Evaluation of Antimicrobial Efficacy of Calcium Hypochlorite as an Endodontic Irrigant on a Mixed-culture Biofilm: An Ex vivo Study

Introduction: Calcium hypochlorite (CH) has been recently suggested as an endodontic irrigant. The aim of this investigation was to evaluate the antimicrobial efficacy of CH compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX) against multispecies biofilm in surface and deep dentinal tubules. Methods and Materials: Minimal inhibitory concentration (MIC) of irrigant agents was assessed using a microdilution method. One hundred and twenty of human maxillary incisor teeth were prepared and infected with suspension of Entrococcus faecalis, Fusobacterium nucleatum and Prevotella intermedia in an anaerobic jar for 7 days. Depending on irrigation solutions, specimens were divided into 4 groups (n=30); group 1: 2% CHX, group 2: 5.25% sodium hypochlorite, group 3: 5% calcium hypochlorite, group 4: positive control (normal saline (NS)). Fifteen remained specimens were used as negative control. Surviving bacteria were sampled before (S1) and after irrigation from surface (S2) and deep (S3) dentin. The medium turbidity was visualized with spectrophotometry. Data were analyzed using analysis of variance followed by Tukey post hoc test (α=0.05). Results: The MIC of CH against E. faecalis, F. nucleatum and P. intermedia was 25, 8 and 7.5 µg/mL respectively. There were no significant differences in S1 among the test groups. Moreover, 2% CHX and 5% CH had significantly lower medium turbidity at both S2 and S3, in comparison with 5.25% NaOCl (P=0.018 and 0.031, respectively). But there were no significant differences between 2% CHX and 5% CH at both S2 and S3 (P=0.862 and 0.978, respectively). Conclusion: Under the conditions of this ex vivo study, 5% CH and 2% CHX are more effective than 5.25% NaOCl in the reduction of mixed-culture biofilm.Keywords: Calcium Hypochlorite; Chlorhexidine; Endodontics; Sodium Hypochlorite

Effect of Phentolamine as Reversal of Soft-Tissue Anesthesia on Post-Endodontic Pain in Patients with Symptomatic Irreversible Pulpitis: A Randomized Clinical Trial

Introduction: Phentolamine mesylate (OraVerse) is mostly used to reverse soft tissue anesthesia after dental procedures. The aim of the present study was to evaluate the effect of the injection of OraVerse on postoperative pain after root canal treatment in patients with symptomatic irreversible pulpitis. Methods and Materials: In this randomized single-blind clinical trial study, 100 patients (50 per group) with symptomatic irreversible pulpitis in the first or second mandibular molars, randomly received either OraVerse or sham treatment after a single-visit root canal therapy. Each patient recorded their pain score, using a Heft Parker visual analogue scale, before and after 6, 12, 24, 36, 48, and 72 h of the treatment. They also monitored their soft-tissue anesthesia every 15 min for 5 h. Data were analyzed by t-test and repeated measured ANOVA statistical tests. The level of significance was set at 0.05. Results: Patients who received phentolamine had significantly higher pain scores at 6- and 12-h postoperative intervals compared with those receiving sham treatment (P=0.01 and P=0.00 respectively). Consumption of analgesics in OraVerse group was significantly higher than that of the sham group (P=0.48). Conclusion: Although phentolamine accelerated the reversal of normal soft tissue sensation after the dental visit, it increased postoperative pain in patients suffering from symptomatic irreversible pulpitis, which may limit phentolamine administration in this group.Keywords: Anesthesia; Inferior Alveolar Nerve; Lidocaine; Phentolamine Mesylate; Postoperative Pai