Influence of Blood Contamination on Bond Strength of a Self-Etching System

OBJECTIVES: To detect the influence of blood contamination (BC) on the bond strength (BS) of a self-etching bonding system (SES) to enamel and dentine. METHODS: 25 human molars were longitudinally sectioned on the mesio-distal axis in order to obtain 50 specimens, which were embedded in acrylic resin. At first, the specimens were ground to expose a flat surface of enamel, and a bond strength test was performed. Afterwards, the samples were ground again in order to obtain a flat surface of dentine. Ten groups (total: n=100) were assigned according to substrate (enamel and dentine), step in the bonding sequence when contamination occurred (before the acidic primer and after the bonding resin), and contamination treatment (dry or rinse and dry procedure). Fresh human blood was introduced either before or after SES application (Clearfil SE Bond) and treated with air drying, or by rinsing and drying following application. Composite resin (Filtek Z-250,3M ESPE) was applied as inverted, truncated cured cones that were debonded in tension. RESULTS: The mean tensile BS values (MPa) for enamel/dentine were 19.4/23.0 and 17.1/10.0 for rinse-and-dry treatment (contamination before and after SES, respectively); while the measurements for the dry treatment, 16.2/23.3 and 0.0/0.0 contamination before and after SES, respectively. CONCLUSIONS: It was determined that blood contamination impaired adhesion to enamel and dentine when it occurred after bond light curing. Among the tested contamination treatments, the rinse-and-dry treatment produced the highest bond strength with BC after SES application, but it was not sufficient to recover the BS in the contamination-free group

Estudo de resistência à tração de três sistemas adesivos associados a resina composta em superfícies dentinárias

Este trabalho teve como objetivo comparar a resistência à tração de três sistemas adesivos associados a resina composta aderidos à superfície dentinária. Quarenta e cinco superfícies de dentina foram obtidas a partir de molares humanos extraídos, sobre elas foi preparado "smear layer" e foram divididas em 3 grupos: G1) adesivo autocondicionante + resina micro-híbrida; G2) adesivo de componente único + ácido e resina micro-híbrida e G3) adesivo convencional (ácido + "primer" + bond) + resina micro-híbrida, aplicados de acordo com as instruções dos fabricantes. Os corpos-de-prova foram preparados para teste de tração, imersos em água destilada por 24 horas a 37ºC. Findo este tempo, o teste de tração foi realizado em máquina de ensaio Inströn com velocidade constante de 0,5 mm/min. Os resultados foram expressos em MPa e submetidos a análise de variância (p < 0,05). Os autores concluíram que: o tipo de sistema adesivo influenciou na resistência à tração das resinas compostas testadas; o sistema adesivo de componente único apresentou os melhores resultados de resistência adesiva.The aim of this in vitro study was to compare the tensile bond strength of 3 different bonding systems, associated to composite resins, bonded to dentinal surfaces. Forty-four dentinal surfaces were obtained from recently extracted human molars. A standardized smear layer was obtained and the surfaces were divided in 3 groups: G1) self etch + microhybrid composite; G2) single-component adhesive + phosphoric acid + microhybrid composite and G3) conventional system (acid + primer + bond) + microhybrid composite. Specimens made of composite resin were constructed in the shape of an inverted truncated cone with 3 mm of diameter. Tensile bond strength test was performed at the speed of 0.5 mm/min, and the results were expressed in MPa. The analysis of variance ANOVA (p < 0.05) determined that the type of bonding system used influenced tensile bond strength. Tukeys test, however, showed that the results of the comparison between G2 and G3 were the only statistically significant ones, with G2 showing greater values of tensile bond strength

Aging influence on roughness and color stability of encapsulated glass ionomer cements

Objetivo: Analisar efeitos de diferentes envelhecimentos sobre a rugosidade e a cor de cimentos de ionômero de vidro (CIV) encapsulados. Materiais e métodos: Foram testados dois cimentos de ionômero de vidro [convencional/ Self Cure (SC) e resino modificado/Light Cure (LC)] e envelhecimentos [(baseline, pós-ciclagem térmica e pós- -ciclagem térmica + armazenamento por sete meses)]. 52 discos (n = 13) foram confeccionados. A cor foi avaliada por dois espectrofotômetros (VITA Easyshade e Konica Minolta CE3700A), e a rugosidade pelo perfilômetro óptico (Proscan 2100, Scantron). Resultados: ANOVA dois fatores e teste de Tukey (p &lt; 0,05) foram realizados. Os CIVs apresentaram diferenças estatisticamente significantes entre si (p &lt; 0,05) para rugosidade (SC = 0,202 μm e LC = 0,241), os envelhecimentos alteraram significativamente a rugosidade baseline = 0,278 μm, ciclado = 0,220 μm e ciclado-armazenado = 0,167 μm, e para cor (SC ΔE = 3,89 e o LC ΔE = 4,94). Para ΔL*, Δa*, Δb* houve diferença na interação dos fatores, com maior alteração do ΔL* para o CIV LC após ciclagem + armazenagem. Para Δa* houve diferença estatisticamente significante (p &lt; 0,05) entre os envelhecimentos, sendo maior para o grupo CIV LC após ciclagem. Maior alteração Δb* foi observada para o CIV LC após ciclagem + armazenagem. Conclusões: Os diferentes CIVs possuem rugosidade superficial e cor diferentes. O CIV LC mostrou-se mais rugoso quando comparado ao SC, porém ambos se tornaram menos rugosos com o passar do tempo. O protocolo de envelhecimento que mais interfere na rugosidade e na cor de diferentes tipos de CIV é a ciclagem térmica seguida de armazenamento.Objective: To analyze effects of differents agings on the roughness and color of different encapsulated glass ionomer cements (GIC). Materials and methods: Two glass ionomer cements (Conventional/Self Cure (SC) and modified resin/Light Cure (LC)) and three aging (baseline, post-thermal cycling and post-thermal cycling + storage for 7 months). Fifty-two discs (n = 13) were made. The color stability was performed with spectrophotometers (VITA Easyshade and Konica Minolta CE3700A), and the roughness test with optical profilometer (Proscan 2100, Scantron). Results: The data were analyzed with two-way ANOVA and Tukey’s test (p &lt; 0.05). The GICs presented statistically significancy when compared (p &lt; 0.05), for roughness (SC = 0,202μm e LC = 0,241), the aging protocols tested promoted a significant change in surface roughness baseline = 0,278μm, post-cycling = 0,220μm and storage = 0,167μm and for the color (SC ΔE = 3,89 and LC ΔE = 4,94). However, the interaction between the factors was not statistically significant (p &gt; 0.05). For ΔL*, Δa*, Δb*, there was a difference in the interaction of the factors, with a greater change in ΔL* for the GIC LC post-thermal cycling + storage). For Δa* there was a statistically significant difference (p &lt; 0.05) between aging, being the higher alteration for the GIC LC group post-thermal cycling. Greater change in the b* coordinate was observed for the GIC LC post-thermal cycling + storage. Conclusions: The different GICs presented different surface roughness and color. The resin-modified GIC LC showed to be rougher when compared to the conventional GIC SC. However, both GICs became less rough over time. The post-thermal cycling + storage for 7 months was the aging protocol that most interfered in the roughness and color of different types of GICs

Importância do tempo de espera pós-tratamento clareador no selamento marginal de restaurações classe V em resina composta

The aim of this study was to evaluate changes in mineral content of bleached enamel and the infl uence of post-bleaching time interval on the marginal seal of class V composite restorations. Forty bovine incisors were restored using Magic Bond adhesive and Fill NT Premium composite according to the manufacturer’s instructions. The teeth were randomly divided into 4 experimental groups (n = 10): G1, not bleached (control); G2, bleached and immediately restored; G3, bleached and restored after 7 days; G4, bleached and restored after 14 days. The mineral content was evaluated by QLF (quantitative light-induced fl uorescence). The microleakeage scores were analyzed by 3 calibrated examiners. There was no statistical difference between the groups regarding change of the bleached mineral substrate (repeated measures ANOVA, p = 0.2130) and the microleakage scores (Friedman, p = 0.2551). It was concluded that the bleaching protocol used is safe because it does not cause mineral changes in the bleached enamel, and that the post-bleaching time interval observed before performing adhesive procedures did not affect the marginal seal of composite resin restorations.O objetivo deste estudo foi avaliar o conteúdo mineral do esmalte submetido ao clareamento dental e a influência do tempo de espera após o tratamento clareador no selamento marginal de restaurações classe V em resina composta. Neste estudo, a variável de resposta selamento marginal foi avaliada por metodologia de microinfiltração, segundo o fator de variação tempo de espera para o procedimento restaurador, imediatamente após, e 7 e 14 dias após o tratamento clareador. O conteúdo mineral foi avaliado pelo método QLF (quantitative light-induced fluorescence). As unidades experimentais foram compostas por 40 coroas de incisivos bovinos que foram distribuídas entre os 4 grupos experimentais (n = 10): G1, dentes bovinos não clareados (controle); G2, dentes clareados e imediatamente restaurados; G3, dentes clareados e restaurados após 7 dias; G4, dentes clareados e restaurados após 14 dias. Os escores de infi ltração foram analisados por 3 examinadores previamente calibrados. Não foi observada diferença estatística entre os grupos com relação à alteração mineral do substrato clareado (ANOVA para mensurações repetidas, p = 0,2130) e ao grau de microinfiltração marginal (Friedman, p = 0,2551). Pôde-se concluir que o protocolo clareador utilizado é seguro por não acarretar alterações minerais do esmalte clareado, e que o tempo de espera para a realização de procedimentos adesivos não interferiu no selamento marginal de restaurações em resina composta

Laser Phototherapy Enhances Mesenchymal Stem Cells Survival in Response to the Dental Adhesives

Background. We investigated the influence of laser phototherapy (LPT) on the survival of human mesenchymal stem cells (MSCs) submitted to substances leached from dental adhesives. Method. MSCs were isolated and characterized. Oral mucosa fibroblasts and osteoblast-like cells were used as comparative controls. Cultured medium conditioned with two adhesive systems was applied to the cultures. Cell monolayers were exposed or not to LPT. Laser irradiations were performed using a red laser (GaAlAs, 780 nm, 0.04 cm2, 40 mW, 1 W/cm2, 0.4 J, 10 seconds, 1 point, 10 J/cm2). After 24 h, cell viability was assessed by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide reduction assay. Data were statistically compared by ANOVA followed by Tukey’s test (P<0.05). Results. Different cell types showed different viabilities in response to the same materials. Substances leached from adhesives were less cytotoxic to MSCs than to other cell types. Substances leached from Clearfil SE Bond were highly cytotoxic to all cell types tested, except to the MSCs when applied polymerized and in association with LPT. LPT was unable to significantly increase the cell viability of fibroblasts and osteoblast-like cells submitted to the dental adhesives. Conclusion. LPT enhances mesenchymal stem cells survival in response to substances leached from dental adhesives

Longitudinal evaluation of the effect of saliva contamination during the bonding protocol with a self-etch adhesive system

Aim: To evaluate the influence of saliva contamination on the short- and long-term bond strength of a self-etch adhesive system. Methods: One hundred and twelve non-carious human molars were randomly divided according to: substrate (enamel/dentin); presence of saliva [none (control-C), before primer (BP), after primer (AP) and after bonding agent (AB)]; treatment of the contamination [none (1), rinsing + drying (2), drying (3) and primer re-application (4)] and specimen storage (24 h or 6 months). A self-etch adhesive system was applied to the dental surfaces followed by incremental insertions of composite resin. After storage in water at 37 o C, the specimens were perpendicularly cut into beams for microtensile bond strength testing. Data in MPa were compared by ANOVA followed by Tukey′s test (p< 0.05). Micrographs were obtained by low vacuum scanning electron microscopy. Results: Control groups (G1 and G8) presented higher bond strength than all other groups. The factors presence of saliva, treatments of the contaminant and specimen storage showed no statistically significant results for the two dental substrates. Contaminants could be detected by LV-SEM. Six-month storage did not affect bond strength. Conclusions: The presence of saliva during the application of the self-etch system was deleterious to the bond to enamel and dentin, irrespective of the operative step in which the contamination occurred