Evaluate and compare the disinfecting efficacy of two supplementary antimicrobial protocols in teeth with apical periodontitis

This study aims to evaluate and compare the disinfecting efficacy of two supplementary antimicrobial protocols in teeth with apical periodontitis: Er,Cr:YSGG laser activated irrigation and ultrasonic activation using a piezoelectric ultrasonic device (Dentsply International Inc., York, PA, USA) and Irrisafe tip (Satelec/Acteon, Merignac, France), comparing the detection of bacteria before and after instrumentation.

Secondary aims are to assess presence of bacteria before and after chemomechanical preparation using two microbiological methods:

• ATP level analysis using the Endocator device
• Quantitative PCR (qPCR) for total bacterial quantification.

Inclusion Criteria:

• Adult patients able to give informed consent and willing/able to comply with study procedures and follow-up.
• Molar teeth indicated for endodontic treatment.
• Teeth with intact pulp-chamber walls (no extensive coronal destruction).
• Necrotic pulp confirmed by pulp testing.
• Clinical and radiographic evidence of asymptomatic apical periodontitis.

Exclusion Criteria:

• Immature teeth
• Teeth with calcified or obliterated canals
• Teeth with extensive coronal destruction
• Teeth with previous endodontic treatment
• Symptomatic apical periodontitis
• Teeth with periodontal pockets greater than 4 mm
• Patients who have received systemic antibiotics in the last 3 months
• Patients with a history of diabetes or immune impairment
• Pregnant patients

No individual participant data will be shared. All data collected will be used exclusively for this study and will be presented only in aggregated and de-identified form, in accordance with the approved protocol and informed consent.