Abstract
As a model experiment to understand the mechanism of adhesion of the MMA/TBBO resin to dentin, polymerization of MMA/TBBO was investigated in the presence of a collagen sheet treated with the aqueous citric acid(CA)solutions of copper fluoride(CF), ferric fluoride(FF), or ferric chloride(FC), which is usually used as a treating agent in bonding of the resin to dentin.The curing time of MMA/TBBO resin was considerably reduced in the presence of collagen treated with CF-CA or FF-CA solutions when compared to that with FC-CA solution.Molecular weight of PMMA depended on the site of polymerization;PMMA polymerized inside the collagen sheet was the highest and that polymerized outside was the lowest.Bond strength to dentin treated with CF-CA, FF-CA solutions was as strong as that treated with FC-CA solution.Treatment of dentin with CF-CA or FF-CA was as effective as that with FC-CA in bonding the MMA/TBBO resin.These results suggested that ferric compounds adsorbed to collagen are involved in polymerization of MMA and thus influence bond strength of the MMA/TBBO resin to dentin.
