Effects of natural products-based dentifrices on acrylic resin for denture bases: A simulated period of 4 years.

PURPOSE: To evaluate the antimicrobial activity of dentifrices based on Malva sylvestris and propolis and the effect on the acrylic resin. METHODS: The inhibitory effect against Candida albicans, Enterococcus faecalis and Streptococcus mutans was determined. The specimens of resin were divided into groups: Control (brushing with distilled water); brushing with Colgate; brushing with Protex; brushing with Malvatricin, brushing with Proporalcare Dental Gel and brushing with Green Propolis Dental Gel. Brushing was carried out in a brushing machine. Roughness and color were assessed. The data were analyzed by ANOVA, followed by the Bonferroni post test (α= 0.05). RESULTS: The products evaluated showed antimicrobial activity against all microorganisms (P< 0.05), except Proporalcare Dental Gel, which was not effective against E. faecalis. Greater roughness (P< 0.05) was observed in the samples treated with Colgate. The samples from control and Protex groups showed the lowest color variation and the highest luminosity, with a difference in relation to the others (P< 0.05), which showed higher values, although clinically acceptable. CLINICAL SIGNIFICANCE: The dentifrices based on natural products can be indicated for cleaning prostheses, since they showed antimicrobial activity and did not cause perceptible color changes of the resin tested. The dentifrices did not produce adverse effects on the surface of the resin or did so less than the conventional dentifrice.

Crystallization conditions of two adjacent epidote + diopside-bearing granitic stocks, northeastern Brazil.

The Tamboril and Olho d'Água granitic stocks are part of the abundant calc-alkalic magmatic epidote-bearing granitic rocks in the Cachoeirinha-Salgueiro Terrane (CST) in the Transversal Zone Domain, northeastern Brazil. The equigranular Olho d'Água stock is composed of medium-grained clinopyroxene-amphibole-biotite tonalite; the porphyritic Tamboril stock is medium- to coarse-grained amphibole biotite ± clinopyroxene granodiorite. Abundances of clinopyroxene and epidote vary inversely in both stocks. Amphibole-rich clots are regarded as fragments from the source region captured by granodioritic/tonalitic magma during its ascent. Epidote composition in the Olho d'Água stock (Ps18-26) and in Tamboril stock (Ps17-20) is consistent with crystallization under oxygen fugacity between QFM and HM buffers. In the Olho d'Água stock, calculated values of pressure range from 5.1 to 6.6 kbar and in the Tamboril stock from 6.2 to 7.0 kbar. Solidification temperatures estimated from plagioclase-hornblende pairs in the Olho D´Água stock range from 637 to 679 °C and for Tamboril from 587 to 641 °C. Zr-saturation temperature estimates are 788 to 819 °C (Olho d'Água) and 807 to 829 °C (Tamboril). Altogether our data suggest that the studied stocks crystallized from two distinct magmatic pulses formed from fractional melting of a single amphibolitic source. These two magma pulses underwent subsequent crystallization, in a convective magmatic chamber, at rather high pressure.

Biological aspects and feeding behavior of cotton aphid in watermelon cultivars submitted to silicon application / Aspectos biológicos e comportamento alimentar do pulgão-do-algodoeiro em cultivares de melancia submetidas à aplicação de silício

This research aimed to evaluate the biological aspects and the feeding behavior of Aphis gossypii in watermelon cultivars submitted to silicon application. The experiment was conducted at the Institute of Education, Agriculture and Environment of the Federal University of Amazonas, Humaitá, Brazil. The experimental design was completely randomized in a 2×3 factorial (with and without silicon; cultivars Crimson Sweet, Fairfax and Charleston), with ten replications. The application of silicic acid (1%) was carried out directly on the substrate using dose equivalent to 1 ton SiO2·ha-1, 25 days after sowing. The rearing of aphids was kept in cucumber plants, cultivar Caipira. Insect biology tests were conducted to evaluate the duration of the prereproductive, reproductive and postreproductive periods, longevity, number of nymphs, and feeding behavior using the honeydew secretion technique. Analysis of variance was performed using the statistical program SISVAR and the means were compared by the F and Scott­Knott test (p ≤ 0.05). The silicon application to watermelon plants affects the reproduction and feeding of A. gossypii. The watermelon plants cultivar Crimson Sweet treated with silicon has high resistance to feeding by A. gossypii.(AU)

Nesta pesquisa objetivou-se avaliar os aspectos biológicos e o comportamento alimentar de Aphis gossypii em cultivares de melancia submetidas à aplicação de silício. O experimento foi conduzido no Instituto de Educação, Agricultura e Ambiente da Universidade Federal do Amazonas, Humaitá, Brasil. Utilizaram-se o delineamento experimental inteiramente ao acaso e o esquema fatorial 2×3 (sem silício e com silício; cultivares Crimson Sweet, Fairfax e Charleston), com dez repetições. A aplicação do ácido silícico (1%) foi realizada diretamente no substrato, com dose equivalente a 1 ton SiO2·ha-1, 25 dias após a semeadura. Os pulgões da criação foram mantidos em plantas de pepino, cultivar Caipira. Foram conduzidos ensaios de biologia do inseto para avaliação da duração dos períodos pré-reprodutivo, reprodutivo e pós-reprodutivo, longevidade, número de ninfas e comportamento alimentar por meio da técnica de secreção de honeydew. Realizou-se a análise de variância dos dados utilizando-se o programa estatístico SISVAR e as médias foram comparadas pelo teste de F e Scott­Knott (p ≤ 0,05). A aplicação de silício em plantas de melancia afeta a reprodução e a alimentação de A. gossypii. Plantas de melancia do cultivar Crimson Sweet tratadas com silício apresentam alta resistência à alimentação por A. gossypii.(AU)

A simplified protocol to determine total fluoride concentration in NaF/silica-based toothpastes

Aim: To determine total fluoride (TF) concentration in Na2FPO3/Ca-based toothpastes, using fluoride ion selective electrode (F-ISE) by the direct technique, it is necessary to use acid (Ac+) to hydrolyze the FPO32- ion and to dissolve insoluble fluoride salts bound to the abrasive. For NaF/silica-based toothpastes, the use of acid is not necessary (Ac-) and a simplified protocol could be followed. Methods: Thus, we evaluated TF concentration in seven brands of NaF/silica-based toothpastes, following the validated conventional Cury's protocol (Ac+) or a simplification of this protocol (Ac-).Fluoride was analyzed with ISE calibrated with fluoride standard solutions prepared in the same conditions as the samples (Ac+ or Ac-). Results: The mean (±SD; n=21) of TF concentrations (µg F/g) found by Ac+ (971.3±191.2) and Ac- (982.4±201.3) protocols were not statistically different (t test, p=0.22). The TF concentrations found agree with those declared by the manufacturers, except for one toothpaste imported from China. Conclusion: The findings suggest that the determination of fluoride in NaF/silica-based toothpastes can be accurately made using a simplified protocol of analysis

Biological aspects and feeding behavior of cotton aphid in watermelon cultivars submitted to silicon application / Aspectos biológicos e comportamento alimentar do pulgão-do-algodoeiro em cultivares de melancia submetidas à aplicação de silício

This research aimed to evaluate the biological aspects and the feeding behavior of Aphis gossypii in watermelon cultivars submitted to silicon application. The experiment was conducted at the Institute of Education, Agriculture and Environment of the Federal University of Amazonas, Humaitá, Brazil. The experimental design was completely randomized in a 2×3 factorial (with and without silicon; cultivars Crimson Sweet, Fairfax and Charleston), with ten replications. The application of silicic acid (1%) was carried out directly on the substrate using dose equivalent to 1 ton SiO2·ha-1, 25 days after sowing. The rearing of aphids was kept in cucumber plants, cultivar Caipira. Insect biology tests were conducted to evaluate the duration of the prereproductive, reproductive and postreproductive periods, longevity, number of nymphs, and feeding behavior using the honeydew secretion technique. Analysis of variance was performed using the statistical program SISVAR and the means were compared by the F and Scott­Knott test (p ≤ 0.05). The silicon application to watermelon plants affects the reproduction and feeding of A. gossypii. The watermelon plants cultivar Crimson Sweet treated with silicon has high resistance to feeding by A. gossypii.(AU)

Nesta pesquisa objetivou-se avaliar os aspectos biológicos e o comportamento alimentar de Aphis gossypii em cultivares de melancia submetidas à aplicação de silício. O experimento foi conduzido no Instituto de Educação, Agricultura e Ambiente da Universidade Federal do Amazonas, Humaitá, Brasil. Utilizaram-se o delineamento experimental inteiramente ao acaso e o esquema fatorial 2×3 (sem silício e com silício; cultivares Crimson Sweet, Fairfax e Charleston), com dez repetições. A aplicação do ácido silícico (1%) foi realizada diretamente no substrato, com dose equivalente a 1 ton SiO2·ha-1, 25 dias após a semeadura. Os pulgões da criação foram mantidos em plantas de pepino, cultivar Caipira. Foram conduzidos ensaios de biologia do inseto para avaliação da duração dos períodos pré-reprodutivo, reprodutivo e pós-reprodutivo, longevidade, número de ninfas e comportamento alimentar por meio da técnica de secreção de honeydew. Realizou-se a análise de variância dos dados utilizando-se o programa estatístico SISVAR e as médias foram comparadas pelo teste de F e Scott­Knott (p ≤ 0,05). A aplicação de silício em plantas de melancia afeta a reprodução e a alimentação de A. gossypii. Plantas de melancia do cultivar Crimson Sweet tratadas com silício apresentam alta resistência à alimentação por A. gossypii.(AU)

Evaluation of cutaneous rejuvenation associated with the use of ortho-silicic acid stabilized by hydrolyzed marine collagen.

BACKGROUND: Organic silicon plays an important role in dermal structure by promoting neocollagenesis. Thus, the supplementation of silicon in a highly bioavailable form can be used for skin rejuvenation. AIMS: This study aimed to evaluate skin changes associated with the use of ortho-silicic acid stabilized by hydrolyzed collagen. PATIENTS/METHODS: Patients were randomized to receive 600 mg of ortho-silicic acid stabilized by hydrolyzed collagen (group 1, n = 11) or placebo (group 2, n = 11) to be taken 15 minutes before breakfast for 90 days. Clinical, photographical, and patients' subjective evaluations were conducted. RESULTS: A total of 22 patients were included. Clinical evaluations demonstrated changes in skin texture, firmness, and hydration statistically superior in group 1. Brightness, firmness, and overall appearance showed trends for a difference favoring group 1 according to patients' subjective evaluations. Objective images showed no statistical differences. No side effects, hypersensitivity, or systemic symptoms were observed in group 1. Treatment satisfaction in group 1 reached 80%. CONCLUSIONS: Ortho-silicic acid stabilized by hydrolyzed collagen in a daily dose of 600 mg showed positive results in skin rejuvenation according to clinical evaluation in firmness, hydration, and skin texture. Further studies with larger and representative samples should be conducted to confirm our results.

Use of silicon for skin and hair care: an approach of chemical forms available and efficacy.

Silicon is the second most abundant element on Earth, and the third most abundant trace element in human body. It is present in water, plant and animal sources. On the skin, it is suggested that silicon is important for optimal collagen synthesis and activation of hydroxylating enzymes, improving skin strength and elasticity. Regarding hair benefits, it was suggested that a higher silicon content in the hair results in a lower rate of hair loss and increased brightness. For these beneficial effects, there is growing interest in scientific studies evaluating the efficacy and safety of using dietary supplements containing silicon. Its use aims at increasing blood levels of this element and improving the skin and its annexes appearance. There are different forms of silicon supplements available and the most important consideration to be made in order to select the best option is related to safety and bioavailability. Silicon supplements are widely used, though there is wide variation in silicon bioavailability, ranging from values below 1% up to values close to 50%, depending on the chemical form. Therefore, the aim of this study was to evaluate the scientific literature related to the different chemical forms of silicon supplements available and the limitations and recent progress in this field. According to reported studies, among the different chemical forms available, the orthosilicic acid (OSA) presents the higher bioavailability, whereas the others forms have absorption inversely proportional to the degree of polymerization. However, clinical studies evaluating safety and efficacy are still lacking.

Use of silicon for skin and hair care: an approach of chemical forms available and efficacy

Abstract Silicon is the second most abundant element on Earth, and the third most abundant trace element in human body. It is present in water, plant and animal sources. On the skin, it is suggested that silicon is important for optimal collagen synthesis and activation of hydroxylating enzymes, improving skin strength and elasticity. Regarding hair benefits, it was suggested that a higher silicon content in the hair results in a lower rate of hair loss and increased brightness. For these beneficial effects, there is growing interest in scientific studies evaluating the efficacy and safety of using dietary supplements containing silicon. Its use aims at increasing blood levels of this element and improving the skin and its annexes appearance. There are different forms of silicon supplements available and the most important consideration to be made in order to select the best option is related to safety and bioavailability. Silicon supplements are widely used, though there is wide variation in silicon bioavailability, ranging from values below 1% up to values close to 50%, depending on the chemical form. Therefore, the aim of this study was to evaluate the scientific literature related to the different chemical forms of silicon supplements available and the limitations and recent progress in this field. According to reported studies, among the different chemical forms available, the orthosilicic acid (OSA) presents the higher bioavailability, whereas the others forms have absorption inversely proportional to the degree of polymerization. However, clinical studies evaluating safety and efficacy are still lacking.

Rinsing with antacid suspension reduces hydrochloric acid-induced erosion.

OBJECTIVE: Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin. DESIGN: The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests. RESULTS: Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026). CONCLUSIONS: The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss.

Efeito de duas técnicas de gradação da zircônia no limite de fadiga de próteses parciais fixas monolíticas de três elementos / Effect of two grading zirconia techniques on the fatigue limit of fullcontour 3-unit fixed dental prothesis

O objetivo deste estudo foi avaliar os efeitos de duas técnicas de gradação da zircônia no limite de fadiga de próteses parciais fixas (PPFs) de 03 elementos. Blocos pré-sinterizados de 3Y-TZP (zircônia policristalina parcialmente estabilizada por 3% mol de ítria) foram fresados para obter 69 PPFs, que foram divididas em 3 grupos (n = 23). O grupo controle (CTL) foi sinterizado e glazeado odedecendo os parâmetros usuais. Nos dois grupos experimentais as PPFs receberam sílica/vidro antes da sinterização. O grupo sílica sol-gel (SSG) foi graduado pela rota de processamento sol-gel, enquanto o grupo vidro-zircônia-vidro (GZG) foi graduado pela técnica de suspensão (slurry). Os grupos graduados não receberam a camada de glaze após a sinterização. Todas as PPFs foram cimentadas nos pilares de compósito com cimento resinoso de dupla polimerização, incluídas em poliuretano e armazenadas em água por cinco dias. A carga inicial do teste de fadiga foi calculada com base nos resultados do ensaio monotônico de três amostras de cada grupo. Para determinar o limite de fadiga 20 amostras de cada grupo foram submetidas ao método da escada ou staircase (100.000 ciclos/5 Hz). Os limites de fadiga (em Newton) foram: CTL = 1607,27; SSG = 1824,31; GZG = 2006,57 e o teste de Dixon e Mood indicou diferença estatística entre os grupos (intervalo de confiança de 95%). As infiltrações de sílica e vidro no corpo da zircônia, por dois diferentes métodos de gradação, aumentaram o limite de fadiga de PPFs em zircônia monolítica(AU)

The aim of this study was to evaluate the effects of two grading zirconia techniques on the fatigue limit of 3-unit fixed dental prostheses (FDPs). Presintered blocks of 3YTZP (3 mol% yttria-stabilized tetragonal zirconia polycrystal) were milled to obtain sixty-nine 3-unit FDPs, which were divided into three groups (n = 23). The control group (CTL) was sintered and glazed following the usual parameters. In the two experimental groups presintered FDPs received silica/glass before sintering. Silica sol-gel group (SSG) was graded by the sol-gel processing route, while the glasszirconia-glass group (GZG) was graded by a slurry technique. Graded groups did not receive a glaze layer after sintering. All FDPs were then luted with a dual-curing resin cement on composite abutments, embedded in polyurethane and stored in water for five days. The initial load of the fatigue test was calculated based on the results of the monotonic testing applied on three specimens of each group. To determine the fatigue limit, 20 samples of each group were subjected to staircase testing (100,000 cycles/5 Hz). The fatigue limits (in Newtons) were CT = 1607.27, SSG = 1824.31, and GZG = 2006.57, and the Dixon and Mood test indicated statistically significant differences among groups (95% confidence interval). The infiltration of silica and glass on zirconia bulk, by two different grading methods, increased the fatigue limits of monolithic zirconia FDPs(AU)

Influence of different toothpaste abrasives on the bristle end-rounding quality of toothbrushes.

OBJECTIVES: To evaluate the influence of different toothpaste abrasives on the bristle wear and bristle tip morphology of toothbrushes with different degrees of hardness. MATERIAL AND METHODS: Ninety samples of bovine incisor teeth were used in this study. The samples were randomly divided into three groups according to the bristle hardness of the toothbrush used: soft bristles (S); extra-soft bristles (ES); hard bristles (H). The toothbrushes of each group were randomly divided into six subgroups with five toothbrushes each, according to the abrasive of the toothpaste used in the simulation: Negative control (distilled water); toothpaste 1 (silica); toothpaste 2 (hydrated silica); toothpaste 3 (calcium carbonate, calcium bicarbonate and silica); toothpaste 4 (tetrapotassium pyrophosphate, silica and titanium dioxide); toothpaste 5 (calcium carbonate). The samples were placed in a toothbrushing simulating machine that simulating three months of brushing. The toothbrush bristles were evaluated by the bristle wear index, and the bristle tips morphology was evaluated by the bristle tip morphology index. RESULTS: The ES brush presented the highest bristle wear among the toothbrushes. Additionally, the S brushes showed better morphology of the bristles followed by ES and H brushes. The type of abrasive only influenced the bristle tip morphology of the ES brushes. The toothpaste 3 induced the worse bristle tip morphology than all the other toothpastes. CONCLUSIONS: Different abrasives have influence only on the bristle tip morphology of the ES brushes.

Una década de monitoreo de plomo en sangre en niños escolares del área metropolitana de Monterrey, NL / A decade of lead monitoring in schoolchildren in the metropolitan area of Monterrey NL, Mexico

Objetivo. Establecer las concentraciones de plomo (Pb) en sangre en niños escolares de 1998 y 2008, así como su asociación con factores de riesgo. Material y métodos. Se llevó a cabo un monitoreo de Pb en sangre de niños de entre 6 y 12 años que cursan educación primaria en 17 escuelas diferentes, ubicadas en distintas zonas del área metropolitana de Monterrey, de 1998 a 2008. Resultados. Se obtuvieron niveles séricos de 9.6 ± 3.0 (µg/dL rango de 3.18 a 20.88) en 1998 y de 4.5±4.8 µg/dL (rango de 3.3 a 53.7) en 2008, lo que mostró una disminución de 2.1 veces en nivel de Pb (p<0.01). Conclusiones. La reducción de los niveles séricos de Pb demuestran los mejores controles ambientales e industriales y probablemente el éxito de retirar el Pb de la gasolina durante los años noventa.

Objective. To establish the blood lead concentration and associated risk factors in schoolchildren during 1998 and 2008. Materials and methods. A blood lead screening was conducted in schoolchildren of 6-12 years of age, enrolled in 17 elementary schools of the metropolitan area of Monterrey, México, during 1998 and 2008. Results. The mean blood lead level were 9.6 ± 3.0 (µg/dL range of 3.18 to 20.88) in 1998 and 4.5±4.8 µg/dL (range of 3.3 to 53.7) showing a 2.1-times reduction in blood lead levels (p<0.01). Conclusions. This reduction in blood lead levels demonstrate environmental and industrial control improvements and the benefits of fading out the leaded gasoline during the 1990's.

The influence of desensitizing dentifrices on pain induced by in-office bleaching.

The purpose of this study was to evaluate whether the use of desensitizing dentifrices used 15 days prior to and after in-office tooth bleaching could eliminate or reduce tooth sensitivity. After institutional review board approval and informed consent, 45 subjects were selected and divided into 3 groups according to the dentifrice selected: Colgate Total (CT), Colgate Sensitive Pro-Relief (CS) or Sensodyne ProNamel (SP). The subjects used toothpaste and a toothbrush provided to them for 15 days prior to bleaching. They were then submitted to two in-office bleaching sessions (Whiteness HP Blue Calcium). Their tooth sensitivity was assessed using the Visual Analog Scale (VAS) for a week after each session. Their tooth shade alteration was measured with a Vitapan Classical shade guide to determine if the dentifrices could influence the effectiveness of the bleaching agent. The data were submitted to Wilcoxon, Kruskal-Wallis and Mann-Whitney tests (α = 0.05). The use of desensitizing dentifrices did not affect the bleaching efficacy. In regard to tooth sensitivity, there was a statistically significant difference between the results of the Control Group and Group T2 after the first session (p = 0.048). There was no statistically significant difference in the results for the other groups after the first session. In regard to the second session, there was no statistically significant difference in the results for all the groups. The use of a desensitizing dentifrice containing nitrate potassium reduced tooth sensitivity during the bleaching regimen. Dentifrices containing arginine and calcium carbonate did not reduce tooth sensitivity. Color change was not influenced by the dentifrices used.

The influence of desensitizing dentifrices on pain induced by in-office bleaching

The purpose of this study was to evaluate whether the use of desensitizing dentifrices used 15 days prior to and after in-office tooth bleaching could eliminate or reduce tooth sensitivity. After institutional review board approval and informed consent, 45 subjects were selected and divided into 3 groups according to the dentifrice selected: Colgate Total (CT), Colgate Sensitive Pro-Relief (CS) or Sensodyne ProNamel (SP). The subjects used toothpaste and a toothbrush provided to them for 15 days prior to bleaching. They were then submitted to two in-office bleaching sessions (Whiteness HP Blue Calcium). Their tooth sensitivity was assessed using the Visual Analog Scale (VAS) for a week after each session. Their tooth shade alteration was measured with a Vitapan Classical shade guide to determine if the dentifrices could influence the effectiveness of the bleaching agent. The data were submitted to Wilcoxon, Kruskal-Wallis and Mann-Whitney tests (α = 0.05). The use of desensitizing dentifrices did not affect the bleaching efficacy. In regard to tooth sensitivity, there was a statistically significant difference between the results of the Control Group and Group T2 after the first session (p = 0.048). There was no statistically significant difference in the results for the other groups after the first session. In regard to the second session, there was no statistically significant difference in the results for all the groups. The use of a desensitizing dentifrice containing nitrate potassium reduced tooth sensitivity during the bleaching regimen. Dentifrices containing arginine and calcium carbonate did not reduce tooth sensitivity. Color change was not influenced by the dentifrices used.

Effect of brushing and accelerated ageing on color stability and surface roughness of composites.

OBJECTIVES: The aim of this study was to evaluate the effect of brushing and artificial accelerated ageing (AAA) on color stability and surface roughness of aesthetic restorative materials. METHODS: One hundred and twenty specimens (12 mm diameter × 2 mm thick), 40 of each material (n=8) were obtained using nanosized composite Z350 (3M ESPE), nanohybrid composite Tetric N-Ceram (Ivoclar Vivadent) and ceramic IPS e.max Ceram (Ivoclar Vivadent), as control. Initial color (Spectrophotometer PCB 6807) and surface roughness (Surfcorder SE 1700) readouts were taken and the samples were separated into five groups (n=8) and treated as follows: Group 1: mechanical brushing with dentifrice RDA* 68 (Colgate), Group 2: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening), Group 3: AAA, Group 4: AAA followed by mechanical brushing with dentifrice RDA* 68 and Group 5: AAA followed by mechanical brushing with dentifrice RDA* 180. Mechanical brushing was performed for 205 min and AAA for 480 h; new color and surface roughness readouts were taken. Data were statistically analyzed (two-way ANOVA repeated measures, Bonferroni test, p<0.05). RESULTS: Dentifrice abrasiveness was not significant for color change and surface roughness. When submitted to AAA+brushing, the color stability of Tetric was statistically significant (p<0.05) with both dentifrices and with dentifrice RDA* 180 for Z350. The roughness was different (p<0.05) for Z350 when brushed with RDA* 68 after AAA. CONCLUSIONS: Dentifrice abrasiveness did not interfere in the ability to remove stains and roughness from aged samples. However, staining is material-dependent. CLINICAL SIGNIFICANCE: The abrasiveness of dentifrice does not change the color and surface roughness of the composites and does not help to remove surface stains from the aged samples.

Efeito do silício na intensidade da cercosporiose e na nutrição mineral de mudas de cafeeiro / Effect of silicon on the intensity of brown eye spot and on the mineral nutrition of coffee seedlings

O presente trabalho objetivou estudar o efeito do silício na intensidade da cercosporiose e na nutrição mineral de mudas de cafeeiro. No experimento 1, testou-se seis doses de ácido silícico (0, 0,5; 1; 2; 4 e 6 g kg­1 de solo) em mudas da cultivar Catuaí Vermelho IAC 99 inoculadas com o fungo Cercospora coffeicola. No experimento 2, foram realizadas microanálises de raios-X para a avaliação de nutrientes presentes nas folhas das mudas de cafeeiro das cultivares Topázio MG1190 e Icatu Precoce IAC 3282, inoculadas e não inoculadas com C. coffeicola, com e sem silicato de cálcio (1 g kg-1 de solo). Com o aumento das doses de ácido silícico observou-se redução na área abaixo da curva de progresso do número de lesões por folha (AACPNLF), redução linear nos teores foliares de magnésio e fósforo e aumento nos teores de enxofre e cobre. Os teores foliares de boro apresentaram comportamento quadrático, diminuindo com o aumento das doses de ácido silícico e aumentando a partir da dose de 4 g kg-1 de solo. Em microanálise de raio X, mudas de cafeeiro com cercosporiose apresentam menores picos de potássio e cálcio, independente da cultivar utilizada.

Our objective was to verify the effect of silicon on the intensity of brown eye spot and on the mineral nutrition of coffee seedlings. In the first experiment, 6 doses of silicic acid (0, 0.5, 1, 2, 4 and 6 g kg-1 soil) were tested using a complete randomized block design with 4 replicates with 6 coffee seedlings cultivar Catuaí Vermelho IAC 99 inoculated with the fungus Cercospora coffeicola. In the second experiment, X-ray microanalysis in a scanning electron microscope was performed on 2 coffee cultivars (Topazio MG1190 and Icatu Precoce IAC 3282), inoculated and non-inoculated with C. coffeicola, treated and untreated with calcium silicate (1 g kg-1 of soil). With the increase of the silicic acid doses, there was observed a reduction in the area under the disease progress curve of the number of lesions per leaf (AUPCNLL), coupled with a linear reduction in the foliar contents of magnesium and phosphorus as well as an increase in the contents of sulfur and copper. The foliar contents of boron presented a quadratic behavior, decreasing with the increase of silicic acid and increasing with the dose of 4 g kg-1 of soil. In X-ray microanalysis, coffee seedlings with brown eye spot presented lower peaks of potassium and calcium, regardless of the cultivar used.

In vitro study on tooth enamel lesions related to whitening dentifrice.

BACKGROUND: The tooth whitening substances for extrinsic use that are available in Brazil contain hydrogen peroxide or carbamide peroxide. Several studies have attributed the appearance of lesions in the enamel morphology, including hypersensitivity, to these substances. Such lesions justify fluoride therapy and application of infrared lasers, among other procedures. However, there is no consensus among researchers regarding the relevance of the severity of lesions detected on the tooth surface. OBJECTIVES: The present study was carried out with an aim of evaluating in vitro the effects of the hydrogen peroxide, carbamide peroxide and sodium bicarbonate contained in dentifrice formulations, on human tooth enamel. MATERIALS AND METHODS: After darkening process in laboratory, human premolars were brushed using dentifrice containing the two whitening substances (Rembrandt - carbamide peroxide and Mentadent - hydrogen peroxide) and the abrasive product (Colgate - sodium bicarbonate). The degree of specimen staining before and after this procedure was determined using spectrophotometry. Scanning electron microscopy (SEM) was used to obtain images, which were analyzed to show the nature of the lesions that appeared on the enamel surface. RESULTS: The effectiveness of the whitening caused by hydrogen peroxide and carbamide peroxide and the abrasion caused by bicarbonate were confirmed, given that the treated test pieces returned to their original coloration. Based on SEM, evaluation of the enamel surfaces subjected to the test products showed that different types of morphologic lesions of varying severity appeared. CONCLUSIONS: Whitening dentifrice containing hydrogen peroxide and carbamide peroxide produced lesions on the enamel surface such that the greatest sequelae were associated with exposure to hydrogen peroxide.

Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats.

Higher blood lead (BPb) levels have been reported in children living in communities that receive fluoride-treated water. Here, we examined whether fluoride co-administered with lead increases BPb and lead concentrations in calcified tissues in Wistar rats exposed to this metal from the beginning of gestation. We exposed female rats and their offspring to control water (Control Group), 100mg/L of fluoride (F Group), 30mg/L of lead (Pb Group), or 100mg/L of fluoride and 30mg/L of lead (F+Pb Group) from 1 week prior to mating until offspring was 81 days old. Blood and calcified tissues (enamel, dentine, and bone) were harvested at day 81 for lead and fluoride analyses. Higher BPb concentrations were found in the F+Pb Group compared with the Pb Group (76.7+/-11.0microg/dL vs. 22.6+/-8.5microg/dL, respectively; p<0.001). Two- to threefold higher lead concentrations were found in the calcified tissues in the F+Pb Group compared with the Pb Group (all p<0.001). Fluoride concentrations were similar in the F and in the F+Pb Groups. These findings show that fluoride consistently increases BPb and calcified tissues Pb concentrations in animals exposed to low levels of lead and suggest that a biological effect not yet recognized may underlie the epidemiological association between increased BPb lead levels in children living in water-fluoridated communities.

Comparative investigation of the efficacy of triclosan/copolymer/sodium fluoride and stannous fluoride/sodium hexametaphosphate/zinc lactate dentifrices for the control of established supragingival plaque and gingivitis in a six-month clinical study.

OBJECTIVE: This double-blind clinical study, conducted at the University of Puerto Rico, San Juan, Puerto Rico, was designed to compare the efficacy of two commercially available dentifrices for the control of supragingival plaque and gingivitis. METHODS: Qualifying adult male and female subjects from the San Juan, Puerto Rico area were randomly assigned to one of two treatment groups: 1) a commercially available dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, and 0.243% sodium fluoride (Colgate Total); and 2) a commercially available dentifrice containing 0.454% stannous fluoride, sodium hexametaphosphate, and zinc lactate (Crest Pro-Health). All subjects received an oral soft and hard tissue examination, and were dispensed their assigned dentifrice product, along with a soft-bristled adult toothbrush for home use. Subjects were instructed to brush their teeth for one minute, twice daily (morning and evening), using only the dentifrice provided. Examinations for supragingival plaque and gingivitis, and oral soft and hard tissue assessments were repeated after six weeks, three months, and six months of product use. RESULTS: One-hundred and nine (109) subjects complied with the protocol and completed the six-month examinations. At the six-month examination, both treatment groups exhibited statistically significant reductions from baseline with respect to supragingival plaque and gingivitis scores. Relative to the Crest Pro-Health Toothpaste group, the Colgate Total Toothpaste group exhibited statistically significant reductions in supragingival plaque index scores of 18.5%, 20.7%, and 25.8% after six weeks, three months, and six months of product use, respectively. For gingival index scores, statistically significant reductions of 20.5%, 18.9%, and 17.1% were exhibited after six weeks, three months, and six months of product use, respectively. CONCLUSION: The results of this double-blind clinical study support the conclusion that a dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, and 0.243% sodium fluoride provides a significant reduction in established supragingival plaque and gingivitis, as compared to a dentifrice containing 0.454% stannous fluoride, sodium hexametaphosphate, and zinc lactate when used over a period of six months.

Short Communication: In vitro evaluation of the abrasiveness of acidic dentifrices.

AIM: This in vitro study evaluated the abrasiveness of acidic fluoride (F) dentifrices with different F concentrations on bovine enamel. METHODS: Enamel blocks (4.0 x 4.0 mm2, n=120) were selected according to their surface microhardness and divided into 12 groups. Slurries of dentifrices were used containing 0 (placebo), 275, 412, 550 and 1,100 ppm F (pH 4.5 or 7.0), as well as testing two commercial dentifrices (Crest, positive control, 1,100 ppm F and Colgate Baby, 500 ppm F). Enamel blocks were partially protected with an adhesive tape (control area) and then brushed by an automated toothbrushing machine (16,000 strokes). During this process, 0.4 ml of the slurries were injected every 2 mins on the enamel blocks. After toothbrushing, enamel wear was determined by profilometry. STATISTICS: Results were analyzed by ANOVA and Tukey's test (p<0.05). RESULTS: The mean values for pH in the suspensions during treatment were 6.93, 4.32, 7.56 and 8.19 for neutral experimental dentifrices, acidic experimental dentifrices, Crest and Colgate baby, respectively. The abrasiveness of the acidic dentifrices was similar (p<0.05) to the neutral ones, whereas commercial dentifrices yielded lower abrasion (p<0.05). CONCLUSION: It was concluded that a reduction of the pH of dentifrices does not increase their abrasiveness.