Dissolution of root canal sealer cements in volatile solvents

There are few published data on the solubility profiles of endodontic sealers in solvents commonly employed in root canal retreatment. This study tested the hypothesis that root canal sealer cements are insoluble in the volatile solvents chloroform and halothane.

Standardized samples (n = 5) of glass ionomer (Ketac Endo), zinc oxide-eugenol (Tubli-Seal EWT), calcium hydroxide (Apexit) and epoxy resin (AH Plus) based sealers were immersed in chloroform or halothane for 30 s, 1 min, 5 min and 10 min. Mean loss of weight was plotted against time of exposure, and differences in behaviour assessed by multiple paired t-tests (P < 0.01).

Clear differences were shown in the solubility profiles of major classes of root canal sealer cements in two common volatile solvents. In comparison with other classes of material, Ketac Endo was the least soluble in chloroform and halothane (P < 0.01), with less than 1% weight loss after 10 min exposure to either solvent. Apexit had low solubility with 11.6% and 14.19% weight loss after 10 min exposure to chloroform and halothane, respectively. The difference between solvents was not significant (P > 0.01). Tubli-Seal EWT was significantly less soluble in halothane than chloroform (5.19% and 62.5% weight loss after 10 min exposure, respectively (P < 0.01)). Its solubility in halothane was not significantly different from that of Apexit. AH Plus was significantly more soluble than all other materials in both chloroform and halothane (96% and 68% weight loss after 10 min exposure, respectively (P < 0.01)).

There are significant differences in the solubility profiles of major classes of root canal sealer in common organic solvents. Efforts should continue to find a more universally effective solvent for use in root canal treatment.