Técnica alcoólica simplificada para a cimentação de pinos intrarradiculares pré-fabricados / Effect of ethanol-wet bonding on retetion of post to root dentin

Pinos de fibra de vidro têm ganhado popularidade devido o módulo de elasticidade próximo ao da dentina, estética e adesão. Contudo, a degradação do sistema adesivo e cimento apresenta-se como uma desvantagem do conjunto pino-cimento-dentina. Assim, a técnica alcoólica foi desenvolvida com a finalidade de minimizar a degradação e aumentar a durabilidade de união. Este estudo in vitro teve como objetivo avaliar as propriedades físicas de dois cimentos resinosos e respectiva área de união entre pino e dentina radicular tratada de acordo com dois protocolos de cimentação. Foram utilizados dentes incisivos bovinos. As coroas foram seccionadas na junção cemento-esmalte e as raízes receberam tratamento endodôntico e preparo do conduto. Previamente à cimentação dos pinos de fibra de vidro, as raízes foram divididas aleatoriamente de acordo com o tratamento de superfície radicular: técnica convencional e técnica alcoólica simplificada. Foram empregados dois tipos de cimentos resinosos na fixação do pino: RelyXTM ARC/ Scotchbond Multi-Purpose Plus (3M ESPE) e RelyXTM U200 (3M ESPE). Após a cimentação, as raízes foram armazenadas em 100% de umidade à temperatura ambiente por sete dias para o escaneamento por meio de microtomografia computadorizada (micro CT) ou por 24 horas e 1 ano para o teste de push-out e microscopia eletrônica de varredura (MEV). Para análise do micro CT, foi usado o programa NRecon para gerar imagens de reconstrução e o programa CTan para a análise tridimensional das mesmas quanto à porcentagem de porosidades na linha de cimentação. A contração pós-gel (%) dos cimentos foi mensurada empregando-se a técnica de extensometria. Para o ensaio do teste de push-out, as raízes foram seccionados e foram obtidos dois espécimes em cada terço radicular. O ensaio usou célula de carga de 5000 N e velocidade de 0,5 mm/min. Os espécimes foram examinados em estereoscópio para identificação do modo de fratura. Imagens foram obtidas por MEV para a avaliação da linha de cimentação. O efeito dos fatores em estudo e sua interação sobre porcentagem de porosidades na linha de cimentação foi verificado por ANOVA e teste post-hoc de Tukey (p≤0,05). A contração pós-gel dos cimentos foi avaliada pelo teste t de student. Enquanto a resistência de união foi analisada pelos testes de Kruskal-Wallis e MannWhitney (p≤0.05). Quando avaliado a porosidade na linha da cimentação a técnica alcoólica com cimento resinoso RelyXTM U200 apresentou os menores valores de porosidade na linha de cimentação para os terços cervical e apical. A contração pós gel apresentou valores mais altos para o cimento resinoso RelyXTM ARC. Os valores de resistência de união imediata não diferiram entre os grupos e terços radiculares. Porém, foi afetada negativamente após 12 meses de armazenamento. Apesar do efeito negativo, a técnica alcoólica simplificada associada ao cimento resino RelyXTM U200 apresentou melhor valor de resistência de união quando comparado ao protocolo convencional desse cimento resinoso. Concluiu-se que, o cimento resino RelyXTM U200 com a técnica alcoólica simplificada apresentou a menor porcentagem de porosidade nos terços cervical e apical e que o cimento resinoso RelyXTM U200 apresentou o menor grau de contração de polimerização pós-gel.(AU)

Effect of ethanol-wet bonding on retetion of post to root dentin Fiber post have been an alternative to cast metal posts due to the modulus of elasticity similar to dentin. However, one of the causes of failure is cement degradation. The ethanol-wet bonding was developed with the purpose of reducing this degradation and increasing the durability of bonding between dentin and cement. The aim of this in vitro study was to evaluate the mechanical properties of two resin cements and the respective bonding interface between root and dentin treated according to two cementation protocols. Bovine incisor teeth were used. The crowns were sectioned at the cemento-enamel junction and the roots received endodontic treatment and post space preparation. Prior to the cementation of fiberglass, roots were randomly divided according to root surface treatment: conventional technique and ethanol-wet bonding. Two types of resin cements were used to cement the posts: RelyXTM ARC / Scotchbond Multi-Purpose Plus (3M ESPE) and RelyXTM U200 (3M ESPE). After cementation, the roots were stored at 100% humidity at room temperature for seven days for scanning by computerized microtomography (micro CT) or for 24 hours and 1 year for push-out and scanning electron microscopy. For the analysis of micro CT, NRecon software was used to generate tridimensional images and CTan software analyzed the porosity percentage (%) in the luting line. The post-gel contraction (%) of the cements was measured using the strain gauge technique. For push-out test, the roots were sectioned and two specimens were obtained in each root third, with 1.0 mm of thickness each. The test used load cell of 5000N and speed of 0.5mm / min. The specimens were examined in stereoscope to identify the mode of fracture. Images obtained by scanning electron microscopy for the evaluation of the cement line. The effect of the factors under study and their interaction on percentage of porosities in the cementation line was verified by ANOVA and Tukey post-hoc test (p≤0.05). The postgel shrinkage was analyzed by Student's t test and bond strength in the root thirds was verified by Kruskal-Wallis e Mann-Whitney test (p≤0.05). When evaluating the porosity in the cementation line, the ethanol-wet bonding with RelyXTM U200 presented the lowest values of porosity in the cementation line for the cervical and apical thirds. The RelyXTM U200 resin cement showed the lowest degree of post-gel polymerization shrinkage. Immediate bond strength values did not differ between groups and root thirds. However, storage for 12 months produced a negative effect. Despite this effect, the association between simplified ethanol wet-bonding with RelyXTM U200 exhibit better values of bond strength when compared the conventional protocol for this resin cement. It was concluded that RelyXTM U200 with ethanol wet-bonding had the lowest percentage of porosity in the cervical and apical thirds and RelyXTM U200 resin cement showed the lowest degree of post-gel polymerization shrinkage.(AU)

The Occluding Effect of Penetrating Resin Combined with Ethanol Wet-bonding on Dentin Tubule / 中国医科大学学报

Objective To compare the occluding effect of conventional penetrating resin,Single Bond desensitizer,and penetrating resin combined with ethanol wet-bonding on dentin tubules.Methods Sixty isolated premolar teeth were prepared to form dentin discs.The 60 teeth were divided into 3 groups based on a random number table:Group A,conventional penetrating resin;Group B,Single Bond desensitizer,and Group C,penetrating resin combined with ethanol wet-bonding.Each group comprised 20 teeth.Dentin discs were split in half along the longitudinal axis.Half of the disc served as the control;the other half was coated with desensitizer.Microscopic characteristics of the dentin surface and profile were determined by using a field emission scanning electron microscope.Results In group A,70.10％±2.13％ of the dentin tubule openings were covered by the resin.The penetration depth was 50±10.59 μm,and the resin was short and discontinuous.In group B,86.35％±1.73％ of the dentin tubules openings were covered.The penetration depth was 69± 11.98 μm,and the resin was sparse.In group C,95.65％± 1.46％ of dentin tubules openings were covered.The penetration depth was 177±9.17 μm,and the resin was compact and filled.Conclusion Penetrating resin combined with ethanol wet-bonding occludes dentin tubules better than conventional penetrating resin and Single Bond desensitizer.

Effect of additional etching and ethanol-wet bonding on the dentin bond strength of one-step self-etch adhesives

OBJECTIVES: This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. MATERIALS AND METHODS: Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. RESULTS: In GB, XV and SE (pH 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. CONCLUSIONS: The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

Effects of matrix metallproteinases on dentin bonding and strategies to increase durability of dentin adhesion

The limited durability of resin-dentin bonds severely compromises the longevity of composite resin restorations. Resin-dentin bond degradation might occur via degradation of water-rich and resin sparse collagen matrices by host-derived matrix metalloproteinases (MMPs). This review article provides overview of current knowledge of the role of MMPs in dentin matrix degradation and four experimental strategies for extending the longevity of resin-dentin bonds. They include: (1) the use of broad-spectrum inhibitors of MMPs, (2) the use of cross-linking agents for silencing the activities of MMPs, (3) ethanol wet-bonding with hydrophobic resin, (4) biomimetic remineralization of water-filled collagen matrix. A combination of these strategies will be able to overcome the limitations in resin-dentin adhesion.