EVALUATION OF FRACTURE-RESISTANCE OF RESINS USED FOR PROVISIONAL RESTORATIONS

Fracture resistance of provisional restorations is an important concern for the restorative dentist. Fracture resistance of a material is directly related to the transverse strength. This study evaluated the transverse strengths of provisional resins under varied conditions. Uniform samples were made from seven resins and tested immediately after the set of the material, after 7 days of dry storage, and after 7 days of wet storage. The fractured samples from the 7-day wet storage group were repaired with the same provisional material the sample was made from and fractured again to determine transverse strength for repaired samples. Five of the resins tested demonstrated statistically similar strength in the 7-day wet group. Two were found to be significantly weaker. Absorption of water resulted in a slight, but insignificant decrease in strength. Transverse strengths varied widely in the repaired group, and all materials showed a statistically significant reduction compared with the 7-day wet storage group. © 1990.