Root Canal Therapy for Fracture-Induced Endodontic Disease in the Dog K

Volume 49 | Issue 1 Article 1 1987 Root Canal Therapy for Fracture-Induced Endodontic Disease in the Dog K. E. Queck Iowa State University C. L. Runyon University of Prince Edward Island Follow this and additional works at: https://lib.dr.iastate.edu/iowastate_veterinarian Part of the Endodontics and Endodontology Commons, Small or Companion Animal Medicine Commons, and the Therapeutics Commons Recommended Citation Queck, K. E. and Runyon, C. L. (1987) "Root Canal Therapy for Fracture-Induced Endodontic Disease in the Dog," Iowa State University Veterinarian: Vol. 49 : Iss. 1 , Article 1. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol49/iss1/1 This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Root Canal Therapy for Fracture-Induced Endodontic Disease in the Dog K.E. Queck, DVM* C.L. Runyon, DVM, MS* * Introduction tissue, an intermediate dentinal layer, and an out Endodontics is a division of veterinary dentistry er layer ofenamel or cementum (Figure 1). The in that deals with pathologic conditions of the tooth ner pulp tissue consists of nerves, vessels, and pulp. Endodontic disease occurs whenever viable arteries which provide sensory and metabolic func pump tissue is exposed and becomes infected. It tion to the interior of the teeth. Connective tissue is a common sequela to tooth fractures, and occurs is also present to support the root's functional cells, less frequently following dental decay and severe the odontoblasts. The odontoblasts line the pulp periodontal disease. It is the second most common chamber walls, and produce a substance known as disease in the oral cavity of companion animals. 5 dentin. Dentin acts to separate, buffer, and pro Endodontic therapy is undertaken to salvage the tect the tooth from harmful external stimuli.! undamaged portion of an infected tooth. Proce External to the dentin lies enamel (on the crown) dures used include root canal debridement and pul or cementum (covering the tooth). Enamel, com potomies. In the past, endodontic therapy was posed of96 % inorganic material, is the hardest sub performed only on an experimental basis in valu stance in the body. It functions to completely cover able zoo animals and guard dogs, since few and protect the dentin from external exposure. In veterinarians possessed either the training or equip contrast, cementum, a softer substance ofonly 50 Ok ment to routinely perform the procedures. inorganic material, functions as a bony lattice to However, as more veterinarians gain expertise in this which fibers of the periodontal ligament attach, field, endodontic therapy will become a viable op firmly suspending the tooth in the alveolar tion to tooth extraction for the average household socket. 2,3 pet. At the root apex, the pulp tissue narrows and di The most frequent endodontic problem present vides into numerous small branches. This region is ed to the veterinary practitioner is a fractured tooth known as the apical delta, and may contain between with subsequent pulpal damage. This article will five and ftfty branches of the pulpal nerve. 4 This review the pathogenesis, diagnosis, and treatment area is especially important to evaluate prior to en of this common problem in the dog. dodontic therapy, since apical abscesses nearly al ways develop following pulpal death. 5 Dental Anatomy Disease The mature canine tooth is divided into two Endodontic disease is caused primarily by trauma parts: the crown, which projects above the gum induced fractures of the teeth, which expose vital line and is used for mastication, and the root, which pulp tissue and allow bacterial invasion. Less often, lies within the alveolar bone ofthe jaw and anchors caries and/or severe peridontal disease with exposure the tooth in place. On cross section, each tooth is of the root apex may also lead to decay. 6,7,8,9 also made up ofthree layers: an inner layer ofpulp The pathogenesis ofendodontic disease is shown in the Figure 2. Whenever the pulp tissue is ex posed, a pulpitis develops, followed by periapical abscess formation. Ninety-percent ofthe cases lead *Dr. Queck is a 1986 graduate ofthe College ofVeterinary Medi to periodontal ligament and alveolar bone destruc cine at Iowa State University. tion, and eventually tooth avulsion. Only ten per **Dr. Runy?n is. an assistant professor at the Atlantic Veterinary College, UOlVerSlty of PEl, Charlottetown, Prince Edward Island, dent of the cases develop into oral-nasal fistulas Canada. which chronically drain. 4 Iowa State University Veterinanan ............----- enamel CROWN ~~--- dentin ~----..~-- pulp chamber l...-rtJI---.....A-- cervical line ...........~~~ ..........................- furcation ROOT I •• FIGURE 1: Normal anatomy of a multi-rooted tooth in the dog. 2 Decay FTe ~Periodontal Disease Exposed Pulp Tissue Bac!eria Infected Pulp Tissue Exten}ion of Infe tion r Chronic Periapical Abscess Periodontal Ligament & Oral-Nasal Fistula Alveolar Bone Destruction Formation · .~. Tooth l vulsion Cronich Draining "Sore" FIGURE 2: Pathogenesis of endodontic disease in the dog. Vol. 49, No. 1 5 Diagnosis be considered. If the pulp tissue has been chroni Diagnosis of endodontic disease is difficult since cally exposed and is infected, full endodontic ther animals rarely will show signs associated with ex apy in the form of a root canal, with or without posed nerve endings and subsequent pulpal infec an apicoectomy, is indicated. Endodontic therapy tion. lO Signs seen are associated with pulpal pain, is contraindicated if complete fracture lines are and include favoring one side of the mouth when present in the tooth root, or in recently erupted chewing, rubbing the mouth with the paws, leth teeth with wide apical ends. In these types ofteeth argy, and fever. A reluctance to retrieve objects by it is difficult to obtain a complete filling seal, and obedience-trained dogs may also be noticed. tooth extraction is indicated.4 However, these subjective signs ofendodontic dis ease disappear as the pulpal nerve tissues become Materials & Methods more devitalized and unable to respond, and the For endodontic therapy, canine patients are pain diminishes. 7,9 placed in a surgical plane of anesthesia using in Cross changes from endodontic disease may also halant anesthetics. A cuffed endotracheal tube is be present. Externally, swelling, abscesses, and oral used to prevent aspiration pneumonia, and a rolled nasal fistulas may be evident. On oral exam, pulp towel is placed under the animal's neck to ventral tissue vitality can be evaluated by the color of the ly position the muzzle and facilitate drainage. dentin over the end of the pulp chamber or the Prophylactic bacteriocidal antibiotics are recom translucent characteristics ofthe tooth. 1 Ifthe pulp mended for use if the tooth is infected or if ultra tissue is black, it has been exposed for a long per sonic cleaning will accompany the treatment. 12 iod oftime and is necrotic. Ifthe pulp tissue is red Instruments and materials needed for endodon or pink, exposure has occurred more recently and tic therapy include: (1) denJal c;lrill with a low-speed pulpal death will follow within the next six to eight handpiece; (2) suction apparatus; (3) endodontic een months. Ifthe end ofthe pulp chamber is tan files, 55mm in length, sizes #10 through #140; (4) or brown in color, the tooth has successfully pro dental burs: round, invened cone, fissure, and tected the pulp tissue by secondary dentin deposi bone; (5) retrograde amalgam carrier and amalgam tion, and will remain vital. A pinkish transluscent plugger; (6) silver alloy pellets, mercury, and amal hue to the enamel is indicative of pulpal hemor gamator; (7) zinc oxide and eugenol paste; (8) so rhage, while pulpal devitalization will give the tooth lutions of calcium hydroxide, 2.5 % sodium a dull gray color. hypochlorite, 3% hydrogen peroxide, and sterile Radiographically, endodontic disease can be di saline; (9) scalpel and blade; (10) paper, cotton, or agnosed by examining the region ofthe pulp apex. gutta percha points; and (11) 1:50,000 epinephrine Radiolucency around one or more of the root tips /saline solution. indicates an abscess or a cystic process is occurring Prior to endodontic therapy, the affected tooth secondary to pulp exposure and infection.ll One should be cleaned ofexcessive calculus and plaque. author feels that pulpal death always results in ap Many veterinarians ultrasonically clean all of the ical abscess formation, so that radiography is a reli teeth and rinse the mouth with a dilute antiseptic able means for endodontic disease diagnosis. 5 solution, before proceeding. The environment can However, in the early stages of abscess formation never be made surgically sterile due to the resident bony changes are not radiographically evident, so bacterial population, but it can be cleaned up con a diagnosis of endodontic disease cannot be elimi siderably by following this procedure. nated on the basis of negative radiographic find ings. 12 Full Endodontic Treatment All endodontic treatment procedures require ade Treatment quate access to the pulp canal. In incisor teeth, the The goal of endodontic therapy is to preserve a fracture site provides ready access to the pulp tis dead, but functional tooth that will last through sue, and all endodontic procedures are carried out out the animal's lifetime. 13 This is achieved by through this site. An additional access site is need removing all infected pulp tissue, disinfecting the ed in canine teeth, since the extremely long, curved pulp canal, and filling the pulp chamber so that roots make complete filing difficult. The extra ac both the apex and crown are effectively sealed. If cess site is made near the gingiva on the affected traumatic exposure of the pulp has just occurred tooth's rostal margin.

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