Substitutes for N-phenylglycine in adhesive bonding to dentin.
Using bond strength measurements, we investigated a number of related compounds in order to elucidate the role of the surface-active ingredient, N-phenylglycine (NPG), in experimental two-step and three-step bonding protocols resulting in adhesive bonding to dentin. All active compounds identified for the two-step or the three-step protocol were N-aryl-alpha-amino acids, and the results delineate some of the key features of the NPG molecule for bonding. For the three-step protocol, there was a requirement for a secondary or tertiary aromatic amino group, a carboxylic acid group, and a single (secondary or tertiary) methylene unit between those two functional groups of the amino acid. For the two-step protocol, additional substitutions at the para position of the phenyl ring on the amine improved the bond strength. In both protocols, para-methyl- and para-chloro-substituted NPG analogues ranked higher than NPG. A "catalytic" effect of the aromatic tertiary amino group on the polymerization of the adhering resin in both procedures could not be ruled out.
Johnston
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AD
Paffenbarger Research Center, American Dental Association Health Foundation, Gaithersburg, Maryland 20899.
Asmussen
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E
Bowen
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RL
D000268:Adhesiveness; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000138:chemical synthesis*; D003799:Dental Stress Analysis; D003804:Dentin; D005998:Glycine / Q000031:analogs & derivatives*; D013718:Tensile Strength
D003738:Dental Cements; C021316:N-phenylglycine; D005998:Glycine