Comparison of Dentin Caries Remineralization with Four Bioactive Cements.

The treatment of deep carious lesions involves the use of ion-releasing agents to seal the lesions. These agents release minerals, leading to the remineralization of the remaining demineralized dentin. This study aimed to compare the dentin caries remineralization with bioactive cements. 60 Dentin blocks were prepared from the dentin of human third molars. Artificial carious lesions were induced on the blocks with pH cycling. The samples were divided into five groups (n=12). Dycal, Oxford ActiveCal PC, Biodentine, and ACTIVA BioACTIVE were applied using a mold. One group did not receive any cement. The samples were stored in remineralization solution for 30 days. The cement was removed using a #15 blade, and the dentin surface was evaluated using Energydispersive X-ray Spectroscopy and X-ray Diffraction. One-way ANOVA did not show a significant difference in the weight percentages of calcium and phosphorus and the calcium-to-phosphorus ratios between the groups. The highest and the lowest weight percentages of calcium and phosphorus were observed in Biodentine and control groups, respectively. There were no significant differences in the remineralization properties of bioactive cements. Hydroxyapatite crystals were not formed in any of the adjacent dentin using these cements.

Cytotoxic Evaluation and Determination of Organic and Inorganic Eluates from Restorative Materials.

Over the last years, diverse commercial resin-based composites have dominated as dental filling materials. The purpose of the present study was to determine organic and inorganic eluates from five restorative materials using GC/MS and ICP-OES and to compare the effect on cell survival of human gingival fibroblasts of a conventional and a bioactive resin. Five commercially available restorative materials were employed for this study: ActivaTM Bioactive Restorative, ENA HRi, Enamel plus HRi Biofunction, Fuji II LC Capsule, and Fuji IX Capsule. Disks that were polymerized with a curing LED light or left to set were immersed in: 1 mL methanol or artificial saliva for GC/MS analysis, 5mL deionized water for ICP-OES, and 5mL of culture medium for cell viability. Cell viability was investigated with a modified staining sulforhodamine B assay.The following organic substances were detected: ACP, BHT, BPA, 1,4-BDDMA, CQ, DBP, DMABEE, HEMA, MCE, MeHQ, MOPA, MS, TMPTMA, and TPSb and the ions silicon, aluminum, calcium, sodium, and barium. Activa Bioactive Restorative was found to be biocompatible. Elution of organic substances depended on material's composition, the nature of the solvent and the storage time. Ions' release depended on material's composition and storage time. The newly introduced bioactive restorative was found to be more biocompatible.

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.

Organic Eluates Derived from Intermediate Restorative Dental Materials.

A great number of different types of materials have been used in dentistry as intermediate restoratives. Among them, new resin-based bases have been released in the dental market. The present study focuses on the identification of the organic eluates released from such materials and the study of their surface microstructure in combination with their corresponding elemental composition. For this purpose, the following materials were used:ACTIVA™BioACTIVE-BASE/LINER™, Ketac™Bond Glass Ionomer, SDR™ and Vitrebond™Light Cure Glass Ionomer Liner/Base. Methanolic leachates derived from polymerized materials were analyzed by means of gas chromatography-mass spectrometry (GC-MS). Scanning electron microscopy(SEM) was used for the surface monitoring of suitably prepared specimens. The GC-MS analysis revealed the elution of twenty different substances from the three resin-based materials, while none was eluted from the glass ionomer base. The SEM analysis for Vitrebond™ presented small pits, the one for Ketac™Bond presented elongated cracks, while no voids were present for ACTIVA™BioACTIVE-BASE/LINER™ and SDR™. Moreover, the resin matrix of some dental materials may inhibit elements' accumulation on the surface layers. Particularly, the detected organic eluents may be related to potential toxic effects.

Forensic study of mechanical properties of dental restoration after burial in mangrove environment.

Conducting research in the field of forensic sciences with methodologies that simulate situations found in the day-to-day practice of a given field of expertise is relevant insofar as this approach can produce results that are as close as possible to reality. In this context, the present study provided situations based on burial in a mangrove environment to estimate the changes in the mechanical properties (Knoop microhardness, roughness and color) of dental restorations utilizing silver amalgam, composite resin and glass ionomer cement over the time of burial. The silver amalgam showed a significant increase in surface roughness and a reduction in Knoop microhardness. Composite resin showed a statistically significant increase in color variation, and the glass ionomer cement showed significant increases in color variation and Knoop microhardness. These results allowed us to conclude that teeth restored with silver amalgam, composite resin and glass ionomer cement submitted to burial in mangrove environments produce different changes in surface roughness, Knoop microhardness and color properties depending on the time of burial to which the victims were submitted. These proprieties could help the forensic sciences to estimate time intervals for burial in mangrove environments.

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).

Exploring the unexpected influence of the Si:Ge ratio on the molecular architecture and mechanical properties of Al-free GICs.

Germanium (Ge)-based glass ionomer cements have demonstrated the ability to balance strength with extended setting times, a unique set of characteristics for aluminum-free glass ionomer cements. However, the mechanical properties of current Ge-based glass ionomer cements significantly deteriorate over time, which jeopardizes their clinical potential. This work explores the effect of incrementally decreasing the Si:Ge ratio in the glass phase of zinc-silicate glass ionomer cements to identify potential mechanisms responsible for the time-induced mechanical instability of Ge-based glass ionomer cements. The influence of Ge was evaluated on the basis of changes in mechanical properties and molecular architecture of the cements over a 180-day period. It was observed that the compressive strength and modulus of the cements were sustained when Si:Ge ratios were ≥1:1, but when Si:Ge ratios are <1:1 these properties decreased significantly over time. These mechanical changes were independent of structural changes in the glass ionomer cement matrices, as the level of metal-carboxylate crosslinks remained constant over time across the various Si:Ge ratios explored. However, it was noted the temporal decline of mechanical properties was proportional to the increased release of degradation byproducts, in particular Ge that was released from the cements in substantially greater quantities than other glass constituents. Unexpectedly, the slowest setting cement (Si:Ge 1:1) was also the strongest; behavior that is uncommon in Si-based glass ionomer cements, supports the potential of Ge-containing glass ionomer cements as injectable bone cements in applications such as percutaneous vertebroplasty.

Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal.

Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The light-cured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities.

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...

Influence of heat and ultrasonic treatments on the setting and maturation of a glass-ionomer cement.

PURPOSE: To compare the effect of different treatments (heat capsule, ultrasound, and dual treatments) on the setting kinetics and maturation properties of a conventional GIC (EQUIA, GC) to that of standard setting. METHODS: The optimal durations of the heat and ultrasonic treatments were determined by monitoring changes in the COO-/COOH ratio, surface hardness, and temperature within the samples. The influence of optimal treatments on the maturation properties of the GIC (microhardness, and 3-point flexural strength) were assessed using GIC samples incubated in artificial saliva for 24 hours, 1 month, and 3 months. RESULTS: The optimal durations of the heat and ultrasonic treatments for accelerating setting were 5 minutes and 35 seconds, respectively. The dual treatment using the optimal conditions of the individual treatments further enhanced the setting kinetics. A temperature peak (49°C) within the GIC was detected during setting. Only the dual treatment increased the mechanical properties of the GIC after 24 hours compared to the control, while no significant difference was observed after 1 and 3 months.

Characterization of dental interfaces with electron tomography.

Understanding the interface between dental materials and tooth is critical in the prevention of secondary caries. Assessing this interface with high-resolution clarity has traditionally been challenging. This work highlights electron tomography, carried out in the transmission electron microscope, as a novel technique to obtain both three-dimensional and nanometer scaled information on dental materials in contact with dentin. In this study, commercial calcium aluminate and glass ionomer based luting agents in contact with human dentin were prepared for electron microscopy via focused ion beam milling. Imaging with high-angle annular dark field provided compositional contrast, and combined with tilting over large angular ranges, enabled the reconstruction of the three-dimensional interface between tissue and cement. The characteristics of the interface were observed with this extra dimensionality and superior resolution, providing evidence for the viability of this technique in interfacial studies of dental materials.

Comparison of a SiO(2)-CaO-ZnO-SrO glass polyalkenoate cement to commercial dental materials: glass structure and physical properties.

Glass polyalkenoate cements (GPCs) have previously been considered for orthopedic applications. A Zn-GPC (BT 101) was compared to commercial GPCs (Fuji IX and Ketac Molar) which have a setting chemistry analogous to BT 101. Handling properties (working, T (w) and setting, T (s) times) for BT 101 were shorter than the commercial GPCs. BT 101 also had a higher setting exotherm (S (x) -34 °C) than the commercial GPCs (29 °C). The maximum strengths for BT 101, Fuji IX, and Ketac Molar were 75, 238, and 216 MPa (compressive, σ (c)), and 34, 54, and 62 MPa (biaxial flexural strengths, σ (f)), respectively. The strengths of BT 101 are more suitable for spinal applications than commercial GPCs.

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...

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.

Microhardness and chemical analysis of high-viscous glass-ionomer cement after 10 years of clinical service as ART restorations.

OBJECTIVES: The aim of this study was to evaluate the Knoop microhardness (KHN) and chemical composition of high-viscous glass-ionomer cement (HVGIC) after 10 years of clinical service. METHODS: Six HVGIC samples were cut from 10-year ART restorations. The sections were embedded in acrylic moulds with their longitudinal profile exposed. KHN was determined by performing three sequences of five indentations at 10, 30, 50, 70 and 90 µm of HVGIC outer surface. For the control group (n=6), HVGIC specimens were stored in distilled water for 24 months. Hardness measurements were taken at days 7, 30, 60, 120, 180, 360, and 720. For chemical analysis using SEM-EDX, 10-year and control specimens were dehydrated and coated with carbon. Data were analysed using T-test and ANOVA/Tukey's test (p<0.05). RESULTS: A significant KHN increase was observed in the control group up to the 180-day period. From this point the values stabilized and no more significant differences were found between the 10-year and the control KHN values. No statistical differences were observed amongst the KHN from inner distances compared to the outer surface of the 10-year HVGIC specimens. In one 10-year specimen, SEM-images identified the transformation of HVGIC in an altered layer with no glass filler particles detectable, and raised Ca, K and P contents. CONCLUSIONS: KHN values of ten-year HVGIC specimens were similar to the control group values at 180-day storage period. Except for one 10-year specimen in that an altered layer could be seen, chemical composition was similar amongst the depths evaluated.

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.