Single versus multiple visits for endodontic treatment of permanent teeth

Giovanni Mergoni, Martina Ganim, Giovanni Lodi, Lara Figini, Massimo Gagliani, Maddalena Manfredi

Should root canal treatment be performed in one dental visit or over several visits?*

Key messages

Single‐visit and multiple‐visit endodontic (root canal) treatments are equally effective, regardless of whether the soft portion at the centre of the tooth containing nerves and blood vessels (dental pulp) is vital (living) or non‐vital (dead).

Both treatment approaches are frequently associated with some short‐term post‐treatment pain.

What is root canal treatment?

Root canal treatment is a common procedure in dentistry that is required when the dental pulp is irreversibly damaged. Root canal treatment is considered successful when there are no symptoms (such as pain), when x‐rays show no signs of damage to bone and other supporting tissues of the tooth, and when there are no gum signs of infection (such as swelling or sinus tract (an abnormal channel)). 

How are root canal treatments performed? 

Root canal treatment can be carried out over one or more appointments. The tooth, after being isolated from saliva by placing a rubber sheet ('dam') around it, is opened through the crown (visible part of the tooth) using a drill, the pulp is accessed and removed. Then, the canal is disinfected before being sealed with a filling.

In the past these procedures were performed over two or more visits, putting a small amount of medicine in the canals in‐between visits to kill any remaining bacteria, but now single‐visit treatments without the use of any interappointment medication are often preferred. 

What did we want to find out?

We wanted to find out if root canal treatment performed in a single visit was better, equal to or worse than root canal treatment over two of more visits in terms of success of the treatment and likelihood of complications after treatment.

What did we do? 

We searched for studies that investigated success and complications of single‐visit versus multiple‐visit root canal treatment in permanent (adult) teeth. We combined the results of relevant studies and rated our confidence in the evidence, based on factors such as study methods and number of people tested.

What studies did we find? 

We found 47 studies with 5805 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. The biggest study involved 390 teeth and the smallest study involved 26 teeth. The studies were conducted in countries around the world, with the largest number (12) in India. 

What did the studies show?

Whether teeth are treated in a single visit or multiple visits may have no effect on the likelihood of tooth extraction (removal), but we are very uncertain about the results (evidence from two studies). Single‐visit and multiple‐visit treatments do not seem to have a different outcome when they are judged using x‐rays taken one year after treatment (evidence from 13 studies).

Participants treated over multiple visits are probably less likely to experience pain in the first week after treatment starts than participants treated in a single visit (evidence from five studies).

There seems to be no difference between single‐ and multiple‐visit treatment for other outcomes (whether or not there is pain after filling and the intensity of that pain, use of painkillers, swelling, whether or not there is sinus tract), but we are uncertain about these results.

What are the limitations of the evidence? 

We are moderately confident in the conclusion that treatment success measured after one year using an x-ray did not differ according to whether the treatment was done in a single visit or over multiple visits. Likewise, we are moderately confident in the finding that pain during the first week after treatment is more likely with single‐visit treatment. However, it is possible there were some flaws in the way the studies were run that could have affected the results. 

We are not confident about the results for the other outcomes because the evidence was based on a few cases and the results varied widely across the studies, some of which had flaws in the way they were run.

How up to date is this evidence?

This review updates our previous versions published in 2007 and 2016. We searched for evidence up to April 2022.

Find out more by reading the full review here:

* This news item is based on the Plain Language Summary of the review.