The aim of this clinical trial is to evaluate the effect of using intra-radicular cryotherapy technique in the form of irrigation with cold sodium hypochlorite

The main questions to answer are:

1. Does Postoperative pain is different between the three groups?
2. Does level of substance P different between the three groups ?

• The patients will be randomly divided into three groups Group 1: control group (n=25) Regular root canal treatment with regular irrigant will be used. Group 2: (n=25) Intraradicular cryotherapy will be performed where :
• Normal root canal treatment will be done with irrigation using sodium hypochlorite cooled to 2°C continuously during our mechanical instrumentation. Then a final flush will be done with cold saline 2°C for 5 minutes. Group 3: (n=25) Normal root canal treatment will be done with irrigation using sodium hypochlorite at room temperature during our mechanical instrumentation. Then a final flush will be done with cold saline 2°C for 5 minutes.

Inclusion Criteria:

• Patients that will be diagnosed with symptomatic apical periodontitis
• Single-rooted premolars (radiographically and clinically assessed)
• Medically free patients.
• Teeth with mature apex

Exclusion Criteria:

• Patients with other pulpal diagnosis.
• Medically compromised patients.
• Pregnant females.
• Patients taking analgesics or anti-inflammatory drugs.

2025