Antimicrobial and Tissue Dissolving Capabilities of Different NaOCl Concentrations

Objective:The objective of this in vitro study was to establish the antimicrobial efficacy and the potential to dissolve vital pulp using different concentrations of sodium hypochlorite (NaOCl) solutions. Materials and Methods: The following solutions were tested: (1) 2% NaOCl (Thick Jik); (2) 3.5% NaOCl (Jik); (3) 6% NaOCl (Vista); (4) 6% NaOCl (Dent-Ionics); (4) 6% NaOCl (Chlor-Xtra) and (5) Water (Control). Antimicrobial Effects: A MacFarland 1 suspension was prepared from an overnight culture of E. faecalis and spread onto 15 CASO-Agar plates. The prepared plates were randomly divided into 5 groups (n=3). Ten microlitres of each solution were dispensed onto four five millimetre diameter filter paper disks on each plate and incubated anaerobically at 37ºC for 24 hours respectively. The antibacterial activity of materials was apparent from circular clear inhibition zones forming around the filtration paper. Measurements were done after incubation at three different positions for each paper disk. An average was calculated for the nine measurements per paper disc on each plate. Tissue dissolving ability: Vital pulp tissue was removed from 4 freshly, extracted, human, third molar teeth and divided into 25 equal portions according to weight. Each specimen was immersed into 40ml of the selected irrigation solution (n=5). The time taken to dissolve the pulp tissue was recorded by means of a digital video camera. Averages between the five recording times for each solution were calculated. All the data was collected and statistically analyzed (Student–t test). Results: No significant inhibition of E. faecalis was observed with sterile water (control) and 3.5% NaOCl. However, the 2% NaOCl and all the other 6% NaOCl solutions showed significant inhibition against E. faecalis. Chlor-Xtra dissolved the pulp tissue in significantly less time compared to all the other groups (p<0.05). Conclusion: Chlor-Xtra demonstrated the best antimicrobial properties as well as tissue dissolving capabilities.