Fluid transport and bacterial penetration along root canal fillings

Abstract

Convective transport of water from the coronal to the apical end of obturated root canals was determined by the movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section using a headspace pressure of 120 kPa (1.2 atm). Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The root canals of 60 human maxillary canines were filled with gutta-percha and sealer by the cold lateral condensation technique. Thirty of these were first exposed to a small motile bacterium, Pseudomonas aeruginosa, growing in a reservoir at the coronal end of each root. After 50 days, two specimens allowed penetration of bacteria to a reservoir at the apical end. All the roots were then assessed quantitatively for convective transport of water. The results were divided into three defined categories: 39 obturated canals were in the 'bacteria tight' category, 14 canals in the 'slight leakage' and 7 canals in the 'gross leakage' category. The two specimens that showed bacterial penetration fell into the slight and gross leakage categories. The previous test for bacterial passage did not statistically influence the fluid transport pattern of these roots which was measured subsequently. These findings indicate that fluids transport through obturated root canals, most of which do not allow the passage of bacteria.

Influence of the length of remaining root canal filling and post space preparation on the coronal leakage of Enterococcus faecalis

“…However, this methodology is not the most effective and has some limitations, as the size of dye molecules may overestimate the infiltration or the interaction between dye and sealer may lead to false results (23).…”

Longitudinal Study on the Influence of Nd:YAG Laser Irradiation on Microleakage Associated with Two Filling Techniques

“…The roots were attached to a FTM as described by Wu et al 23 and De Bruyne et al 24 Roots were connected at both ends to a plastic tube with Al-Fix Gel (Novatio Belgium n.v., Olen, Belgium) and additionally sealed with Quick-Bond (Novatio). The plastic tubes on either side of the specimen were filled with distilled water, and a standard glass capillary tube was connected to the plastic tube at the outlet side of the specimen.…”

Lack of correlation between obturation limits and apical leakage

“…On the other hand, very small "through and through" type voids are invisible on radiographs but may be detected by the fluid filtration test as having considerable leakage rates. 16,[28][29][30] Our results showed that there were no statistical differences associated with apical leakage in the three groups analyzed. However, our obturation limits ranged from 0 to 1.68 mm of the main apical foramen, and these limits are in conformity with what are considered to be adequate limits in literature.…”