Epiphany™ Thinning Resin is irritating to rat subcutaneous tissues

A resinous solvent (Epiphany™ Thinning Resin, Pentron Clinical Technologies, LLC, Wallingford, CT, USA) is one of the components of the Resilon-Epiphany root canal filling system. The manufacturer recommends the preparation of the Epiphany root canal sealer with one to two drops of this solvent in order to adjuste its viscosity. However, there is only one previous study evaluating the cytotoxicity of this solvent. Objective: the aim of this study was to evaluate the biocompatibility of the Epiphany™ endodontic sealer prepared with the Epiphany™ Thinning Resin in rat subcutaneous tissues. Methods: Polyethylene tubes with 10 mm in length were filled with the sealer: I - Epiphany prepared with one drop of Epiphany™ Thinning Resin; II – Epiphany prepared with one drop of Epiphany™ Thinning Resin and photoactivated; III – Epiphany associtaed to primer and prepared with one drop of Epiphany™ Thinning Resin; IV – Epiphany associated to primer, prepared with one drop of Epiphany™ Thinning Resin and photoactivated. The tubes containing the sealer were implanted into four different regions of the dorsum of twenty adult male rats (Rattus novergicus albinus, Wistar). The lateral wall of the tubes was used as negative control. After 7, 14, 21 and 42 days, five animals were killed, obtaining 5 samples per group at each analyzed time. Results: After 7, 14 and 21 days, all groups presented a moderate to intense chronic inflammatory reaction, necrosis, foreign-body multinucleate giant cells and great quantity of residual sealer. At 42 days, although the intensity of chronic inflammatory reaction has decreased (mild to moderate), necrosis, foreign-body multinucleate giant cells and residual sealer still were observed. Conclusion: The Epiphany™ endodontic sealer prepared with the Epiphany™ Thinning Resin was irritating to rat subcutaneous tissues.