Molar Efficiency Study of Chlorinated NPG Substitutes in Dentin Bonding

Abstract

This study evaluated and compared the contributions to dentin adhesive bonding of three N-phenylglycine analogues with electron-withdrawing substituents on the aromatic ring. These electron-deficient "N-compounds" included: N-(4-chlorophenyl)-glycine (NCPG), N-methyl-N-(4-chlorophenyl)-glycine (NMNCPG), and N-(3,4-dichlorophenyl)-glycine (NDCPG). An experimental three-step dentin-bonding protocol that consisted of sequential application of acidic ferric oxalate solution, an N-compound in acetone, and a surface-active comonomer in acetone was used. The first and third steps were held constant throughout the study. Each N-compound (NCPG, NMNCPG, NDCPG) was used in step two at ten concentrations ranging from 0.0 mol/L (pure acetone) to 5 x 10(-1) mol/L, depending on solubility. After overnight storage in distilled water, the dentin-to-composite bonds were broken in tension. The data were analyzed with ANOVA, and multiple comparisons were performed with Duncan's Multiple Range test. All statistical tests were controlled at alpha = 0.05. At 5 x 10(-3) mol/L, the relative effectiveness of the three N-compounds (as measured by tensile bond strengths) was NMNCPG > NCPG > NDCPG. Of all concentrations studied, the mean bond strengths produced with NMNCPG were statistically as good as or better than those produced by the other two compounds, and NCPG was always as good as or better than NDCPG. Increased electron-withdrawing from the nitrogen of the amine group by the substituents narrowed the effective concentration range for dentin bonding and, in general, produced lower mean bond strengths between dentin and composite.

Influence of method and period of storage on the microtensile bond strength of indirect composite resin restorations to dentine

“…Some of the solutions most commonly used as storage media for in vitro studies are formalin, 8 thymol 9 and sodium azide. 10 The media in which teeth are stored after harvesting and the duration of storage, however, may influence the bond-strength results. 11 The present study was performed to evaluate the influence of the method and period of teeth storage on the adhesive bond strength of indirect composite resin restorations to bovine dentine by microtensile bond testing.…”

N-phenyliminodiacetic Acid as an Etchant/Primer for Dentin Bonding

“…The occlusal one-third of the coronal portion of each tooth was removed with a slowly rotating diamond blade (Isomet, Buehler Ltd., Lake Bluff, IL) under running tap water to expose a flattened dentin surface perpendicular to the long axis of the tooth. The teeth were then secured in bond-testing assemblies with poly(methyl methacrylate) resin (COE Tray Plastic, Coe Laboratories, Inc., Chicago, IL), leaving the flattened dentin surfaces exposed for bonding as previously described (Bowen, 1965;Miniotis et al, 1993). After the samples were mounted, the exposed dentin was resurfaced with an Emery cloth strip (320 grit), and the assemblies were stored in distilled water at room temperature (23°+ 1C).…”