Effect of one-bottle adhesive systems on the fluoride release of a resin-modified glass ionomer

A dhesive systems associated to resin-modified glass ionomer cements are employed for the achievement of a higher bond strength to dentin. Despite this benefit, other properties should not be damaged. This study aimed at evaluating the short-time fluoride release of a resin-modified glass ionomer cement coated with two one-bottle adhesive systems in a pH cycling system. Four combinations were investigated: G1: Vitremer (V); G2: Vitremer + Primer (VP); G3: Vitremer + Single Bond (VSB) and G4: Vitremer + Prime & Bond 2.1 (VPB). SB is a fluoride-free and PB is a fluoride-containing system. After preparation of the Vitremer specimens, two coats of the selected adhesive system were carefully applied and light-cured. Specimens were immersed in demineralizing solution for 6 hours followed by immersion in remineralizing solution for 18 hours, totalizing the 15-day cycle. All groups released fluoride in a similar pattern, with a greater release in the beginning and decreasing with time. VP showed the greatest fluoride release, followed by V, with no statistical difference. VSB and VPB released less fluoride compared to V and VP, with statistical difference. Regardless the one-bottle adhesive system, application of coating decreased the fluoride release from the resin-modified glass ionomer cements. This suggests that this combination would reduce the beneficial effect of the restorative material to the walls around the restoration.Sistemas adesivos são associados aos cimentos de ionômero de vidro modificados por resina para a obtenção de maior resistência adesiva à dentina. Apesar deste benefício, outras propriedades não devem ser prejudicadas. Este estudo se propôs a avaliar a liberação de flúor a curto prazo de um cimento de ionômero de vidro modificado por resina coberto com dois diferentes sistemas adesivos em um modelo de ciclagem de pH. Quatro associações foram testadas: G1: Vitremer (V); G2: Vitremer + Primer (VP); G3: Vitremer + Single Bond (VSB) and G4: Vitremer + Prime & Bond 2.1 (VPB). SB é um sistema sem flúor e PB contém flúor. Após a confecção das amostras de Vitremer, duas camadas de cada sistema selecionado foram aplicadas e fotopolimerizadas. Em seguida, as amostras foram imersas em solução desmineralizante por 6 horas, seguida da imersão em solução remineralizante por 18 horas, totalizando 15 dias de ciclagem. Todos os grupos liberaram flúor sob o mesmo padrão, apresentando maior liberação inicial e decrescendo ao longo do tempo. VP apresentou a maior liberação de flúor, seguida de V, sem diferença estatística. VSB and VPB liberaram menor quantidade de flúor em relação a V e VP, com diferenças estatisticamente significantes. Independentemente do sistema adesivo de frasco único, houve redução da liberação de flúor pelo cimento de ionômero de vidro modificado por resina. Isto sugere que esta associação poderia reduzir o efeito benéfico do material restaurador em torno da restauração

Efeito do número de ciclos térmicos na microinfiltração de restaurações de resina composta

Thermocycling simulates, in vitro, thermal changes that occur in the oral cavity. The aim of this study was to evaluate the influence of the number of cycles on microleakage. Class V cavities (1.5 mm deep, 3 mm in height and 3 mm in width) were prepared in bovine teeth, restored with a Single Bond/Z250 restorative system (3M/ESPE) and then divided into five groups of ten teeth each: group 1 was not thermocycled (control group), and groups 2, 3, 4 and 5 were thermocycled 500, 1,000, 2,500 and 5,000 times, respectively (5º-55º ± 2ºC, 15 s dwell time). The teeth were immersed in 0.5% basic fuchsin aqueous solution for 24 h, sectioned and the sections with the highest degree of microleakage were selected, scanned and the extent of dye penetration was measured by the ImageTool program. The results submitted to one-way ANOVA showed no significant differences between the groups (p >; 0.05). The averages of microleakage values in millimeters were: group 1 (3.92); group 2 (3.13); group 3 (4.48); group 4 (4.33) and group 5 (3.42). Thus, it was concluded that there is no relation between the increase of the number of cycles and the increase in microleakage.A ciclagem térmica tem por objetivo simular, in vitro, as mudanças térmicas intra-orais que ocorrem clinicamente. Sendo o seu efeito bastante discutido, o presente trabalho tem como objetivo avaliar a relação da ciclagem térmica e o número de ciclos na infiltração marginal. Foram confeccionadas cavidades classe V com dimensões de 3 mm de altura, 3 mm de largura e 1,5 mm de profundidade, em dentes bovinos. Os dentes foram restaurados com o sistema Single Bond/Z250 (3M/ESPE) e, então, divididos em 5 grupos de 10 dentes cada: grupo 1 (controle) sem ciclagem; grupos 2, 3, 4 e 5 com 500, 1.000, 2.500 e 5.000 ciclos, respectivamente (5º-55º ± 2ºC, 15 segundos por banho). A seguir, os dentes foram seccionados e analisados em microscópio com 100 X de aumento para a escolha da fatia mais infiltrada, que foi escaneada e quantificada pelo programa ImageTool. Os dados submetidos ao teste ANOVA a um critério não apresentaram diferença significante (p >; 0,05), resultando em valores médios de infiltração em milímetros: grupo 1 (3,92), grupo 2 (3,13), grupo 3 (4,48), grupo 4 (4,33) e grupo 5 (3,42). A análise dos dados permitiu concluir que não há relação entre o aumento do número de ciclos e o aumento da infiltração marginal

Efeito de tratamentos de superfície na velocidade de escoamento de sistemas adesivos simplificados

OBJECTIVES: To determine the roughness of glass surfaces submitted to different treatments and to correlate it with the spreading velocity of two adhesive systems. MATERIALS AND METHODS: Glass slides were used as substrates to evaluate the spreading velocity of Single Bond and Prime & Bond NT adhesive systems. Six different surface treatments were compared: 1) no treatment; 2) silanization (SL); 3) sandblasting (SB); 4) SB + SL; 5) 10% hydrofluoric acid treatment (HF); 6) HF + SL. Before and after treatments, surface roughness was measured by a profilometer (Ra, µm). Drop volumes (10 µl) of the adhesive systems were deposited onto substrates with a micropipette to observe materials spreading during 30s. Data were expressed in mm/s as spreading velocity. Statistical significances among groups were analyzed using one-way and two-way-ANOVA designs and the SNK test. RESULTS: Significant differences in spreading velocity were found between materials (p < 0.001) and among treatments (p < 0.001). Silanization decreased the spreading velocity for both adhesives in comparison to groups where it was not performed (p < 0.05). Differences in roughness were found only for SB surfaces that were rougher than the others (p < 0.05). Silanization decreased the roughness of SB surfaces (p < 0.05). Linear regression did not indicate any correlation between spreading velocity and roughness (R = 0.173). CONCLUSION: Although surface treatments yielded different roughness, they did not provide differences in the spreading velocity of the simplified bonding systems studied. Silanization decreased bonding systems' spreading velocities.OBJETIVO: Determinar a rugosidade de superficies submetidas a diferentes tratamentos e correlacionar rugosidade com velocidade de escoamento de sistemas adesivos MATERIAL AND MÉTODOS: Lâminas de vidro foram utilizadas como substrato para avaliar a velocidade de escoamento dos sistemas adesivos Single Bond and Prime & Bond NT. Seis diferentes tratamentos de superfície foram comparados: 1- sem tratamento; 2 - silanização (SL); 3 - jateamento (J); 4 - J + SL; 5 - condicionamento com ácido fluorídrico a 10% (HF); 6 - HF + SL. Antes e após os tratamentos, foi mensurada a rugosidade das superficies (Ra, µm). Gotas de 10 µl de adesivo foram despositadas sobre as superficies e as velocidades de escoamento foram observadas durante 30 seg. Dados de velocidade de escoamento foram expressos em mm/s. Significâncias estatísticas entre grupos foram analisadas pelos testes ANOVA (um e dois critérios) e SNK. RESULTADOS: Houve diferenças significantes na velocidade de escoamento entre materiais (p < 0.001) e entre tratamentos (p < 0.001). Silanização diminuiu a velocidade de escoamento para ambos os adesivos em comparação aos grupos não silanizados (p < 0.05). Houve diferença entre rugosidades inicial e final somente para o grupo jateado, que se apresentou como o mais rugoso (p < 0.05). Silanização diminuiu a rugosidade das superficies jateadas (p < 0.05). Regressão linear não indicou correlação entre velocidade de escoamento e rugosidade (R = 0.173). CONCLUSÕES: Embora os tratamentos de superfície tenham produzido diferentes rugosidades, não produziram diferenças na velocidade de escoamento dos sistemas adesivos estudados. Silanização diminuiu a velocidade de escoamento dos sistemas adesivos

Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall

Interface integrity can be maintained by setting the composite in a layering technique and using liners. Objective The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC) lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. Material and Methods Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control) – no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond) + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond) + four oblique layers. Resin composite (Filtek Z250, 3M ESPE) was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE) dyed with a fluorescent reagent (Rhodamine B) to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM) analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa). Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>;0.05). CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. Conclusions RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations

Push-out bond strength and SEM evaluation of a new bonding approach into the root canal

Objective: This study evaluated the performance of different adhesive systems in fiber post placement aiming to clarify the influence of different hydrophobic experimental blend adhesives, and of one commercially available adhesive on the frictional retention during a luting procedure. Material and Methods: One luting agent (70 Wt% BisGMA, 28.5% TEGDMA; 1.5% p-tolyldiethanolamine) to cement fiber posts into root canals was applied with 4 different adhesive combinations: Group 1: The etched roots were rinsed with water for 30 s to remove the phosphoric acid, then rinsed with 99.6% ethanol for 30 s, and blot-dried. A trial adhesive (base to catalyst on a 1: 1 ratio) was used with an experimental luting agent (35% Bis-GMA, 14.37% TEGDMA, 0.5% EDMAB, 0.13% CQ); Group 2: A trial adhesive (base to catalyst on a 1: 2 ratio) was luted as in Group 1; Group 3: One-Step Plus (OSP, Bisco Inc.) following the ethanol bonding technique in combination with the luting agent as in Group 1; Group 4: OSP strictly following the manufacturer's instructions using the luting agent as in Group 1. The groups were challenged with push-out tests. Posted root slices were loaded until post segment extrusion in the apical-coronal direction. Failure modes were analyzed under scanning electron microscopy. Results: Push-out strength was not significantly influenced by the luting agent (p&gt;0.05). No statistically significant differences among the tested groups were found as Group 1 (Exp 1 - ethanol-wet bonding technique)=Group 2 (Exp 2 - ethanol-wet bonding technique)= Group 3 (OSP - ethanol-wet bonding technique)= Group 4 (control, OSP - water-wet bonding technique) (p&gt;0.05). The dominating failure modes in all the groups were cohesive/adhesive failures, which were predominantly observed on the post/luting agent interface. Conclusions: The results of this study support the hypothesis that the proposal to replace water with ethanol to bond fiber posts to the root canal using highly hydrophobic resin is plausible, but this seems to be more the proof of a concept than a clinically applicable procedure

Comparison of two techniques for enamel remineralization

Six patients enrolled at the Hospital of Rehabilitation of Craniofacial Anomalies, University of São Paulo, aging 16 to 20 years, were selected. All patients presented with white spots in both sides of the superior arch, which totalized 41 spots. The left side of the arch was submitted to remineralization by means of the conventional technique with Reminer, a commercially available product. In the right side, a modified technique was employed, with the utilization of fluoridated dentifrices every night, during 8 weeks. It was observed that successful remineralization occurred in 62% of the spots when the conventional technique was employed, whereas, when fluoridated dentifrices were utilized, there was partial remineralization in 10% of the spots. The utilization of Reminer was more effective than the utilization of fluoridated dentifrices.Foram selecionados seis pacientes do Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo, com idade entre 16 e 20 anos, apresentando um total de 41 manchas brancas nos dois lados da arcada superior. No lado esquerdo da arcada, foi feita remineralização utilizando-se a técnica com o produto comercial Reminer. No lado direito, foi utilizada uma técnica modificada, com o uso de dentifrícios fluoretados pelo paciente durante a noite, diariamente, em um período de oito semanas. Observou-se remineralização em 62% das manchas com o uso da técnica com Reminer e remineralização parcial em 10% das lesões com a utilização de dentifrícios fluoretados. A utilização do produto comercial Reminer apresentou-se mais eficaz que o uso de dentifrícios fluoretados

Cytotoxicity and biocompatibility of direct and indirect pulp capping materials

There are several studies about the cytotoxic effects of dental materials in contact with the pulp tissue, such as calcium hydroxide (CH), adhesive systems, resin composite and glass ionomer cements. The aim of this review article was to summarize and discuss the cytotoxicity and biocompatibility of materials used for protection of the dentin-pulp complex, some components of resin composites and adhesive systems when placed in direct or indirect contact with the pulp tissue. A large number of dental materials present cytotoxic effects when applied close or directly to the pulp, and the only material that seems to stimulate early pulp repair and dentin hard tissue barrier formation is CH

In vitro interactions between lactic acid solution and art glass-ionomer cements

OBJECTIVES: Production of acids such as lactic acid contributes to establish a cariogenic environment that leads to dental substrate demineralization. Fluoride plays an important role in this case and, as fluoride-releasing materials, glass-ionomer cements are expected to contribute to minimize deleterious reactions. This study evaluated interactions of glass-ionomer cements used in atraumatic restorative treatment (ART-GICs) with an aqueous lactic acid solution, testing the null hypotheses that no changes occur in the pH of the solution or on the surface roughness and mass of the ART-GICs when exposed to lactic acid solution over a 6-week period. MATERIAL AND METHODS: Ketac Molar, Fuji IX, Vitro Molar and Magic Glass were tested, and compared to Filtek Z250 and Ketac Fil Plus as control groups. Six specimens of each material were made according to manufacturers' instructions. The pH of the solution and roughness and mass changes of each specimen were determined over 6 weeks. Each specimen was individually stored in 2 mL of 0.02 M lactic acid solution for 1 week, renewing the solution every week. pH of solution and mass of the specimens were monitored weekly, and surface roughness of the specimens was assessed before and at the end of the 6-week acid challenge. pH and mass data were analyzed statistically by repeated measures using one-way ANOVA and Tukey's post-hoc tests for each material. Paired t-tests were used for roughness analysis. Tukey's post-hoc tests were applied to verify differences of final roughness among the materials. Significance level was set at 5%. RESULTS: The null hypotheses were partially rejected. All materials were able to increase the pH of the lactic acid solution and presented rougher surfaces after immersion, while mass change was minimal and generally not statistically significant. CONCLUSIONS: These findings can be helpful to predict the performance of these materials under clinical conditions. A protective action against the carious process with significant surface damage due to erosion may be expected

Influence of Erosive and Abrasive Cycling on Bonding of Diferent Adhesive Systems Enamel: An in situ study

This study evaluated the impact of orange juice on the bond strength (BS) of dentin bonding systems (DBSs) to enamel surface after simulation with an in situ/ ex vivo erosive cycling. One hundred and ninety two bovine enamel fragments (4x4x2 mm) were obtained and randomized regarding superficial microhardness and distributed to palatal devices for 8 volunteers, in three phases (one for each DBS), containing 8 blocks, which were, allocated in 4 pairs. Daily, these pairs were subjected extraorally to the following conditions: CONTneither erosive nor abrasive challenge; ERO- erosive challenge only; ABR- abrasive challenge only and ERO + ABR- with erosive and abrasive challenges. Erosive cycles (immersion in orange juice, 3 times/day/5 min/5 days) or/and abrasive challenges (electric toothbrush, 3 times/day/1 min/5 days) were performed. After these cycles, all specimens were restored with the adhesive systems Adper Scotchbond Multi Purpose (MP), Adper Single Bond 2 (SB) or Clearfil SE Bond (SE), and the composite resin Filtek Z250. After 7 days, sticks (area ≅1 mm2) were obtained and subjected to the microtensile bond strength test (μTBS) at 0.5 mm/min. Data was statistically analyzed by ANOVA and Tukey tests (a=0.05). Failure modes were determined using a digital microscope (40×). DBS was the only statistical significant factor. SE was the unique DBS not affected in any challenge, whereas MP and SB performed according to the scenario. The adhesive and mixed failures were predominant in all groups. Overall performance suggested that BS to enamel after erosive /abrasive challenged by orange juice was not affected and it was material-dependen