Human saliva penetration of coronally unsealed obturated root canals.

By Khayat A, Lee SJ, Torabinejad M.

Date: 08/1998
Journal: JOE

Purpose: to determine the length of time for bacteria present in natural human saliva to penetrate through the entire root canal system obturated by lateral and vertical condensation techniques in an in vitro model.

N= 40 molars (palatal of maxillary and distal of mandibular)


•The teeth were cleaned and shaped using a step-back technique

•30 root canals were obturated with GP and Roth’s sealer (15 lateral condensation, 15 vertical condensation), the roots were coated with nail polish except for the apical 2 mm

•5 teeth were obturated with single cone without sealer (+ve control), and 5 teeth obturated by lateral condensation and completely coated with nail polish (-ve controls). •By preparing a special apparatus, the coronal portions of the filling materials were placed in contact with human saliva (Fig. 1 and 2)

•The number of days required for bacteria in saliva to penetrate the entire root canals were determined.

Most highlighted Results:

  •All root canals were recontaminated in less than 30 days (average of 29 days for lateral and 25 for vertical groups).

•No statistical significant difference was found between the two methods of obturation.

•No bacterial leakage occurred in the negative control group.

•Complete bacterial leakage occurred within 2 days in the positive control group.

•Examination of cleared teeth showed penetration of ink through the entire junction of filling materials and the dentinal walls in all of the specimens.

Most highlighted results:

-Initial measurement after 24 hours didn’t show endotoxin or bacteria.

-All + control showed endotoxin leakage after 8 days, while

– control only one sample had endotoxin leakage at day 8.

-38% of experimental gp showed endotoxin leakage after 8 days increased to 81% after 70 days.

-All + control showed bacterial leakage after 15 days.

-19% of experimental grp showed bacterial leakage after 43 days and 67% after 70 days Table.1.

-The mean leakage time was 23 days for endotoxin and 62 days for bacteria in the experimental gp.

Clinical Significance:

Bacterial and endotoxin penetration in this in vitro study could possibly effect the decision making of retx in teeth with compromised restoration. However, other factors should be considered in regards to retx.