The use of resin composite pins to improve retention of class IV resin composite restorations

This study evaluated the effect of an intracoronal resin composite pin on C lass IV resin composite restorations. A control group of 16 bovine teeth wa s prepared with standardized conventional Class IV preparations. For an exp erimental group, 16 similar Class IV preparations were made, with the addit ion of an intracoronal pin channel prepared with a #330 bur into the dentin , All specimens were restored with Herculite XRV and OptiBond according to the manufacturer's recommendations. After one week, specimens were placed i n an Instron Universal Testing Machine and loaded at 90 degrees to the long axis until the restorations failed. Results indicated that the mean fractu re load of the Class IV restoration group, with the resin composite pin, wa s 36% higher than the conventional Class IV group (p=0.02). An intracoronal resin composite pin may aid the retention and resistance form of complex r esin composite restorations.