Abstract
To clarify the adhesion mechanism of MMA resin containing 4-methacryloxyethyl trimellitic acid (4-MET) to dental enamel, two kinds of experiments were carried out: (1) Using human premolars, scanning electron microscopic observation and an artificial caries producing test were performed on the enamel surfaces where applied resins had been extracted in hot acetone. At the enamel surface where 4-MET/MMA-TBB or 4-MET/MMA-BPO・Amine resin was extracted, an acid and acetone resistant layer appeared, and prevented artificial caries formation for 7 days. At the enamel surface of 2-hydroxy-3-β-naphthoxypropyl methacrylate (HNPM)/MMA-TBB or methacryllic acid (MA)/MMA-TBB resin, caries-like lesions were 30% smaller than controls, but no acid and acetone resistant layer was detected. (2) On the infrared absorption spectra of the mixture of resins and hydroxyapatite, an absorption band of carboxylate at 1, 560 cm-1 was found with 4-MET or MA.This suggested reactivity between 4-MET or MA and Ca++. The acid and acetone resistant layer on the enamel surface where 4-MET/MMA-TBB or 4-MET/MMA-BPO・Amine resin was applied was produced by the excellent permeability and reactivity of the resins. These properties may contribute toward the high adhesiveness to dental enamel.
