Clinical Efficacy of Treatment Procedures in Endodontic Infection Control

Objective: To evaluate the clinical efficacy of interappointment medication with calcium hydroxide in the control of root canal infection. Methods: One-hundred-and-two teeth diagnosed with chronic apical periodontitis were randomly subjected to one of three different treatment strategies. The root canal treatment was carried out as single visit treatment (SV-group, n=42), using calcium hydroxide as a root canal dressing between the first and second appointment (CH –group, n=34), or leaving the canal empty between the appointments (EC-group, n=26). During the first appointment samples were taken immediately after the initial access to the pulp (A sample) and after instrumentation of the root canal (Pi1 sample). During the second appointment samples were taken after mechanical removal of the interappointment dressing (Pd sample) and after final instrumentation (Pi2 sample). Results: All three groups showed similar proportions of positive A samples (86%-94%). Pi1 samples showed growth percentages of 14, 15 and 21% for the SV, EC and CH groups, respectively. Pd samples in the CH group revealed bacteria in 29% of the cases, reduced to 9% after irrigation with sodium hypochlorite (Pi2). In the EC group, a remarkable increase in culture positive cases was detected with 69% yielding growth in the Pd sample. However, only 4% of the EC cases revealed bacteria in the Pi2 sample. There was a dominance of anaerobic microorganisms during the first appointment, changing to mainly Gram positive facultative bacteria in the second appointment in both the CH and EC groups. Conclusions: The present study indicates good clinical efficacy of instrumentation with sodium hypochlorite irrigation in the control of root canal infection. A calcium hydroxide dressing did not further reduce the number of bacteria-free canals, emphasizing the need to develop more efficient interappointment dressings.