The purpose of this randomized clinical trial was to evaluate the incidence of postoperative pain after root canal treatment using different final irrigation protocols. Patients whom need root canal treatment for first time were included. The presence of postoperative pain was assessed after root canal treatment cases at 12, 24, 48, 72 hrs and 1 week.

The aim of this clinical study was to evaluate the intensity and duration of postoperative pain following different final irrigation procedures. Patients who have asymptomaticdevital teeth required endodontic treatment were included in this study and routine root canal treatment procedure was applied to these teeth. All of the patients have been recruited from the Istanbul Medipol University Dental Clinics in Istanbul. Ninety asymptomatic teeth were randomly participated into 3 treatment groups in terms of intracanal medicament applied. The presence of postoperative pain was assessed after 12, 24, 48, 72 hrs and 1 week. Postoperative pain was recorded by each patient by using visual analogue pain scale. Before the treatments, the nature of the study, complications and associated risks were totally explained and written informed consent was obtained from all study participants. The patients were offered local anesthetic before the treatment start. The routine root canal treatment procedure was applied. Different final irrigation solutions applied in accordance to the manufacturers' instructions. At the end of treatment, each patient was given an evaluation sheet, explained the treatment procedure and using of visual analogue pain scales, and informed to be returned during the following one week. After one week the teeth was examined according to for pain intensity, percussion & palpation sensitivity, swelling, analgesic intake and clinical status.

Inclusion Criteria:

-Patients who were healthy volunteers and who have devital premolar and molar teeth with PAI 3-5score requiring root canal treatment for first time.

Patients who were not included the study who;

• were pregnant or breast feeding during the duration of the study,
• have systemic disease, have any pain and/or any facial swelling, abscess,
• were immunocompromised,
• were under 18 yrs. and over 65 yrs. age,
• were taking antibiotics or corticosteroids within previous three days,
• have multiple teeth that required root canal treatment at the same time period; for eliminating pain referral,
• have root canals that could not be well-treated with orthograde root canal treatment.

Exclusion Criteria:

-The patients who forgot to fill out the form and took antibiotics and/or analgesics right after the first appointment of the therapy were excluded from the study.

Double (Participant and Outcomes Assessor) The patients were unaware as to which study group they had been allocated.