_applied_  
_sciences_  
_Review_  
**The Incidence and Intensity of Postendodontic Pain and**  
**Flareup in Single and Multiple Visit Root Canal Treatments:**  
**A Systematic Review and Meta-Analysis**  
**[PERSON] \({}^{\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered},\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered}}\),**  
**[PERSON] \({}^{\text{\textregistered}}\)**, [PERSON] \({}^{\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered}}\), [PERSON] \({}^{\text{\textregistered}}\),**  
**[PERSON] \({}^{\text{\textregistered}}\) and [PERSON] \({}^{\text{\textregistered},\text{\textregistered}}\)**  
\begin{tabular}{l}
1 Department of Preventive Dental Sciences, Division of Pedodontics, College of Dentistry, Jazan University, \\  2 45412, Saudi Arabia; [EMAIL_ADDRESS] (S.V.); [EMAIL_ADDRESS] (P.C.M.) \\
2 Preventive Dental Science Department, College of Dentistry, King [PERSON] Bin Abdulaziz University for Health Sciences, Ryadh 11481, Saudi Arabia; [EMAIL_ADDRESS] \\
3 King Abdullah International Medical Research Center, Ryadh 11481, Saudi Arabia \\
4 Department of Restorative Dental Sciences, College of Dentistry, Jazan University, Jazan 45412, Saudi Arabia, [EMAIL_ADDRESS]. (H.C.); [EMAIL_ADDRESS] (S.B). \\
5 Department of Oral and Maxillo Facial Sciences, University of Rome La Sapienza, 00161 Rome, Italy; [EMAIL_ADDRESS] (L.T.); [EMAIL_ADDRESS] (A.M.) \\
6 Department of Oral Pathology and Microbiology, [PERSON] Patil Dental College and Hospital, \\   [PERSON] Vidyapetth, Pune 411018, India; [EMAIL_ADDRESS] \\
7 Department of Oral Pathology and Microbiology, Sri Venkateswara Dental College and Hospital, \\   Chemnai 600130, India; [EMAIL_ADDRESS] \\
8 Department of Preventive and Restorative Dentistry, College of Dental Medicine, University of Sharjah, \\   Shajah 27272, United Arab Emirates; [EMAIL_ADDRESS] \\
9 Department of Maxillofacial Surgery and Diagnostic Sciences, Division of Oral Pathology, \\   College of Dentistry, Jazan University, Jazan 45412, Saudi Arabia \\
* Correspondence: [EMAIL_ADDRESS] \\ \end{tabular}  
**Abstract** To assess the incidence and intensity of postendodontic pain and flareup in single and multiple visit root canal treatment (RCT) and determine if the difference between the two is significant, a search of PubMed, Medline, Embase, Cochrane, Scopus and Web of science was conducted. The grey literature was searched using Google Scholar and Saudi digital library. Randomised controlled trials evaluating the incidence and intensity of postendodontic pain and flareup published in English from 1 January 2000 to 15 April 2020 were searched. The PRISMA protocol was followed to select the articles. A random effects model was used for the meta-analysis of the data in the included studies. Twenty-one articles were included in the review. Three compared both the incidence and the intensity, while the rest compared either one of the parameters. Most studies used both hand-driven and rotary instruments and irrigated with sodium hypochlorite. Twelve studies used an intracanal medicament. Although individual studies showed discordant treatment outcomes, the meta-analysis did not reveal any significant difference in the incidence or the intensity of the postendodontic flareup between the single and multiple visit RCT groups. Single or a multiple visit root canal treatment is not an independent determinant for the risk of postendodontic pain or a flareup.  
**Keywords:** endodontics; flareup; pain; root canal treatment; postendodontic pain