Microleakage at the resin-alloy interface of chemically retained composite resins for cast restorations

New retentive mechanisms between veneering resins and casting alloys are claimed to have a chemical bond that results in a high bond strength combined with low microleakage between the veneering resin and cast restoration. This study compared the microleakage of four chemical bonding mechanisms when three veneering resins were bonded to two dental casting alloys. Resin-veneered alloy disks were immersed in red India ink and kept at 37 degrees C for 72 hours. The disks were then bench dried for 24 hours. The resin veneer was sectioned into eight sectors in an engineering milling machine and these resin sectors were removed to display the microleakage pattern. It was concluded that (1) no microleakage was found in two combinations, and (2) the highest microleakage was with Sr-Isosit-N/Panavia EX/Firmilay combinations.