Potential systematic error in laboratory experiments on microbial leakage through filled root canals: an experimental...

Area of Science:

• Endodontics
• Microbiology
• Dental Materials Science

Background:

• Root canal treatment aims to prevent bacterial leakage.
• A two-chamber model is commonly used to evaluate root filling efficacy.
• Understanding bacterial leakage routes is crucial for endodontic success.

Purpose of the Study:

• To assess bacterial leakage routes in a two-chamber model for evaluating root fillings.
• To compare leakage in intact versus root-filled teeth using this model.

Main Methods:

• Human mandibular premolars were intact, instrumented and left open, or root-filled.
• Teeth were sealed in a two-chamber system with Enterococcus faecalis seeded in the upper chamber.
• Leakage was monitored for 120 days, followed by histological analysis using confocal microscopy and FISH.

Main Results:

• Bacterial leakage occurred from day 56, with no significant difference between root-filled and intact teeth.
• Leakage was observed between cementum and wax, and between root filling and tubular dentine.
• Fluorescence was absent at the root filling-sclerotic dentine interface, but present in secondary dentinal tubules.

Conclusions:

• The two-chamber model used was unsuitable for comparing root filling materials.
• Dentine structure significantly influences bacterial leakage pathways.
• Further histological investigation into dentine-root filling interactions is warranted.