EFFECT OF PREPOLYMERIZED ZIRCONIUM REINFORCED COMPOSITE RESIN DOUBLE MEGA INSERTS ON THE MARGINAL ADAPTATION OF RESIN BASED COMPOSITE RESTORATIONS
The purpose of this in vitro experimental study was to assess the effect of pre-polymerized zirconium reinforced composite resin double mega inserts on the marginal adaptation of resin based composite restorations.
Resin based composite (RBC) is the most commonly used as direct restorative material in anterior and posterior teeth. The drawback of polymerization shrinkage in RBC that is maximum 3% by volume can produce stress at composite-tooth interface and may initiate failure of RBC restorations.
Eighty human mandibular molars were prepared for class II and class V cavities with dimensions of 3.5mm depth, 3mm height and 3.5mm width. The specimens were divided into control and experimental groups with forty specimens in each group. Both groups were further divided into two sub-groups by type of prepared cavity as A1, A2 for control group and B1, B2 for experimental group respectively with 20 specimens in each group. The cavities in control group were filled with conventional composite resin while cavities in experimental group were filled with pre-polymerized zirconium (30% by weight) reinforced resin composite double mega-inserts. All the specimens were cured and microleakage was assessed by dye penetration method using microscope. The dye penetration test revealed that control group specimens had more microleakage than experimental group specimens.
It was concluded from the present study that pre-polymerized zirconium reinforced resin composite double mega inserts reduced the marginal leakage and improved the marginal adaptation in both class II and class V restorations.