In Vitro Evaluation of the Effectiveness of Dental Bleaching with Carbamide Peroxide and Violet Light.

Objective: The aim of the current study was to use the CIELab system to evaluate the performance of the whitening treatment involving violet light-emitting diode (LED) combined with a home 10% and 22% carbamide peroxide dental bleaching technique on dental enamel. Methods: Fifty blocks of bovine dental enamel were divided into five groups: control group (control), receiving only LED irradiation; Whitening 10%, receiving 10% carbamide peroxide treatment; Whitening 10%+VL, receiving 10% carbamide peroxide treatment combined with LED irradiation; Whitening 22%, receiving 22% carbamide peroxide treatment; and Whitening 22%+VL, receiving 22% carbamide peroxide treatment combined with violet LED irradiation. Color tests were performed before the protocols, after 1 week and after 2 weeks of treatment by using a spectrophotometer and the CIELab parameters: L*, (a*) and (b*). The Whitening 10%, Whitening 10%+VL, Whitening 22% and Whitening 22%+VL groups were submitted to 10% and 22% carbamide peroxide 8 h per day for 14 days, whereas the Control was only stored in artificial saliva. For irradiation in the Control, Whitening 10%+VL, and Whitening 22%+VL groups, we used violet LED at a wavelength of 405-410 nm activated for 60 permanent seconds and 30 sec of pause once per week. As all data exhibited normal distribution, the comparisons were performed by using two-way repeated-measures analysis of variance. A post hoc t-test was employed, followed by the Ryan-Holm stepdown Bonferroni procedure. Results: After 1 week, the Whitening 22%+VL group differed significantly from all other groups in relation to hue, while no difference was found between the remaining groups (p < 0.05). Analyzing lightness, the Whitening 22%+VL and Whiteness10%+VL groups differed from the other groups (p > 0.05). In the 2nd week, the Whitening 22%+VL groups differed significantly from all other groups (p < 0.05) in hue, chroma, and lightness. The comparative analysis of bleaching times within the same group revealed significant differences in the Whitening 22%+VL group between baseline and week 1, baseline and week 2, as well as weeks 1 and 2 in terms of hue (p > 0.05). In the Whitening 22%+VL group, significant differences (p < 0.05) were found between baseline and week 2 as well as between weeks 1 and 2 in chroma (p > 0.05). In the Whitening 22%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, baseline and week 2, as well as between weeks 1 and 2 in lightness. In the Whitening 10%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, between baseline and week 2, as well as between weeks 1 and 2 in lightness. Conclusions: Tooth whitening treatment involving 10% and 22% carbamide peroxide combined with violet light promoted changes in the three axes of color (ΔH, ΔC, and ΔL) of the specimens evaluated. The use of the gel bleach alone was more efficient when the higher concentration was used. When violet light was combined with the gel, the lower concentration was more efficient.

Five-year clinical evaluation of a universal adhesive: A randomized double-blind trial.

OBJECTIVE: To evaluate the five-year clinical performance of Scotchbond Universal Adhesive (SU; 3M Oral Care, St. Paul, MN, USA) in non-carious cervical lesions (NCCLs) using two evaluation criteria. METHODS: Thirty-nine patients participated in this study. Two hundred restorations were assigned to four groups: SU-ERm: etch-and-rinse + moist dentin; SU-ERd: etch-and-rinse + dry dentin; SU-Set: selective enamel etching; and SU-SE: self-etch. A nanofilled composite resin was placed incrementally. The restorations were evaluated at baseline and after 5 years using both the World Dental Federation (FDI) and the United States Public Health Service (USPHS) criteria. The survival rates (retention/fractures) were calculated with the Kaplan-Meier and the log-rank test. For the secondary outcomes, Friedman repeated measures analysis of variance by rank was applied (α = 0.05). RESULTS: After 5 years the recall rate was 86%. The retention/fracture rates were 93% for Erm and ERd, 88.4% for SEet and 81.4% for SE. A significant difference was observed for SE vs. ERd and SE vs. ERm (p = 0.01). Also, marginal discoloration and adaptation showed significant differences with ERm and ERd resulting in fewer marginal discrepancies than SE (p < 0.05). SIGNIFICANCE: After 5 years, the clinical behavior of the universal adhesive in the etch-and-rinse strategy was better when compared to the self-etch strategy. The use of selective enamel etching is highly recommended for the self-etch strategy. The FDI and USPHS evaluation criteria showed similar results after 5 years.

Niacin prevents mitochondrial oxidative stress caused by sub-chronic exposure to methylmercury.

Humans and animals can be exposed to different chemical forms of mercury (Hg) in the environment. For example, methylmercury (MeHg)-contaminated fish is part of the basic diet of the riparian population in the Brazilian Amazon Basin, which leads to high total blood and plasma Hg levels in people living therein. Hg induces toxic effects mainly through oxidative stress. Different compounds have been used to prevent the damage caused by MeHg-induced reactive oxygen species (ROS). This study aims to investigate the in vivo effects of sub-chronic exposure to low MeHg levels on the mitochondrial oxidative status and to evaluate the niacin protective effect against MeHg-induced oxidative stress. For this purpose, Male Wistar rats were divided into four groups: control group, treated with drinking water on a daily basis; group exposed to MeHg at a dose of 100 µg/kg/day; group that received niacin at a dose of 50 mg/kg/day in drinking water, with drinking water being administered by gavage; group that received niacin at a dose of 50 mg/kg/day in drinking water as well as MeHg at a dose of 100 µg/kg/day. After 12 weeks, the rats, which weighed 500-550 g, were sacrificed, and their liver mitochondria were isolated by standard differential centrifugation. Sub-chronic exposure to MeHg (100 µg/kg/day for 12 weeks) led to mitochondrial swelling (p < 0.05) and induced ROS overproduction as determined by increased DFCH oxidation (p < 0.05), increased gluthatione oxidation (p < 0.05), and reduced protein thiol content (p < 0.05). In contrast, niacin supplementation inhibited oxidative stress, which counteracted and minimized the toxic MeHg effects on mitochondria.

Temporomandibular disorder and headache in university professors.

[Purpose] Temporomandibular disorder is a condition with a multifactor etiology that involves the temporomandibular joint, bones, surrounding muscles and facial pain is the most common symptom. This study evaluated the possible association between headache and temporomandibular disorder in university professors. [Participants and Methods] Twenty-seven professors were recruited and answered the Axis II of the Research Diagnostic Criteria for Temporomandibular Disorders for the evaluation and diagnosis of temporomandibular disorder and filled out a "Headache Diary" proposed by the American Headache Society. [Results] The university professors showed headache and temporomandibular disorder, but no association was found between the two conditions. Comparing the gender, the males were most frequently affected, but females had more intensity of signs and symptoms. There is a lack of data on the population addressed in the present study. [Conclusion] Indeed, this was the first such study developed with university professors. It is of considerable importance to develop further studies to investigate the possible association between headache and temporomandibular disorder.

Protective effects of niacin against methylmercury-induced genotoxicity and alterations in antioxidant status in rats.

This study investigates the potential beneficial effects of niacin (NA; vitamin B3) supplementation in rats chronically exposed to methylmercury (MeHg). Animals were randomly assigned to one of 4 groups (n = 6): Group I, control, received distilled water by gavage; Group II, received MeHg (100 µg/kg/d) by gavage; Group III, received NA (50 mg/kg/d) in drinking water; Group IV, received MeHg (100 µg/kg/d) by gavage + NA (50 mg/kg/d) in drinking water. Biochemical parameters levels of glucose, triglycerides, total cholesterol and fractions, and enzyme activities aspartate transaminase (AST) and alanine transaminase (ALT) were determined. Further, oxidative stress markers activity of glutathione peroxidase (GPx) and catalase (CAT) activity, as well as levels of reduced glutathione (GSH), malondialdehyde (MDA), and nitric oxide, were examined, and the comet assay was performed, using blood/plasma. Hg levels were measured in blood, brain, and kidneys of animals. Our results demonstrated that NA reduced adverse effects produced by MeHg. The mechanism underlying these effects appears to be related to the intrinsic antioxidant potential of NA. Considering the beneficial effects attributed to NA following MeHg exposure and that fish are the main source of both NA and MeHg, future studies need to evaluate the potential counteractive effect of NA against the adverse consequences of MeHg exposure in fish-eating populations.

Arsenic speciation in Brazilian rice grains organically and traditionally cultivated: Is there any difference in arsenic content?

Inorganic arsenic contamination in rice is a global public concern due to the risks associated. In spite of being an important issue, few studies concerning differences between inorganic arsenic in rice grains under organic and conventional methods of cultivation are available in Brazil, which is an important producer and consumer. In the present work, samples of polished and husked rice (organic and conventional) and gastronomic rice (Arborio, Carnaroli and red/black rice) were analyzed and the results compared to FAO/Codex maximum limits. The total determination and speciation analysis of arsenic were carried out by ICP-MS and HPLC-ICP-MS, respectively. The results showed no significant statistical differences in total As concentration in organic rice (157.7±56.1ngg-1) vs. conventional rice (137.4±46.6ngg-1) and also in organic husked rice (227.7±95.5ngg-1) vs. conventional husked (217.7±60.9ngg-1). However, inorganic As was 45% higher in organic polished rice than in conventional polished rice and 41% higher in organic husked rice than in conventional husked rice. Gastronomic rice presented total arsenic ranging from 65.4 to 348ngg-1 for black and Arborio rice, respectively. Regarding the maximum levels adopted by Codex for i-As (200ngg-1), no violation was found.

Alternative Aging Solutions to Accelerate Resin-Dentin Bond Degradation.

PURPOSE: This study evaluated the effect of aging solutions on the durability of resin-dentin bonds by means of microtensile bond strength (µTBS) and nanoleakage (NL) tests. MATERIALS AND METHODS: The adhesive system Adper Single Bond 2 (3M ESPE) was applied according to the manufacturer's instructions to the flattened occlusal surface of 40 extracted human molars. After bonding, teeth were sectioned to obtain bonded sticks (0.8 mm2 area) which were tested in tension immediately or after different storage periods (1 week, 1 month, or 6 months). Bonded sticks were kept immersed in 5 different solutions: 1) distilled water (DW); 2) 99.9% propionic acid (PA); 3) 99% acetic acid (AA); 4) 75% ethanol (ET), and 5) mineral oil (MO). To determine NL, bonded sticks from each experimental condition were immersed in silver nitrate and analyzed by SEM. Data were analyzed by two-way repeated measure ANOVA and Tukey's test (α=0.05). RESULTS: Faster degradation of bond strength (1 week) could be seen for AA and ET (p<0.05) in comparison with DW. Specimens stored in PA and DW showed bond strengths significantly reduced after one and six months, respectively (p<0.05). No degradation of the resin-dentin bond strengths was observed for specimens stored in MO (p>0.05). Nanoleakage increased for all groups except MO after storage. CONCLUSION: Propionic acid, acetic acid, and ethanol can be used as alternative aging solutions to more quickly obtain results on the bond resistance to degradation.

A new universal simplified adhesive: 36-Month randomized double-blind clinical trial.

STATEMENT OF THE PROBLEM: It is still debatable which technique should be used with universal adhesives, either etch-and-rinse (wet or dry) or self-etch strategy (with or without selective enamel etching). PURPOSE OF THE STUDY: To evaluate the 36-month clinical performance of Scotchbond Universal Adhesive (SU, 3M ESPE) in non-carious cervical lesions (NCCLs) using two evaluation criteria. METHODS/MATERIALS: Thirty-nine patients participated in this study. Two-hundred restorations were assigned to four groups: ERm: etch-and-rinse+moist dentin; ERd: etch-and-rinse+dry dentin; Set: selective enamel etching; and SE: self-etch. The same composite resin was inserted for all restorations in up to 3 increments. The restorations were evaluated at baseline and at 6-, 18-, and 36-months using both the FDI and the USPHS criteria. Statistical analyses were performed with Friedman repeated measures ANOVA by rank and McNemar test for significance in each pair (α=0.05). RESULTS: Eight restorations (ERm: 1; ERd: 1; Set: 1 and SE: 5) were lost after 36 months, but only significant for SE when compared with baseline (p=0.02 for either criteria). Marginal staining occurred in 6.8% of the restorations (groups ERm, ERd, and Set) and 17.5% of the restorations (group SE), with significant difference for each group when compared with baseline using the FDI criteria (p<0.04), while statistical significance was reached only for SE when compared with baseline using the USPHS criteria (p<0.03). Twenty-eight and 49 restorations were scored as bravo for marginal adaptation using the USPHS and FDI criteria, respectively, with significant difference for each group when compared with baseline (p<0.05). CONCLUSIONS: While there was no statistical difference among bonding strategies when a universal adhesive was used, there were signs of degradation when the universal adhesive was applied in SE mode. The FDI criteria remain more sensitive than the USPHS criteria, especially for the criteria marginal staining and marginal adaptation.

In vitro study of the neuropathic potential of the organophosphorus compounds fenamiphos and profenofos: Comparison with mipafox and paraoxon.

Organophosphorus-induced delayed neuropathy (OPIDN) is a central-peripheral distal axonopathy that develops 8-14 days after poisoning by a neuropathic organophosphorus compound (OP). Several OPs that caused OPIDN were withdrawn from the agricultural market due to induction of serious delayed effects. Therefore, the development of in vitro screenings able to differentiate neuropathic from non-neuropathic OPs is of crucial importance. Thus, the aim of this study was to evaluate the differences in the neurotoxic effects of mipafox (neuropathic OP) and paraoxon (non-neuropathic OP) in SH-SY5Y human neuroblastoma cells, using the inhibition and aging of neuropathy target esterase (NTE), inhibition of acetylcholinesterase (AChE), activation of calpain, neurite outgrowth, cytotoxicity and intracellular calcium as indicators. Additionally, the potential of fenamiphos and profenofos to cause acute and/or delayed effects was also evaluated. Mipafox had the lowest IC50 and induced the highest percentage of aging of NTE among the OPs evaluated. Only mipafox was able to cause calpain activation after 24 h of incubation. Concentrations of mipafox and fenamiphos which inhibited at least 70% of NTE were also able to reduce neurite outgrowth. Cytotoxicity was higher in non-neuropathic than in neuropathic OPs while the intracellular calcium levels were higher in neuropathic than in non-neuropathic OPs. In conclusion, the SH-SY5Y cellular model was selective to differentiate neuropathic from non-neuropathic OPs; fenamiphos, but not profenofos presented results compatible with the induction of OPIDN.

In vitro study of the neuropathic potential of the organophosphorus compounds trichlorfon and acephate.

Organophosphorus-induced delayed neuropathy (OPIDN) is a central and peripheral distal axonopathy characterized by ataxia and paralysis. Trichlorfon and acephate are two organophosphorus compounds (OPs) used worldwide as insecticide and which cause serious effects to non-target species. Despite that, the neuropathic potential of these OPs remains unclear. The present study addressed the neurotoxic effects and the neuropathic potential of trichlorfon and acephate in SH-SY5Y human neuroblastoma cells, by evaluating inhibition and aging of neuropathy target esterase (NTE), inhibition of acetylcholinesterase (AChE), neurite outgrowth, cytotoxicity and intracellular calcium. Additionally, the effects observed were compared to those of two well-studied OPs: mipafox (known as neuropathic) and paraoxon (known as non-neuropathic). Trichlorfon and mipafox presented the lowest percentage of reactivation of inhibited NTE and the lowest ratio IC50 NTE/IC50 AChE. Moreover, they caused inhibition and aging of at least 70% of the activity of NTE at sub-lethal concentrations. All these effects have been associated with induction of OPIDN. When assayed at these concentrations, trichlorfon and mipafox reduced neurite outgrowth and increased intracellular calcium, events implicated in the development of OPIDN. Acephate caused effects similar to those caused by paraoxon (non-neuropathic OP) and was only able to inhibit 70% of NTE activity at lethal concentrations. These findings suggest that trichlorfon is potentially neuropathic, whereas acephate is not.

In-office bleaching with a two- and seven-day intervals between clinical sessions: A randomized clinical trial on tooth sensitivity.

OBJECTIVES: In-office bleaching is usually performed in 2-3 sessions with one-week interval. The impact of shorter interval times on tooth sensitivity has not been evaluated. This study aimed to compare the absolute risk of tooth sensitivity (TS) and colour change after in-office bleaching with a two- and seven-day intervals between sessions. METHODS: We selected for this randomized, single-blind study, 40 patients with colour C2 or darker. We performed two bleaching sessions with a 35% hydrogen peroxide gel with either a 1-week or 2-day interval. We recorded the TS up to 48 h with a VAS scale and the colour at baseline and 30 days after bleaching with a value-oriented shade guide and a spectrophotometer. The risk and intensity of TS were compared with the Fisher's exact test and two-way repeated measures ANOVA. Colour change (ΔSGU and ΔE) were evaluated by Student's t-test (alpha=5%). RESULTS: Approximately 60% of the participants reported TS (65% and 55% for the 7 and 2-day groups). A significant whitening of approximately 6 shade guide units was detected for both groups. No difference was detected between groups. CONCLUSIONS: The reduction of the interval between bleaching sessions from seven to two days reduced the treatment time without increasing the bleaching-induced TS (clinicaltrials.gov identifier: NCT1959789). CLINICAL SIGNIFICANCE: In-office bleaching with a 2-day interval did not increase the risk and intensity of bleaching-induced tooth sensitivity.

Phytoremediation potential of Maná-Cubiu (Solanum sessiliflorum Dunal) for the deleterious effects of methylmercury on the reproductive system of rats.

Methylmercury, organic form of mercury, can increase the number of abnormal sperm and decrease sperm concentration and testosterone levels possibly due to the damage caused by reactive species to germ and Leydig cells. Maná-cubiu (Solanum sessiliflorum Dunal) is a native fruit from Amazon rich in iron, zinc, niacin, pectin, and citric acid, used in foods, beverages, and medicinal purposes, since it has been useful for treatment of various diseases caused by oxidative stress or nutritional deficiency. Therefore, this study evaluated the phytoremediation potential of this fruit on damages caused by exposure to MeHg on sperm quantity and quality and the histological aspect of the testis and epididymis. Wistar male rats (n = 20) were randomly allocated into four groups: Control group (received distilled water), MeHg group (140 µg/Kg), Solanum group (1% of fruit Maná-cubiu on chow), and Solanum plus MeHg group (same treatment as MeHg and Solanum group). The organs were weighted, histopathology; sperm morphology and counts were obtained. The results showed reduction in body weight gain, testis weights, reduced sperm production, and increased histopathological abnormalities in the MeHg-treated group. However, treatment with Solanum plus MeHg revealed a protective effect of this fruit on damages caused by MeHg.

A new universal simplified adhesive: 6-month clinical evaluation.

STATEMENT OF THE PROBLEM: Multimode adhesives, which can be used as etch-and-rinse or as self-etch adhesives, have been recently introduced without clinical data to back their use. PURPOSE OF THE STUDY: To evaluate the 6-month clinical performance of Scotchbond Universal Adhesive (SU; 3M ESPE, St. Paul, MN, USA) in noncarious cervical lesions (NCCLs) using two evaluation criteria. METHODS/MATERIALS: Thirty-nine patients participated in this study. Two hundred restorations were assigned to four groups: SU-TEm: etch-and-rinse + moist dentin; SU-TEd: etch-and-rinse + dry dentin; SU-SEet: selective enamel etching; and SU-SE: self-etch. The composite resin Filtek Supreme Ultra (3M ESPE) was placed incrementally. The restorations were evaluated at baseline and after 6 months using both the World Dental Federation (FDI) and the United States Public Health Service (USPHS) criteria. Statistical analyses were performed with Friedman repeated measures analysis of variance by rank and McNemar test for significance in each pair (α = 0.05). RESULTS: Only four restorations (SU-SE: 3 and SU-TEm: 1) were lost after 6 months (p > 0.05 for either criteria). Marginal discoloration occurred in one restoration in the SU-SE group (p > 0.05 for either criteria). Only 2/200 restorations were scored as bravo for marginal adaptation using the USPHS criteria (one for SU-SE and one for SU-SEet, p > 0.05). However, when using the FDI criteria, the percentage of bravo scores for marginal adaptation at 6 months were 32%, 36%, 42%, and 46% for groups SU-TEm, SU-TEd, SU-SEet, and SU-SE, respectively (p > 0.05). CONCLUSIONS: The clinical behavior of the multimode adhesive does not depend on the bonding strategy at 6 months. The FDI evaluation criteria are more sensitive than the USPHS criteria. CLINICAL SIGNIFICANCE: At 6 months, the clinical behavior of the new multimode adhesive Scotchbond Universal was found to be reliable when used in noncarious cervical lesions and may not depend on the bonding strategy employed.

Perioperative use of an anti-inflammatory drug on tooth sensitivity caused by in-office bleaching: a randomized, triple-blind clinical trial.

OBJECTIVES: The aim of this study was to determine the effect of etoricoxib 60 mg on tooth sensitivity (TS) caused by in-office bleaching. MATERIALS AND METHODS: A triple-blind, parallel design, randomized clinical trial was conducted on 30 healthy, young adults who received either a placebo or etoricoxib. The drugs were administered 1 h before the bleaching process and after 24 h. Treatment was performed with 35 % hydrogen peroxide gel. The TS was recorded on three scales: VAS, 0-4, and 0-100. Shade evaluations were performed before and 30 days after bleaching with a visual shade guide and a spectrophotometer. The percentage of patients who reported TS at least once during treatment and the TS intensity were evaluated by Fisher's exact and Mann-Whitney U tests, respectively. Tooth color changes were evaluated by repeated measures ANOVA. RESULTS: There were no significant differences in the percentage of patients with TS, intensity of TS, and color between the groups. CONCLUSIONS AND CLINICAL SIGNIFICANCE: The anti-inflammatory medication etoricoxib 60 mg was unable to reduce the presence and intensity of TS. NCT01300780 (protocol No. 17838/2010).