analytical protocol was fast, taking around 30 min until evaluation of results. The validation parameters were evaluated with satisfactory results: in terms of linearity r > 0.99 (160-240 µg/mL) and no deviation was observed. The RSD of precision was <5%, and an average recovery of 99% was observed for accuracy. The proposed method was thus considered adequate for routine analysis in the pharmaceutical industries.

Pyrogallol Induces Apoptosis in Human Platelets.

Pyrogallol is a polyphenol that generates the superoxide anion. In this study, we investigated the influence of pyrogallol on human platelets. Our data showed that exposure of platelets to pyrogallol induced numerous manifestations of apoptosis including depolarization of mitochondrial inner membrane and release of cytochrome c from the mitochondria. Pyrogallol also induced downstream extra-mitochondrial apoptotic responses, including activation of caspase-3 and phosphatidylserine exposure on the outer leaflet of the plasma membrane. Addition of glutathione significantly rescued cells from pyrogallol- induced apoptosis, as evidenced by a decrease of all markers of apoptosis. Thus, pyrogallol appears to produce depletion of intracellular glutathione content in platelets, the main non-protein antioxidant in the cells. Furthermore, inhibition of γ-glutamyl transpeptidase, an enzyme that plays the main role in the cellular supply of glutathione, reverted the glutathione (GSH) protection over platelet apoptosis. Our results indicate that pyrogallol induces apoptosis by suppressing the natural anti-oxidation in human platelets.

Cytotoxic potential of denture base and reline acrylic resins after immersion in disinfectant solutions.

STATEMENT OF PROBLEM: The daily immersion of dentures in disinfectant solutions can cause the incorporation of toxic substances in the acrylic resins, and studies evaluating the cumulative effect of disinfectant solutions on cell culture are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the cytotoxic potential of cell cultures of denture base and reline acrylic resins after immersion in disinfectant solutions. MATERIAL AND METHODS: Disk-shaped specimens (14×1.2 mm) were obtained and divided into groups (n=9) according to the disinfectant solutions (distilled water [control], 2% chlorhexidine digluconate, 3.8% sodium perborate, 0.5% sodium hypochlorite, and apple vinegar) and to the storage period (0, 1, 3, and 6 months). Solutions were changed daily. After the different storage periods, specimens were immersed in culture medium for 24 hours, and extracts were obtained. Human keratinocytes were cultivated, and the cellular metabolism was evaluated by using Alamar Blue. Data were submitted to 3-way analysis of variance and Games-Howell post hoc tests (α=.05). RESULTS: Both of the acrylic resins tested showed similar biocompatibility properties after immersion in different solutions (P=.400). Immersion in distilled water, 3.8% sodium perborate, and 0.5% sodium hypochlorite did not affect the cellular metabolism of the keratinocytes (P>.05), regardless of the immersion period and the type of acrylic resin (P>.05). Immersion in 2% chlorhexidine digluconate or apple vinegar resulted in high cytotoxicity over time, until the third month (P<.05), after which no changes were observed (P>.05). CONCLUSIONS: The type of acrylic resin (base or reline) had no significant effect on the viability of cells. Vinegar and chlorhexidine digluconate solutions increased in cytotoxic effect over time, and were strongly cytotoxic after 6 months of immersion. Sodium perborate and sodium hypochlorite were noncytotoxic in all periods of time tested.

Dentin bond strength and nanoleakage of the adhesive interface after intracoronal bleaching.

This study evaluated dentin bond strength (BS) and nanoleakage of non- and pre-etched dentin immediately (T0 ,), 7 days (T7 ), and 14 days (T14 ) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non- and pre-etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72-h interval. Afterwards, pulp chamber dentin was prepared for the BS test at different evaluation times (n = 5): T0 , T7 , and T14 . Composite blocks were built on pulp chamber and sectioned in slices. Slices were reduced to an hour-glass shape with a cross-sectional area of 0.8 mm2 and submitted to microtensile BS test. Two additional specimens for each group were prepared for nanoleakage evaluation by transmission electron microscopy (TEM). Results were analyzed by ANOVA (two-way) and Dunnett's test (p < .05). BS decreased immediately after intracoronal bleaching for both sound and pre-etched dentin (p < .05). At T14 , the BS of non-etched bleached dentin increased for all groups, whereas the pre-etched SPe group presented BS similar to the Ce. Nanoleakage within the hybrid layer was perceptible immediately after bleaching, although a decrease in nanoleakage was observed for all groups at T14 . Adhesive restorations should be performed 7-14 days after bleaching, according to the bleaching agent used. Intracoronal bleaching should be performed preferably with sodium perborate if previous dentin etching is applied.