[Bonding of crown fragments with dentin bonding agents and porcelain veneers]

Measurements of fracture strengths of incisors from sheep, previously fractured and then restored by reattaching the fragments with a light-curable resin, revealed that pretreatment of the fracture surfaces with dentin bonding agents such as Gluma, Tenure or Scotchbond2 and acid-etching of the enamel, gave values of about half the fracture strength of intact teeth. Measurements furthermore demonstrated that pretreatment by a combination of dentin bonding agents and acid-etching of the enamel yielded higher fracture strengths of the restored teeth, than that of teeth restored using only one of the two pretreatments. Fractured incisors, restored by Gluma-treatment of the dentin, acid-etching of the enamel and fragment-bonding with a light-curable resin, were further restored with porcelain veneers after preparation. Fracture strength measurements of such restored teeth revealed strength not significantly different from that of intact teeth. It is suggested that such restorations, could have a reasonably long period of function clinically.