Detailed Description (Extended technical description of the protocol)
This study is designed as a randomized controlled trial to compare the intensity of postoperative pain 24 hours after non-surgical root canal treatment using two different irrigating solutions: 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl). The central hypothesis is that the type of irrigant influences early postoperative pain, but that this effect may be modified by patient-specific factors such as gender and age.
Methodology:
Following ethical approval and informed consent, 90 adult patients indicated for non-surgical root canal treatment will be enrolled using a non-probability consecutive sampling technique. Participants will be randomly allocated to one of two parallel groups (n=45 per group): Group A (2% CHX) and Group B (5.25% NaOCl). The sample size was calculated a priori using the pwr package in R, assuming a 95% confidence level, 80% power, and a moderate effect size based on previous studies.
A standardized endodontic protocol will be followed for all participants to ensure consistency and minimize bias:
Procedure: After administering local anesthesia (2% lignocaine with 1:80,000 adrenaline), the operative field will be isolated with a rubber dam. Standard endodontic access will be prepared, and the working length will be determined using digital radiography.
Instrumentation and Irrigation: Chemo-mechanical preparation will be performed. Irrigation will be carried out using 2 ml of the assigned solution after each instrument. The solution will be delivered using a 27-gauge side-vented needle (Max-i-Probe) kept 1-2 mm short of the working length and maintained in motion to prevent apical extrusion. The flow rate will be controlled at 2-4 ml/min.
Obturation and Follow-up: Canals will be dried with sterile paper points and obturated with gutta-percha and sealer. Participants will be provided with a questionnaire to record their pain after 24 hours using a Visual Analog Scale (VAS). Pain scores will be categorized as no pain (0), mild (1-30), moderate (31-50), or severe (51-100).
Data Analysis:
Data will be analyzed using R software (version 4.3.3). Descriptive statistics (mean, SD, frequencies) will be calculated. Comparative analyses between the two groups will be conducted using the Student's t-test for mean pain scores and the Chi-square test for categorical pain types. Statistical significance will be set at p < 0.05. A key aspect of the analysis plan includes pre-planned subgroup analyses stratified by gender and age to explore their interaction with the irrigant used.
