Sorción de humedad y resistencia a la disolución ácida de dos ionómeros de vidrio de restauración: estudio in vitro / Sorption of moisture and resistance to acid dissolution of two restoration glass ionomers: in vitro study

Resumen Introdución: En general el Ionómero de vidrio tiene algunas desventajas en la parte clínica, como es la fragilidad y la sensibilidad inicial a la humedad, lo que puede causar una disminución de la vida útil de la restauración. Estos efectos que sufre el ionómero como la sorción de humedad y la solubilidad a los ácidos puede causar daño a la restauración, facilitar su fractura y filtración marginal, lo que puede conllevar a una recidiva de caries y pérdida de sus propiedades. Objetivo: comparar in vitro la sorción de humedad y disolución ácida de dos ionómeros de restauración. Método: Se elaboraron 20 muestras de ionómero de vidrio Ketac molar y 20 de Fuji II. Se realizó una primera medición del peso con balanzas de precisión, obteniéndose un peso inicial. Los especímenes fueron sumergidos en agua destilada durante 24 horas, almacenadas en un calefactor; cada muestra fue pesada con una balanza de precisión, estableciéndose el porcentaje de humedad sorbida a partir del peso inicial. Posteriormente las muestras fueron sumergidas en solución de ácido cítrico al 3% durante 24 horas, para volver a ser pesadas, evaluándose la perdida de material por acción erosiva del ácido en porcentaje de peso. Conclusiones: La sorción de humedad en peso fue de 2,59% en el ketac molar y 1,45% en el Fuji II; al comparar las muestras mediante la prueba t, se obtuvo diferencias estadísticamente significativas. El porcentaje de pérdida de material por acción erosiva del ácido fue de 10,81% para Ketac molar y 18,62% para el Fuji II; al comparar las muestras mediante la prueba t, se obtuvo diferencias estadísticamente significativas. Se concluyó que la sorción de humedad fue mayor en el Ketac molar y la mayor solubilidad a la acción del ácido cítrico fue del Fuji II.

Abstract Introduction: Glass Ionomer has certain clinical disadvantages, such as fragility and moisture sensitivity, which might reduce the restauration´s lifespan. This effects, such as water absorption and acid solubility may damage the restauration, cause fracture and marginal filtration, this could trigger cavity relapse and the loss of the correct mechanical properties. Objective: Compare in vitro moisture sorption and acid solution of two restoration ionomers. Method: 20 samples of Ketac molar glass ionomer and 20 of Fuji II were made. A first weight measurement was made with precision scales, obtaining an initial weight. The specimens were submerged in distilled water for 24 hours, stored in a heater; Each sample was weighed with a precisión balance, establishing the percentage of moisture absorbed from the initial weight. Subsequently, the samples were submerged in 3% citric acid solution for 24 hours, to be re-weighed, evaluating the loss of material due to erosive action of the acid in percentage of weight. Conclusions: The moisture sorption by weight was 2.59% in the molar ketac and 1.45% in the Fuji II; When comparing the samples using the t-test, statistically significant differences were obtained. The percentage of material loss due to erosive action of the acid was 10.81% for molar Ketac and 18.62% for Fuji II; When comparing the samples using the t-test, statistically significant differences were obtained. It was concluded that the moisture sorption was higher in the molar Ketac and the greatest solubility to the action of citric acid was Fuji II.

Effect of Ions Released and pH of Two Glass Ionomer Cements in Human Gingival Fibroblasts / Efecto de la liberación de iones y pH de dos cementos de ionómero de vidrio en fibroblastos gingivales humanos

Abstract 20. Conventional glass ionomer cements are used as dental provisional restorative materials, which present several advantages such as adhesion to the tooth mineral phase among others. On the other hand, the knowledge about biological property of glass ionomers shows various approaches and results. In this work, it was studied the in vitro biological response of human gingival fibroblasts in contact with commercial cements of glass ionomer: Mirafil® and Ionglass® and with their extracts, according to ISO 10993. The extracts of the cements, in which the cells were cultured, were adjusted at different concentrations ranging 0.1% to 100%. The cellular metabolic activity of gingival fibroblasts was measured using the Alamar Blue® reagent. The results showed a significant effect on the cellular metabolic activity correlated with the concentration of liberated ions (Al³+ and Ca²+) for both ionomers, as well as the pH variations of the culture media. This could mean that the cellular metabolic activity is substantially influenced by ions and pH of the cell culture.

Resumen 24. Los cementos de ionómero de vidrio convencionales se utilizan como materiales de restauración provisional para uso dental, los cuales presentan varias ventajas como la adhesión a la fase mineral de los dientes. Por otro lado, las propiedades biológicas de los ionómeros de vidrio muestran diversos enfoques y resultados. En éste trabajo se estudió la respuesta biológica in vitro de fibroblastos gingivales humanos en contacto con cementos comerciales de ionómero de vidrio: Mirafil® e Ionglass® y con sus respectivos extractos según la norma ISO 10993. Los extractos de los cementos en los que se cultivaron las células estaban en diferentes concentraciones: de 0.1% a 100%. La actividad metabólica celular se midió usando el reactivo Alamar Blue®. Los resultados mostraron un efecto significativo sobre la actividad metabólica celular correlacionada con la concentración de iones liberados (Al³+ y Ca²+) para ambos ionómeros, así como las variaciones de pH de los medios de cultivo. Ello podria explicar la influencia por los iones y el pH del cultivo celular en la actividad metabólica celular.

Efficacy of Sealing with Glass Ionomer Cement and Transversal Brushing Technique in Erupting First Molars: 18-Month Clinical Follow-Up

Objective: To verify the effectiveness of sealing with glass ionomer cement and transversal brushing in the prevention and treatment of initial caries lesions in erupting permanent molars of children aged 5-7 years. Material and Methods: Healthy teeth with ICDAS scores 1 or 2 were selected. One hundred and thirty-one children (79 teeth in the control group - 75 teeth in the test group) were randomly assigned into the two experimental groups: (1) transversal brushing technique for plaque control with conventional flat bristles and fluoridated dentifrice or (2) sealing the occlusal surfaces with glass ionomer cement (Vitro Molar®). Follow-up was performed for 18 months and the survival analysis was applied to test the occurrence of lesion progression. Results: The mean age of children was 5.4 years and it was verified that, by examining the initial tooth condition, the probability of progression was 66% lower when the tooth had initial caries lesions than when it was healthy; the probability of molar progression was about 74% lower in the test group compared to the control group. The mean time for lesion development in the test group (16.8 months; SD = 0.5) was greater than that in the control group (16.5 months; SD = 0.5; p=0.008). Conclusion: Sealing reduces the progression of caries disease in initial lesions when compared to the transversal brushing technique.

Performance of Preventive Methods Applied to the Occlusal Surface of Primary Teeth: A Randomized Clinical Study

Objective: To evaluate the clinical performance of three preventive materials on the occlusal surfaces of primary molars over a 36-month period. Material and Methods: The study was conducted with a split-mouth design involving four experimental groups: G1 ­ resin-modified glass ionomer cement (Vitremer®); G2 - resin sealant (Alpha Seal Light®); G3 - silver diamine fluoride (Cariostatic®); and G4 - control group without material. Thirty-two children aged 36 to 60 months, attending a pediatric clinic, with a deft index ≥ 1 and four primary second molars participated in the study. The material retention was evaluated in G1 and G2, and the presence of incipient caries was evaluated in all groups. Data were submitted to the Wilcoxon test and survival test (α = 5%). Results: At three, six, 12, 24 and 36 months, G2 exhibited greater material loss (maximum loss: 44%) in comparison to G1 (maximum loss: 35%), but this difference did not achieve statistical significance (p = 0.214). The highest incidence of incipient caries occurred in G3 (20%), but no significant differences were found between groups at any evaluation time (p = 0.154). Conclusion: There were no statistically significant differences between the evaluated products regarding material retention and dental caries, although there was more material loss in teeth that received the Alpha Seal® sealant resin, and a greater number of carious lesions in the Cariostatic® group (silver diamine fluoride).

Assessment of Glass Ionomer Cements (GIC) Restorations after Acidic Erosive Challenges: An in vitro Study

Objective: To analyze the marginal adaptation of two different Glass Ionomer Cements (GIC) after erosive challenges. Material and Methods: Sixty sound extracted primary canines were selected and class V cavities were made. Teeth were allocated into 6 groups according to restorative material: 1) high-viscosity GIC (Ketac™Molar Easymix) and 2) resin-modified GIC with nanoparticles (Ketac™N100), low pH beverage erosive challenge (Orange juice and Coca-Cola) or distilled water as control. Thereafter the sample was restored and subjecting to thermocycling. The sample was immersed for a 10-days period for the erosive simulation and then embedded in methylene blue solution during 4 hours. Finally teeth were sectioned for further analysis. Marginal adaptation test was performed by two trained examiners using the Salama et al. criteria. Descriptive and Kruskal-Wallis test (α=5%) were used to analyze the data. Results: The groups treated with Ketac™Molar EasyMix were similar in terms of marginal sealing ability when submitted to Orange juice and Coca-Cola but significantly worse than water. For samples restored with the Ketac™N100 the worst results were found in the Coca-Cola group. Conclusion: Erosive challenges with acidic drinks affected the marginal adaptation of the tested GIC.

Influência da densidade tubular em diferentes profundidades dentinárias na estabilidade de união de cimentos de iônomero de vidro / Influence of tubular density in diferent dentin depths in bonding stability of glass ionomer cements

O objetivo do estudo foi avaliar a influência da densidade tubular em diferentes profundidades dentinárias na estabilidade de união de dois cimentos de ionômero de vidro (CIV) de alta viscosidade. Vinte terceiros molares foram alocados em 6 grupos experimentais, de acordo com a profundidade da dentina - proximal, oclusal superficial ou oclusal profunda, e os CIVs - Fuji IX (GC Corp.) e Ketac(TM) Molar Easy Mix (3M/ESPE). Inicialmente os dentes foram cortados a fim de se obter fatias de aproximadamente 1 mm de espessura de dentina proximal, oclusal superficial e profunda. Em seguida, foi realizado uma análise topográfica das secções das diferentes superfícies e profundidades em microscopia confocal a laser (100X) para obtenção das médias da densidade tubular em cada profundidade. Cânulas de polietileno foram então posicionadas sobre as secções de dentina pré-tratadas e preenchidas pelos CIVs. Os espécimes foram armazenados em água destilada por 24 h e 12 meses a 37°C, em seguida foram submetidos ao ensaio de microcisalhamento (0,5 mm/min). Após o ensaio, foi realizada a análise do padrão de fratura em estereomicroscópio (400X). Os dados obtidos foram submetidos à Análise de Variância para dados repetidos, seguido do teste de Tukey (?=5%). Verificamos que a densidade dos túbulos dentinários, em diferentes profundidades de molares permanentes, é inversamente proporcional a resistência de união de cimentos de ionômero de vidro de alta viscosidade. Foi ainda observado em todos os grupos que a resistência de união após 24 horas é maior do que em 12 meses, indicando degradação da interface adesiva ao longo do tempo.

The aim of this study was to evaluate the influence of dentin tubule density of different depths in the bond stability of two high viscous glass ionomer cements (GIC). Twenty (third) molars were assigned into 6 experimental groups, according to the depth of dentin - proximal, superficial or deep occlusal occlusal and the GICs - Fuji IX (GC Corp.) and Ketac (TM) Molar Easy Mix (3M / ESPE). Initially, the teeth were cut to obtain slices approximately 1 mm thick for approximal, superficial and deep occlusal surfaces. Then it was performed a topographical analysis of sections of different depths surfaces and laser confocal microscopy (100X) to obtain averages of the tubular density at each depth. Polyethylene cannulae were then positioned on the pre-treated dentin sections and filled with GIC. The specimens were stored in distilled water for 24 h and 12 months at 37°C were then subjected to microshear bonding test (0.5 mm / min). After the test, a fracture analysis pattern was performed in stereomicroscope (400X). The data were submitted to ANOVA for repeated measures followed by the Tukey test (? = 5%). We found that the density of dentinal tubules at different depths of permanent molars, is inversely proportional to the bond strength of high viscosity glass ionomer cements. It was observed in all groups which bond strength after 24 hours is higher than in 12 months, indicating degradation of the interface over time.

Acción de los agentes blanqueadores sobre materiales de restauración / Action of bleaching agents on restorative materials

El propósito del trabajo será analizar comparativamente los diversos efectos que producen sobre las restauraciones dentales agentes blanqueadores.El objetivo será valorar los cambios que experimentan en la superficie los materiales de restauración, sometidos a la acción de un agente blanqueador. La metodología utilizada será visualización microscópica electrónica de barrido ambiental. Los resultados obtenidos tendrán transferencia relevante a Insti-tuciones formadoras de recursos humanos en Salud Bucal, al campo profesional odontológico y a empresas o fabricantes para el mejoramiento de su producto...

Surface micromorphological changes of glass ionomer following application of 1.23% acidulated phosphate fluoride: A scanning electron microscope study.

Objectives: The purpose of this study was to evaluate the surface micromorphological changes of conventional glass ionomer cement (GIC) (Fuji II, GC Corporation, Tokyo, Japan) and high strength, high viscosity GIC (Fuji IX GP, GC Corporation) subjected to 1.23% acidulated phosphate fluoride (APF) gel for 4 min. It also evaluated the surface micromorphological changes that occurred in these materials when they were coated with a layer of glass ionomer varnish prior to the application of 1.23% APF gel. Materials and Methods: A total of 60 uniform glass ionomer cylinders were prepared (30 of each Fuji II and Fuji IX) and stored in distilled water for 48 h, following which they were divided into six groups depending on the surface treatment. Group 1: Fuji II alone, Group 2: Fuji IX alone, Group 3: Fuji II + 1.23% APF gel for 4 min, Group 4: Fuji IX + 1.23% APF gel for 4 min, Group 5: Fuji II + varnish + 1.23% APF gel for 4 min, and Group 6: Fuji IX + varnish + 1.23% APF gel for 4 min. After the required surface treatment had been done, the specimens were mounted, coated, and evaluated under scanning electron microscope. Statistical Analysis: Kruskal–Wallis test applied to compare the level of degradation among the groups subjected to treatment was highly significant (P < 0.001). Mann–Whitney test was applied to test the association between glass ionomer varnish and level of surface degradation and was also statistically significant (P = 0.001). Results: The results indicated that APF gel etched the surface of both Fuji II and Fuji IX. However, Fuji IX showed to possess better resistance to the erosive effect of APF than Fuji II. It was also observed that application of glass ionomer varnish prior to APF gel application protected the glass ionomer from the erosive effect of APF gel. Conclusion: APF gel caused erosive wear of the GICs esp. Fuji II. Hence, it is advisable to avoid the use of APF containing preparations for regular home use especially in children having glass ionomer restoration. If APF gel is indicated or preferred for professional application, it is recommended to apply glass ionomer varnish on the restored teeth prior to the APF gel application.

A ação de sucos de frutas sobre materiais restauradores utilizados em lesões cervicais não cariosas / The action of fruit juices upon restorative materials used in noncarious cervical lesions

O presente estudo in vitro analisou o efeito de 3 sucos de fruta com baixo pH (suco de cupuaçu, taperebá e laranja), e saliva artificial (controle) sobre materiais restauradores indicados em lesões cervicais não cariosas: resina composta nanoparticulada (Filtek Z350 XT), cimento de ionômero de vidro resino modificado (Vitremer) e um cimento de ionômero de vidro convencional (Fuji II). Os materiais foram avaliados, quantitativamente, quanto à alteração de: peso, rugosidade superficial e microdureza superficial, e qualitativamente, por microscopia eletrônica de varredura (MEV). Foram confeccionados 144 corpos de prova para cada teste quantitativo (n=12) e 45 para o MEV (n=3), de (8mm de diâmetro x 2mm de altura). Os corpos de prova foram preparados, mantidos em saliva artificial por 24 h à 37º C, receberam acabamento em politriz, e em seguida foram realizadas as leituras iniciais. Durante um período de 10 dias consecutivos, os corpos de prova foram submetidos ao desafio erosivo (nos respectivos sucos de frutas) durante 30 minutos três vezes ao dia, totalizando 90 minutos/dia e mantidos em saliva artificial entre os intervalos. Após o período de ciclagem erosiva, foram realizadas as leituras finais...

This in vitro study examined the effects of 3 fruit juices with low pH (cupuaçu, taperebá and orange) and artificial saliva (control) upon restorative materials indicated in noncarious cervical lesions: nanoparticle composite resin (Filtek Z350 XT), resin-modified glass ionomer cement (Vitremer) and a glass ionomer cement (Fuji II). The materials were evaluated quantitatively as for alterations in weight, surface roughness and surface microhardness, and qualitatively by scanning electronic microscopy (SEM). 144 specimens were prepared for each quantitative test (n = 12) and 45 for the SEM (n = 3), of (8mm diameter x 2mm height). The specimens were prepared, stored in artificial saliva for 24 hours at 37º C, were finished in a polishing machine, and then the initial readings were performed. During a period of 10 consecutive days, the specimens were subjected to erosive challenge (in the respective juices) for 30 minutes, three times a day, and totaling 90 minutes/day and kept in artificial saliva between intervals. After the erosive cycling period, the final readings were taken. The data were analyzed using t test, ANOVA and Tukey...

Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives.

Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI) restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm) were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14). The cavities in groups 1, 2 and 3 were restored using a composite resin (APX). The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC). Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch) were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05). Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05). The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

Avaliação dos níveis de cinza de cimentos ionômero de vidro em imagens digitais indiretas / Evaluation of the gray-scale values of glass ionomer cement in indirect digital imaging

Objetivo: Comparar a radiopacidade de quatro marcas comerciais de cimentos ionômero de vidro por meio da mensuração dos níveis de cinza em imagens digitais indiretas. Materiais e Métodos: Foram confeccionados cinco corpos de prova nas espessuras de 1, 2, 3 e 4mm dos seguintes materiais: Magic Glass® R, Maxxion® R, Vidrion® R e Chemflex®. As amostras foram separadas por marca e espessura e radiografadas seguindo uma técnica padronizada. Foram realizadas três radiografias por espessura para cada material avaliado. As imagens obtidas foram posteriormente digitalizadas e analisadas por meio da ferramenta histograma do software Adobe Photoshop 8.0 para a determinação dos níveis de cinza. Para isso, foram realizadas três leituras em áreas diferentes de cada uma das amostras confeccionadas para cada espessura das marcas comerciais avaliadas. Os valores obtidos foram posteriormente submetidos a uma média aritmética e os resultados expressos como média dos níveis de cinza por espessura para cada material. Os dados foram analisados por meio da análise de variância ANOVA (p<0,05) e comparação múltipla de Bonferroni (p<0,05). Resultados: Para todos os cimentos avaliados as espessuras apresentaram diferenças estatisticamente significativas quando comparadas entre si para o mesmo material (p<0,001). Os valores dos níveis de cinza aumentaram conformea espessura dos corpos de prova. As médias dos valores de níveis de cinza encontradas em cada um dos cimentos avaliados, para uma mesma espessura foram diferentes e os resultados estatisticamente significativos p<0,001). Conclusão: Os cimentos ionômeros de vidro apresentaram variações quanto à radiopacidade, sendo que a espessura dos corpos de prova contribuiu para tal propriedade. O Chemflex® apresentou o maior valor médio de níveis de cinza, sendo o material de maior radiopacidade dentre todos os avaliados.

Ação de Escovas Dentais de Diferentes Texturas em Cimentos de ionômero de Vidro Indicados para o Tratamento Restaurador Atraumático / Action of Toothbrushes of Different Textures on Glass Ionomer Cements Indicated for Atraumatic Restorative Treatment

Objetivo: Avaliar a ação de escovas dentais macias e médias em cimentos de ionômero de vidro, analisando os parâmetros alteração de massa e rugosidade superficial. Método: Foram testados dois cimentos de ionômero de vidro de alta viscosidade (Ketac tm Molar Easymix/3M Espe e Vitro Molar/DFL), um convencional (Bioglass R/Biodinâmica) e uma resina composta microhíbrida (Z100 tm/3M Espe). Vinte corpos-de-prova de cada material foram submetidos à escovação simulada com creme dental diluído em água destilada (1:2), divididos em grupos de 10 para cada tipo de escova. Os valores de massa foram obtidos após pesagens consecutivas e estabilização do peso. A rugosidade superficial (Ra) foi determinada pela média aritmética de cinco leituras nas superfícies dos corpos-de-prova. Após registro dos valores iniciais de massa e rugosidade, os corpos-de-prova foram submetidos a 20.000 ciclos de escovação simulada e os valores finais de massa e rugosidade foram verificados. Os dados foram avaliados estatisticamente pelos testes t de Student e Anova com pós-teste de Tukey (p<0,05). Resultados: A escovação determinou desgaste em todos os materiais, sendo o menor valor verificado na resina composta Z100 tm, seguido pelos cimentos de ionômero de vidro Ketactm Molar Easymix, Vitro Molar e Bioglass R. O cimento de ionômero de vidro de alta viscosidade com menor valor de rugosidade superficial inicial e final foi o Ketac tm Molar Easymix, com valor médio de 0,50 μ m, sendo estatisticamente diferente dos outros cimentos de ionômero de vidro. Conclusão: As escovas dentais macias e médias causaram desgastes semelhantes.

Objective: To evaluate the action of soft- and middle-bristle toothbrushes on glass ionomer cements indicated for atraumatic restorative treatment by analyzing the parameters mass change and surface roughness. Method: One conventional (Bioglass R/Biodinâmica) and two high-viscosity (Ketac tm Molar Easymix/3M ESPE and Vitro Molar/DFL) glass ionomer cements and a microhybrid composite resin (Z100 tm/3M ESPE) were tested. Twenty specimens of each material were subjected to simulated toothbrushing with dentifrice diluted with distilled water (1:2), divided in groups of 10 specimens for each type of toothbrush. The mass values were obtained after consecutive recordings and weigh stabilization. Surface roughness (Ra) was determined by the arithmetic mean of five readings on specimen surface. After recording the initial mass and surface roughness values, the specimens were subjected to 20,000 cycles of simulated toothbrushing, and the final mass and surface roughness values were recorded. Data were analyzed statistically by the Student’s t-test and ANOVA with Tukey’s post-test (p<0.05). Results: Toothbrushing produced wear of all materials; Z100 tm composite resin exhibited the highest value, followed by Ketac tm Molar Easymix, Vitro Molar® and Bioglass R glass ionomer cements. Ketac™ Molar Easymix was the high-viscosity glass ionomer cement with lower initial and final surface roughness (Ra= 0.50 μm) and differed significantly from the other glass ionomer cements. Conclusion: Soft- and medium-bristle toothbrushes caused similar wear on the materials.

Liberação e recarga de flúor por cimentos de ionômero de vidro / Fluoride release and uptake by glass ionomer cements

OBJETIVO: Avaliar a liberação de flúor de seis cimentos de ionômero de vidro convencional e dois modificados por resina antes e após a recarga com fluoreto de sódio neutro a 2 por cento. Uma resina composta foi usada como grupo-controle. MÉTODOS: Cinco amostras de cada material foram confeccionadas, utilizando-se uma matriz de teflon, e posteriormente imersas em 5,0 ml de água deionizada. Nos dias 1, 2, 3, 5, 7 e 14 foram realizadas aferições em eletrodo específico para determinação da quantidade de flúor liberado. No 15º dia, as amostras foram submetidas à aplicação tópica de gel de fluoreto de sódio neutro a 2 por cento durante 4 minutos e em seguida foram lavadas, secas e novamente imersas em 5,0 ml de água deionizada. Aferições da liberação de flúor foram realizadas nos dias 1, 2, 7 e 14 após a recarga. RESULTADOS: Os dados, submetidos à análise de variância e aos testes de Tukey e de Student (p<0,05), mostraram diferenças estatísticas significativas entre os materiais antes e após a recarga. Os materiais com maior liberação inicial de flúor foram Maxxion R> Vidrion R> Vitro Fil> Vitro Molar> Vitro Fil LC> Riva Self Cure> Vitremer> Ketac Molar> Z-250. Após a aplicação tópica de flúor, todos os materiais foram capazes de apresentar recarga de flúor. CONCLUSÃO: Concluiu-se que cimentos de ionômero de vidro são capazes de liberar flúor em água deionizada e podem recarregar flúor através de uma aplicação tópica de fluoreto de sódio neutro a 2 por cento.

OBJECTIVE: Evaluated the fluoride released from six conventional and two resin-modified glass ionomer cements before and after a topical application of a 2 percent neutral sodium fluoride gel. A composite resin was used as control. METHODS: Five specimens of each material were prepared by the use of a Teflon matrix and immersed in 5.0 ml of deionized water. On days 1,2,3,4,5,6,7 and 14, a specific electrode was used to determine the amount of fluoride released. On day 15, a 2 percent neutral sodium fluoride gel was applied topically on the specimens for 4 minutes. The specimens were then rinsed, dried and again immersed in 5.0 ml of deionized water. The mount of fluoride released was measured 1, 2 7 and 14 days after fluoride uptake. RESULTS: Analysis of variance, the Tukey's test and the Student's t-test (p<0.05) revealed significant differences between the materials before and after the uptake. The materials that released the greatest amounts of fluoride initially were Maxxion R> Vidrion R> Vitro FIL> Vitro Molar> Vitro Fil LC> Riva Self Cure > Vitremer> Ketac Molar> Z-250. All materials were capable of absorbing fluoride. CONCLUSION: Glass ionomer cements are capable of releasing fluoride in deionized water and absorbing fluoride from a topical application of a 2 percent neutral sodium fluoride gel.

Abrasive wear of conventional glass ionomer cements / Desgaste abrasivo de cimentos de ionômetro de vidro convencionais

Este trabalho tem por finalidade avaliar a resistência abrasiva de 3 diferentes marcas de cimento de ionômero de vidro (CIV) restauradores, do tipo convencional, disponíveis no mercado nacional. Para isso foi utilizado o teste de agressividade, onde um disco dinâmico revestido com porcelana desgasta, em condições adequadamente estabelecidas, um disco estático revestido com o material restaurador estudado. Neste método valores menones de agressividade indicam maior resistência ao desgaste abrasivo. Foram confeccionados 24 corpos de provas, sendo 8 para cada marca. As marcas de CIV avaliadas foram: Vidrion R (fabricado pela empresa brasileira SSWhite), Ketac Fil Plus (fabricado pela empresa americana 3M ESPE) e Fuji IX GP (fabricado pela empresa japonesa GC), que posteriormente foi substituído pela marca Vitro Fill (fabricado pela empresa brasileira DFL Indústria e Comércio Ltda.). Os materiais foram confeccionados de acordo com as instruções dos respectivosfabricantes. Os testes foram executados em duas etapas: na primeira não houve controle do tempo de exposição ao ambiente, e as análises dos dados revelaram grande influência desta exposição na propriedade de resistência ao desgaste abrasivo. Em uma segunda etapa, o tempo de exposição foi rigidamente controlado, assim como a umidade do ar e a temperatura ambiente, desde a confecçãodos corpos de prova até a finalização dos ensaios, otendo-se assim os resultados desejados. Deste modo, além da classificação de cada marca de acordo com a resistência ao desgaste abrasivo, também foi mostrado que o tempo de exposição deste material ao ar ambiente deve receber atenção especial em trabalhos que versem sobre propriedades mecânicas do cimento de ionômero de vidro.

An evaluation was made of the abrasive strenght of three different brands of conventional glass ionomer cement (GIC) for dental restoration available on the Brazilian market. The evaluation was based on an agressiveness assay in which, under pre established conditions, a disk coated with porcelain wears down a static disk coated with the restorative material under study. According to this method, low agressiveness values indicate high abrasive wear resistance...

Avaliação histopatológica em tecido conjuntivo subcutâneo de ratos de um cimento de ionômero de vidro experimental para forramento cavitário / Histopathologic evaluation in rats' subcutaneous connective tissue of a glass ionomer cement experimental for cavity lining

O cimento de ionômero de vidro representa um marco dentro da Odontologia, pois veio agregar propriedades físicas e biológicas favoráveis que não eram obtidas com outros materiais. Uma de suas propriedades, a biocompatibilidade, foi o tema do nosso trabalho, que teve como objetivo avaliar, comparativamente, em tecido conjuntivo subcutâneo de ratos o potencial irritativo em nível I de um cimento de ionômero de vidro em fase experimental e o resultado da associação do pó experimental com o líquido de cimentos de ionômero de vidro já disponíveis comercialmente. Foram utilizados 60 ratos (Rattus norvegicus, Albinus, Holtzman), divididos em 5 grupos de 3 animais cada, para os períodos de 7,15, 30 e 60 dias. Os materiais utilizados foram: Vitrebond (Grupo I), Ionomaster F (Grupo II), Pó experimental + Líquido do Cimento de Ionômero de vidro Vitrebond (Grupo III), Pó experimental + Líquido do Cimento de Ionômero de vidro do Ionomaster F (Grupo IV) e Pó experimental + Líquido experimental (Grupo V). Pó e liquido experimentais foram desenvolvidos pelo Instituto de Química de Araraquara ­ UNESP/Brasil. O Vitrebond e Ionomaster F agiram como controle e todos foram veiculados em tubos de polietileno e implantados no tecido conjuntivo subcutâneo dos ratos. Decorridos os períodos experimentais, os tubos foram removidos e encaminhados para tramitação laboratorial. Os cortes foram avaliados em microscopia óptica comum para análise descritiva do quadro reacional. Considerando-se cada evento histopatológico foi apresentada a estatística descritiva de cada grupo. A avaliação de diferença significativa entre os materiais, considerando os períodos experimentais e os escores atribuídos aos eventos histopatológicos em estudo, foi realizada pelo teste de Kruskal ­ Wallis. Adicionalmente, foram efetuadas comparações múltiplas de postos médios pelo teste de Dunn. Os resultados encontrados através de análise estatística e avaliação subjetiva permitiram concluir que, o cimento ionomérico experimental em estudo comparativo de biocompatibilidade (Nível I), a cimentos ionoméricos já comercializados apresentou-se biologicamente viável tendo em vista que ao longo dos períodos analisados níveis de eventos histopatológicos semelhantes foram observados. Há, no entanto, necessidade de maiores estudos sobre a biocompatibilidade desses cimentos contendo nióbio, em outros modelos experimentais (Níveis II e III), onde se inclui necessariamente o complexo dentina-polpa

Glass ionomer cement represents a hallmark in the Dentistry Science, since it aggregates favorable physical and biological properties, which were not obtained by the other cements. Biocompatibility, one of its properties, was the aim of this study, which was to evaluate, comparably, in the subcutaneous tissue of rats, the level I aggravation potential of glass ionomer cement in experimental phase and the result between the association of the experimental powder and the liquid from commercially available glass ionomer cements. Sixty rats were used (Rattus novergicus, Albinus, Holtzman), divided into 5 groups of 3 animals each, in the following time periods of 7, 15, 30 and 60 days. Commercial materials used were: Vitrebond (Group I), Ionomaster F (Group II), Experimental powder + Liquid of Glass Ionomer Cement Vitrebond (Group III), Experimental powder + Liquid of Glass Ionomer Cement Ionomaster F (Group IV), and Experimental powder + Experimental Liquid (Group V). Experimental powder and liquid were developed by Chemical Institute of Araraquara ­ UNESP/Brasil. Vitrebond and Ionomaster F were utilized as control and every group were carried within poly (ethylene) tubes and implanted in the subcutaneous connective tissue of the rats. Tubes were removed after the appropriate experimental times and were taken to laboratory processing. Cuts were evaluated under optical light microscopyto obtain descriptive analyze of the reaction overview. According to each histopathological event, descriptive statistics were presented to each group. The significant difference evaluation among materials, considering experimental times and scores attributed to the histopathological events studied, was performed by Kruskal-Wallis test. Besides this, multiple comparisons were effectuated of mean points by Dunn test. Results obtained from statistical analyzes and semi-quantitative evaluation, gave us the opportunity to conclude that experimental glass ionomer cement, when compared to commercial cements, presented biologically viable, in comparative study of biocompatibility (level I), considering that during analyzed experimental times, levels of histopathological events were similar. However, there is the necessity of further studies about biocompatibility of these cements containing niobium, in other experimental models (levels II and III), where must be included pulp-dentin complex

[Comparison of different reinforcement methods of weakened buccal walls in premolar teeth]

In order to improve the aesthetics and functional quality of restorations, the combined amalgam-composite restorations have been introduced. The aim of this study was to compare different reinforcement methods, in weakened buccal walls of premolar teeth. In this in vitro study, 70 similar and intact premolar teeth were used. The specimens were divided into seven groups of ten. In six groups, the three reinforcing materials composite [A], Compoglass F [B] and glass ionomer [C] with two methods: I: buccal and distal wall reinforcement. II: buccal, distal and pulpal floor reinforcement was used. In the seventh group [D], the Scotchbond M.P.P adhesive as a control group was applied. Then specimens were restored conventionally with amalgam and submitted to 500 thermal cycles [5°C-55°C]. The specimens were loaded through Instron testing machine at a crosshead speed of 1 mm/min with angle of 45 degree. Statistical analyzes of ANOVA, Duncan and chi- square tests were used to analyse fracture strength, location and type of fracture. The highest strength was detected in group with composite reinforcement on buccal and distal walls and pulpal floor. The highest failure mode was adhesion type and observed in composite reinforcement and control group. The highest cohesive and mixed failure mode was respectively observed in Compoglass and glass ionomer groups. This study showed that composite resin was the best material for reinforcement of weakened walls with favourable aesthetic property

[Comparison of enamel fluoride uptake between three different glass ionomers used in orthodontic banding: an in vitro study]

Decalcification of the teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that fluoride-releasing glass ionomer cements could decrease the risk of enamel decalcification under orthodontic bands. The objective of this study was to compare enamel fluoride uptake from three different glass ionomer cements [Aqua Cem, Resilience and Bandite] used for band cementation in permanent teeth in vitro. In an experimental in vitro randomized trial, 33 sound premolars that were extracted for orthodontic purposes were randomly divided into thee groups. In each group one of the glass ionomer cements was tested. A 6 mm diameter adhesive tape was placed over the center of buccal enamel surface of each tooth and then the entire surfaces of them were painted with two layers of an acid protective nail polish. After removing adhesive tapes, brackets were cemented with one of the cements over the window. Then all the specimens were immersed in 5ml deionized water for one month. Brackets were debonded and remnants of cements were removed. The windows were etched with 1mI perchloric acid 0.5 M for 60 seconds and then 4 ml of 0.5 M Total Ionic Strength Adjustment Buffer [TISAB] was added to perchloric acid. Fluoride and calcium concentration of the solutions were determined by Potentiometer and Inductively Coupled Plasma, respectively. The depth of etch and fluoride concentration in the enamel were calculated, and the results were analyzed with one way ANOVA and Kruskal-Wallis test. In Resilience the mean fluoride concentrations group were higher and depths of etch were lower than in the other two groups. But there was no statistically significant difference between them. It seemed that an increase in fluoride uptake may be capable of rendering a tooth more resistant to dental decalcification

Interferência do material restaurador no dignóstico do grau de mineralização da dentina através da fluorescência a laser (DIAGNOdent) / Interference of restorative materials on diagnosis of dentin mineralization degree by laser fluorescence (DIAGNOdent)

Equipamentos tem sido introduzidos na clínica odontológica, objetivando auxiliar no diagnóstico de cárie. O DIAGNOdent (fluorência a laser) permite quantificar a mineralização da estrutura analisada. A efetividade do mesmo para diagnóstico de cárie já foi comprovada. No entanto, o uso deste aparelho através do material restaurador, objetivando avaliar recidiva de cárie, ainda é pouco estudado. Neste sentido, este trabalho objetivou avaliar a interferência do material restaurador no diagnóstico da mineralização da dentina, abaixo do mesmo. Este estudo "in vitro" utilizou 20 molares com preparos classe I na oclusal, distribuídos em 3 grupos: restaurados com resina, amálgama e ionômero. A aferição com o DIAGNOdent foi realizada antes e após a restauração. Para a análise dos resultados utilizou-se testes de t de Student e análise de variância com pós-teste de Tukey Kramer (a=0,05). Nos dentes restaurados com resinas e amálgama não houve diferença significativa entre as medidas anteriores à restauração e após as mesmas (p=0,0710 e 0,3685, respectivamente). No entanto, diferença significativa foi observada (p=0,0062) para o grupo do ionômero de vidro. Este estudo sugere a possibilidade de uso do DIAGNOdent, objetivando avaliar cárie recidivante, em restaurações de amálgama e resina tendo em vista que estes não interferiram na fluorescência medida.

Microinfiltração marginal em copings de níquel-cromo submetidos à ação de S. mutans / Microleakage in nickel-chromium copings submitted to the action of S. mutans

Foi avaliada in vitro a microinfiltração marginal do corante azul de metileno em “copings” de níquel-cromo cimentados com diferentes agentes cimentantes e submetidos à ação de bactérias da espécie Streptococcus mutans. Foram utilizados 18 pré-molares humanos divididos em 4 grupos, sendo 1 grupo controle (Grupo 1 - controle negativo, dente hígido) e 3 grupos experimentais (Grupo 2 - “coping” cimentado com cimento de ionômero de vidro modificado por resina; Grupo 3 - “coping” cimentado com cimento resinoso; Grupo 4 - “coping” cimentado com cimento de fosfato de zinco). Os resultados demonstraram que nenhum dos cimentos utilizados impediu, de maneira eficaz, a infiltração do corante azul de metileno a 0,5 por cento, sendo que o cimento de fosfato de zinco demonstrou os piores resultados.

Análise da qualidade microbiológica de materiais odontológicos / Microbiological quality assessment of dental materials

O objetivo foi avaliar a qualidade microbiológica de materiais odontológicos (Vitrebond- 3M, Z100 - 3M, Single Bond - 3M e Permite C - SDI) antes, durante e após serem usados. As amostras foram colocadas em Erlemayer contendo Calet (DIFCO) e incubadas a 32-35°C por 20 dias. Quando turvado, o meio foi semeado em MHa (Merck) e Alet (DIFCO), e incubado. Identificados os morfotipos, as bactérias foram transferidas para Agar Nutriente (Merck), para identificação. Verificou-se que os materiais testados vieram de fábrica sem contaminação, havendo pouca probabilidade de contaminação cruzada pelo uso desses materiais