Does the use of universal adhesive systems improve the durability of the bond strength of orthodontic brackets to enamel?

Background: Universal adhesive systems used for restorative clinical procedures are like orthodontics and may be a viable option. This study evaluated the effectiveness of universal adhesive systems in enhancing the durability of the shear bond strength (SBS) and adhesive remnant index (ARI) of orthodontic brackets to enamel. Material and Methods: 100 bovine incisors were divided into five groups (n=20), according to the applied adhesive systems: Primer Transbond XT; Ambar; Ambar Universal; Single Bond Universal; Adper Single Bond 2. Bracket from each tooth were submitted to SBS test after 24 hours, and 12 months later. The amount of remaining adhesive was evaluated through ARI. Results: After 24 hours, there was no difference in BS between the control and the other groups (p>0.05). However, there were difference between TOTALETCHING1 group and the Ambar Universal (p=0.015) and Single Bond Universal groups (p=0.011). After 12 months, Primer Transbond XT, Ambar, Ambar Universal and Adper Single Bond 2 showed no differences in the SBS (p>0.05). Nonetheless, Single Bond Universal presented superior result when compared to Primer Transbond XT (p=0.046) and Ambar (p=0.011) groups. The SBS of all groups reduced significantly after 12 months (p<0.05). There was no difference between ARI scores in each individually assessed group (p>0.05), for both periods. Following 24 hours, a difference was observed between the groups (p=0.043), fact that didn't occur after 12 months (p=0.109). Conclusions: Adhesive systems, such as Ambar Universal and Single Bond Universal are efficient in bonding orthodontic brackets to enamel when associated with Transbond XT adhesive paste. Key words:Bond strength; Primer Transbond XT, orthodontic brackets, adhesive systems.

Photobiomodulation Reduces Pain-Related Symptoms Without Interfering in the Efficacy of In-Office Tooth Bleaching: A Systematic Review and Meta-Analysis of Placebo-Controlled Clinical Trials.

Objective: This systematic review aimed to determine whether the use of photobiomodulation (PBM) with low-level laser therapy prevents tooth sensitivity induced by in-office tooth bleaching with hydrogen. Methods: Placebo-controlled clinical trials were included to evaluate the efficacy of PBM with low-level laser therapy in the prevention of tooth sensitivity after in-office tooth bleaching. Searches were conducted on the Medline database via PubMed, Scopus, Web of Science, EBSCO, SciELO, LILACS, Cochrane, DOSS, and Google Scholar until July 2020, and fixed-effects meta-analysis was performed for tooth sensitivity [standardized mean differences (MDs)] and color changes (MDs). Results: Five studies were included in this systematic review and meta-analysis, with a total of 288 patients, 123 patients in the PBM group and 165 patients in the placebo group. In the meta-analysis, despite high heterogeneity, PBM significantly reduced the tooth sensitivity after the first [p < 0.001; Cohen's d = -0.32, 95% confidence interval (CI) = -0.46 to -0.18], second (p < 0.001; Cohen's d = -0.30, 95% CI = -0.46 to -0.15), and third (p < 0.001; Cohen's d = -0.82, 95% CI = -1.06 to -0.58) sessions of in-office tooth bleaching, without impairing the ΔE (p = 0.300). Conclusions: The results of this systematic review and meta-analysis suggest that PBM significantly prevents pain-related symptoms after the first three weekly sessions of in-office tooth bleaching with hydrogen.

Covid-19 in the State of Ceará: behaviors and beliefs in the arrival of the pandemic. / COVID-19 no estado do Ceará, Brasil: comportamentos e crenças na chegada da pandemia.

This study aimed to evaluate the behavioral aspects and beliefs of the population of Ceará in the face of the COVID-19 pandemic. An online questionnaire was conducted on sociodemographic aspects and opinions related to the pandemic. Absolute and relative frequencies were calculated, the association between variables was performed with Chi-square, and the level of significance was 5%. The final sample had 2,259 participants, and an association was observed between females and perceiving themselves with a high risk of infection (p = 0.044) and males with non-performance of voluntary quarantine (p < 0.001). People aged 80 years and over were partially quarantined due to the flow of people at home (p < 0.001). Participants with elementary school education had a lower risk of infection than participants with a higher level of education (p < 0.001). This group includes people who did voluntary quarantine the least (p < 0.001). Participants living in the inland region of the state had less direct contact with someone tested positive for the Coronavirus (p = 0.031) and are less reclusive (p < 0.001). We can conclude that the approach to the COVID-19 pandemic varies by social aspects, such as gender, age, education, and place of residence, as well as the belief system of the population of the State of Ceará.

Cuidados com a transmissão: o que levou o Ceará ao epicentro da COVID-19? / Transmission care: what led Ceará to be the epicenter of COVID-19? / Cuidados de la transmisión: ¿qué ha hecho Ceará para ser el epicentro de la COVID-19?

Objetivo: Investigar os cuidados e as percepções da população cearense na busca de respostas sobre o que pode ter levado o Ceará ao epicentro da COVID-19 no Nordeste do Brasil. Métodos: Aplicou-se um questionário online contendo perguntas sobre aspectos sociodemográficos, percepções e cuidados relacionados à transmissão do coronavírus 2 com 2.452 pessoas em 2020. Foi realizada estatística descritiva, além da associação entre variáveis por meio do teste qui-quadrado, com nível de significância de 5%. Resultados: Os homens usavam menos máscaras e lavavam menos as mãos (p<0,001) que as mulheres (p<0,001). Aqueles que vivem no interior cumprem menos o isolamento social (p=0,004), usam menos máscaras, têm lavado menos as mãos (p<0,001) e percebem que as pessoas ao seu redor não cumprem as medidas de prevenção usando máscaras (p<0,001). Semelhantemente, os mais jovens são os que estão menos em isolamento social (p<0,001) e os que menos utilizam máscaras (p<0,001). Aqueles com nível médio são os que mais estão trabalhando, e os com nível fundamental são os mais favoráveis ao retorno ao trabalho (p<0,001), os que menos confiam no sistema de saúde (p=0,002) e os que menos usam máscaras (p<0,001). Conclusão: Aspectos culturais e comportamentais, notadamente de homens, jovens, pessoas com baixa escolaridade e moradores do interior já sinalizavam para que o estado viesse a ser um epicentro regional da pandemia no Brasil.

Objective: To investigate the care taken by the population of Ceará and their perceptions in search for answers about what may have led Ceará to be the epicenter of COVID-19 in Northeastern Brazil. Methods: An online questionnaire containing questions about sociodemographic aspects and perceptions and care related to the transmission of coronavirus 2 was administered to 2452 people in 2020. Descriptive statistics was performed and associations between variables was checked by the Chi-squared test with a 5% significance level. Results: Men wore masks and washed their hands less often (p<0.001) than women (p<0.001). Those who lived in the countryside self-isolated less (p=0.004), wore masks less often, washed their hands less often (p<0.001) and perceived that people around them did not comply with preventive measures like wearing masks (p<0.001). Similarly, the youngest were those who self-isolated the least (p<0.001) and those who least wore masks (p<0.001). Those with secondary education were the ones who were working the most and those with primary education were the most keen on returning to work (p<0.001), the ones who least trusted the health system (p=0.002) and who least wore masks (p<0.001). Conclusion: Cultural and behavioral aspects, particularly among men, young people, people with low education and countryside dwellers, were already a sign back then that the state would become a regional epicenter of the pandemic in Brazil.

Objetivo: Investigar los cuidados y las percepciones de la población de Ceará en la búsqueda de respuestas sobre lo que ha permitido Ceará ser el epicentro de la COVID-19 en el Noreste de Brasil. Métodos: Se ha aplicado una encuesta online con preguntas sobre los aspectos sociodemográficos, las percepciones y los cuidados de la transmisión del coronavirus 2 con 2.452 personas en 2020. Se ha realizado la estadística descriptiva y la asociación entre variables a través de la prueba chi-cuadrado con el nivel de significación del 5%. Resultados: Los hombres usaban menos mascarillas y lavaban menos las manos (p<0,001) que las mujeres (p<0,001). Los que viven en pueblos cumplen menos el aislamiento social (p=0,004), usan menos mascarillas, lavan menos las manos (p<0,001) y perciben que las personas de su alrededor no cumplen las medidas de prevención usando las mascarillas (p<0,001). De manera similar, los más jóvenes son los que menos cumplen el aislamiento social (p<0,001) y los que menos usan las mascarillas (p<0,001). Aquellos con el nivel medio de educación son los que más trabajan y los con el nivel básico son los más favorables para volver al trabajo (p<0,001), los que se fían menos del sistema de salud (p=0,002) y los que menos usan las mascarillas (p<0,001). Conclusión: Los aspectos culturales y de conducta de hombres, jóvenes, personas de baja escolaridad y los que viven en pueblos han contribuido para que el estado fuera el epicentro regional de la pandemia en Brasil.

Fatores etiológicos e prevalência de lesões bucofaciais em surfistas de Fortaleza

RESUMO O estudo investigou fatores etiológicos e prevalência de lesões bucofaciais em surfistas profissionais e amadores em Fortaleza, Ceará. Aplicou-se um questionário em 150 surfistas homens e usaram-se testes estatísticos (qui-quadrado e teste t de Student) com nível de significância p < 0,05. Em 56% encontrou-se alguma lesão bucofacial. Queimaduras de lábio e de face, laceração de mucosa e fratura dentária foram as mais prevalentes. Comparando surfistas competidores com não competidores houve significância entre ocorrência de lesões com fundo de rocha (p = 0,032) e com prancha (p = 0,003) e maior presença de lesões entre os competidores (p = 0,003). Conclui-se que fraturas dentárias e queimaduras facial e labial são prevalentes em surfistas e que há mais chances de ocorrência de lesões quanto maiores forem a idade e o tempo de prática.

ABSTRACT The study investigated etiological factors and the prevalence of orofacial lesions in surfers professionals and amateurs in Fortaleza, Brazil. A questionnaire was applied to 150 male surfers and statistical tests (Chi-square and Student t) were used with significance level p <0.05. In 56%, there was some orofacial lesion. Lip and face burns, mucosal laceration and dental fracture were the most prevalent. Comparing competitive surfers with non-competitors there was significance between the occurrence of rock bottom injuries (p=0.032) and surfboard (p=0.003) and greater presence of injuries among competitors (p=0.003). It is concluded that dental fractures and facial and lip burns are prevalent in surfers and that there is a greater chance of occurrence of injuries the greater the age and the time of practice of them.

RESUMEN El estudio investigó factores etiológicos y prevalencia de lesiones bucofaciales en surfistas profesionales y aficionados en Fortaleza, Ceará. Se aplicó un cuestionario en 150 surfistas de sexo masculino y se utilizaron pruebas estadísticas (chi cuadrada y prueba de la t de Student) con un nivel de relevancia estadística de p <0,05. En el 56% se encontró alguna lesión bucofacial. Las más frecuentes fueron quemaduras del labio y de la cara, laceración de mucosa y fractura dental. Al comparar a surfistas competidores con otros no competidores hubo relevancia entre lesiones producidas por el fondo (p = 0,032) y por la tabla (p = 0,003), y mayor existencia de lesiones entre competidores (p = 0,003). Se concluye que las fracturas dentales y las quemaduras facial y labial son frecuentes en surfistas y hay más probabilidad de que se produzcan lesiones cuanto mayor es la edad y el tiempo de práctica.

COVID-19 no Estado do Ceará: Comportamentos e crenças na chegada da pandemia / Covid-19 in the State of Ceará: Behaviors and beliefs in the arrival of the pandemic

O objetivo deste estudo foi avaliar os aspectos comportamentais e as crenças da população cearense frente a pandemia de COVID-19. Foi realizado um questionário onlinesobre aspectos sociodemográficos e opiniões relacionados a pandemia. Foram calculadas frequências absoluta e relativa, a associação entre variáveis foi realizada comQui-quadrado eo nível de significância foi de 5%. A amostra final contou com 2.259 participantes e foi observada associação entre o gênero feminino com um alto risco de contaminação (p=0,044) e o gênero masculino com a não realização voluntária da quarentena (p<0,001). Pessoas com 80 anos ou mais realizaram quarentena parcialmente devido ao fluxo de pessoas em casa (p<0,001).Os participantes com o ensino fundamental consideraram que estão em um nível de risco menos alto que os participantes com grau de escolaridade mais elevado (p<0,001). Neste grupo estão as pessoas que menos fizeram quarentena voluntária (p<0,001). Os participantes que moram no interior do Estado, tiveram menos contato direto com alguém testado positivamente para o coronavírus (p=0,031) e estão menos reclusos (p<0,001).É possível concluir que a abordagem frente a pandemia de COVID-19 varia de acordo com aspectos sociais, como gênero, idade, escolaridade e local de residência, assim como o sistema de crenças da população do Estado do Ceará.

The aim of this study as to evaluate the behavior al aspects and belief sof the population of Ceará in the face of the COVID-19 pandemic. An online questionnaire was conducted on sociodemographic aspects and opinions related to the pandemic. Absolute and relative requencies were calculated, the association between variables was performed with Chi-square and the level of significance as 5%. The final sample had 2,259 participants and an association was observed between the female gender with a high riskofcontamination (p = 0.044) and the male gender with voluntary non-performance of the quarantine (p <0.001). People aged 80 and over werepartiallyquarantinedduetotheflowofpeopleat home (p <0.001). Participants with primary education considered that they were at a lower risk level than participants with a higher level of education (p <0.001). In this group are the people who did the least voluntary quarantine (p <0.001). Participants who live in the interior of the state hadless direct contact with someone tested positive for the coronavírus (p = 0.031) and are lessinmates (p <0.001). It is possible to conclude that the approach to the COVID-19 pandemic varies according to social aspects, such as gender, age, education and place of residence, as well as the belief system of the population of the Stateof Ceará.(AU)

Effect of Metalloproteinase Inhibitors on Bond Strength of a Self-etching Adhesive on Erosively Demineralized Dentin.

PURPOSE: To analyze the influence of epigallocatechin-3-gallate (EGCG) and chlorhexidine (CHX) on adhesive-dentin bond strength of a self-etch adhesive to sound dentin (SD) and eroded dentin (ED). MATERIALS AND METHODS: Thirty-six middle-dentin samples were assigned to six groups (n = 6) according to pretreatment (DW: distilled water, control; 0.1% EGCG; or 2% CHX) and erosive challenge (presence or absence). Specimens were subjected to 2-h acquired pellicle formation, then half of them were exposed to 1% citric acid three times a day for five days. SD and ED were treated with the tested solutions for 60 s, and then Clearfil SE Bond was applied before resin composite buildup. Bonded teeth were longitudinally sectioned into sticks and half were immediately tested, while the remaining specimens were tested after six months. The mode of fracture was examined and the microtensile bond strength (µTBS) measured. Statistical analysis was performed with ANOVA and Bonferroni tests. RESULTS: At both time periods, regardless of the dentin substrate, EGCG groups did not show bond strengths that were significantly different from those obtained with DW (p > 0.05), while CHX generated lower values than did DW (p < 0.05). On SD, there was a bond strength reduction only in the CHX groups after six months. However, for ED, the bond strength significantly decreased in all groups. CONCLUSION: CHX negatively affected both dentin substrates, while the pretreatment with EGCG did not affect µTBS over time on SD. µTBS may be influenced by the substrate over time and EGCG can be used as an alternative to CHX to maintain the bond strength of self-etching adhesives.

Avaliação do efeito de técnicas de acabamento e polimento na rugosidade superficial de resinas compostas / Evaluation of the effect of finishing and polishing techniques on surface roughness of composite resins

Introdução: o acabamento e o polimento das resinas compostas (RC) podem interferir diretamente na rugosidade desses materiais, estando relacionadas com a adesividade de placa bacteriana, manchamento, brilho e lisura. Objetivo: comparar a rugosidade superficial de duas RC, sendo uma micro-híbrida (Filtek Z250) e outra nanoparticulada (Filtek Z350), após a realização dos procedimentos de acabamento e polimento. Métodos: utilizando-se uma matriz metálica, confeccionaram-se quinze discos de cada RC. A lisura superficial proporcionada pela fita de poliéster foi avaliada por meio de um rugosímetro (Hommel Tech-T1000), obtendo-se dados iniciais. Realizou-se a mensuração em triplicata, obtendo-se o valor da rugosidade média (Ra). Lixaram-se as superfícies de topo dos espécimes e seguiu-se nova obtenção da Ra. Os espécimes foram, aleatoriamente, distribuídos em três grupos: GI ­ discos de óxido de alumínio; GII ­ pontas siliconadas e GIII ­ discos de diamante micronizado, sendo obtida a Ra final. Os dados foram analisados pelo teste de Kruskal-Wallis e Qui-quadrado (α=1%). Resultados: a média e o desvio-padrão expresso em µm foram: Z-250 GI - 0,16 (0,09), GII - 0,32 (0,06) e GIII - 0,06 (0,02) e para Z-350 GI - 0,06 (0,01), GII - 0,49 (0,14) e GIII - 0,07 (0,01). Para Z-250, o GIII apresentou melhor polimento, sendo, estatisticamente, diferente de GI e GII (p≤0,01). Para Z-350, não houve diferença estatística entre os GI e GIII, mas eles foram superiores ao GII (p≤0,01). Conclusão: o disco de diamante micronizado proporcionou melhores valores de lisura superficial independente do tipo de resina composta empregada.

Introduction: finishing and polishing of composite resins (CR) can directly interfere with the roughness of these materials, being related to bacterial plaque adhesion, staining, gloss and smoothness. Objective: to compare the surface roughness of two CR, a micro-hybrid (Filtek Z250) and a nanoparticulate (Filtek Z350) after finishing and polishing. Methods: using a metal matrix, fifteen disks of each CR were made. The surface smoothness provided by the polyester tape was evaluated by a rugosimeter (Hommel Tech-T1000) obtaining initial data. Measurements were made in triplicate, and the mean roughness value (Ra) was obtained. The top surfaces of the specimens were sieved and re-obtained the Ra. The specimens were randomly distributed into three groups: GI - aluminum oxide discs; GII - silicone tips and GIII - micronized diamond discs, obtaining the final Ra. Data were analyzed by the Kruskal-Wallis test and chi-square test (α = 1%). Results: the mean and standard deviation expressed in µm were: Z-250 GI - 0.16 (0.09), GII - 0.32 (0.06) and GIII - 0.06 (0.02) and for Z -350 GI - 0.06 (0.01), GII - 0.49 (0.14) and GIII - 0.07 (0.01). For Z-250, the GIII presented better polishing, being statistically different from GI and GII (p≤0.01). For Z-350, there was no statistical difference between GI and GIII, but these were higher than GII (p≤0.01). Conclusion: the micronized diamond disk provided better surface smoothness values independent on the type of composite resin used.

Pretreatment with Sodium Fluoride Maintains Dentin Bond Strength of a Two-Step Self-Etch Adhesive after Thermal Stressing.

PURPOSE: To evaluate the effect of sodium fluoride and chlorhexidine digluconate on the composite-dentin bond strength of a self-etch adhesive after thermocycling. MATERIALS AND METHODS: Eighteen human third molars were prepared to expose a flat dentin surface and were divided into 3 groups (n = 6) according to the 3 cavity cleaning solutions: distilled water, 2% chlorhexidine digluconate (CHX), or 1.23% sodium fluoride (NaF). Solutions were rubbed onto dentin surfaces for 60 s, followed by bonding with Clearfil SE Bond, and a 5-mm-thick composite crown buildup. Bonded teeth were stored in distilled water for 24 h and then longitudinally sectioned to obtain bonded sticks. Half of the specimens were immediately tested in tension at 0.5 mm/min, while the remaining specimens were tested after 60,000 thermal cycles. Data were analyzed using two-way ANOVA and the Holm-Sidak method. RESULTS: There was no significant difference between the groups after 24 h (p > 0.05). Thermocycling resulted in significant bond strength reduction for distilled water and CHX (p < 0.05). When 24 h bond strengths were compared to the thermocycling group, NaF maintained its bond strength (p > 0.05), while significant reductions were observed for distilled water and CHX (p < 0.05). CONCLUSIONS: Pretreatment with NaF maintained the bond strength of Clearfil SE Bond to dentin after 60,000 thermal cycles, but pretreatment with CHX did not.

Physicochemical Properties of a Methacrylate-Based Dental Adhesive Incorporated with Epigallocatechin-3-gallate

This study aimed to evaluate the influence of epigallocatechin-3-gallate (EGCG) incorporation on the physicochemical properties of a methacrylate-based dental adhesive. EGCG was added to Adper Easy One (3M-ESPE) except in control group, to obtain concentrations of 0.01% w/w and 0.1% w/w of EGCG-doped adhesives. For water sorption (WS) and solubility (SL) surveys, resin discs were assayed following ISO recommendations (n=10). The degree of conversion (DC) was analyzed by FTIR whereas flexural strength (FS) was tested by three-point bending with bar specimens (n=10). Data were subjected to one-way ANOVA and Tukey's test (p<0.05). No significant difference in the DC, WS and FS were found between the different concentrations of EGCG (p>0.05). Adhesives containing 0.1% or 0.01% of EGCC demonstrated similar values of SL (p>0.05) and higher than those found for adhesive without EGCC (p<0.05). In conclusion, the addition of EGCC to adhesive reduced the solubility without affecting the other evaluated properties.

Esse estudo teve como objetivo avaliar a influência da incorporação de epigalocatequina-3-galato (EGCG) nas propriedades físico-químicas de um sistema adesivo à base de metacrilato. O EGCG foi adicionado ao Adper Easy One (3M-ESPE), exceto para o grupo controle, para a obtenção das concentrações de 0,01% e 0,1% p/p. No ensaio de sorção (S) e solubilidade (SL), foram confeccionados discos de resina de acordo com as recomendações da ISO (n=10). O grau de conversão (GC) foi analisado através de FTIR, enquanto a resistência flexural (RF) foi avaliada em teste de flexão de três pontos com espécimes em forma de barra (n=10). Os dados foram submetidos à Análise de Variância a um critério e teste de Tukey (p<0,05). Não houve diferença significativa entre as concentrações de EGCG testadas no GC, SL e RF (p>0,05). Adesivos contendo EGCG a 0,1% ou 0,01% apresentaram valores similares de SL (p>0,05) e maiores do que os valores obtidos pelo adesivo não incorporado por EGCG. Conclui-se que a adição de EGCG ao adesivo reduziu a solubilidade sem afetar as outras propriedades avaliadas.

Physicochemical properties of a methacrylate-based dental adhesive incorporated with epigallocatechin-3-gallate.

This study aimed to evaluate the influence of epigallocatechin-3-gallate (EGCG) incorporation on the physicochemical properties of a methacrylate-based dental adhesive. EGCG was added to Adper Easy One (3M-ESPE) except in control group, to obtain concentrations of 0.01% w/w and 0.1% w/w of EGCG-doped adhesives. For water sorption (WS) and solubility (SL) surveys, resin discs were assayed following ISO recommendations (n=10). The degree of conversion (DC) was analyzed by FTIR whereas flexural strength (FS) was tested by three-point bending with bar specimens (n=10). Data were subjected to one-way ANOVA and Tukey's test (p<0.05). No significant difference in the DC, WS and FS were found between the different concentrations of EGCG (p>0.05). Adhesives containing 0.1% or 0.01% of EGCC demonstrated similar values of SL (p>0.05) and higher than those found for adhesive without EGCC (p<0.05). In conclusion, the addition of EGCC to adhesive reduced the solubility without affecting the other evaluated properties.

Effect of surface pretreatments on the microtensile bond strength of lithium-disilicate ceramic repaired with composite resin.

The aim of this study was to evaluate the influence of ceramic surface treatments and silane drying temperature on the microtensile bond strength (µTBS) of a resin composite to a lithium disilicate ceramic. Twenty blocks (7x7x5 mm) of lithium disilicate-based hot-pressed ceramic were fabricated and randomly divided into 4 groups: G1: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with room-temperature air; G2: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with 45 ± 5 °C warm air; G3: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with 45 ± 5 °C warm air; G4: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with air at room-temperature. After treatments, an adhesive system (Single Bond 2) was applied, light-cured and direct restorations were built up with a resin composite (Filtek Z250). Each specimen was stored in distilled water at 37 °C for 24 h and cut into ceramic-composite beams with 1 mm2 of cross-sectional area for µTBS testing. Statistical analysis was performed with one-way ANOVA and Student-Newman-Keuls test (α=0.05). µTBS means (S.D.) in MPa were: G1: 32.14 (7.98), G2: 35.00 (7.77) and G3: 18.36 (6.17). All specimens of G4 failed during the cutting. G1 and G2 presented significantly higher µTBS than G3 (p<0.05). There was no statistically significant difference between G1 and G2 (p>0.05). As far as the bond strength is concerned, surface pretreatment of lithium-disilicate ceramic with hydrofluoric acid and silane application can be used as an alternative to repair ceramic restorations with composite resin, while surface pretreatment with sandblasting should be avoided.

Effect of Surface Pretreatments on the Microtensile Bond Strength of Lithium-Disilicate Ceramic Repaired with Composite Resin

The aim of this study was to evaluate the influence of ceramic surface treatments and silane drying temperature on the microtensile bond strength (µTBS) of a resin composite to a lithium disilicate ceramic. Twenty blocks (7x7x5 mm) of lithium disilicate-based hotpressed ceramic were fabricated and randomly divided into 4 groups: G1: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with room-temperature air; G2: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with 45 ± 5 °C warm air; G3: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with 45 ± 5 °C warm air; G4: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with air at room-temperature. After treatments, an adhesive system (Single Bond 2) was applied, light-cured and direct restorations were built up with a resin composite (Filtek Z250). Each specimen was stored in distilled water at 37 °C for 24 h and cut into ceramic-composite beams with 1 mm2 of cross-sectional area for µTBS testing. Statistical analysis was performed with one-way ANOVA and Student-Newman-Keuls test (α=0.05). µTBS means (S.D.) in MPa were: G1: 32.14 (7.98), G2: 35.00 (7.77) and G3: 18.36 (6.17). All specimens of G4 failed during the cutting. G1 and G2 presented significantly higher µTBS than G3 (p<0.05). There was no statistically significant difference between G1 and G2 (p>0.05). As far as the bond strength is concerned, surface pretreatment of lithium-disilicate ceramic with hydrofluoric acid and silane application can be used as an alternative to repair ceramic restorations with composite resin, while surface pretreatment with sandblasting should be avoided.

O objetivo deste estudo foi avaliar a influência dos tratamentos de superfícies e a temperatura de secagem do silano na resistência de união de resina composta à cerâmica de disilicato de lítio. Vinte blocos (7x7x5 mm) de cerâmica à base de disilicato de lítio foram fabricados e aleatoriamente divididos em quatro grupos: G1: condicionamento com ácido fluorídrico a 9,5% por 20 s e secagem do silano com ar à temperatura ambiente; G2: condicionamento com ácido fluorídrico a 9,5% por 20 s e secagem do silano com ar aquecido a 45± 5 °C; G3: jateamento com partículas de óxido de alumínio de 50 µm e secagem do silano com ar aquecido a 45 ± 5 °C; G4: jateamento com partículas de óxido de alumínio de 50 µm e secagem do silano com ar à temperatura ambiente. Após os tratamentos, o adesivo Adper Single Bond 2 foi aplicado, fotoativado e foi construído um platô de resina composta (Filtek Z250). Cada espécime foi armazenado em água destilada a 37 °C por 24 h e cortados em forma de palito de área adesiva de 1 mm2 para a realização do teste de microtração. Os dados foram submetidos à ANOVA e ao teste de Student-Newman-Keuls (α=0,05). As médias (D.P.) dos valores de resistência de união em MPa foram: G1: 32,14 (7,98), G2: 35,00 (7,77) e G3: 18,36 (6,17). G1 e G2 apresentaram maiores valores de resistência de união que G3 (p<0,05). Não houve diferença estatística entre as médias dos valores dos grupos G1 e G2 (p>0,05). Levando-se em consideração a resistência de união, o pré-tratamento de cerâmica de disilicato de lítio com ácido fluorídrico e aplicação de silano pode ser uma alternativa para o reparo de restaurações de cerâmicas com resinas compostas, enquanto que o pré-tratamento de superfície com o jateamento deve ser evitado.

Effect of the flavonoid epigallocatechin-3-gallate on resin-dentin bond strength.

PURPOSE: To evaluate the effect of dentin pretreatment with epigallocatechin-3-gallate solution on the preservation of the resin/dentin interface with etch-and-rinse adhesives. MATERIALS AND METHODS: Thirty extracted human molars were prepared to expose the dentin surface and divided into 5 groups according to the pretreatment solution. Dentin surfaces were etched (35% phosphoric acid for 15 s), rinsed, and air dried. Dentin was rewetted either with distilled water, 3 different epigallocatechin-3-gallate solutions (EGCG; 0.02%, 0.1%, or 0.5% w/v), or 2% chlorhexidine digluconate solution for 60 s. Adper Single Bond 2 was applied and a subsequent 5-mm-thick resin crown was built up. Bonded teeth were longitudinally sectioned to obtain sticks with a cross-sectional area of 1.0 mm2. Half of the specimens were immediately tested, while the remaining specimens were tested after storage in 3 mMol/l sodium azide solution at 37°C for six months. The mode of fracture was examined. Bond strength values were analyzed with ANOVA and Student-Newman-Keuls tests. RESULTS: After 24 h of storage, mean bond strengths of 0.5% EGCG were significantly lower than those found for the other groups (p < 0.05), except for 0.02% EGCG (p > 0.05). Resin-dentin bond strengths after 6 months were not significantly different among the experimental groups (p > 0.05). Storage in water for 6 months resulted in a significant decrease in bond strength for the water control group only (p < 0.05). The bond strengths of the experimental groups remained stable after 6 months of water storage (p > 0.05). CONCLUSION: Pretreatment with EGCG preserved the bond of Adper Single Bond 2 to dentin after six months of storage equally well as pretreatment with chlorhexidine digluconate.

Efficacy of smear layer removal by cavity cleaning solutions: an atomic force microscopy study / Eficácia da remoção da lama dentinária por soluções de limpeza cavitária: estudo de microscopia de força atômica

PURPOSE: To evaluate the efficacy of smear layer removal by cavity cleaning agents by the use of atomic force microscopy (AFM). METHODS: Five intact human third molars were sectioned in the coronal portion to obtain dentin disks, which were ground with 600-grit abrasive paper for 10 s. Serial longitudinal sections were made perpendicular to each other to create four specimens, from each tooth. The specimens were divided into four treatment groups: GI, 2 percent chlorhexidine; GII, calcium hydroxide solution; GIII, 1.23 percent fluoride solution; and GIV, 37 percent phosphoric acid. The solutions were applied with a brush for 60 s, with the exception of the 37 percent phosphoric acid, which was applied for 15 s and rinsed with distilled water for 60 s. The specimens were examined by AFM. RESULTS: All of the specimens in GI and GII showed 100 percent of the dentin tubules obliterated by the smear layer. However, all of the specimens in GIII and GIV showed 0 percent of the dentin tubules obliterated by the smear layer. CONCLUSION: The 1.23 percent fluoride solution was effective in removing the smear layer and can be used as a cavity cleanser.

OBJETIVO: Avaliar a eficácia da remoção de lama dentinária por agentes de limpeza cavitária através da análise de microscopia de força atômica (MFA). METODOLOGIA: Cinco terceiros molares humanos hígidos foram seccionados transversalmente na porção coronária, obtendo discos de dentina de 2 mm, que foram desgastados com lixas de granulação 600, por 10 s.Foram feitos cortes seriados longitudinais e perpendiculares entre si, obtendo-se quarto espécimes de cada dente. Os espécimes foram divididos em 4 grupos: GI- clorexidina a 2 por cento; GII- água de hidróxido de cálcio; GIII- solução fluoretada a 1,23 por cento; GIV - ácido fosfórico 37 por cento. As soluções foram aplicadas com pincel por 60 s, com exceção do ácido fosfórico que foi aplicado por 15 s e lavado com água destilada pelo mesmo tempo. Os espécimes foram analisados por MFA. RESULTADOS: Todos os espécimes de GI e GII apresentaram 100 por cento dos túbulos dentinários obliterados por lama dentinária. Os espécimes de GIII e GIV apresentaram 0 por cento dos túbulos obliterados por lama dentinária. CONCLUSÃO: A solução de fluoretada a 1,23 por cento foi eficiente na remoção de lama dentinária, podendo ser empregada na limpeza de cavidades.