title: N-phenyliminodiacetic acid as an etchant/primer for dentin bonding.
abstract: Effective composite-to-dentin bonding has been achieved by the sequential use of dilute aqueous nitric acid (HNO3) and acetone solutions of N-phenylglycine and a carboxylic acid monomer, e.g., p-PMDM. Both the HNO3 pre-treatment and the surface-initiated polymerization that results from reaction of infused N-phenylglycine and PMDM have been identified as key elements of this bonding system. In this study, N-phenyliminodiacetic acid, a unique imino acid derivative with acidic and chelating potential, was evaluated as a dual etchant/primer for dentin bonding. A randomized, 2(3) factorial design was used to study the effects of 3 factors on tensile bond strength (TBS): conditioner (HNO3 vs. no HNO3), primer (N-phenylglycine vs. N-phenyliminodiacetic acid), and primer solvent (acetone vs. acetone:H2O). The three-step protocol consisting of HNO3, N-phenylglycine in acetone, and PMDM in acetone served as the control. The hypothesis tested was that N-phenyliminodiacetic acid could act as both an effective conditioner (i.e., etchant) and as a primer. Two-step protocols that included only N-phenyliminodiacetic acid and PMDM were compared with the control. TBS (n = 10 per group) were determined after 24-hour storage in H2O and analyzed by ANOVA and Duncan's Multiple Range test. Primer solvent was critical for obtaining significant bonding to dentin when HNO3 was omitted. N-phenyliminodiacetic acid in acetone without prior HNO3 etching gave the lowest ranking mean TBS (95% CI, 3.8 +/- 1.9 MPa). In contrast, the mean TBS obtained from samples treated with N-phenyliminodiacetic acid in acetone:H2O without prior HNO3 etching was not statistically different (p > 0.05) from the mean TBS for the control (95% CI, 9.3 +/- 1.8 and 9.8 +/- 1.9 MPa, respectively). Due to its dual function as etchant and primer, N-phenyliminodiacetic acid in acetone:H2O provides for a simplified bonding technique that yields strong, PMDM-mediated adhesion to dentin.
authors.affiliation: Clinical Center/CODC, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: G E
authors.initials: GE
authors.lastname: Schumacher
authors.forename: J M
authors.initials: JM
authors.lastname: Antonucci
authors.forename: P S
authors.initials: PS
authors.lastname: Bennett
authors.forename: J E
authors.initials: JE
authors.lastname: Code
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D006801:Humans; D007098:Imino Acids / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D017220:Dentin-Bonding Agents; D007098:Imino Acids; C104424:N-phenyliminodiacetic acid; C021316:N-phenylglycine; D005998:Glycine; C008109:iminodiacetic acid