Ninety-seven maxillary and mandibular molar teeth were evaluated for the presence of naturally occurring furcation canals using the fluid filtration method. Only one specimen demonstrated a naturally occurring patent furcation canal. An artificial furcation canal was created with a 0.33-mm drill bit in the 96 teeth lacking naturally occurring furcation canals. Fluid filtration measurements were made before and after the artificial canal was made, and these served as the negative and positive controls for each tooth. The 96 teeth were randomly divided into eight equal groups, and the floor of the pulp chambers was sealed using 3 mm of either Tytin or Dispersalloy amalgams, Vitremer, FluoroCore, gutta-percha with sealer, Tytin with Ali-Bond 2 or Amalgambond, or Dispersalloy with Ali-Bond 2. Analysis of measured microleakage at 3 months indicated that Tytin amalgam used alone had significantly more microleakage than all other materials; however, this difference did not exist when bonding agents were used with Tytin. All materials leaked significantly less than the positive controls.