The trial participants are patients with single-canal teeth with necrotic pulps undergoing root canal treatment on two visits. During the 1st visit, access cavity, root canal cleaning and shaping using rotary files and 2.5% NaOCl irrigation. After apical preparation, a final flush with either a levofloxacin-fluconazole-dexamethasone mixture or cold saline will be used then the tooth access cavity will be sealed with a temporary filling. After the first visit, the participants will be given a pain chart with a numerical rating scale to rate their pain levels from zero to 10 at 6, 12, 24, and 48 hours. Three microbial swabs will be collected for each participant: before instrumentation (S1), after instrumentation before final irrigation (S2), and after final irrigation (S3). After collecting data from all participants, statistical analysis will be conducted to compare the pain intensity and microbial load reduction percentages between the two groups.
The aim of this study is to compare the effect of antimicrobial-corticosteroid mixture and cryotherapy as final root canal irrigating solutions on post-instrumentation pain in single-canal teeth with necrotic pulps.