ABSTRACT
The purpose of this study was to determine the effect of accidental dentin primer contact with etched enamel on shear bond strength of composite resin to enamel. Four dentin bonding systems were included in this study: GLUMA Dentin Bond, Scotchbond, and Prisma Universal Bond 2 and 3. Eighty extracted human permanent anterior teeth were used and divided in eight test groups. The vestibular surfaces were ground and acid etched. For each dentin bonding system 10 samples were treated with dentin primer prior to placement of resin. Shear bond testing showed that enamel contact with dentin primer in the above two systems decreased the shear bond strength between composite and enamel by 31 to 44%.
Subject(s)
Composite Resins , Dental Bonding , Dental Enamel/drug effects , Dentin-Bonding Agents , Resin Cements , Acid Etching, Dental , Dentin-Bonding Agents/chemistry , Dentin-Bonding Agents/pharmacology , Glutaral/chemistry , Glutaral/pharmacology , Humans , Materials Testing , Polymethacrylic Acids/chemistry , Polymethacrylic Acids/pharmacology , Surface Properties/drug effects , Tensile StrengthABSTRACT
Wild-type Zymomonas mobilis strains inhibit the growth of Escherichia coli. We report the first isolation of noninhibitory strains, called Zymomonas inhibition negative (Zin), after treatment with N-methyl-N'-nitro-N-nitrosoguanidine. A standardized soft-agar overlay procedure for detecting E. coli growth inhibition was also developed.
