When silence turns to pain: Decoding endodontic flare-ups
Paper Details
When silence turns to pain: Decoding endodontic flare-ups
Abstract
Endodontic flare-up remains one of the most clinically challenging and unpredictable complications of root canal therapy, turning a relatively routine procedure into an acute emergency with sudden onset of pain and/or swelling within hours to days of an appointment. Although it has been studied for decades, the multifactorial etiology with microbial, mechanical, chemical and immunological factors still challenge clinicians in terms of its predictable prevention and management. This review aims to collate current evidence on the definition, epidemiology, classification, etiopathogenesis and risk factors of endodontic flare-ups, with particular emphasis on the roles of microbial persistence (especially Enterococcus faecalis), host inflammatory mediators and iatrogenic factors such as apical extrusion of debris and irrigants. Evidence-based preventive and management strategies ranging from occlusal reduction, intracanal medicaments, pharmacological control of pain and inflammation to judicious use of antibiotics are discussed along with contemporary diagnostic aids such as cone beam computed tomography and emerging artificial intelligence assisted radiographic analysis. We propose a clinical decision-making algorithm to assist the practitioner from diagnosis to resolution. The overall incidence of severe flare-up is low (2-9% in contemporary series), but its unpredictable nature and impact on patient trust mean that there is a need for continued research into individualized risk stratification and minimally invasive prevention.
Ahmed YE, Emara RS, Sarhan SM, El Boghdadi RM, El-Bayoumi MAA, El-Far HMM, Sabet N E, Abou El-Nasr HM, Gawdat SI, Amin SAW. 2020. Post-treatment endodontic pain following occlusal reduction in mandibular posterior teeth with symptomatic irreversible pulpitis and sensitivity to percussion: a single-centre randomized controlled trial. International endodontic journal, 53(9), 1170–1180. https://doi.org/10.1111/iej.13328
Akshoy U, Pehlivan S, Buhara O. 2021. The top risk factors for endodontic flare-up: a Monte Carlo simulation. Clinical oral investigations 25(6), 3681–3690. https://doi.org/10.1007/s00784-020-03692-9
Almasoud L, Elsewify T, Elemam R, Eid B. 2025. Effect of Cryotherapy and Occlusal Reduction on Postoperative Endodontic Pain in Mandibular First Molars with Symptomatic Apical Periodontitis: A Prospective, Parallel, Double-Blinded Randomized Controlled Trial. European journal of dentistry 19(2), 472–481. https://doi.org/10.1055/s-0044-1791219
Aloufi AS. 2026. Detection of Periapical Lesions Using Artificial Intelligence: A Narrative Review. Diagnostics (Basel, Switzerland) 16(2), 301. https://doi.org/10.3390/diagnostics16020301
Alves V deO. 2010. Endodontic flare-ups: a prospective study. Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 110(5), e68–e72. https://doi.org/10.1016/j.tripleo.2010.05.014
American Association of Endodontists. AAE guidance on the use of systemic antibiotics in endodontics. Chicago: AAE; 2017.
Ardila CM, Pineda-Vélez E, Vivares-Builes AM. 2026. Antimicrobial effectiveness of intracanal medicaments against Enterococcus faecalis in endodontics: a systematic review with structured domain-based interpretative synthesis and exploratory meta-analysis. Frontiers in oral health 7, 1854046. https://doi.org/10.3389/froh.2026.1854046
Caviedes-Bucheli J, Rios-Osorio N, Rey-Rojas, Laguna-Rivero F, Azuero-Holguin MM, Diaz LE, Curtidor H, Castaneda-Ramirez JJ, Munoz HR. 2018. Substance P and Calcitonin gene-related peptide expression in human periodontal ligament after root canal preparation with Reciproc Blue, WaveOne Gold, XP EndoShaper and hand files. International endodontic journal 51(12), 1358–1366. https://doi.org/10.1111/iej.12952
Chagas Carvalho Alves N, Raiane Mamede Veloso S, de Andrade Silva S, de Almeida AC, Tavares Velozo Telles C, Romeiro K, de Melo Monteiro GQ, de Albuquerque DS. 2021. Influence of occlusal reduction on pain after endodontic treatment: A systematic review and meta-analysis. Scientific reports 11(1), 14019. https://doi.org/10.1038/s41598-021-93119-6
Cope AL, Francis N, Wood F, Thompson W, Chestnutt IG. 2024. Systemic antibiotics for symptomatic apical periodontitis and acute apical abscess in adults. The Cochrane database of systematic reviews 5(5), CD010136. https://doi.org/10.1002/14651858.CD010136.pub4
Doumani M, Almaqboul F, Alduwaysan SSS, Alzahrani MA, Al Ghamdi SA, Alzahrani M N, Alanazi AT, Al Ghamdi NM, Alsalem AH, Alturaif D, Almokayad FH, Alqahtani AS, Alanaz L. 2025. Effectiveness of Artificial Intelligence in Endodontic Diagnosis and Treatment Evaluation: A Systematic Review. Cureus 17(11), e96091. https://doi.org/10.7759/cureus.96091
Eftekhar B, Moghimipour E, Pourakbar Jahandideh P, Jalali S, Mahmoudian M. 2013. Analgesic effect of odontopaste and a compound intracanal medicament between root canal therapy appointments. Jundishapur journal of natural pharmaceutical products 8(4), 169–174. https://doi.org/10.17795/jjnpp-12473
Elashiry MM, Bergeron BE, Tay FR. 2023. Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence. Microbial pathogenesis 183, 106337. https://doi.org/10.1016/j.micpath.2023.106337
Emara RS, Abou El Nasr HM, El Boghdadi RM. 2019. Evaluation of postoperative pain intensity following occlusal reduction in teeth associated with symptomatic irreversible pulpitis and symptomatic apical periodontitis: A randomized clinical study. International endodontic journal 52(3), 288–296. https://doi.org/10.1111/iej.13012
Gbadebo SO, Sulaiman AO, Anifowose OO. 2016. Endodontic flare up: Incidence and association of possible risk factors. African journal of medicine and medical sciences 45(2), 207–212. https://adhlui.com.ui.edu.ng/jspui/handle/123456789/2841
Karobari MI, Adil AH, Mathur A, Snigdha, NT. 2026. Applications and clinical translation of artificial intelligence in CBCT-based detection of endodontic lesions: A scoping review. Oral radiology 42(2), 251–261. https://doi.org/10.1007/s11282-025-00876-5
Magar SS, Sr Alfayyadh AY, Alruwail KK, Almunahi HFF, Alsharari AHL, Magar SP. 2022. The determination of flare-up incidence and associated risk factors during endodontic treatment: an observational retrospective study. Cureus 14(11), e31424. https://doi.org/10.7759/cureus.31424
McGillivray A, Dutta A. 2024. The influence of laser-activated irrigation on post-operative pain following root canal treatment: A systematic review. Journal of Dentistry 144, 104928. https://doi.org/10.1016/j.jdent.2024.104928
Méndez-Millán JA, León-López M, Martín-González J, Saúco-Márquez JJ, Cabanillas-Balsera D, Segura-Egea JJ. 2022. Antibiotic Over-Prescription by Dentists in the Treatment of Apical Periodontitis: A Systematic Review and Meta-Analysis. Antibiotics (Basel, Switzerland) 13(4), 289. https://doi.org/10.3390/antibiotics13040289
Milani AS, Froughreyhani M, Taghiloo H, Nouroloyouni A, Jafarabadi MA. 2022. The effect of antibiotic use on endodontic post-operative pain and flare-up rate: A systematic review with meta-analysis. Evidence-based dentistry, https://doi.org/10.1038/s41432-021-0205-z
Morse DR, Furst ML, Belott RM, Lefkowitz RD, Spritzer IB, Sideman BH. 1987. Infectious flare-ups and serious sequelae following endodontic treatment: A prospective randomized trial on efficacy of antibiotic prophylaxis in cases of asymptomatic pulpal-periapical lesions. Oral surgery, oral medicine, and oral pathology 64(1), 96–109. https://doi.org/10.1016/0030-4220(87)90123-x
Nair M, Rahul J, Devadathan A, Mathew J. 2017. Incidence of Endodontic Flare-ups and Its Related Factors: A Retrospective Study. Journal of International Society of Preventive and Community Dentistry 7(4), 175–179. https://doi.org/10.4103/jispcd.JISPCD_61_17
Negm MM. 2001. Intracanal use of a corticosteroid-antibiotic compound for the management of posttreatment endodontic pain. Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 92(4), 435–439. https://doi.org/10.1067/moe.2001.115975
Nguyen-Nhon D, Nagendrababu V, Pulikkotil SJ, Rossi-Fedele G. 2020. Effect of occlusal reduction on postendodontic pain: A systematic review and meta-analysis of randomised clinical trials. Australian endodontic journal: the journal of the Australian Society of Endodontology Inc 46(2), https://doi.org/10.1111/aej.12380
Ohshima J, Morita M, Kawanishi Y, Abe S, Tanaka N, Shimaoka, T, Maezono H, Kinomoto Y, Hayashi M. 2026. Factors associated with endodontic flare-ups: A systematic review and meta-analysis. Int. Endod. J. 59(9), 1778-1791. DOI: 10.1111/iej.70164.
Omaia M, Negm M, Nashaat Y, Nabil N, Othman A. 2025. The effect of triple antibiotic paste as an intracanal medicament with an anti-inflammatory agent on post-operative pain of asymptomatic uniradicular necrotic teeth: A double blind randomized clinical trial. F1000Research 8, 1687. https://doi.org/10.12688/f1000research.19699.3
Onay EO, Ungor M, Yazici AC. 2015. The evaluation of endodontic flare-ups and their relationship to various risk factors. BMC oral health 15(1), 142. https://doi.org/10.1186/s12903-015-0135-2
Setzer FC, Li J, Khan AA. 2024. The Use of Artificial Intelligence in Endodontics. Journal of dental research 103(9), 853–862. https://doi.org/10.1177/00220345241255593
Tanalp J. 2022. A critical analysis of research methods and experimental models to study apical extrusion of debris and irrigants. International endodontic journal 55(1), 153–177. https://doi.org/10.1111/iej.13686
Vasudevan A, Santosh SS, Selvakumar RJ, Sampath DT, Natanasabapathy V. 2022. Dynamic Navigation in Guided Endodontics – A Systematic Review. European endodontic journal 7(2), 81–91. https://doi.org/10.14744/eej.2022.96168
Vianna ECB, Herkrath FJ, Martins IEB, Lopes LPB, Marques AAF, Sponchiado Júnior EC. 2020. Effect of Occlusal Adjustment on Postoperative Pain after Root Canal Treatment: A Randomized Clinical Trial. Brazilian dental journal 31(4), 353–359. https://doi.org/10.1590/0103-6440202003248
Wagh KS, Warhadpande MM, Dakshindas DM. 2022. Prevalence of endodontic flare-up following intracanal medicament placement in permanent teeth undergoing endodontic treatment – A systematic review. Journal of Conservative Dentistry 25(1), 3–8. https://doi.org/10.4103/jcd.jcd_332_21
Yang S, Meng X, Zhen Y, Baima Q, Wang Y, Jiang X, Xu Z. 2024. Strategies and mechanisms targeting Enterococcus faecalis biofilms associated with endodontic infections: A comprehensive review. Frontiers in cellular and infection microbiology 14, 1433313. https://doi.org/10.3389/fcimb.2024.1433313
S. Vidya, T. Vinay Kumar Reddy*, K. Vijay Venkatesh, B. Shyam, Seetha Kunhikannan, 2026. When silence turns to pain: Decoding endodontic flare-ups. Int. J. Biosci., 29(4), 23-37.
Copyright © 2026 by the Authors. This article is an open access article and distributed under the terms and conditions of the Creative Commons Attribution 4.0 (CC BY 4.0) license.