Weeping canal: Causes and clinical management





Persistent exudate; Root canal therapy; Endodontics.


Objective: The aim of this integrative literature review was to address the causes and clinical management of the canal with persistent exudate or “weeping canal”, which is a clinical entity characterized by the presence of persistent inflammatory exudate in the canal, despite ongoing root canal treatment even after multiple appointments. Methodology: A bibliographic survey was carried out in the Pubmed, Scopus and EBSCO databases, in English and without restriction of publication date. The search terms used in combination were: wet canal, weeping canal, persistent exudate, persistent intracanal exudation, and root canal treatment. Results and conclusion: It is concluded that the main cause described is microbial, in the form of bacterial biofilm or recalcitrant infection. Regarding its clinical management, a series of approaches are available, such as paper points, intracanal dressing, and aspiration systems such as Endovac, while the use of Nd:YAG laser requires more studies to support its clinical use.


Alshahrani M, DiVito R, DiVito E. (2016). Root Canal Catheterization. En Alshahrani M, DiVito E, De Moor R (Eds.), Lasers in Endodontics. (pp. 40). Cham: Springer International Publishing.

Ayer, A., Vikram, M., & Suwal, P. (2015). Dens Evaginatus: A Problem-Based Approach. Case reports in dentistry, 2015, 393209. https://doi.org/10.1155/2015/393209

Baumgartner, J. C., Watkins, B. J., Bae, K. S., & Xia, T. (1999). Association of black-pigmented bacteria with endodontic infections. Journal of endodontics, 25(6), 413–415. https://doi.org/10.1016/S0099-2399(99)80268-4

Bhaskar S. N. (1972). Nonsurgical resolution of radicular cysts. Oral surgery, oral medicine, and oral pathology, 34(3), 458–468. https://doi.org/10.1016/0030-4220(72)90325-8

Brown D. (2017). Paper points revisited: risk of cellulose fibre shedding during canal length confirmation. International endodontic journal, 50(6), 620–626. https://doi.org/10.1111/iej.12663

Chong, B. S., & Pitt Ford, T. R. (1992). The role of intracanal medication in root canal treatment. International endodontic journal, 25(2), 97–106. https://doi.org/10.1111/j.1365-2591.1992.tb00743.x

Convissar RA. (2015) Principles and Practice of Laser Dentistry - E-Book. Elsevier Health Sciences.

de Freitas, L. F., & Hamblin, M. R. (2016). Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy. IEEE journal of selected topics in quantum electronics : a publication of the IEEE Lasers and Electro-optics Society, 22(3), 7000417. https://doi.org/10.1109/JSTQE.2016.2561201

Dompe, C., Moncrieff, L., Matys, J., Grzech-Leśniak, K., Kocherova, I., Bryja, A., Bruska, M., Dominiak, M., Mozdziak, P., Skiba, T., Shibli, J. A., Angelova Volponi, A., Kempisty, B., & Dyszkiewicz-Konwińska, M. (2020). Photobiomodulation-Underlying Mechanism and Clinical Applications. Journal of clinical medicine, 9(6), 1724. https://doi.org/10.3390/jcm9061724

Durack C, Brady E. (2019). Root Canal Filling. En Patel S, Barnes J (Eds.), The principles of Endodontics. (3ra ed., pp.103) NewYork, NY: Oxford University Press.

Fava, L. R., & Saunders, W. P. (1999). Calcium hydroxide pastes: classification and clinical indications. International endodontic journal, 32(4), 257–282. https://doi.org/10.1046/j.1365-2591.1999.00232.x

Ferreira, F. B., Ferreira, A. L., Gomes, B. P., & Souza-Filho, F. J. (2004). Resolution of persistent periapical infection by endodontic surgery. International endodontic journal, 37(1), 61–69. https://doi.org/10.1111/j.1365-2591.2004.00753.x

Glass G. E. (2021). Photobiomodulation: A review of the molecular evidence for low level light therapy. Journal of plastic, reconstructive & aesthetic surgery : JPRAS, 74(5), 1050–1060. https://doi.org/10.1016/j.bjps.2020.12.059

Gomes, B. P., Drucker, D. B., & Lilley, J. D. (1994). Associations of specific bacteria with some endodontic signs and symptoms. International endodontic journal, 27(6), 291–298. https://doi.org/10.1111/j.1365-2591.1994.tb00271.x

Gomes, B. P., Pinheiro, E. T., Gadê-Neto, C. R., Sousa, E. L., Ferraz, C. C., Zaia, A. A., Teixeira, F. B., & Souza-Filho, F. J. (2004). Microbiological examination of infected dental root canals. Oral microbiology and immunology, 19(2), 71–76. https://doi.org/10.1046/j.0902-0055.2003.00116.x

Gulabivala K, Ng Y-L. (2014). Management of non-surgical root-canal treatment failure. En Gulabivala K, Ng, Y-L (Eds.), Endodontics. (4ta ed., pp.217) China: Mosby.

Gutmann J, Lovdahl P. (2014). Problem-Solving Clinical Techniques in Enlarging and Shaping the Root Canal. En Gutmann J, Lovdahl P (Eds.), Problem Solving in Endodontics Prevention.(5ta ed.,pp.200).China: Mosby.

Hamblin M. R. (2017). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS biophysics, 4(3), 337–361. https://doi.org/10.3934/biophy.2017.3.337

Hassan F. E. (1995). A new method for treating weeping canals: clinical and histopathologic study. Egyptian dental journal, 41(4), 1403–1408.

Kahler B. (2015). Healing of a cyst-like lesion involving an implant with nonsurgical management. Journal of endodontics, 41(5), 749–752. https://doi.org/10.1016/j.joen.2014.12.013

Keleş, A., & Alçin, H. (2015). Use of EndoVac System for Aspiration of Exudates from a Large Periapical Lesion: A Case Report. Journal of endodontics, 41(10), 1735–1737. https://doi.org/10.1016/j.joen.2015.05.019

Kikuchi, I., Wadachi, R., Yoshioka, T., Okiji, T., Kobayashi, C., & Suda, H. (2003). An experimental study on the vasoconstriction effect of calcium hydroxide using rat mesentery. Australian endodontic journal : the journal of the Australian Society of Endodontology Inc, 29(3), 116–119. https://doi.org/10.1111/j.1747-4477.2003.tb00532.x

Koppang, H. S., Koppang, R., Solheim, T., Aarnes, H., & Stølen, S. O. (1989). Cellulose fibers from endodontic paper points as an etiological factor in postendodontic periapical granulomas and cysts. Journal of endodontics, 15(8), 369–372. https://doi.org/10.1016/S0099-2399(89)80075-5

Lomçali, G., Sen, B. H., & Cankaya, H. (1996). Scanning electron microscopic observations of apical root surfaces of teeth with apical periodontitis. Endodontics & dental traumatology, 12(2), 70–76. https://doi.org/10.1111/j.1600-9657.1996.tb00100.x

Mohammadi, Z., & Dummer, P. M. (2011). Properties and applications of calcium hydroxide in endodontics and dental traumatology. International endodontic journal, 44(8), 697–730. https://doi.org/10.1111/j.1365-2591.2011.01886.x

Nair, P. N., Sjögren, U., Schumacher, E., & Sundqvist, G. (1993). Radicular cyst affecting a root-filled human tooth: a long-term post-treatment follow-up. International endodontic journal, 26(4), 225–233. https://doi.org/10.1111/j.1365-2591.1993.tb00563.x

Natkin, E., Oswald, R. J., & Carnes, L. I. (1984). The relationship of lesion size to diagnosis, incidence, and treatment of periapical cysts and granulomas. Oral surgery, oral medicine, and oral pathology, 57(1), 82–94. https://doi.org/10.1016/0030-4220(84)90267-6

Peters, C. I., Koka, R. S., Highsmith, S., & Peters, O. A. (2005). Calcium hydroxide dressings using different preparation and application modes: density and dissolution by simulated tissue pressure. International endodontic journal, 38(12), 889–895. https://doi.org/10.1111/j.1365-2591.2005.01035.x

Ricucci, D., Candeiro, G. T., Bugea, C., & Siqueira, J. F., Jr (2016). Complex Apical Intraradicular Infection and Extraradicular Mineralized Biofilms as the Cause of Wet Canals and Treatment Failure: Report of 2 Cases. Journal of endodontics, 42(3), 509–515. https://doi.org/10.1016/j.joen.2015.12.014

Santos Soares, S. M., Brito-Júnior, M., de Souza, F. K., Zastrow, E. V., Cunha, C. O., Silveira, F. F., Nunes, E., César, C. A., Glória, J. C., & Soares, J. A. (2016). Management of Cyst-like Periapical Lesions by Orthograde Decompression and Long-term Calcium Hydroxide/Chlorhexidine Intracanal Dressing: A Case Series. Journal of endodontics, 42(7), 1135–1141. https://doi.org/10.1016/j.joen.2016.04.021

Signoretti, F. G., Gomes, B. P., Montagner, F., & Jacinto, R. C. (2013). Investigation of cultivable bacteria isolated from longstanding retreatment-resistant lesions of teeth with apical periodontitis. Journal of endodontics, 39(10), 1240–1244. https://doi.org/10.1016/j.joen.2013.06.018

Siqueira J. F., Jr (2001). Aetiology of root canal treatment failure: why well-treated teeth can fail. International endodontic journal, 34(1), 1–10. https://doi.org/10.1046/j.1365-2591.2001.00396.x

Siqueira JF, Rôças IN, Lopes H. (2015) Medicação Intracanal. En Siqueira JF, Lopes H (Eds.), Endodontia: Biologia e Técnica. (4ta ed., pp. 479). Brasil:Elsevier.

Siqueira JF, Rôças IN. (2016) Intracanal Medication. En Chong BS (Ed.) Harty’s Endodontics in Clinical Practice. (7ma ed., pp.141). Churchill Livingstone.

Siqueira JF, Rôças IN. (2020) Microbiology of Apical Periodontitis. En Ørstavik D, (Ed.), Essential endodontology: Prevention and Treatment of Apical Periodontitis. (3ra ed., pp 121) Hoboken, NJ: Wiley-Blackwell.

Siqueira, J. F., Jr, & Rôças, I. N. (2013). Microbiology and treatment of acute apical abscesses. Clinical microbiology reviews, 26(2), 255–273. https://doi.org/10.1128/CMR.00082-12

Sousa, E. L., Martinho, F. C., Nascimento, G. G., Leite, F. R., & Gomes, B. P. (2014). Quantification of endotoxins in infected root canals and acute apical abscess exudates: monitoring the effectiveness of root canal procedures in the reduction of endotoxins. Journal of endodontics, 40(2), 177–181. https://doi.org/10.1016/j.joen.2013.10.008

Sundqvist, G., Johansson, E., & Sjögren, U. (1989). Prevalence of black-pigmented bacteroides species in root canal infections. Journal of endodontics, 15(1), 13–19. https://doi.org/10.1016/S0099-2399(89)80092-5

Tronstad L.(2003). Endodontic Complications. En Tronstad L (Ed.), Clinical Endodontics. (2da ed., pp. 224) New York: Thieme.

Walton RE, Keiser K. (2009). Endodontic Emergencies and Therapeutics. En Torabinejad M, Walton RE (Eds.), Endodontics: Principles and Practice. (4ta ed., pp 156). St. Louis, Mo: Saunders/Elsevier.

Weine FS. (2004) Endodontic therapy. St. Louis, Mo. Mosby.

Yoshino, A., Tabuchi, M., Uo, M., Tatsumi, H., Hideshima, K., Kondo, S., & Sekine, J. (2013). Applicability of bacterial cellulose as an alternative to paper points in endodontic treatment. Acta biomaterialia, 9(4), 6116–6122. https://doi.org/10.1016/j.actbio.2012.12.022

Zhang, C., Du, J., & Peng, Z. (2015). Correlation between Enterococcus faecalis and Persistent Intraradicular Infection Compared with Primary Intraradicular Infection: A Systematic Review. Journal of endodontics, 41(8), 1207–1213. https://doi.org/10.1016/j.joen.2015.04.008



How to Cite

ÁLVAREZ VÁSQUEZ, J. L. .; GUAZHIMA FERNÁNDEZ, M. C. .; DURÁN ORTIZ, N. C. . Weeping canal: Causes and clinical management. Research, Society and Development, [S. l.], v. 10, n. 9, p. e52910918558, 2021. DOI: 10.33448/rsd-v10i9.18558. Disponível em: https://rsdjournal.org/index.php/rsd/article/view/18558. Acesso em: 23 sep. 2021.



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