Bacterial reduction and persistence after endodontic treatment procedures

Area of Science:

• Microbiology
• Endodontics
• Molecular Biology

Background:

• Persistent bacteria after endodontic disinfection can cause treatment failure.
• Over 50% of endodontic bacteria are unculturable, requiring cultivation-independent investigation.
• Understanding persistent bacteria is crucial for effective endodontic treatment.

Purpose of the Study:

• To evaluate bacterial reduction from intracanal disinfection procedures.
• To identify bacterial taxa persisting after endodontic treatment.
• To utilize culture-independent methods for comprehensive analysis.

Main Methods:

• Collection of samples from infected root canals at three stages: pre-treatment (S1), post-instrumentation with sodium hypochlorite (NaOCl) (S2), and post-calcium hydroxide medication (S3).
• Analysis using 16S rRNA gene clone library and real-time polymerase chain reaction (PCR).
• Culture-independent assessment of bacterial load and composition.

Main Results:

• Intracanal disinfection procedures (instrumentation and medication) achieved significant bacterial reduction (99.67% and 99.85%).
• Five of 15 canals showed negative bacterial results post-treatment.
• Forty-three distinct bacterial taxa were identified, with 56% being uncultivated phylotypes; 19 taxa persisted post-treatment, notably Streptococci.

Conclusions:

• Culture-independent methods offer detailed insights into intracanal disinfection efficacy.
• Effective strategies are needed to target persistent endodontic bacteria, including uncultivated phylotypes.
• Further research using these methods can improve endodontic treatment outcomes.