Impact of Apical Shaping Diameter on Bacterial Load Reduction in Multispecies Infected Root Canals.

Area of Science:

• Endodontics
• Microbiology
• Dental Materials Science

Background:

• Intraradicular bacterial infections are a primary cause of endodontic treatment failure.
• Effective disinfection protocols are crucial for eliminating microorganisms within the root canal system.
• Apical preparation size and disinfection methods significantly influence bacterial load reduction.

Purpose of the Study:

• To evaluate the impact of increased apical shaping on bacterial reduction.
• To assess the efficacy of different disinfection protocols, including diode laser and XP-endo Finisher (XPF), in conjunction with varying apical preparation sizes.

Main Methods:

• Seventy infected human lower incisors were prepared using different chemomechanical techniques.
• Groups varied in apical preparation size (e.g., 25/3%, 30/3%, 30/5%) and disinfection methods (XPF, diode laser, or syringe irrigation).
• Bacterial load was quantified using colony counts on Plate Count Agar (PCA) plates.

Main Results:

• All tested groups demonstrated significantly higher bacterial reduction compared to the control (p < 0.001).
• Larger apical preparation sizes (30/3% and 30/5%) showed significantly greater efficacy than smaller sizes (25/3%) when combined with XPF or diode laser.
• No significant differences were found between XPF and diode laser within the same apical preparation size groups.

Conclusions:

• Increasing the apical preparation diameter is preferred for maximizing bacterial removal.
• Enhanced apical enlargement, particularly with larger diameters, improves the effectiveness of disinfection protocols like diode laser and XPF.
• The combination of enlarged apical preparation and advanced disinfection techniques is key to achieving substantial microbial reduction in root canals.