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

Review question

Is there any difference in effectiveness when undertaking root canal treatment in one visit compared to over several visits, and what are the effects on pain and complications, regardless of whether medication is used?

Background

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.

Study characteristics

We searched the literature up to 14 June 2016. We found 25 relevant studies with a total of 3780 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.

Key results

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.

Quality of 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.

Authors' conclusions: 

There is no evidence to suggest that one treatment regimen (single-visit or multiple-visit root canal treatment) is better than the other. Neither can prevent all short- and long-term complications. On the basis of the available 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).

Read the full abstract...
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 (i.e. pain) and clinical signs (i.e. swelling and sinus tract) in teeth without radiographic evidence of periodontal involvement (i.e. normal periodontal ligament). The success of RoCT depends on a number of variables related to the preoperative condition of the tooth, as well as the endodontic procedures. This review updates the previous version published in 2007.

Objectives: 

To determine whether completion of root canal treatment (RoCT) in a single visit or over two or more visits, with or without medication, makes any difference in term of effectiveness or complications.

Search strategy: 

We searched the following electronic databases: Cochrane Oral Health's Trials Register (to 14 June 2016), Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 5), MEDLINE Ovid (1946 to 14 June 2016), and Embase Ovid (1980 to 14 June 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials to 14 June 2016. We did not place any restrictions on the language or date of publication when searching the electronic databases.

Selection criteria: 

We included randomised controlled trials (RCTs) and quasi-RCTs of people needing RoCT. We excluded surgical endodontic treatment. The outcomes of interest were tooth extraction for endodontic problems; radiological failure after at least one year, i.e. periapical radiolucency; postoperative pain; swelling or flare-up; painkiller use; sinus track or fistula formation; and complications (composite outcome including any adverse event).

Data collection and analysis: 

We collected data using a specially designed extraction form. We contacted trial authors for further details where these were unclear. We assessed the risk of bias in the studies using the Cochrane tool and we assessed the quality of the body of evidence using GRADE criteria. When valid and relevant data were collected, we undertook a meta-analysis of the data using the random-effects model. For dichotomous outcomes, we calculated risk ratios (RRs) and 95% confidence intervals (CIs). For continuous data, we calculated mean differences (MDs) and 95% CIs. We examined potential sources of heterogeneity. We conducted subgroup analyses for necrotic and vital teeth.

Main results: 

We included 25 RCTs in the review, with a total of 3780 participants, of whom we analysed 3751. We judged three studies to be at low risk of bias, 14 at high risk, and eight as unclear.

Only one study reported data on tooth extraction due to endodontic problems. This study found no difference between treatment in one visit or treatment over multiple visits (1/117 single-visit participants lost a tooth versus 2/103 multiple-visit participants; odds ratio (OR) 0.44, 95% confidence interval (CI) 0.04 to 4.78; very low-quality evidence).

We found no evidence of a difference between single-visit and multiple-visit treatment in terms of radiological failure (risk ratio (RR) 0.91, 95% CI 0.68 to 1.21; 1493 participants, 11 studies, I2 = 18%; low-quality evidence); immediate postoperative pain (dichotomous outcome) (RR 0.99, 95% CI 0.84 to 1.17; 1560 participants, 9 studies, I2 = 33%; moderate-quality evidence); swelling or flare-up incidence (RR 1.36, 95% CI 0.66 to 2.81; 281 participants, 4 studies, I2 = 0%; low-quality evidence); sinus tract or fistula formation (RR 0.98, 95% CI 0.15 to 6.48; 345 participants, 2 studies, I2 = 0%; low-quality evidence); or complications (RR 0.92, 95% CI 0.77 to 1.11; 1686 participants, 10 studies, I2 = 18%; moderate-quality evidence).

The studies suggested people undergoing RoCT in a single visit may be more likely to experience pain in the first week than those whose RoCT was over multiple visits (RR 1.50, 95% CI 0.99 to 2.28; 1383 participants, 8 studies, I2 = 54%), though the quality of the evidence for this finding is low.

Moderate-quality evidence showed people undergoing RoCT in a single visit were more likely to use painkillers than those receiving treatment over multiple visits (RR 2.35, 95% CI 1.60 to 3.45; 648 participants, 4 studies, I2 = 0%).

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