CLSM-Guided Imaging for Quantifying Endodontic Disinfection

Area of Science:

• Microbiology
• Endodontics
• Microscopy

Background:

• Effective microbial elimination in the root canal system is vital for successful endodontic treatment.
• Standardization of in vitro study designs is necessary to improve the validity and comparability of endodontic disinfection research.
• Existing methods for evaluating endodontic disinfection lack sufficient standardization, impacting the reliability of in vitro results.

Purpose of the Study:

• To optimize and standardize in vitro models for evaluating endodontic disinfection procedures.
• To improve the visualization and quantification of bacterial penetration and irrigation depths in root canals.
• To introduce a reliable tooth selection method for in vitro endodontic studies.

Main Methods:

• Optimization of tooth selection, pretreatment, inoculation, and imaging steps for in vitro endodontic models.
• Development and application of Sclerosis Grading (SCG) for comparable tooth selection.
• Utilizing confocal laser scanning microscopy (CLSM) with LIVE/DEAD staining for bacterial visualization.
• Employing sonically activated EDTA for root pretreatment and an overflow model for Enterococcus faecalis inoculation.

Main Results:

• Individual anatomical variations significantly influence bacterial penetration depth.
• Sonically activated EDTA pretreatment and specific inoculation/incubation methods improved visualization of bacterial penetration.
• Sodium hypochlorite (NaOCl) pretreatment demonstrated negative effects on reproducibility and should be avoided.
• Sclerosis Grading (SCG) facilitates specific and comparable tooth selection for in vitro studies.
• Nonsclerotized teeth (SCG0) are suitable for a simplified centrifugation-based inoculation model.

Conclusions:

• Confocal laser scanning microscopy (CLSM)-guided imaging is a powerful tool for quantifying endodontic infection and disinfection after methodological refinement.
• The optimized model, including Sclerosis Grading (SCG), enhances the validity and comparability of in vitro endodontic disinfection studies.
• Standardized in vitro models are crucial for advancing our understanding of endodontic disinfection and improving clinical outcomes.