Effect of Intracanal Cryotherapy on Postoperative Endodontic Pain

Effect of Intracanal Cryotherapy on Endodontic Postoperative Pain in Teeth With Asymptomatic Irreversible Pulpitis and Asymptomatic Apical Periodontitis: A Four-Arm Randomized Controlled Trial

This study aimed to evaluate the effects of cooled and room-temperature NaOCl irrigation on postoperative endodontic pain in single-rooted teeth diagnosed with asymptomatic irreversible pulpitis (AIP) or asymptomatic apical periodontitis (AAP).

Study Overview

• Status: Completed
• Conditions: Periapical Periodontitis; Cryotherapy; Asymptomatic Irreversible Pulpitis
• Intervention / Treatment: Other: root canal treatment and cryotherapy

• Study Type: Interventional
• Enrollment (Actual): 132
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Centre
    • Rize, Centre, Turkey (Türkiye)
      • Recep Tayyip Erdoğan University Faculty of Dentistry, Department of Endodontics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: GROUP 1- Asymptomatic irreversible pulpitis - control; 20 mL of 2.5% NaOCl was kept in a glass beaker at room temperature and monitored with a digital thermometer to maintain a temperature of 22°C. Final irrigation in Groups 1 was performed using this solution.	Other: root canal treatment and cryotherapy; All endodontic procedures were completed in a single visit by one operator with 6 years of clinical experience. Only 1 tooth per patient was included. Local anesthesia was administered using 2 mL articaine HCl containing 1:100,000 epinephrine. After rubber dam isolation and access cavity preparation, working length was determined using an electronic apex locator and confirmed radiographically. Root canals were prepared with Endoart Smart Gold files to size 40/.04 and, when needed, up to 2 larger sizes according to canal anatomy. Apical patency was maintained 1 mm beyond the working length using a size 10 K-file. Between instruments, canals were irrigated with 2 mL of 2.5% NaOCl using a 30-gauge side-vented needle. NaOCl was ultrasonically activated three times for 20 seconds to aid smear-layer removal. Canals were then irrigated with saline, followed by 5 mL of 17% EDTA for 1 minute.
Experimental: GROUP 2- Asymptomatic irreversible pulpitis- cryotherapy; For Group 2, 20 mL of 2.5% NaOCl was divided into eight 2.5-mL syringes and cooled to 2 °C in a refrigerator. The syringes were then placed in an insulated container filled with ice to maintain the target temperature during transport to the clinic and until use. A digital thermometer was used to verify that the solution remained at 2 °C. Each syringe was removed individually immediately before irrigation and delivered over approximately 40 seconds.	Other: root canal treatment and cryotherapy; All endodontic procedures were completed in a single visit by one operator with 6 years of clinical experience. Only 1 tooth per patient was included. Local anesthesia was administered using 2 mL articaine HCl containing 1:100,000 epinephrine. After rubber dam isolation and access cavity preparation, working length was determined using an electronic apex locator and confirmed radiographically. Root canals were prepared with Endoart Smart Gold files to size 40/.04 and, when needed, up to 2 larger sizes according to canal anatomy. Apical patency was maintained 1 mm beyond the working length using a size 10 K-file. Between instruments, canals were irrigated with 2 mL of 2.5% NaOCl using a 30-gauge side-vented needle. NaOCl was ultrasonically activated three times for 20 seconds to aid smear-layer removal. Canals were then irrigated with saline, followed by 5 mL of 17% EDTA for 1 minute.
Other: GROUP 3- Asymptomatic apical periodontitis - control (n=33); 20 mL of 2.5% NaOCl was kept in a glass beaker at room temperature and monitored with a digital thermometer to maintain a temperature of 22°C. Final irrigation in Groups 1 and 3 was performed using this solution.	Other: root canal treatment and cryotherapy; All endodontic procedures were completed in a single visit by one operator with 6 years of clinical experience. Only 1 tooth per patient was included. Local anesthesia was administered using 2 mL articaine HCl containing 1:100,000 epinephrine. After rubber dam isolation and access cavity preparation, working length was determined using an electronic apex locator and confirmed radiographically. Root canals were prepared with Endoart Smart Gold files to size 40/.04 and, when needed, up to 2 larger sizes according to canal anatomy. Apical patency was maintained 1 mm beyond the working length using a size 10 K-file. Between instruments, canals were irrigated with 2 mL of 2.5% NaOCl using a 30-gauge side-vented needle. NaOCl was ultrasonically activated three times for 20 seconds to aid smear-layer removal. Canals were then irrigated with saline, followed by 5 mL of 17% EDTA for 1 minute.
Experimental: GROUP 4- Asymptomatic apical periodontitis - cryotherapy; For Group 4, 20 mL of 2.5% NaOCl was divided into eight 2.5-mL syringes and cooled to 2 °C in a refrigerator. The syringes were then placed in an insulated container filled with ice to maintain the target temperature during transport to the clinic and until use. A digital thermometer was used to verify that the solution remained at 2 °C. Each syringe was removed individually immediately before irrigation and delivered over approximately 40 seconds.	Other: root canal treatment and cryotherapy; All endodontic procedures were completed in a single visit by one operator with 6 years of clinical experience. Only 1 tooth per patient was included. Local anesthesia was administered using 2 mL articaine HCl containing 1:100,000 epinephrine. After rubber dam isolation and access cavity preparation, working length was determined using an electronic apex locator and confirmed radiographically. Root canals were prepared with Endoart Smart Gold files to size 40/.04 and, when needed, up to 2 larger sizes according to canal anatomy. Apical patency was maintained 1 mm beyond the working length using a size 10 K-file. Between instruments, canals were irrigated with 2 mL of 2.5% NaOCl using a 30-gauge side-vented needle. NaOCl was ultrasonically activated three times for 20 seconds to aid smear-layer removal. Canals were then irrigated with saline, followed by 5 mL of 17% EDTA for 1 minute.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Between- and Within-Group Comparisons of Postoperative Pain Scores Over Time	During the first week after treatment

Collaborators and Investigators

• Sponsor: Recep Tayyip Erdogan University

Study record dates

Study Major Dates

• Study Start (Actual): May 11, 2026
• Primary Completion (Actual): June 26, 2026
• Study Completion (Actual): July 3, 2026

Study Registration Dates

• First Submitted: July 13, 2026
• First Submitted That Met QC Criteria: July 13, 2026
• First Posted (Actual): July 17, 2026

Study Record Updates

• Last Update Posted (Actual): July 17, 2026
• Last Update Submitted That Met QC Criteria: July 13, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Periapical Diseases; Jaw Diseases; Periodontitis; Periapical Periodontitis; Therapeutics; Cryotherapy
• Other Study ID Numbers: 12 (Israel lung Association)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No