Resilon obturation system was discontinued following its introduction as an alternative to traditional gutta percha and sealer. In-vitro models support anecdotal reports of degraded Resilon filling material. This may represent a significant health concern for the patient. The aim of this study was to determine the proportion of Resilon degradation in non-healed endodontic cases and to present a case series describing retreatments of non-healed Resilon obturated teeth. Patients previously treated with Resilon (R) or Gutta-Percha (GP) that had a non-healed canal that needed a retreatment were enrolled. The proportion of degraded filling material was statistically significantly different between R and GP treated groups (p=.0003) with 78% of R canals being degraded compared to 0% of GP canals. The difference in the proportionality of degradation between the two materials was marginally significant (p=.054) when dichotomized time to follow-up and presence of an orifice barrier were controlled for in the multivariate analysis.