Effects of Instrumentation and NaOCl Concentration on Microbial DNA Load Employing a Sonic Activation Device

Area of Science:

• Endodontics
• Microbiology
• Molecular Biology

Background:

• Bacterial contamination is a primary cause of endodontic failure.
• Effective disinfection of root canals is crucial for successful treatment.
• Sonic activation enhances irrigant penetration and efficacy.

Purpose of the Study:

• To quantify bacterial DNA load reduction in mesial root canals of mandibular molars.
• To evaluate the impact of instrumentation, irrigant type, and sonic activation on bacterial DNA reduction.
• To determine the interaction between instrumentation and irrigant type in reducing bacterial load.

Main Methods:

• Human mandibular molars were contaminated with plaque and subjected to root canal preparation with sonic activation.
• Three irrigant groups were tested: 7.55% NaOCl, 1.88% NaOCl, and sterile saline.
• Bacterial DNA was quantified using quantitative polymerase chain reaction (qPCR) at baseline, after initial preparation (size 25/.04), and after enlargement (size 30/.04).

Main Results:

• Instrumentation with sonic activation significantly reduced bacterial DNA load (P < 0.0001).
• Most bacterial reduction occurred during initial preparation to size 25/.04.
• No significant difference in bacterial DNA reduction was observed between the different irrigant types or concentrations when combined with sonic activation.

Conclusions:

• Root canal instrumentation combined with sonic activation is the primary driver of bacterial DNA load reduction.
• The type and concentration of irrigant play a minor role in bacterial reduction when sonic activation is employed.
• Sonic activation significantly enhances the antibacterial efficacy of root canal preparation.