Effect of Intracanal Cryotherapy on Postoperative Endodontic Pain

Inclusion Criteria: 1. Systemically healthy patients with 18-70 years of age 2. Single-rooted teeth with a single root canal, diagnosed with either AIP and normal periapical tissues or AAP. Pulpal and periapical diagnoses were established according to the American Association of Endodontists (AAE) \[20\] diagnostic terminology. Included teeth were categorized into 2 diagnostic groups: AIP with normal periapical tissues and AAP associated with pulp necrosis. AIP was provisionally diagnosed in teeth with extremely deep caries approximating or reaching the pulp, a positive response to cold testing (Dispodent, Nadu, India), and no clinical symptoms. Periapical radiographs showed a PAI score of 1 without periodontal ligament widening. The diagnosis was confirmed intraoperatively by persistent pulpal bleeding that remained uncontrolled after 10 minutes of application of a sterile cotton pellet moistened with 2.5% sodium hypochlorite. AAP was diagnosed in teeth with a PAI score of ≥3 in the absence of clinical symptoms. None of the included teeth exhibited tenderness to percussion. All periapical radiographs were obtained using a phosphor storage plate system and the paralleling technique (Myray parallel holder, NDental, Imola, Italy) under standardized exposure parameters (70 kV, 8 mA, 0.360 s). Exclusion Criteria: 1) Teeth with canal calcification, complex or atypical canal anatomy, root resorption, incomplete root development, or a history of endodontic treatment of the study tooth. 2\) Teeth initially diagnosed with AIP in which pulpal bleeding was controlled within 10 min after access cavity preparation, as these teeth were considered eligible for vital pulp therapy. 3\) Teeth initially diagnosed with AIP in which pulp necrosis was identified after access cavity preparation. 4\) Teeth in which root canal treatment could not be completed in a single visit. 5\) Patients who had taken analgesics within 12 hours before the appointment or antibiotics within the previous month. 6\) Teeth with periodontal probing depths \>3 mm or clinical/radiographic signs of periodontal disease. 7\) Teeth with insufficient coronal tooth structure to allow an adequate ferrule. 8\) Pregnant or breastfeeding patients and patients with systemic conditions or regular medication use that could affect treatment outcomes.