Evaluation of Compressive Strength of Repaired Direct Composite Resin Restorations

The aim of the study was to evaluate and to compare the compressive parameters of repaired composite restoration when using different types of composite resins and a universal bonding agent as an intermediate layer. Aged micro-filled hybrid and nano-filled hybrid composite resins were chosen to simulate old restoration. The same micro-filled hybrid composite resin was used as a repair material. A universal bonding agent applied in etch-and-rinse and self etch strategies was used as an intermediate layer in restoration repair. Non-aged composite resins were considered as control. Compressive strength and compressive modulus were determined by evaluating the samples in a universal testing machine. Lower values of the tested parameters were recorded after aging both types of composite resin when compared to control. Higher values of compressive strength were recorded when nano-filled hybrid composite resin was repaired when compared to micro-filled hybrid composite resin. The strategy of universal bonding agent application as an intermediate layer did not influenced the compressive properties of repaired restoration.