Table 1. Ability to regain patency and re-establish working length during retreatment for the different groups.

	Group 1A (%)	Group 1B (%)	Group 2A (%)	Group 2B (%)
Patency Regained	100	100	93	14*
WL re-established	100	100	93	93

Mean volume percentages (%) of the remaining filling material are shown in the table. For patency regained, a statistically significant difference was found between Group 2B and each of the remaining groups (^*p < 0.001). Patency could be regained in only 14% of cases that were obturated with BC Sealer and retreated without chloroform. For WLs there were no significant differences between the groups. WL, working length.