Prevention of root canal therapy emergencies by two step root canal preparation

Objective To determine the effect of adopting two step Root canal preparation preventing from endodontic interappointment emergencies.Methods 120 cases of chronic periapical periodontitis,pulp necrosis,remaining root and remaining crowns that needed to treat the root canal were divided in two groups randomly.One group used two step Root canal preparation,the control group used one step Root canal preparation.Each group had60 samples.Results Acute disease incidence in experimental groups was 23.3%,obviously lower than40% in control group.Conclusion Two step-Root canal preparation can effectively prevent endodontic interappomtment emergencies.