[Application of succinoxy methacrylates for direct bonding system].
Three types of succinoxy methacrylates [2-succinoxyethyl methacrylate (2SEM), 2-succinoxypropyl methacrylate (2PrM) and 2-succinoxy-3-phenoxypropyl methacrylate (SPPM)] were synthesized in order to develop a new direct-bonding adhesive which has sufficient bond strength to mild etched enamel and stainless steel brackets for occlusal and orthodontic force. Experimental direct-bonding adhesives consisted of a MMA solution containing synthesized monomers (5-10 mol%), PMMA powder and an oxidized tri-n-butyl borane as an initiator. A MMA solution without synthesized monomers was used as the control. Preparation of 10% and 40% phosphoric acid solutions and 1M maleic acid solution was carried out for use as etchants. The bond strength to unetched and etched enamel, polished stainless steel, simulated brackets and brackets was measured. The enamel surfaces etched with each etchant and the fractured resin and enamel surfaces after the bond test were observed with SEM and the ease of debonding of adhesive was investigated to totally evaluate the experimental direct-bonding adhesives. The results were as follows: 1) The amount of decalcification for 10% phosphoric acid and 1M meleic acid solutions was less than that for 40% phosphoric acid solution. The SEM micrograph showed most clearly the appearance of enamel prisms on the enamel surface treated with 40% phosphoric acid solution. 2) The experimental direct-bonding adhesives had higher bond strength to the polished enamel, the polished stainless steel and the simulated bracket than the control. 3) The bond strength to the etched enamel was comparable to that of the control. 4) The treatment of 1M maleic acid solution provided the same bond strength to enamel as that of 40% phosphoric acid solution and the higher bond strength than of 10% phosphoric acid solution. The bond strength to enamel treated with 1M maleic acid solution and 40% phosphoric acid solution decreased very slightly by immersion in water and thermal cycling. 5) The MMA solutions containing each 20 mol% synthesized monomer were adequate to direct-bonding adhesive monomers on the basis of the results of bond strength and manipulation. 6) The strongest bond strength between bracket and etched enamel was obtained with the direct-bonding adhesive containing 2SEM under all conditions. 7) The SEM micrographs showed that the tooth-resin interface failure for each adhesive occurred during bond testing. 8) There was little remaining of the resin on the tooth surface after debonding regardless of types of direct bonding adhesives.
Kawai
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D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel; D008689:Methacrylates / Q000737:chemistry*; D008768:Methylmethacrylates / Q000737:chemistry; D013193:Stainless Steel
D003738:Dental Cements; D008689:Methacrylates; D008768:Methylmethacrylates; D013193:Stainless Steel