Should the pre-endo proximal wall reconstruction be replaced after endodontic procedures?

This laboratory study aims to evaluate if irrigating protocols during endodontic treatment can influence the retention of pre-endo resin composite reconstructions. Methods: Human molars were embedded in acrylic resin and the deep dentin surfaces exposed. Adhesive procedures were performed at the periphery to simulate proximal pre-endo reconstructions with a universal adhesive (iBond universal, Kulzer) and composite (Venus Pearl, Kulzer). The specimens were randomly assigned to one of the following irrigating protocols (n=20): C: No treatment; SH: 5.25% sodium hypochlorite for 10 min + final water rinse; CHX: The same as SH + final 2% chlorhexidine rinse for 2 min; EDTA: The same as SH + final EDTA rinse for 2 min. The shear bond strength test (SBS) was performed after 24 h or 10.000 thermocycles (TC; 5-55 °C, 30s dwell time). Data were statistically analyzed (p<0.05). Results: The irrigating solution, ageing and their interactions statistically influenced the results (p<0.001). At baseline, EDTA recorded the highest SBS values, with no differences between CTRL, SH and CHX (p<0.05). TC statistically decreased the bonding values in all groups and no differences were observed irrespective of the irrigating protocol (p>0.05). Conclusions: The irrigating solutions did not influence the bonding performances of resin composite restorations. Clinically, this would translate in the possibility to maintain the pre-endo proximal wall for the final coronal restoration. However, further studies are warranted.