Influência de agentes antiproteolíticos na resistência de união da interface dentina, adesivo e cimento resinoso / Influence of antiproteolytic agents on dentin, adhesive and luting cement interface

O objetivo deste trabalho, foi avaliar a influência de agentes antiproteolíticos, imediatamente e após 12 meses, na cimentação adesiva. Foram utilizadas as porções coronárias de 64 molares humanos hígidos. As amostras foram divididas aleatoriamente em 4 grupos, de acordo com o tratamento da dentina: CT (grupo controle); CXL (grupo clorexidina); EGCG (grupo epigalocatequina-3-galato); AT (grupo antocianina). Para a restauração, foram confeccionados cilindros em resina composta Filtek Z350 XT. Após o condicionamento ácido da dentina, as soluções antiproteolíticas foram aplicadas e mantidas sobre a superfície por 60 s, em seguida as restaurações foram cimentadas às amostras com o adesivo Adper Single Bond 2 + cimento resinoso Variolink II. Todos os grupos foram subdivididos de acordo com o tempo de armazenamento em água destilada para o ensaio mecânico: I (Imediato = após 24 h); A (Armazenado = após 12 meses). As amostras foram cortadas em palitos e submetidas ao teste de microtração. Os dados obtidos foram submetidos ao teste de ANOVA a 2 fatores, seguido do teste de Tukey (α=5%). Foram encontradas diferenças para os fatores Tratamento (p=0,03) e Armazenamento (p=0,00). Os valores em MPa de média e desvio padrão para interação entre os fatores Tratamento X Armazenamento, foram: CT.I: 42.56 (±7,60) A; EGCG.I: 39.6 (±8,99) A; CLX.I: 39.37 (±9,44) A; AT.I: 38.69 (±8,65) A; CT.A: 31.85 (±6,96) A; AT.A: 31.29 (±4,89) AB; EGCG.A: 30.94 (±9,91) AB; CLX.A: 18.68 (±4,53) B. Foram confeccionadas duas amostras adicionais de cada grupo para avaliação descritiva da microdureza knoop de subsuperfície e avaliação qualitativa da interface adesiva em MEV. Conclui-se que as soluções de EGCG e AT foram capazes de manter a estabilidade da resistência de união após 12 meses de armazenamento e que a solução de CLX afetou negativamente os valores de resistência de união comparado aos demais subgrupos(AU)

The aim of this study was to evaluate immediately and longitunally the antiproteolytic agent influence to adhesive cementation. Were used 64 coronary portion of sound human molars. The samples were divided into 4 groups according to the dentin treatment: CG (Control group); CLX (chlorhexidine group); EGCG (epigallocatechin-3- gallate group); AT (anthocyanin group). Cylindrical composite blocks were prepared using a resin composite Filtek Supreme for the restorations. The solutions were applied on the acid-etched dentin and were kept for 60 s. The resin composite blocks were cemented with the adhesive system Adper Single Bond 2 + resin cement Variolink II. All groups were subdivided according to the storage time in distilled water for mechanical testing: I (Immediate = after 24 h); S (Stored = after 12 months). Samples were cut into beams and tested in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The data were submitted to two-way ANOVA, followed by the Tukey test (α = 5%). Significant differences were found for the Treatment factor (p = 0.03) and Storage factor (p = 0.00). The mean values and standard deviation for interaction between the factors Treatment X Storage, were CG.I: 42.56 (± 7.60) A; EGCG.I: 39.6 (± 8.99) A; CLX.I: 39.37 (± 9.44) A; AT.I: 38.69 (± 8.65) A; CG.S: 31.85 (± 6.96) A; AT.S: 31.29 (± 4.89) AB; EGCG.S: 30.94 (± 9.91) AB; CLX.S: 18.68 (± 4.53) B. Two additional samples from each group were confectioned to descriptive analyses of microhardness knoop of dentin subjacent to the bonding interface and a qualitative interface evaluation with SEM (scanning electron microscope). It can be conclude that EGCG and AT solutions were able to maintain the bond strength stability after 12 months of storage and CLX solution adversely affect the bond strength values compared to other subgroups(AU)

Afastamento gengival: técnicas e materiais / Gingival retraction: techniques and materials

Este trabalho teve como objetivo levar o leitor a uma revisão da literatura sobre os diferentes métodos de afastamento gengival, suas técnicas, indicações e contraindicações. Foram abordadas as variações dos métodos e técnicas, a fim de facilitar a escolha mais adequada às diferentes situações clínicas. São feitas considerações sobre as soluções químicas, os fios utilizados para o afastamento gengival, as pastas adstringentes, bem como a combinação entre eles. Foram elaborados quadros comparativos entre os diferentes métodos de afastamento gengival, entre as soluções químicas mais utilizadas e entre as diferentes marcas comerciais existentes.

This paper aims to take the reader on a review of literature about the diff erent methods of gingival retraction, their techniques, indications and contraindications. Variations of the methods and techniques were discussed in order to facilitate the most appropriate choice for diff erent clinical situations. Some considerations were made about the chemical solutions, the gingival retraction cords, as well as their combination. Comparative tables among the diff erent gingival retraction methods, the most used chemical solutions, and the diff erent trademarks were prepared.

The effect of CPP-ACP and Nd:YAG laser on the bond strength of softened dentin

The purpose of this study was to investigate the effect of CPP-ACP treatment and Nd:YAG laser on microtensile bond strength (µTBS) of softened dentin. Sixty samples were obtained from thirty sound third molars. All samples were submitted to dentin softening procedure, by the immersion of the specimens in 30 mL of Sprite Zero for 30min. Afterwards, the samples were randomly divided according to the CPP-ACP treatment: CG-Control group; MP-treated with CPP-ACP paste (MI Paste); MPP-treated with CPP-ACP+900 ppm NaF paste (MI Paste Plus). Each group was further divided according to bonding procedure: NL-No laser; L–Laser irradiation after adhesive application and before polymerization. The laser parameters used were 1.4 W, 10 Hz, 140 mJ/pulse, with an optic fiber of 320 µm, generating energy of 174 J/cm2 per pulse. All samples were restored with Clearfil SE Bond/Filtek Z350 XT. After 24 h, the restored samples were cut into beams (± 1 mm2adhesive interface area) and subjected to a µTBS test. Data were analyzed by two-way ANOVA test and Holm-Sidak post-hoc method (α = 0.05). The treatment with CPP-ACP pastes did not significantly affect softened dentin µTBS (p = 0.070). Statistic revealed significant reduction on µTBS values for CG/L, leading to the rejection of the second null hypothesis (p < 0.001). Both CPP-ACP based pastes did not affect µTBS of softened dentin for the adhesive system utilized. The Nd:YAG laser irradiation after application of adhesive system did affect µTBS values of softened dentin samples untreated with CPP-ACP based pastes.

Avaliação da liberação de íon fluoreto de cimentos ionoméricos antes e após a recarga e com proteção da superfície / Fluoride ion release from glass ionomer cements before and after recharge and surface protection

Objetivo: Avaliar a liberação de íon fluoreto de 2 cimentos de ionômerode vidro (CIV) anidro e 2 modificados por resina composta antes e apósrecarga com fluoreto de sódio neutro a 2% por 4min. e após a proteçãoda superfície do CIV Maxxion R com um adesivo odontológico, umverniz cavitário e um esmalte incolor para unhas.Métodos: Com uma matriz de aço inox com 2mm x 6mm,confeccionou-se 5 corpos de prova de cada material, que foramimersos em 5mL de água deionizada, trocada a cada 24h. Foramrealizadas leituras em um potenciômetro nos dias 1, 2, 9 e 17 na 1ª e 2ªetapas, e as amostras foram tamponadas com solução TISAB III. Na 2ªetapa, as amostras foram submetidas à recarga e novamente imersasem 5mL de água deionizada. Na 3ª etapa foi realizada a proteção dasuperfície dos CIVs e feitas leituras nos 5min., 24h, 48h e 72h. Utilizouseos testes estatísticos Post Hoc de Tukey e t Student (p<0,05).Resultados: Observou-se diferença estatisticamente significante aocomparar a 1ª com a 2ª etapas em todos os materiais, exceto no dia 2para o Vidrion R e para o VitroFil LC. Na 3ª etapa observou-se que emtodos os materiais, comparando os primeiros 5 min. com os outrostempos, as diferenças entre as médias da liberação das concentraçõesde íon fluoreto foram estatisticamente significantes. Ao 0comparar osdemais tempos, tanto o verniz quanto o esmalte incolor para unhasapresentou diferença estatisticamente significante entre 24h e 48h,bem como em 24h e 72h.Conclusão: Os CIVs anidros tiveram maior efetividade na liberação deíon fluoreto e na recarga em comparação com os CIVs modificados porresina composta e o Maxxion R apresentou um comportamentohomogêneo e estatisticamente significante nas duas etapas. Todos osmateriais protetores testados foram eficazes, e o esmalte incolor paraunhas apresentou o melhor comportamento...

Objective: To evaluate fluoride ion release from two anhydrous glassionomer cements (GICs) and two resin-modified GICs (RMGICs) before and after recharge with 2% neutral sodium fluoride for 4 min and after surface protection of the Maxxion R GIC with an adhesive system, a cavity varnish and a colorless nail polish. Method: A stainless steel 2x6 mm matrix was used for fabricating 5 specimens of each material, which were immersed in 5 mL of deionized water, renewed every 24 h. Measurements with a potentiometer were performed on days 1, 2, 9 and 17, in the 1st and 2nd phases, and thespecimens were buffered with a TISAB III solution. In the 2nd phase, thespecimens were subjected to recharge and immersed again in 5 mL ofdeionized water. In the 3rd phase, the GIC surfaces were protected andreadings were made at 5 min, 24 h, 48 h and 72 h. TukeyÆs post-hoc and StudentÆs t tests were used for statistical analyses (p<0.05). Results: There was statistically significant difference in the comparison between the 1st and 2nd phases for all materials, except at day 2 for Vidrion R and VitroFil LC. In the 3rd phase, it was observed that for all materials, comparison of the first 5 min with the other times revealedstatistically significant differences among the means of fluoride ionrelease. In the comparison with the other times, both the varnish and the colorless nail polish presented statistically significant differencebetween 24 and 48 h as well as between 24 and 72 h. Conclusion: The anhydrous GICs were more effective in fluoride ion release and recharge compared with the RMGICs. Maxxion R presented a homogeneous and statistically significant behavior in both phases. All materials for surface protection were efficient and the colorless nail polish had the best behavior...