Titanium dioxide nanotubes added to glass ionomer cements affect S. mutans viability and mechanisms of virulence

Abstract This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.

Antimicrobial and anti-caries effect of new glass ionomer cement on enamel under microcosm biofilm model

Abstract The occurrence of caries lesions adjacent to restorations is a serious problem in Dentistry. Therefore, new antimicrobial restorative materials could help to prevent recurrent carious lesions. This study evaluated the effect of a new glass ionomer cement (Ion Z) on the viability of a microcosm biofilm and on the development of enamel demineralization. Enamel samples were filled with the following materials (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) and D) no restoration (control). The samples were then exposed to human saliva mixed with McBain saliva (1:50) containing 0.2% sucrose for 14 days. The live and dead bacteria were quantified by fluorescence using a confocal laser-scanning microscope. The enamel demineralization was analyzed using transverse microradiography (TMR). The data were submitted to ANOVA/Tukey or Kruskal-Wallis/Dunn test (p<0.05). Ion Z induced a higher percentage of dead bacteria (60.96±12.0%) compared to the other groups (Maxxion R: 39.8±6.7%, Ketac Fil Plus: 43.7±9.71% and control 46.3±9.5%). All materials significantly reduced the average mineral loss compared to control (Ion-Z 25.0±4.2%vol, Maxxion R 23.4±8.0%vol, Ketac Fil Plus 30.7±7.7 and control 41.2±6.6%vol). Ion-Z was the only material able to significantly improve the mineral content at the surface layer (Zmax: 63.5±18.2%vol) compared to control (38.9±11.3%vol). Ion-Z shows antimicrobial potential, but its anti-caries effect was similar to the other materials, under this model.

Resumo A ocorrência de lesões de cárie adjacentes a restaurações é um sério problema na Odontologia. Portanto, novos materiais restauradores antimicrobianos poderiam ajudar a prevenir as lesões cariosas recorrentes. Este estudo avaliou o efeito de um novo cimento de ionômero de vidro (Ion Z) sobre a viabilidade de um biofilme microcosmo e o desenvolvimento da desmineralização do esmalte. Amostras de esmalte foram restauradas com os seguintes materiais (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) e D) sem restauração (controle). As amostras foram submetidas a uma mistura de saliva humana com saliva de McBain (1:50) contendo sacarose a 0,2% por 14 dias. As bactérias vivas e mortas foram quantificadas por fluorescência usando um microscópio confocal de varredura à laser. A desmineralização do esmalte foi analisada usando microradiografia transversal (TMR). Os dados foram submetidos aos testes ANOVA/Tukey ou Kruskal-Wallis/Dunn (p<0,05). O Ion Z induziu uma porcentagem mais elevada de bactérias mortas (60,96 ± 12,0%) comparado aos outros grupos (Maxxion R: 39,8 ± 6,7%, Ketac Fil Plus: 43,7 ± 9,71% e controle 46,3 ± 9,5%). Todos os materiais reduziram significativamente a perda mineral média em relação ao controle (Ion-Z 25,0 ± 4,2% vol, Maxxion R 23,4 ± 8,0% vol, Ketac Fil Plus 30,7 ± 7,7% vol e controle 41,2 ± 6,6% vol). O Ion-Z foi o único material capaz de melhorar significativamente o conteúdo mineral na camada superficial (Zmax: 63,5 ± 18,2% vol) em comparação com o controle (38,9 ± 11,3% vol). Ion-Z mostrou potencial antimicrobiano, mas seu efeito anti-cárie foi semelhante aos outros materiais, sob este modelo.

Evaluation of physical-mechanical properties, antibacterial effect, and cytotoxicity of temporary restorative materials

Abstract The objective of this study was to compare selective physical-mechanical properties, antibacterial effects and cytotoxicity of seven temporary restorative materials (TRM): five resin-based materials [Bioplic (B), Fill Magic Tempo (FM), Fermit inlay (F), Luxatemp LC (L) and Revotek LC (R)], and zinc oxide-eugenol cement (IRM) and glass ionomer cement (GIC) as the controls. Material and methods The physical-mechanical properties were evaluated by determining microleakage (ML), ultimate tensile strength (UTS) and Shore D hardness (SDH). In addition, the polymerization rate (Pr-1), depth of cure (DC), water sorption and solubility (WS/SL) were evaluated. The antimicrobial effects of the materials were assessed by biofilm accumulation of Streptococcus mutans (BT) and the direct contact test (DCT) by exposure to Enterococcus faecalis for 1 and 24 h, and cytotoxicity by MTT assay. The data were analyzed by ANOVA or Kruskall-Wallis tests, and a complementary post-hoc method (p<0.05). Results Group B, followed by FM and GIC had significantly lower percentages of microleakage in comparison with the other groups; Groups FM and L showed the highest WS, while Groups R and FM showed the significantly lowest SL values (p<0.05). Group R showed the statistically highest UTS mean and the lowest DC mean among all groups. Group F showed the lowest S. mutans biofilm accumulation (p=0.023). Only the Group L showed continued effect against E. faecalis after 1 h and 24 h in DCT. The L showed statistically lower viability cell when compared to the other groups. Conclusions These findings suggest the antibacterial effect of the temporary materials Fill Magic and Bioplic against S. mutans, while Luxatemp showed in vitro inhibition of S. mutans biofilm accumulation and E. faecalis growth. Regarding the cell viability test, Luxatemp was the most cytotoxic and Fill Magic was shown to be the least cytotoxic.

The effects of different restorative materials on periodontopathogens in combined restorative-periodontal treatment

Abstract Objective The aim of the study was to evaluate the association between subgingival restorations and the target periodontopathogenic bacteria (Pg, Td and Pi) in subgingival biofilm during one year after combined restorative-periodontal treatment. Material and Methods Seventeen systemically healthy subjects, who were positive for the presence of three cervical lesions associated with gingival recessions in three different adjacent teeth, were included in the study. A total of 51 combined defects were treated with connective tissue graft plus a nanofilled composite resin (NCR+CTG), a resin-modified glass ionemer cement (RMGI+CTG) and a fluoride-releasing resin material with pre-reacted glass (PRG), called giomer (Giomer+CTG). Periodontal clinical measurements and subgingival plaque samples were obtained from all combined defects at baseline and at 6 and 12 months after the surgery. The number of bacteria were evaluated by the real-time polymerase chain reaction (qPCR) method. Results No statistically significant difference in the amount of DNA copies of Pg, Td and Pi was observed in any of the groups at any time points (p>0.05). In addition, there was no statistically significant difference in the amount of DNA copies of the bacteria at baseline and at 6 and 12 months postoperatively, regardless of treatment group (p>0.05). Conclusion This study suggests that subgingivally placed NCR, RMGI and giomer restorations can show similar effects on periodontopathogenic bacteria in the treatment of gingival recessions that are associated with noncarious cervical lesions (NCCLs).

Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial

Abstract In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Evaluation in vivo of biocompatibility of differents resin-modified cements for bonding orthodontic bands

ABSTRACT The focus of this study was to test the hypothesis that there would be no difference between the biocompatibility of resin-modified glass ionomer cements. Sixty male Wistar rats were selected and divided into four groups: Control Group; Crosslink Group; RMO Group and Transbond Group. The materials were inserted into rat subcutaneous tissue. After time intervals of 7, 15 and 30 days morphological analyses were performed. The histological parameters assessed were: inflammatory infiltrate intensity; reaction of multinucleated giant cells; edema; necrosis; granulation reaction; young fibroblasts and collagenization. The results obtained were statistically analyzed by the Kruskal-Wallis and Dunn test (P<0.05). After 7 days, Groups RMO and Transbond showed intense inflammatory infiltrate (P=0.004), only Group RMO presented greater expression of multinucleated giant cell reaction (P=0.003) compared with the control group. After the time intervals of 15 and 30 days, there was evidence of light/moderate inflammatory infiltrate, lower level of multinucleated giant cell reaction and thicker areas of young fibroblasts in all the groups. The hypothesis was rejected. The Crosslink cement provided good tissue response, since it demonstrated a lower level of inflammatory infiltrate and higher degree of collagenization, while RMO demonstrated the lowest level of biocompatibility.

Streptococcus Mutans Biofilm Influences on the Antimicrobial Properties of Glass Ionomer Cements

Abstract The aim of this study was to evaluate the in vitro antibacterial and biofilm inhibition properties of glass ionomer restorative cements. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX were analyzed using the following tests: a) agar plate diffusion test to evaluate the inhibitory activity of cements against S. mutans (n=8); b) S. mutans adherence test by counting colony-forming units after 2 h of material/bacteria exposure (n=10); c) biofilm wet weight after seven days of bacterial accumulation on material disks, with growth medium renewed every 48 h (n=10); d) pH and fluoride measurements from the medium aspired at 48 h intervals during the 7-day biofilm development (n=10). Data from the a, b and c tests were submitted to Kruskal-Wallis and Mann-Whitney tests and the fluoride-release and pH data were submitted to two-way ANOVA and Tukey tests (a=5%). Vitremer followed by Ketac Nano showed the greatest inhibitory zone against S. mutans than the conventional ionomers. Vitremer also showed higher pH values than Ketac Nano and Fuji IX in the first 48 h and released higher fluoride amount than Ketac Nano e Ketac Molar Easymix throughout the experimental period. The chemical composition of restorative glass ionomer materials influenced the antibacterial properties. The resin modified glass ionomer (Vitremer) was more effective for inhibition of S. mutans and allowed greater neutralization of the pH in the first 48 h. However, the type of glass ionomer (resin modified or conventional) did not influence the weight and adherence of the biofilm and fluoride release.

Resumo O objetivo neste estudo foi avaliar in vitro as propriedades antibacterianas e a inibição do biofilme de cimentos de ionômero de vidro restauradores. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX foram avaliados através dos seguintes testes: a) teste de difusão em ágar para avaliar a inibição de S. mutans nos cimentos (n=8); b) adesão de S. mutans pela contagem de unidades formadoras de colônia após 2h de exposição material/bactéria (n=10); c) peso do biofilme úmido após sete dias de acúmulo bacteriano nos discos do material, com meio de cultura renovado após 48 h (n=10); d) mensuração do pH e liberação de flúor do meio aspirado nos intervalos de 48 h durante 7 dias de crescimento do biofilme (n=10). Os dados dos testes a, b e c foram submetidos aos testes Kruskal-Wallis e Mann-Whitney e os dados de liberação de flúor e pH a ANOVA dois fatores e Tukey (a = 5%). Vitremer seguido pelo Ketac Nano mostrou maior zona de inibição contra S. mutans quando comparados aos ionômeros convencionais. Vitremer também apresentou valores de pH mais elevados do que Ketac Nano e Fuji IX nas primeiras 48 h e liberou maior quantidade de flúor do que Ketac Nano e Ketac Molar Easymix durante todo o período experimental. A composição química dos ionômeros de vidro restauradores influenciou nas propriedades antibacterianas. O ionômero de vidro modificado por resina (Vitremer) foi mais eficaz na inibição de S. mutans e permitiu maior neutralização do pH nas primeiras 48 h. No entanto, o tipo de ionômero de vidro (modificado por resina ou convencional) não influenciou no peso e adesão do biofilme e na liberação de flúor.

Efeito do desafio erosivo nas propriedades e na estabilidade de união de materiais restauradores ao esmalte e dentina de dentes decíduos / Effect of erosive challenge on the properties and bond stability of restorative materials to enamel and dentin of primary teeth

Este estudo avaliou o efeito do desafio erosivo nas propriedades e na estabilidade de união de materiais restauradores ao esmalte e dentina decídua. Duzentos e quarenta molares decíduos foram alocados em 24 grupos, de acordo com substrato - esmalte ou dentina, condição prévia do substrato - hígido ou erodido, material restaurador - resina composta associada ao sistema adesivo - RC, cimento de ionômero de vidro de alta viscosidade - CIVAV, ou modificado por resina - CIVMR, e tratamento após procedimento adesivo - controle (imersão em solução salina/7dias) ou desafio erosivo (imersão em bebida a base de cola por 5 min/3x ao dia/7 dias). Os dentes dos grupos esmalte e dentina erodidos foram submetidos ao desafio erosivo previamente aos procedimentos restauradores. Cânulas de polietileno foram posicionadas sobre superfícies planas dos substratos pré-tratados, para então serem preenchidas por um dos materiais avaliados. Após armazenamento por 24h a 37°C, os espécimes foram submetidos a um dos tratamentos propostos. Metade dos espécimes foi submetida imediatamente ao teste de microcisalhamento e a outra metade após 12 meses de armazenamento em água a 37ºC. Posteriormente, a análise do padrão de fratura foi realizada em estereomicroscópio (400X). Para a análise de resistência à flexão (RF) e rugosidade superficial (RS), trinta corpos de prova foram confeccionados (10x2x1mm). Após armazenamento por 24h, a leitura inicial de RS de dez corpos de prova selecionados aleatoriamente foi obtida. Os corpos de prova foram então imersos em um dos tratamentos propostos - desafio erosivo ou solução salina, para então ser realizada a segunda leitura. Decorrido esta análise, os corpos de prova foram submetidos ao teste de RF (1mm/min). Os valores de resistência de união (RU), bem como de RS e RF obtidos foram submetidos a Análise de Variância e Teste de Tukey (?=5%). Análise de Weibull foi também conduzida considerando os valores de RF...

This study evaluated the effect of erosive challenge on the properties and bond stability of restorative materials to primary enamel and dentin. Two hundred and forty primary molars were assigned into 24 groups, in according to the substrate - enamel or dentin, the precondition of substrate - sound or eroded, the restorative material - resin composite associated to adhesive system - RC, high-viscous glass ionomer cement- HVGIC or resin-modified glass ionomer cement - RMGIC, e the treatment after restorative procedure - control (immersion in saline solution/7 days) or erosive challenge (immersion in cola-based drink for 5 min/3x per day/7 days). Teeth from the eroded dentin and enamel groups were subjected to erosive challenge prior to bonding procedures. Polyethylene tubes were placed on flat surfaces of the pretreated substrates, and then were filled up with one of evaluated materials. After storage for 24h at 37ºC, the specimens were submitted to one of the proposed treatments. Half of the specimens were immediately submitted to the microshear bond strength test, and the other half after 12 months of water storage at 37ºC. Subsequently, the failures pattern evaluation was performed in stereomicroscopy (400X). For the assessment of flexural strength (FS) and superficial roughness (SR), thirty specimens were built up (10x2x1mm). After storage for 24h, the first reading of SR from ten specimens randomly selected was obtained. Specimens were immersed in one of proposed treatments - erosive challenge or saline solution, to then be performed the second reading. After this assessment, specimens were submitted to FS (1mm/min)...

Antibacterial effects of several current orthodontic materials against Streptococcus mutans / Efectos antibacterianos de varios materiales ortodóncicos usuales frente al Streptococcus mutans

The aim of this study was to examine the antibacterial effect of several current orthodontic materials against a certain oral bacterium. The antibacterial activities of six orthodontic composite resins (Transbond LR, Light Cure Retainer (LCR), Light Bond, System 1+, Kurasper F, Transbond XT adhesive), two orthodontic bonding materials (Transbond XT primer and System 1+ activator) and two glass ionomer cements (GIC) [Multicure Glass Ionomer and Ketac Cem GIC] were evaluated against Streptococcus mutans. The hard materials were put into the Teflon mould. The liquid materials were put on a paper disc. All materials were handled under aseptic conditions and placed on agar culture plates. All plates were incubated at 5% CO2 and 37 ºC for 48 hours. The bacterial growth inhibition zones including the diameter of the sample were measured in millimetres. As a result of this study, the multicure GIC showed the highest antibacterial effectiveness, but no inhibition zones were noted for ketac cem GIC. The light bond adhesive of the Reliance orthodontic bonding system produced high antibacterial effect against S mutans, while the Reliance composite (LCR) did not show any antibacterial effect (p < 0.05). Both composite and primer of the transbond XT system demonstrated significant antibacterial effect against the test bacterium when compared to transbond LR (p < 0.05). Among the materials tested, kurasper F, Ormco system 1+ and system 1+ activator showed slight or no inhibitory effect against the test bacterium in this study. In patients who have relatively high salivary levels of Streptococci mutans before treatment, the multicure GIC, the Reliance light bond adhesive, and transbond XT system which had high level antibacterial properties could be applied.

El objetivo de este estudio fue examinar el efecto antibacteriano de varios materiales ortodóncicos actuales sobre cierta bacteria oral. Se evaluaron las actividades antibacterianas frente al Streptococcus mutans, de seis resinas compuestas (composites) ortodóncicas (Transbond LR, Light Cure Retainer (LCR), Light Bond, System 1+, Kurasper F, Transbond XT), dos adhesivos ortodóncicos (Transbond XT y Sistema 1+ activador) y dos cementos de ionómeros de vidrio (GIC) [ionómero de vidrio Multi-cure y Ketac Cem GIC]. Los materiales duros fueron puestos en el molde de Teflón. Los materiales líquidos fueron puestos en un disco del papel. De todos los materiales fueron manipulados bajo condiciones asépticas y pusieron en el agar cultive los platos. Todos las placas fueron manipuladas en condiciones asépticas, y colocados en placas de cultivo agar. Todas las placas fueron incubadas a 5% CO2 y 37 ºC durante 48 horas. Las zonas de inhibición del crecimiento bacteriano, incluido el diámetro de la muestra, fueron medidas en milímetros. Un aspecto del resultado de este estudio, fue que el Multi-Cure GIC mostró la efectividad antibacteriana más alta, en cambio no se observó ninguna zona de inhibición para el ketac cem GIC. El adhesivo Light Bond del sistema Reliance para la adhesión ortodóncica, produjo altos efectos antibacterianos frente al S mutans, mientras que el composite de Reliance (LCR) no mostró efecto antibacteriano alguno (p < 0.05). Tanto el composite como el iniciador (primer) del sistema XY transbond probaron poseer un efecto antibacteriano significativo frente a la bacteria de la prueba, cuando se les comparó con el transbond LR (p < 0.05). Entre los materiales probados, kurasper F, Ormco Sistema 1+ y sistema 1+ activador no mostraron efecto inhibitorio alguno, o sólo ligeramente, frente a las bacterias de la prueba en este estudio. En pacientes con niveles salivales relativamente altos de Streptococci mutans antes del tratamiento, podrían aplicarse el Multi-Cure GIC, el adhesivo Reliance Light Bond, y el sistema transbond XT - los cuales tuvieron un alto nivel de propiedades antibacterianas.

Inspeção do cimento de ionômero de vidro em duas camadas no tratamento restaurador atraumático (Art): estudos in vitro e in vivo / Inspection of the ionomer cement glass in two layers in non-traumatic restorative treatment (ART): in vitro and in vivo studies

o objetivo geral desta tese foi compilar resultados de estudos realizados in vitro e in vivo utilizando-se a técnica de inserção em duas camadas do cimento de ionômero de vidro (CIV) para restaurações ocluso-proximais executadas segundo a filosofia do Tratamento Restaurador Atraumático (ART). Foi primeiramente realizada uma revisão sistemática da literatura sobre restaurações nessas superfícies em dentes decíduos, avaliando a longevidade de restaurações atraumáticas, comparadas ao tratamento convencional, com o objetivo de validar a necessidade de novos estudos nessa área. Após essa avaliação, foram realizados e incluídos 3 artigos in vitro, o primeiro avaliando o vedamento marginal, e os outros dois avaliando a resistência adesiva em dentina sadia e cariada; dentre os estudos in vivo, dois foram realizados, sendo o primeiro como estudo piloto, e o segundo como ensaio clínico controlado randomizado. A revisão sistemática demonstra que o ART, em cavidades ocluso- proximais, apesar de ter baixa longevidade clínica, é comparável às restaurações realizadas por métodos convencionais. Em linhas gerais, a inserção do CIV em duas camadas, sendo a primeira mais fluida, (com proporção pó-líquido de 1 :2) seguida da colocação de uma camada de CIV com consistência normal (proporção pó-líquido de 1:1) apresenta resultados satisfatórios em relação ao controle, em termos laboratoriais. Clinicamente, porém, a inserção em duas camadas não se traduz em maior longevidade quando comparada à técnica de ART convencional. Outros aspectos parecem influenciar clinicamente a longevidade de restaurações ocluso- proximais de maneira geral, e não somente as restaurações realizadas segundo a filosofia do ART.

The main objective of this thesis was to compile results of in vitro and in vivo studies using the two-Iayer technique with glass ionomer cement (GIC) for occlusoproximal cavities in Atraumatic Restorative Treatment (ART). One systematic review paper regarding restoration longevity in these types of cavities was also performed, comparing restoration longevity of ART restorations and conventional treatment, to verify the necessity to perform other researches in this field. In this way, we included 3 in vitro studies, regarding marginal adaptation and bond strength, both in sound and caries-affected dentin; two in vivo studies were included, one as a pilot study, and the second one as controlled clinical trial. Systematic review showed that both ART and conventional restorations have comparable and low survival rates in primary teeth. In general, the two-Iayers technique, inserted as the first layer more fluid (powder-liquid ratio of 1 :2), followed by a conventional consistency (powder liquid ratio 1:1) showed better results in laboratorial environment. Clinically, the two layers insertion had no influence in survival rates, being comparable to conventional ART restorations longevity. Others aspects may be negatively associate to restoration longevity for occlusoproximal cavities in general, not only with ART restorations.

Endodontic microorganism susceptibility by direct contact test

El objetivo de este trabajo fue evaluar in vitro la duración del efecto antimicrobiano de los selladores endodónticos mediante la Prueba de Contacto Directo. Los selladores probados fueron: Endomethasone - Septodont®, Endomethasone C – Septodont®, Endion – Voco®, Diaket – ESPE®, Pulp Canal Sealer – SybronEndo® y AH26 – Dentsply DeTrey®. Los microorganismos endodontopáticos (MO) enfrentados fueron: Staphylococcus aureus (Sa), Candida albicans (Ca), Enterococcus faecalis (Ef), Prevotella intermedia (Pi), Porphyromonas gingivalis (Pg) yFusobacterium nucleatum (Fn). Se prepararon las probetas con cada uno de los selladores, se colocaron sobre la superficie de placas de agar sembradas con cada MO y luego de períodos predeterminados se realizaron repiques de las zonas de contacto probeta-agar sembrado y de la zona que no estuvo en contacto con las probetas (testigo). Se realizó la lectura de los resultados: presencia/ausencia de desarrollo microbiano y se analizaronestadísticamente mediante la Prueba de Kruskal- Wallis. Pudo concluirse que las características estructurales y la virulencia de los microorganismos endodontopáticos son determinantes de la respuesta de los mismos frente a los selladores independientemente del tiempo durante el cual estos actúen y del mecanismo por el cual el antiséptico alcance al microorganismo, en este caso por contacto directo.

Effects of a glass-ionomer cement on the remineralization of occlusal caries: an in situ study

Esta pesquisa avaliou a remineralização do esmalte de fóssulas e fissuras de terceiros molares humanos previamente desmineralizados e selados com um cimento de ionômero de vidro (Fuji IX, GC Corporation - Japão) ou com um selante de Bis-GMA (Delton-Dentsply). Dez voluntários participaram deste estudo in situ que consistiu de dois períodos de 30 dias com intervalo de 1 semana entre eles, usando dispositivos intra-orais. Quatro procedimentos de tratamento experimental e um controle foram aleatoriamente distribuídos entre os espécimes que foram usados pelos voluntários: Grupo I, sem qualquer tratamento, controle; Grupo II, processo de cárie artificial; Grupo III, igual ao Grupo II, porém selados com Delton (Dentsply); Grupo IV, igual ao Grupo II, porém selados com Fuji IX (GC Corporation - Japão); Grupo V, igual ao Grupo II, mas sem selamento. Os Grupos I e II não foram submetidos ao meio bucal e serviram de controle. Após um período de trinta dias no meio bucal, os espécimes foram removidos dos dispositivos, montados em resina acrílica, planificados e polidos. Realizaram-se então testes de Dureza Knoop com carga estática de 25 g por 15 segundos. As medidas foram realizadas desde a base da fissura até uma abertura de 600 µm, preestabelecida entre os planos inclinados das cúspides. A cada 100 µm, três penetrações foram realizadas: a primeira a 25 µm da superfície da fissura, a segunda a 75 µm, e a terceira a 125 µm (Micromet 2003). Os dados obtidos foram analisados estatisticamente pelos testes "F" de Brieger e de Bonferroni. Concluiu-se que o selamento com o cimento de ionômero de vidro Fuji IX foi capaz de tornar o esmalte de sulcos e fissuras mais resistente pelo aumento do valor de dureza Knoop.

In vitro activity of zinc oxide-eugenol and glass ionomer cements on Candida albicans

O objetivo deste estudo foi avaliar in vitro a atividade antimicrobiana dos cimentos de ionômero de vidro (CIV) e óxido de zinco e eugenol (OZE) sobre Candida albicans. Corpos-de-prova padronizados de CIV e OZE foram mantidos em contato com suspensão (1 106 células/ml) de C. albicans a 37ºC por 24 horas, 48 horas ou 7 dias. Um grupo controle sem nenhum cimento teste foi incluído. Após o período de incubacão, alíquotas de 0,1 ml foram semeadas em ágar Sabouraud e o número de colônias foi contado. Os resultados foram expressos em logaritmos de valores de unidades formadoras de colônias por ml (log UFC/mL) e analisados estatisticamente pelo teste ANOVA Kruskal-Wallis. Após 48 horas de incubacão, o grupo OZE não apresentou crescimento de C. albicans. Os grupos CIV e controle apresentaram médias similares em todos os períodos testados. De acordo com os resultados obtidos, pode ser concluído que, sob as condicões experimentais testadas, o cimento OZE apresentou-se mais efetivo in vitro sobre C. albicans em relacão ao CIV.

Atividade antimicrobiana de materiais restauradores e selantes / Inhibitory activity of restorative materials and sealants

Avaliou-se a atividade inibitória de diferentes materiais restauradores e selantes de fóssulas e fissuras sobre microrganismos cariogênicos através do método de difusão em ágar, empregado-se o ágar Mueller-Hinton acrescido de 5 por cento de sangue desfribrinado de carneiro. Verificou-se que a maioria dos materiais testados apresentou alguma atividade inibitória frente aos microrganismos isolados, particularmente os cimentos ionoméricos. As resinas compostas, à exceção do Dyract, não evidenciaram atividade antimicrobiana

Evaluation of microleakage in human, bovine and swine enamels

A adequação de dentes bovinos e suínos na substituição de dentes humanos extraídos tem sido avaliada em vários estudos. O objetivo deste estudo in vitro foi analisar o padrão de infiltração marginal em esmaltes humano, bovino e suíno. Cavidades cúbicas (2 x 2 x 2 mm3) foram realizadas em blocos de esmalte obtidos de dentes molares humanos, incisivos bovinos e molares suínos. As cavidades foram restauradas com compósito resinoso fotopolimerizável e cimento de ionômero de vidro. Os espécimes foram submetidos à termociclagem por 1.000 ciclos entre 5 ± 2ºC e 55 ± 2ºC e imersos em azul de metileno a 2%, por 12 horas. A concentração de corante infiltrado foi medida, quantitativamente, através de espectrofotometria. Os dados foram transformados em µg/ml e submetidos à análise estatística ANOVA, seguida pelo teste de Tukey. As médias de infiltração marginal (µg/ml ± DP) nos esmaltes bovino e suíno não foram significativamente diferentes (0,0668 ± 0,0246 vs. 0,0674 ± 0,0286), mas foram superiores e estatisticamente diferentes (p < 0,01) das encontradas no esmalte humano (0,0407 ± 0,0195, p < 0,01), e as médias de infiltração marginal foram superiores nas restaurações realizadas com o cimento de iônomero de vidro (0,0695 ± 0,01313 vs. 0,0471 ± 0,0163, p < 0,01). Os resultados permitiram concluir que os substratos bovino e suíno permitem uma maior infiltração marginal que o esmalte humano, indicando que a capacidade de selamento marginal pode ser afetada por diferenças entre esses substratos. Os resultados indicam que se deve ter prudência na substituição do esmalte humano em estudos laboratoriais de microinfiltração.

Sealing ability of MTA, Super EBA, Vitremer and amalgam as root-end filling materials

Este estudo avaliou a capacidade de selamento do agregado trióxido mineral (MTA Angelus), de um cimento de óxido de zinco e eugenol reforçado (Super EBA), de um cimento de ionômero de vidro reforçado por resina (Vitremer) e de um amálgama sem zinco (GS-80) (controle). Os canais radiculares de oitenta molares inferiores humanos foram acessados, limpos, modelados e obturados. Os ápices foram seccionados, e as cavidades, preparadas. Os dentes foram divididos em 4 grupos de 40 cavidades, retrobturados com os materiais e imersos em azul de metileno por 72 h a 37ºC. As raízes foram então seccionadas transversalmente a cada milímetro e avaliadas sob aumento, observando-se a penetração de corante a cada corte. Os dados foram avaliados usando-se o teste de Kruskal-Wallis (5%), que mostrou diferenças entre todos os materiais (p < 0,001). A ordem crescente de infiltração marginal foi MTA < Vitremer < Super EBA < amálgama. Níveis mais altos de infiltração foram observados nos cortes de primeiro milímetro de amálgama, Vitremer e MTA, quando comparados com o terceiro milímetro (p < 0,05).

Glass-ionomer cement and bone repair in prolonged immobilization-induced stress / Ionômero de vidro e reparo ósseo durante o estresse por imobilização prolongada

O cimento de ionômero de vidro é um material odontológico que pode ser usado para substituir tecido ósseo, porque apresenta biocompatibilidade e induz osteogênese no processo alveolar em ratos normais. O presente trabalho teve o objetivo de avaliar o comportamento do reparo ósseo em ratos estressados implantados com ionômero de vidro. Os animais foram divididos em três grupos: controle, estressados e estressados tratados com benzodiazepínico injetado intraperitonealmente a uma dose de 5mg/kg (Valium®) uma hora antes da imobilização. Um grânulo de ionômero de vidro foi implantado nos alvéolos imediatamente após a extração dos incisivos superiores direitos. Os animais foram sacrificados 7, 15, 21 e 42 dias após a cirurgia, e as pe'cas, descalcificadas e processadas para a histologia. O estresse foi demonstrado pelos níveis de corticosterona no plasma sanguíneo, os quais aumentaram de 6 a 33 vezes nos ratos submetidos à imobilização. O exame histológico demonstrou que os grânulos de ionômero de vidro foram biocompatíveis e progressivamente incorporados durante o processo de reparo, modificado apenas pela condição de estresse. O volume percentual de osso neoformado no interior do alvéolo foi quantificado por método diferencial de contagem de pontos. O grupo estressado apresentou um atraso na neoformação óssea quando comparado ao controle e ao estressado tratado com diazepan. O tratamento com diazepan levou a uma melhora no reparo dos animais estressados implantados