The effect of the viscosity of luting composite on micro leakage around glass ceramic inserts

to evaluate microleakage around class v resin restorations restored with glass ceramic inserts luted with a high-viscous composite resin or a flowable composite resin. materials & methods: sixty extracted human premolars (patient age range 11-16 years) were randomly assigned to three groups. class v preparations in two groups were filled using a glass ceramic insert (lee pharmaceuticals, south el monte, usa.) luted with either hybrid, high viscous composite (tetric cream, ivoclar vivadent, liechtenstein.) or a flowable composite (tetric flow, ivoclar vivadent, liechtenstein). the other two groups served as a control and were bulk filled with either tetric ceram or tetric flow. the same bonding agent. (excite, ivoclar vivadent, liechtenstein) was used to in all groups. the preparations were made with a no. 330 tungsten carbide fissure bur in a water-cooled, high-speed hand piece with a mesio-distal width of 3mm, an occluso-gingival height of 3mm and 2mm deep. all margins had butt joints. by random selection, ten teeth in each group were thermo cycled for either 500 or 5000 cycles, between water baths held at 50c and 550c and ten specimens were not thermocycled. the specimens prepared and examined for microleakage using basic fusion as a marker. results: there was no significant difference in micro leakage scores at zero, 500 or 5000 cycle duration, at the occlusal margins or at the gingival margins, [p>0.05 in all cases] between inserts plus tetricceram and inserts plus tetricflow. there was no significant difference in micro leakage scores between inserts plus tetricceram and bulk filled tetricceram at zero, 500 or 5000 cycle duration, or inserts plus tetricflow and bulk filled tetricflow at zero, 500 or 5000 cycle duration: [p>0.05 in all cases]
there was a significant difference in micro leakage around inserts luted with the tetric flow occlusally (p = 0.0445) and gingivally (p=0.0500), after 5000 cycles compared to the controls at 0 cycles.