Influence of acidic monomer on polymerization of dual-curing resin cements

本研究的目的是考察自酸蚀底漆(SEP)中含有的酸性单体对以自酸蚀底漆为牙齿处理剂的双固化树脂粘固剂(RC)聚合的影响。研究了四种不同组成的商品胶粘剂体系。通过改变SEP处理时间(10s或30s)以及光固化或自固化方式对RC的影响，测定这些RCS与牛牙本质和丙烯酸树脂板(PMMA)的剪切粘结强度，以评价RC的聚合度。测定各SEP在牛牙本质表面的pH值变化，以判断酸性单体的残留量。不同产品混合后即刻的pH值差异在1.5~3.3之间。应用于牙本质表面的SEPS，即使在使用5min后，其pH值也只上升了约0.3~4.5。结果表明，在任何粘接体系中，酸性单体在SEP处理后的牙本质表面仍有较好的残留。SEP的处理时间和RC的固化方式对牙本质的粘结强度无明显影响。然而，在与PMMA的粘接方面，对于两种粘接体系，自固化样品的粘接强度明显低于光固化样品。此外，当树脂嵌体用光固化底漆代替每个SEP对PMMA进行前处理时，所有RCS的自固化样品的粘结强度都显著低于光固化样品，并且两个RCS在自固化模式下几乎不与PMMA粘结，这表明每个SEP中包含的酸性单体会影响RC的自固化模式，可以在SEP中添加自固化的二次催化剂来促进两种产品的树脂水泥聚合。

The purpose of this study was to examine the influences of acidic monomer included in self etching primer (SEP) on polymerization of dual-curing resin cement (RC) which uses a SEP as tooth conditioner. Four commercial adhesive systems with different composition were investigated. The shear bond strengths of these RCs to bovine dentin and acrylic resin plate (PMMA) were measured, changing the treating time of SEP(10s or 30s) and with or without light-irradiation to RC(light-curing or self curing mode, respectively), to estimate the degree of polymerization of RC. The change of pH value of each SEP applied on bovine dentin surface was also measured to estimate the residue of acidic monomer.The pH values of SEPs immediately after mixing were different among products in the range of 1.5〜3.3. The pH values of SEPs applied on dentin surface only rose about 0.3〜4.5 even five minutes after application. This result suggested that the acidic monomers still remained fairly on dentin surface treated with SEP at application of RC.The bond strength to dentin was not significantly influenced with the treating time of SEP and the curing mode of RC for any adhesive system. Regarding the bonding to PMMA, however the self Cured samples showed significant lower bond strengths than the light-cured samples for two adhesive systems. Moreover when the light-curing primer for resin inlay was used instead of each SEP on pre-treating of PMMA, the bond strengths of self cured samples were significantly lower than that of light-cured samples for all the RCs used, and two RCs did not almost bond to PMMA in self curing mode.These results suggested that acidic monomer included in each SEP could influence on the self curing mode of the RC and a secondary catalyst for the self curing might be added into the SEP to accelerate polymerization of the resin cement for two products.