Analysis of Restorative Failure on Filled Teeth

Objectives:To assess effects of different class II cavities on stresses of amalgam and composite resin restoration. Methods: Five kinds of class II MO cavities were prepared on the first molars of mandibles. The cavities were filled by amalgam and composite resin, respectively. The stresses were loaded on the teeth.Results: The stresses were greater in conventional cavities than those in modified cavities when 100N vertical and lateral pressures were loaded on the teeth. But the compressing stress and shear stress in cavities filled by amalgam were smaller in conventional cavities than those in modified cavities. The stresses were smaller in cavities filled by resin than those in cavities filled by significantly, when the cavities were designed as form with slot retention groove and without slot retention groove and as plate form. The Stresses were smaller in two kinds of slot and plate cavities than those in conventional and modified cavities.Conclusions:It is better to design cavities with slot retention groove for amalgam restoration and to design cavities without slot retention groove for composite resin restoration.