To compare the incidence of post-operative pain after single-visit versus two-visit non-surgical endodontic retreatment.

Post treatment failure could be treated by two options including orthograde retreatment and apical surgery . In a previous study, orthograde retreatments presented a success rate of 81 % classified as healed and 93 % as no symptoms and fully functional. In a systematic review, it has also been concluded that endodontic surgery offers more favorable initial success but orthograde retreatment yields to a better long-term outcome . Although early results of single-visit treatments are contradictory ; Completing the treatment in a single appointment reduces the treatment time and cost, decreases micro leakage risk and avoids recontamination of root canals between appointments in multiple-visit treatments . Again, reviewing the literature concerning primary treatment showed that, no significant differences were observed in healing of periapical radiolucency between teeth treated in single-visit and those treated in two-visits. Even, after using calcium hydroxide for four weeks . The presence of a positive bacterial culture at the time of filling did not influence the outcome of treatment .

Thorough online search revealed that, few studies are found concerning post- operative pain after single visit retreatment . The present study is designed to compare the effects of single-visit and two-visit root canal treatments on postoperative pain in retreatment cases. The primary outcome measure of this study is proposed to be whether single-visit root canal retreatment influenced the occurrence of postoperative pain as compared to two-visit treatment.

Inclusion Criteria:

• Clinically asymptomatic.
• Previously treated teeth in need of retreatment due to leakage and/or improper filling.
• No periapical radiolucency.
• No percussion pains.
• Age 20 - 45.
• Premolar teeth.
• Male & female.

Exclusion Criteria:

• Complicating compromised patient.
• Tenderness to percussion and acute apical abscess.
• Presence of an associated sinus tract.
• Presence of swelling in adjacent soft tissue.
• Teeth with periodontal pathologies or mobility.
• Teeth representing root fracture.
• Pregnant women.
• If analgesics or antibiotics have been administrated by the patient during the past 24 hours.