This is an update of a review first published in 2007. Root canal treatment, or endodontic treatment, is a common procedure in dentistry. The main reasons that root canal treatment are needed are persistent inflammation of the dental pulp (pulpitis) and death of the dental pulp (dead or non-vital tooth) caused by tooth decay, cracks or chips, or other accidental damage to teeth. Root canal treatment is considered successful when there are no symptoms, for example pain, and when x-rays show no signs of damage to bone and other supporting tissues of the tooth. The success of root canal treatment depends on the preoperative condition of the tooth, as well as the endodontic procedures used. There are two approaches commonly used. In the first, the root canal treatment is performed in multiple visits to the dental clinic, and a dressing is placed in the tooth between appointments to avoid the build up of bacteria that may cause infections. In the second approach, the treatment is performed in one visit to the dental clinic. Which approach leads to less postoperative complications?
What was the research?
A systematic review to find out whether there is any difference in effectiveness when undertaking root canal treatment in one visit compared to over several visits. What are the effects on pain and complications?
Who conducted the research?
The research was conducted by a team led by Maddalena Manfredi from the University of Parma, Italy, on behalf of Cochrane Oral Health. Lara Figini, Massimo Gagliani and Giovanni Lodi were also on the team.
What evidence was included in the review?
The literature was searched up to 14 June 2016. 25 relevant randomised controlled trials were identified, with a total of 3,780 participants. The studies compared root canal treatment performed at a single appointment with root canal treatment performed over two or more appointments on vital permanent teeth, non-vital permanent teeth, or both.
What did the evidence say?
No apparent difference exists between single- and multiple-visit root canal treatment on x-ray examination, an indicator which does not affect the patient directly, but is known to be important as a measure of effective treatment. Only one study measured the likelihood of tooth extraction due to endodontic problems and did not find evidence of a difference between single- and multiple-visit treatment. Most short- and long-term complications (pain, swelling, fistula, and tooth extraction) were similar in terms of frequency, although people undergoing a single visit were more likely to experience pain in the first week and to take painkillers.
How good was the evidence?
We assessed the available evidence as moderate to low quality because a number of the studies were at high risk of bias, there was inconsistency between study results, and results were imprecise.
What are the implications for dentists and the general public?
There is no evidence to suggest that one treatment regimen (single-visit or multiple-visit root canal treatment (RoCT)) is better than the other. Neither can prevent all short- and long-term complications. On the basis of the available moderate-quality evidence, it seems likely that the benefit of a single-visit treatment, in terms of time and convenience, for both patient and dentist, has the cost of a higher frequency of late postoperative pain (and as a consequence, painkiller use).
What should researchers look at in the future?
As use of rotary nickel titanium instruments is increasing, a well-designed randomized controlled trial, comparing single-visit and multiple-visit RoCT, both performed with such instruments, would be an important contribution. It would be very helpful for clinicians that researchers include tooth loss as a primary outcome in new studies, even reporting if none occurs.
Manfredi, M, Figini L, Gagliani, M, Lodi, G. Single versus multiple visits for endodontic treatment of permanent teeth. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD005296. DOI: 10.1002/14651858.CD005296.pub3.