Single versus multiple visits for endodontic treatment of permanent teeth

Background: Root canal treatment (RoCT), or endodontic treatment, is a common procedure in dentistry. The main indications for RoCT are irreversible pulpitis and necrosis of the dental pulp caused by carious processes, tooth cracks or chips, or dental trauma. Successful RoCT is characterised by an absence of symptoms and clinical signs in teeth without radiographic evidence of periodontal involvement. The success of RoCT depends on a series of variables related to the preoperative condition of the tooth, as well as the endodontic procedures. Objectives: To compare the effectiveness of single- and multiple-visit RoCT, measured as tooth extraction due to endodontic problems and radiological success. To assess the difference in short- and long-term complications between single- and multiple-visit RoCT. Search strategy: The following databases were searched for relevant trials: Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE, and EMBASE. Handsearching was performed for the major oral medicine journals. References of included studies and reviews were checked. Endodontics experts were contacted through e-mail. No language limitations were imposed. Date of last search was 6th March 2007. Selection criteria: Randomised and quasi-randomised controlled trials of patients needing RoCT were included. Surgical endodontic treatment was excluded. The outcomes considered were the number of teeth extracted for endodontic problems; radiological success after at least 1 year, that is, absence of any periapical radiolucency; postoperative pain; painkiller use; swelling; or sinus track formation. Data collection and analysis: Data were collected using a specific extraction form. The validity of included studies was assessed on the basis of allocation concealment, blindness of the study, and loss of participants. Data were analysed by calculating risk ratios. When valid and relevant data were collected, a meta-analysis of the data was undertaken. Main results: Twelve randomised controlled trials were included in the review. Four studies had a low risk of bias, four a moderate risk, and another four had a high risk of bias. The frequency of radiological success and immediate postoperative pain were not significantly different between single- and multiple-visit RoCT. Patients undergoing single-visit RoCT reported a higher frequency of painkiller use and swelling, but the results for swelling were not significantly different between the two groups. We found no study that included tooth loss and sinus track formation among its primary outcomes. Authors' conclusions: No difference exists in the effectiveness of RoCT, in terms of radiological success, between single- and multiple-visit RoCT. Most short-and long-term complications are also similar in terms of frequency, although patients undergoing a single visit may experience a slightly higher frequency of swelling and are significatively more likely to take painkillers.