Concentração de flúor em águas engarrafadas comercializadas no município de São Paulo

O objetivo do estudo foi avaliar a concentração de flúor na água engarrafada comercializada, comparando-a aos valores impressos no rótulo da embalagem. Foram coletadas 229 amostras de água das 35 marcas disponíveis em diversos supermercados, mercearias e lanchonetes de grande circulação nas diferentes regiões do município de São Paulo, em 2006. A concentração de flúor foi determinada por análise em duplicata, utilizando o eletrodo íon-específico. A concentração de flúor variou entre 0,01 e 2,04 mg/l, com diferenças significantes entre os valores estipulados nos rótulos e os encontrados com a análise. Esses resultados reforçam a importância do controle dos níveis de flúor na água engarrafada por parte da vigilância sanitária.

Saliva substitute in combination with high-concentrated fluoride toothpaste: Effects on demineralised dentin in vitro

Objectives: The aim of this in vitro study was to assess the effects of saliva substitutes (modified with respect to calcium, phosphates, and fluorides) in combination with a high-concentrated fluoride toothpaste on demineralised dentin.Methods: Before and after demineralisation of bovine dentin specimens (subsurface lesions; 37 degrees C, pH 5.0, 5 d), one-quarter of each specimen's surface was covered with nail varnish (control of sound/demineralised tissue). Subsequently, specimens were exposed to original Saliva natura (saturation with respect to octacalciumphosphate [S(OCP)]: 0.03; SN 0), or to three lab-produced Saliva natura modifications (S(OCP): 1, 2, and 3; SN 1-3) for 2 and 5 weeks (37 degrees C). An aqueous solution (S(OCP): 2.5) served as positive control (PC). Two times daily (2 min each), Duraphat toothpaste (5000 ppm F(-); Colgate)/saliva substitute slurry (ratio 1:3) was applied gently. Differences in mineral losses (Delta Delta Z) and lesion depths (Delta LD) between values before and after exposure were microradiographically evaluated.Results: After both treatment periods specimens immersed in SN 0 revealed significantly higher mineral losses (lower Delta Delta Z values) and lesion depths (lower Delta LD) compared to PC (p < 0.05; ANOVA). After 5 weeks, specimens stored in SN 1 and 2 showed significantly higher mineral losses compared to PC (p < 0.05), while those stored in SN 3 showed similar results (p > 0.05). No differences in mineral loss could be observed between SN 2 and 3 (p > 0.05).Conclusions: Under the conditions of this limited protocol, the combination of Saliva natura solutions slightly saturated with respect to OCP in combination with a high-concentrated fluoride toothpaste enabled remineralisation of dentin in vitro. Crown Copyright (c) 2009 Published by Elsevier Ltd. All rights reserved.

The influence of daily application of fluoride products on subsurface bovine enamel lesions stored in saliva substitutes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Titanium surface topography after brushing with fluoride and fluoride-free toothpaste simulating 10 years of use

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clinical evaluation of low-level laser therapy and fluoride varnish for treating cervical dentinal hypersensitivity

The aim of this study was to evaluate in vivo the use of low-level galium-aluminium-arsenide (GaAlAs) (BDP 600) laser and sodium fluoride varnish (Duraphat((R))) in the treatment of cervical dentine hypersensitivity. Twelve patients, with at least two sensitive teeth were selected. A total of 60 teeth were included in the trial. Prior to desensitizing treatment, dentine hypersensitivity was assessed by a thermal stimulus and patients' response to the examination was considered to be a control. The GaAlAs laser (15 mW, 4 J/cm(2)) was irradiated on contact mode and fluoride varnish was applied at cervical region. The efficiency of the treatments was assessed at three examination periods: immediately after first application, 15 and 30 days after the first application. The degree of sensitivity was determined following predefined criteria. Data were submitted to analysis and no statistically significant difference was observed between fluoride varnish and laser. Considering the treatments separately, there was no significant difference for the fluoride varnish at the three examination periods, and for laser therapy, significant difference (P < 0.05) was found solely between the values obtained before the treatment and 30 days after the first application. It may be concluded that both treatments may be effective in decreasing cervical dentinal hypersensitivity. Moreover, the low-level GaAlAs laser showed improved results for treating teeth with higher degree of sensitivity.

Release and diffusion of hydroxyl ion from calcium hydroxide-based medicaments

The release and diffusion of hydroxyl ions (OH-) of calcium hydroxide (Ca(OH)2)-based intracanal medications may be affected by the association with other substances. The aim of this study was to evaluate the diffusion of OH- ions through root dentin by the medications: G1, Ca(OH)2/saline; G2, Calen; G3, Calen/camphorated p-monochlorophenol (CMCP); and G4, Calen/0.4% chlorhexidine (CHX). Root canals from bovine teeth were prepared in a standardized manner. A cavity until dentin was prepared in the middle third of the root surface of each specimen. The external surface of the root was made impermeable using a layer of adhesive, except the prepared cavity. The root canals were filled with different medications, and teeth were individually stored in flasks containing 10 ml distilled water at 37 degrees C. The water pH was measured at 1, 3, 7, 14, 21, 30, and 60 days. Data obtained were subjected to anova and Tukeys tests. Increase in pH was observed at 3 days for Calen/CHX and from 7 to 14 days for the other mixtures. Calen paste promoted pH increase up to 21 days. Calen/CMCP had the highest pH up to 21 days, and all groups had similar results at 30 days. At 60 days, the greatest pH values were observed for Calen/CMCP and Calen alone. All different formulations of Ca(OH)2-based medications tested release hydroxyl ion that can diffuse through the dentin.

pH and calcium ion release evaluation of pure and calcium hydroxide-containing Epiphany for use in retrograde filling

Objective: Hydroxyl (OH(-)) and calcium (Ca(++)) ion release was evaluated in six materials: G1) Sealer 26, G2) White mineral trioxide aggregate (MTA), G3) Epiphany, G4) Epiphany + 10% calcium hydroxide (CH), G5) Epiphany + 20% CH, and G6) zinc oxide and eugenol. Material and Methods: Specimens were placed in polyethylene tubes and immersed in distilled water. After 3, 6, 12, 24, and 48 h, 7, 14, and 28 days, the water was assessed for pH with a pH meter and for Ca++ release by atomic absorption spectrophotometry. Results: G1, G2, G4, and G5 had the highest pH until 14 days (p < 0.05). G1 presented the highest Ca(++) release until 6 h, and G4 and G5, from 12 h through 14 days. Ca(++) release was greater for G1 and G2 at 28 days. G6 released the least Ca(++). Conclusions: MTA, Sealer 26, Epiphany, and Epiphany + CH release OH-and Ca(++) ions. Epiphany + CH may be an alternative as retrofilling material.

pH, Calcium Ion Release, and Setting Time of an Experimental Mineral Trioxide Aggregate-based Root Canal Sealer

Introduction: An experimental mineral trioxide aggregate sealer (MTAS) has been developed for use as a root canal sealer. The aim of this study was to evaluate the setting time, pH, and calcium ion release of MTAS compared with white Portland cement (CPB-40; Votorantin Cimentos, Camargo Correa SA, Pedro Leopoldo, MG, Brazil), white MTA Angelus (MTA; Angelus, Londrina, PR, Brazil), and AH Plus (Dentsply DeTrey, Konstanz, Germany). Methods: For the evaluation of setting time, each material was analyzed using Gilmore-type needles. Polyethylene tubes with the materials were immersed in distilled water for the measurement of pH (digital pH meter) and calcium release (atomic absorption spectrophotometry). The evaluations were performed at 3, 6, 12, 24, and 48 hours and 7, 14, and 28 days. Data were analyzed by analysis of variance and the Tukey test at 5% significance level. Results: MTAS showed higher calcium release at all experimental periods, a greater increase in pH up to 48 hours and the longest setting time. Conclusions: MTAS presented favorable properties for its indication as a root canal sealer. (J Endod 2011;37:844-846)

Evaluation of pH and Calcium Ion Release of Calcium Hydroxide Pastes Containing Different Substances

Introduction: The objective of this study was to evaluate the pH and calcium ion release of calcium hydroxide pastes associated with different substances. Methods: Forty acrylic teeth with simulated root canals were divided into 4 groups according to the substance associated to the calcium hydroxide paste: chlorhexidine (CHX) in 2 formulations (1% solution and 2% gel), Casearia sylvestris Sw extract, and propylene glycol (control). The teeth with pastes and sealed coronal accesses were immersed in 10 mL deionized water. After 10 minutes, 24 hours, 48 hours, and 7, 15, and 30 days, the teeth were removed to another container, and the liquid was analyzed. Calcium ion release was measured by atomic absorption spectrophotometry, and pH readings were made with a pH meter. Data were analyzed statistically by analysis of variance and Tukey test (alpha = 0.05). Results: Calcium analysis revealed significant differences (P < .05) for 1% CHX solution and 2% CHX gel at 10 minutes. After 24 hours, 2% CHX gel x Control and 2% CHX gel x 1% CHX solution differed significantly (P < .05). After 48 hours, there were significant differences (P < .05) for 2% CHX gel x Control and Extract x Control. No differences (P > .05) were observed among groups in the other periods. Regarding the pH, there were significant differences (P < .05) for 2% CHX gel x Control and 2% CHX gel x 1% CHX solution after 48 hours and for 2% CHX gel x Control after 15 days. In the other periods, no differences (P > .05) were observed among groups. Conclusions: All pastes behaved similarly in terms of pH and calcium ion release in the studied periods. (J Endod 2009;35:1274-1277)

Evaluation of pH and Calcium Ion Release of Root-end Filling Materials Containing Calcium Hydroxide or Mineral Trioxide Aggregate

Introduction: To evaluate calcium ion release and pH of Sealer 26 (S26) (Dentsply, Rio de Janeiro, RJ, Brazil), white mineral trioxide aggregate (MTA), Endo CPM Sealer (CPM1) (EGEO SRL Bajo licencia MTM Argentina SA, Buenos Aires, Argentina), Endo CPM Sealer in a thicker consistency (CPM 2), and zinc oxide and eugenol cement (ZOE). Methods: Material samples (n = 10) were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 3, 6,12,24, and 48 hours and 7,14, and 28 days, the water pH was determined with a pH meter, and calcium release was assessed by atomic absorption spectrophotometry. An empty tube was used as the control group. Results: The control group presented a pH value of 6.9 at all studied periods and did not show the presence of calcium ion. S26 presented greater hydroxyl ion release up to 12 hours (p < 0.05). From 24 hours until 28 days, S26, MTA, CPM1, and CPM2 had similar results. in ail periods, ZOE presented the lowest hydroxyl ion release. CPM1, followed by CPM2, released the most calcium ions until 24 hours (p < 0.05). Between 48 hours and 7 days, CPM1 and CPM2 had the highest release. A greater calcium ion release was observed for CPM2, followed by CPM1 at 14 days and for S26, CPM1, and CPM2 at 28 days. ZOE released the least calcium ions in all periods. Conclusion: Sealer 26, MTA, and Endo CPM sealer at normal or thicker consistency release hydroxyl and calcium ions. Endo CPM sealer may be an alternative as root-end filling material. (J Endod 2009;35:1418-1421)

Determination of the properties of an experimental glass polyalkenoate cement prepared from niobium silicate powder containing fluoride

Objectives. The purpose of this paper is to modify the conventional calcium fluoro-aluminosilicate glass, which is used in the formation of glass ionomer cements (CIGs) by the niobium addition and to study the properties of GICs obtained.Materials and methods. Sol-gel process was used to prepare the powder at lower temperature than fusion method. Glass-ceramic powder obtained in this way was used to prepare the GICs. The properties such as working and setting times, microhardness and diametral tensile strength were evaluated for the experimental GICs and a commercial luting cement.Results. The ideal powder:liquid (P:L) ratio determined to prepare the experimental GICs was equal to 1:1. The cements prepared using this ratio showed working and setting times similar to the commercial GICs. in mechanical tests it was observed that microhardness and diametral tensile strength of the experimental GICs decreased significantly with the reduction of P:L ratio. on the other hand, the results obtained in microhardness tests indicated that the presence of niobium was a positive factor.Significance. The chemical process allows the development of glass-ceramic powder at 600 degrees C which is the goal of the present paper. It was concluded that GICs containing niobium might be used in dental applications and these results encourage further researches on other compositions. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of 0.05% sodium fluoride solutions on microhardness of resin-modified glass ionomer cements

This study aimed to evaluate the influence of fluoride-containing mouthrinse solutions (Fluorgard and Oral B) on the superficial microhardness of two resin-modified glass ionomer cements (Vitremer and Fuji II LC). Fifteen discs-shaped specimens of each glass ionomer cement (0 10 mm; 2 mm thick) were prepared, thereby forming two groups. After 24-hour storage in artificial saliva, the microhardness was measure and the data were recorded. Next, each group was divided into three subgroups (n = 5), according to the solution to be immersed in. Control specimens were kept in artificial saliva along the whole experiment. The test specimens were kept in mouthrinse solution for 30 days. Vickers surface microhardness was analyzed at predetermined evaluation periods: 24 h, 48 h, 7, 14, 21 and 30 days after specimens' preparation. Data were subjected to three-way ANOVA and to Tukey test (p < 0.05). A better behavior of Fuji II LC was observed and Fluorgard affected most the characteristics of the tested materials. It may be concluded that fluoride-containing solutions influenced the tested characteristics of materials, mainly of Vitremer.

Crystal structure of human PNP complexed with hypoxanthine and sulfate ion

Purine nucleoside phosphorylase (PNP) is a ubiquitous enzyme, which plays a key role in the purine salvage pathway, and PNP deficiency in humans leads to an impairment of T-cell function, usually with no apparent effects on B-cell function. Human PNP has been submitted to intensive structure-based design of inhibitors, most of them using low-resolution structures of human PNP. Here we report the crystal structure of human PNP in complex with hypoxanthine, refined to 2.6 Angstrom resolution. The intermolecular interaction between ligand and PNP is discussed. (C) 2004 Elsevier B.V. All rights reserved.

Proteomic Analysis of Urine in Rats Chronically Exposed to Fluoride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proteomic analysis of kidney in rats chronically exposed to fluoride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)