Adhesive Bonding of Various Materials to Hard Tooth Tissues. III. Bonding to Dentin Improved by Pretreatment and the Use of Surface-active Comonomer

¹ American Dental Association, National Bureau of Standards, Washington, D.C.

The average tensile strength of bonds between a direct-filling resin and surfaces on 5 dentin specimens after soaking for 20 hours in water was between 27.4 and 55 kg/cm² (390 and 780 psi) when the dentin was treated with a 5 per cent ethanol solution of NPG-GMA (adduct of N-phenylglycine and glycidyl methacrylate). After exposure of the bond to water for 19 days, significant adhesion was retained. The value was only 0-0.7 kg/cm² (0-10 psi) when the dentin was untreated or treated with 2-hydroxypropyl methacrylate or 5 per cent ethanol solutions of stearic acid, 12-hydroxy stearic acid, stearoyl sarcosine, and oleoyl sarcosine, respectively. Pretreatment of the dentin surface with a dilute acid or base, followed by rinsing and blotting prior to application of the NPG-GMA, gave the highest adhesion values. Such treatment with 0.01 N NaOH gave an average of 66.8 kg/cm² (950 psi) after 1 day in water.