This prospective randomized, double-blind factorial study aimed to compare the efficacy of three different intracanal medicaments with the placebo in controlling the
postoperative pain after complete
root canal preparation. The study was performed on 64 mandibular molars of 64 patients with diagnosis of
pulp necrosis and acute
apical periodontitis. After chemomechanical procedures using the stepback technique and 1%
sodium hypochlorite, the teeth were randomized into four treatment groups (n=16). In group I, canals were filled with
calcium hydroxide paste mixed with 2%
chlorhexidine gel, group II received 2%
chlorhexidine gel, group III was treated with
calcium hydroxide paste, and group IV received no dressing (control). Before dismissal, preoperative
pain experience was recorded using a visual analog
pain scale. Patients were then instructed to quantify the degree of
pain experienced 4h
after treatment and daily for a further 24, 48, 72 and 96h. Two-way repeated measures ANOVA test and post hoc Tukey's HSD test revealed that at each time interval groups I and II were significantly more effective in reducing the
postoperative pain values than groups III and IV (p<0.05). Dunnett's test showed that groups I and II differed significantly from control whereas difference between group III and control was not significant (p>0.05). Patients with
pulp necrosis and acute
apical periodontitis that had been dressed with
chlorhexidine alone and
calcium hydroxide plus
chlorhexidine gave rise to less
pain than that experienced by patients who had a
calcium hydroxide dressing alone or no dressing at all.