[Studies on dental self-curing resins (22) - adhesion of 4-META/MMA-TBB resin to enamel (author's transl)]

Bovine enamels cleaned with citric acid and FeCl3 which had been brushed or ground were joined with PMMA rods with the 4-META/MMA-TBB cement. Their tensile adhesive strength was measured after post-treatments. Stable adhesive strength such as 6.2 MPa was obtained on an enamel which was brushed and washed with an aqueous solution of 10% citric acid-3% FeCl3 for 30 sec. even after a 60 times percolation test between 4 degrees C and 60 degrees C. It is adequate to clinics. The value increased to 16.1 MPa on ground enamel. These results suggest that phosphoric acid etching, essential nowadays, is not necessary for good adhesion to enamel. Monomers with both hydrophobic and hydrophilic groups like 4-META possess affinity with tooth substrates and promote the infiltration of cements into the enamel. The infiltrated monomers polymerized in situ and strong adhesion with the enamel took place. Comparison of the tag length formed in the enamel by cements, MMA-TBB, HNPM/MMA-TBB, Phenyl-P/MMA-TBB and 4-META/MMA-TBB supports this consideration.