Methods: 480 simulated resin canals were prepared and filled with GP, RS and ER (160 canals each). Each group was divided into 2 subgroups, for penetration force measurements (PFM) (100 canals) and depth indicator test (DIT) (60 canals). PFM group were tested with 50µL or 150µL of for each solvents. The force was measured after 60 second solvent placement. For DIT, the penetration depth was measured at exposure time of 30, 120 and 240 seconds. The results were analysed statistically by the Kruskall-Wallis test and Mann-Whitney test.
Result: Chloroform and xylol significantly soften GP and ER(P<0.05). However, when additional amount of eucalyptol oil was used, the softening effect increased significantly within the gutta-percha group (P<0.05). Longer exposure time and additional amount of chloroform and xylol significantly enhanced its softening effect within the RS group. On the other hand, when xylol and eucalyptol oil were exposed to the ER for longer period of time, the softening effect increased (P<0.05).
Conclusions: Xylol was found to be the most effective solvent for GP and ER whereas eucalyptol oil and orange oil required additional amount and longer exposure time to increase their softening effect toward GP, RS and ER.