An in vivo and in vitro comparison of two dentin bonding agents

The in vitro and in vivo shear bond strengths of two dentin bonding agents to dentin were measured by use of a goat model. The dentin was exposed in the mandibular incisors of 10 adult goats while they were maintained under general anesthesia. Separate gingival and incisal areas of dentin were isolated with Teflon tape, exposing an area 2.83 mm in diameter. GLUMA or Scotchbond II was applied to those dentin areas according to the manufacturers' directions. A column of resin was then applied over the bonding agent and light-cured. Two hours later, the animals were killed and the teeth removed. The teeth were then mounted in acrylic resin, and the resin composite tube was loaded in shear until failure on an Instron. Seven days later, the extracted teeth were re-prepared and the same bonding procedure re-applied. These teeth were placed in the Instron and loaded in shear until failure. Thirteen months later, the teeth bonded with GLUMA were re-prepared and bonded in the same manner as above. The resin composite was loaded in shear until failure. There was no significant difference between the two-hour in vivo bond strength and the seven-day or the 13-month in vitro bond strength with GLUMA. There was no significant difference between the two-hour in vivo or the seven-day in vitro bond strength for Scotchbond II. There was no significant difference between the shear bond strengths of the two dentin bonding agents.