Regional Bond Strength of Four Self-etching Primer/Adhesive Systems to Root Canal Dentin

Abstract

The purpose of this study was to evaluate the regional bond strength of a dual-cure resin core material to root canal dentin using four self-etching primer/adhesive systems. Post spaces were prepared in extracted premolars, and their root canal dentin was treated with one of the following self-etching primer/adhesive systems: ED Primer II and Clearfil Photobond, photo-cure/dual-cure systems of Clearfil Liner Bond 2V, or Clearfil SE Bond. Post spaces were filled with the dual-cure resin core material, and microtensile bond strength (uTBS) at the coronal and apical regions was measured after 24-hour storage.There were no regional differences in uTBS of the photo-cure and dual-cure systems of Clearfil Liner Bond 2V, while ,uTBS at the coronal region of Photobond and SE Bond groups were higher than those at the apical region.At the apical region, photo-cured Clearfil Liner Bond 2V exhibited significantly higher bond strength than those of the other systems.

Effects of photocuring strategy on bonding of dual-cure one-step self-etch adhesive to root canal dentin

“…In the present study, failure within the adhesive resin was probably a result of the undesirable properties of one-step selfetch adhesives. In previous studies 6,23) conducted in the same manner as this study but using two-step self-etch adhesives, only a small number of specimens failed cohesively within the adhesive resin. For the one-step self-etch adhesive used in this study, the liquid B component of Clearfil DC Bond component contained water, and which was mixed with liquid A component and then applied within one single step.…”

“…Presently, esthetic non-metal fiber posts are commonly used for radicular restoration because their moduli of elasticity are comparable to dentin, thereby producing a stress field similar to that of a natural tooth and resulting in reduced root fracture incidences [1][2][3][4][5] . Resin cement or dual-cure resin core material in combination with an adhesive system are generally recommended for bonding fiber posts to the root canal wall [6][7][8][9] . It is noteworthy that in post spaces, light penetration is limited in the deeper region than at the upper region.…”

Avaliação dos ensaios de microtração, push-out e pull-out: resistência de união entre pino de fibra e dentina radicular, análise de elementos finitos e microscopia confocal

“…Isto se dá devido a uma diminuição da variabilidade da amostra. Outros estudos que utilizaram o mesmo tipo de ensaio para avaliar as regiões de dentina radicular também não encontraram diferença estatística, porém em nenhum destes foi descrito o tratamento tido com as falhas prematuras (133,134) .…”

“…Além disso, os resultados destes dois ensaios podem ser baseados no fato de que a completa polimerização ao longo do canal tanto do sistema adesivo como do cimento resinoso, talvez influencie mais na adesão de um pino de fibra (2,134) do que a morfologia da dentina do conduto radicular (7) . Pois quando as fatias são polimerizadas individualmente não ocorre diferença estatística significante entre as regiões, ao contrário de quando a polimerização do sistema adesivo e do cimento resinoso é feita apenas pela entrada do canal, sendo encontrados maiores valores na região cervical em relação à região apical.…”

“…Já foi comprovado que as propriedades mecânicas de cimentos resinosos duais são melhores depois da fotoativação em comparação aos mesmos apenas quimicamente ativados (135) . Portanto as propriedades destes cimentos devem ser diferentes ao longo do conduto radicular devido a menor irradiância nas regiões mais profundas e pode ainda afetar a resistência de união destes com a dentina do conduto radicular (134,136) .…”