Root canal treatment can be completed in a single appointment or across multiple visits, often with an intracanal medicament such as calcium hydroxide placed between appointments. Multiple-visit treatment has traditionally been favored in cases of pulpal necrosis and apical periodontitis based on the rationale that additional disinfection time may improve microbial control and healing. However, advances in irrigation, instrumentation, and obturation techniques have made single-visit treatment increasingly common. This poses an important clinical question: Does completing root canal treatment in multiple appointments lead to better outcomes than completing treatment in a single visit? This review examines the current evidence comparing single- and multiple-visit root canal treatment, with a focus on healing, postoperative pain, and overall treatment outcomes.
A systematic review by Su et al. published in the Journal of Endodontics in 2011 examined this clinical question by comparing healing rates and post-obturation pain between single- and multiple-visit treatment. The review included 10 randomized or quasi-randomized controlled trials involving teeth with infected root canals. No significant difference was found in healing rates or medium-term post-obturation pain between single- and multiple-visit treatment. However, short-term post-obturation pain was significantly lower in the single-visit group. One limitation of this review is the heterogeneity among the included studies, as the trials did not necessarily use identical instrumentation, irrigation, obturation techniques, intracanal medicaments, or outcome definitions. These differences make it difficult to attribute differences in outcomes specifically to the number of treatment appointments. A strength of the review, however, was its focus on randomized or quasi-randomized controlled trials rather than relying primarily on observational studies.3
Similarly, a 1978 study published in the Journal of Endodontics, titled “A Comparative Study of the Single-Visit and the Multiple-Visit Endodontic Procedure,” compared endodontic treatment performed in either a single visit or multiple visits using cases selected from clinical practice over a 20-year period. The study found no significant difference in healing between the single- and multiple-visit groups, although a difference in post-obturation pain was observed, with the findings favoring the multiple-visit approach for pain. A major limitation of this study is its age and methodology. Because the cases were treated over a 20-year period beginning decades ago, the instrumentation, irrigation, and obturation techniques used may differ substantially from contemporary endodontic treatment. While the study provides historical evidence regarding single- versus multiple-visit treatment, its findings may have limited applicability to current clinical practice.2
A systematic review and meta-analysis by Rossi-Fedele et al. evaluated the effectiveness of different irrigation and intracanal dressing protocols in the treatment of apical periodontitis. Among the outcomes evaluated, the authors compared single-visit treatment with multiple-visit treatment using calcium hydroxide as an intracanal medicament. For the specific outcome of radiographic evidence of a normal periodontal ligament space, the meta-analysis found a statistically significant difference favoring single-visit treatment, with moderate certainty of evidence. The authors noted that this finding was influenced by one of the included studies, and removing that study eliminated the statistical significance. Therefore, while the findings suggest that single-visit treatment may be associated with more favorable radiographic healing than multiple-visit treatment with calcium hydroxide, this result should be interpreted cautiously rather than taken as evidence that single-visit treatment is universally superior.1
Overall, the available evidence does not demonstrate a consistent clinical advantage for completing root canal treatment over multiple appointments compared with a single visit. Earlier evidence suggested similar healing rates between the two approaches, while more recent systematic-review evidence likewise has not demonstrated a meaningful difference in radiological outcomes or postoperative pain. Although multiple-visit treatment allows for placement of an intracanal medicament such as calcium hydroxide, the evidence does not clearly establish that this additional appointment results in superior healing. Based on the current literature, single- and multiple-visit root canal treatment appear to have comparable overall outcomes.
1. Rossi-Fedele G, Rödig T. Effectiveness of root canal irrigation and dressing for the treatment of apical periodontitis: A systematic review and meta-analysis of clinical trials. Int Endod J. 2023 Oct;56 Suppl 3:422-435. doi: 10.1111/iej.13777. Epub 2022 May 31. PMID: 35579074.
2. Soltanoff W. A comparative study of the single-visit and the multiple-visit endodontic procedure
Journal of Endodontics, 4, 278-281
3. Su Y, Wang C, Ye L. (2011) “Healing rate and post-obturation pain of single- versus multiple-visit endodontic treatment for infected root canals: a systematic review.” Journal of Endodontics. 2011;37(2):125–132. DOI: 10.1016/j.joen.2010.09.005.
