This study evaluates the antibacterial effectiveness of two different intracanal medicaments, Bio-C Temp and UltraCal XS , in mandibular molar teeth with chronic apical periodontitis. Intracanal bacterial load is assessed before and after root canal preparation, after intracanal medicament removal, and after final irrigation using droplet digital PCR.

This randomized controlled clinical trial investigates the effect of two different intracanal medicaments on the reduction of intracanal bacterial load in mandibular molar teeth diagnosed with chronic apical periodontitis. The study is conducted at Istanbul Medipol University Faculty of Dentistry, Department of Endodontics, and includes systemically healthy participants aged 18-65 years who require primary root canal treatment and present with radiographic evidence of periapical radiolucency.

Participants are randomly assigned to two groups. In the first group, Bio-C Temp is used as the intracanal medicament. In the second group, a UltraCal XS is applied. All teeth are isolated with a rubber dam, and the operative field is disinfected before access cavity preparation. After removal of previous restorations and caries, sterility control samples are collected from the tooth surface.

Working length is determined using an electronic apex locator and confirmed radiographically. Initial microbiological samples are collected from the root canals using sterile paper points. Root canal shaping is performed with heat-treated nickel-titanium rotary files, and canal enlargement is completed with a VDW Rotate #35/.04 file. The irrigation protocol includes 2.5% sodium hypochlorite and 17% EDTA, followed by passive ultrasonic irrigation using an IRRI S ultrasonic tip. Sodium hypochlorite is inactivated with 10% sodium thiosulfate before microbiological sampling.

After chemomechanical preparation, the assigned intracanal medicament is placed 1-2 mm short of the working length, and the access cavity is temporarily sealed. Participants are recalled after 14 days. At the second appointment, the intracanal medicament is removed mechanically and chemically. A neutralization step is performed before further sampling, and the final irrigation and ultrasonic activation protocol is repeated.

Bacterial samples are collected at different stages of treatment, including baseline, after chemomechanical preparation, after medicament removal, and after final irrigation. The bacterial load is quantified using droplet digital PCR, a sensitive molecular method that allows absolute quantification of bacterial DNA. This technique is used to compare the antibacterial effect of Bio-C Temp and calcium hydroxide and to evaluate bacterial reduction throughout the treatment protocol.

Pain levels are also recorded using a visual analog scale. After completion of the sampling and irrigation procedures, the root canals are obturated with gutta-percha using the lateral condensation technique, and the access cavities are restored with composite resin. A final periapical radiograph is taken for treatment control.

Inclusion Criteria:

• Patients aged between 18 and 65 years
• Being systemically healthy (ASA I or ASA II)
• Mandibular molar teeth with a radiographically detectable radiolucent lesion in the periapical region
• Willingness of the volunteer or their legal representative to participate in the study by signing the Informed Consent Form

Exclusion Criteria:

• Patients who have received antibiotics or corticosteroids within the last 3 months
• Patients with systemic diseases
• Teeth that cannot be properly isolated with a rubber dam
• Teeth with periodontal pockets >4 mm and teeth with crown/root fractures
• Individuals who are undergoing or planning to start orthodontic treatment during the study period
• Pregnant or breastfeeding individuals

After its publication in a journal, we want to share our data.

After its publication in a journal, we want to share our data.