Extraction of Incisor and Canine Teeth

IN-DEPTH: DENTAL EXTRACTIONS—FROM CASE SELECTION TO RECOVERY

Jennifer E. Rawlinson, DVM, Diplomate AVDC

1. Introduction worthy of clinical and radiographic examination. 1 The main function of equine incisor teeth is grasping Canines erupt between 4 to 6 years of age. The and grooming, while the canine teeth function for structure of the equine canine tooth is less complex defense and offense. Incisors are radicular, hypso- than the incisors and cheek teeth and in outward dont teeth with long reserve crowns that erupt contin- appearance may seem to be more brachydont in ually throughout the life of the horse.1 Therefore, nature. When looked at more closely, though, the as a horse ages, incisor extraction should theoreti- crown is superficially covered with peripheral ce- cally become easier. The interproximal bone be- mentum and coronal enamel extends deep into the tween the incisors on the maxilla and mandible alveolus, suggesting a tooth more hypsodont in na- is relatively thin. This is significant when consid- ture. The average length of a canine tooth from ering extraction, as the interproximal bone will be crown tip to apex is 5 to 7 cm, and only one-fourth easier to deform, allowing for instrument placement to one-third of this is clinical crown.1 Canine teeth around incisors than the bone surrounding the ca- do not continually erupt as do the incisors and nine teeth. Due to their location in the mouth, cheek teeth, so the length of the tooth within the equine incisors are prone to trauma including dental alveolus changes minimally. Therefore, extraction fracture, supporting bone fracture, avulsion, impac- of the equine canine tooth, even in the older horse, tion, and severe rapid abrasion caused by behavioral can be a significant undertaking, requiring a surgi- or environmental conditions. Supernumerary and cal approach if pathology has not already caused malpositioned incisors can cause significant mal- significant degradation of the periodontium. occlusions and/or feed entrapment leading to peri- Pathology associated with canine teeth has prob- odontal disease. Iatrogenic pulp exposure caused ably been studied the least of all tooth types within by overzealous reduction to treat incisor diagonals, the equine oral cavity, but significant and painful curvatures (“smiles” and “frowns”) can lead to apical pathology can be found associated with this tooth.2 pathology. All of these conditions may necessitate Trauma leading to tooth fracture and avulsion are the extraction of one or more incisor teeth. not uncommon. Mandibular fractures spanning the Though evolution has significantly reduced the interdental space can involve the canine, necessitat- size of the canine teeth through the millennia, ca- ing extraction or root canal therapy. Pulp exposure nine teeth still represent a part of the dentition from past overreduction or abrasion may be found on

NOTES

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Orig. Op. OPERATOR: Session PROOF: PE’s: AA’s: COMMENTS ARTNO: 1st disk, 2nd beb meadel 10 3271 IN-DEPTH: DENTAL EXTRACTIONS—FROM CASE SELECTION TO RECOVERY oral examination. All of the above may necessitate Incisor Extraction extraction of the canine tooth. Simple extraction of incisor teeth can be accom- Tooth resorption associated with equine odonto- plished by using dental elevators to slowly break clastic tooth resorption and hypercementosis down the periodontal ligament. Once the tooth is (EOTRH) is well documented to be associated with moderately mobile, extraction forceps (wolf tooth 3 the canine and incisor teeth. Therefore, in cases or small animal) can be used to elevate the tooth. of EOTRH, radiographs of both the incisors and ca- The Lane’s bone-holding forceps can be particularly nines should be obtained. Severe cases of EOTRH useful for grasping onto the triangular-shaped inci- require staged or complete extraction of the affected sor. These forceps tightly grasp the tooth to allow incisor and canine teeth to alleviate infection and the practitioner to exert rotational and avulsion forces. pain caused by this disease. Resorptive lesions in Once the tooth is extracted, the site is debrided and older horses can be found under excessive tartar flushed. Some practitioners may elect to pack the deposition on the mandibular (more common) and open alveolus with gauze, but, with daily flushing maxillary canine teeth. Exposing these lesions af- by the owner, incisor extraction sites usually heal ter removal of tartar will cause discomfort for the quickly without packing. Impression material pack- horse, and the practitioner should be prepared to ing is not routinely used because it will readily fall address the problem either through extraction un- from the alveolus because of its shape and depth. der primary care or referral to an equine veterinary dental specialist. A surgical approach to incisor extraction involves Incisor extraction can be accomplished in two the creation of a mucogingival flap to reveal under- ways, depending on the nature and severity of the lying tooth and bone. Bone removal with a high- pathology associated with the tooth/teeth. Singu- speed drill and a cutting bur decreases supporting lar incisor extraction not involving EOTRH can be structures and allows for cleaner and quicker ex- accomplished simply by elevation and avulsion.4 traction of the tooth/teeth. Elevation and extrac- In cases of multiple incisor tooth extraction and tion are performed after bone removal, and the area particularly EOTRH cases that require extraction of is debrided, flushed, and smoothed. The mucogin- all incisors, a surgical approach allows for improved gival flap can be partially or completely closed, de- visualization, debridement, and closure. In addi- pending on the nature of the extraction and tion, a surgical approach increases the surgeon’s pathology. ability to deal with complicated extractions in which reserve crowns and roots have fractured as the re- Canine Tooth Extraction sult of initial trauma and resorption. Because of the length of the reserve crown and root situated within a curved alveolus, basic principles 2. Materials and Methods of surgical dental extraction must be used for re- 5 Before starting any extraction technique, the pa- moval. In general, a mucogingival flap must be tient must be properly restrained and sedated with raised to expose the underlying labial bone. De- regional or local anesthesia of the extraction site. pending on the tooth and the pathology affecting Preoperative radiographs to determine the condition the tooth, 60% to 80% of the labial bone plate must of reserve crown, root, and periodontal ligament are be removed with a high-speed dental drill to allow highly recommended. Flushing of the extraction for elevation. Once the reserve crown and root are site and surrounding tissue with antimicrobial rinse uncovered, a dental elevator is used to fatigue the to remove major debris and decrease bacterial pop- periodontal ligament, and the tooth is removed with ulations produces a clean working site with de- extraction forceps. All bone margins should be creased chance for residual feed and serious smoothed with a round diamond bur, and the site contamination after extraction. should be debrided and flushed clean. The flap will need to be closed in a tension-free manner; therefore, Equipment List the periosteum underlying the mucosa will need to be ● Basic surgery tray (scalpel, forceps, Metzen- cut to allow for free movement of the flap. The flap baum and Mayo scissors, needle driver, etc). is sutured closed in a simple interrupted pattern. ● Dental elevators.a Endodontic therapy can sometimes be used to salvage ● Lane’s bone-holding forceps.b some apically infected canine teeth to avoid the ● Wolf tooth extraction forceps.c trauma of oral surgery. ● Periosteal elevator.d Postoperative radiographs are recommended for ● High-speed dental unit.e every extraction procedure to ensure that no dental ● Round carbide bur.f fragments have been left behind and to provide ● Round diamond bur.g documentation of the procedure and lack of adjacent ● Antimicrobial flush (0.12% chlorhexidine hard tissue damage. Postoperative pain medica- solution). tion and antibiotics may also be indicated, depend- ● Suture material (2–0) on a cutting needle.h ing on the extent of the extraction technique.

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Orig. Op. OPERATOR: Session PROOF: PE’s: AA’s: COMMENTS ARTNO: 1st disk, 2nd beb meadel 10 3271 IN-DEPTH: DENTAL EXTRACTIONS—FROM CASE SELECTION TO RECOVERY 3. Discussion ever, in cats with severe tooth resorption, crown Surgical extraction of teeth may sound simple, but amputation is acceptable and successful if no peri- experience demonstrates how challenging this pro- odontal ligament or regional pathology is visible on cedure can be, especially when first learning all the radiographs. Whether horses are similar to cats in steps involved. Extensive incisor extractions and this manner is unknown. The author suspects that canine tooth extraction can be complicated and frus- the degree of regional/dental necrosis, bulbous hy- trating for experienced dental surgeons, and a prac- percementosis, and inflammatory tissue reported by titioner should evaluate his or her ability to perform Staszyk in 2008 would lead to postoperative regional this procedure (training, experience, instrumenta- inflammation and infection if portions of an incom- tion, etc) before attempting it. Case referral may pletely resorbed tooth were purposefully left in the 3 be in the best interest of the patient and all parties alveolus. The practitioner and the owner should involved. In the past, canine teeth have been ex- carefully weigh the pros and cons of this approach if tracted by surgical and nonsurgical procedures with resorption is severe enough for this procedure to be various outcomes. The goal of the surgical proce- considered. dure outlined above is to maximize success while In conclusion, extraction of equine incisor and ca- minimizing uncontrolled collateral damage, frustra- nine teeth can be rewarding for both the patient and tion, and time. The author does not recommend practitioner when performed in a well thought-out extraction of a canine tooth in a nonsurgical manner surgical manner. unless the tooth already displays significant mobil- ity and the reserve crown and root are intact. The References and Footnotes high-speed drill dramatically increases the practi- 1. Dixon P, du Toit N. Dental anatomy. In: Easley J, Dixon tioner’s ability to precisely remove bone and deal P, Schumacher J, editors. Equine Dentistry. 3rd ed. Lon- with more complicated extractions (fractured reserve don: Saunders Elsevier; 2011:51–76. 2. Dixon PM, Tremaine WH, Pickles K, et al. Equine dental crown/root, resorbed teeth, and ankylotic periodon- disease, part 1: a long-term study of 400 cases: disorders tal ligament) in an exacting manner. affecting incisors, canine, and first premolar teeth. Equine It should be noted that mucogingival flaps in Vet J 1999;31:369–377. horses are notorious for dehiscence, especially on 3. Staszyk C, Bienert A, Simhofer H, et al. Equine odontoclas- tic tooth resorption and hypercementosis. Vet J 2008;178: the mandible. The reason for this is not known, but 372–379. time devoted to mastication, labial and frenulum 4. Tremaine W, Schumacher J. Exodontia. In: Easley J, attachments, gravity, and tongue action have all been Dixon P, Schumacher J, editors. Equine Dentistry. 3rd ed. thought to contribute to dehiscence. In the author’s London: Saunders Elsevier; 2011:321–322. experience, dehiscence, if present, usually occurs be- 5. Wiggs R, Lobprise H. Veterinary Dentistry: Principles and Practice. Philadelphia: Lippincott-Raven; 1997. tween days 5 to 10, when granulation tissue, partial primary closure, and wound contraction have al- aWinged dental elevators, size 5 to 8 mm, Miltex Inc., York, PA ready started to occur at the surgical margin. Su- 17402. tures involved with the dehiscence are removed, and bLane bone-holding forceps with ratchet, 13 inch, OrthoMed the owner is instructed to flush the wound twice Inc., Portland, OR 97202. daily with an antimicrobial rinse until complete cWolf tooth forceps, Harlton’s Equine Specialties, Elmwood, WI healing has occurred by second intention (usually 54740. dSeldin periosteal elevator, I.R.H Surgical Co., Sialkot, Paki- 2 to 5 weeks). stan. Sometimes, severely resorbed teeth make com- eiM3 GS Dental Unit, iM3, Vancouver, WA 98682. plete extraction particularly challenging, and there fSize 8 round carbide cutting bur, Henry Schein, Melville, NY has been discussion within the dental community as 11747. gSize 023 round diamond finishing bur, Henry Schein, Melville, to whether clinical crown amputation is acceptable NY 11747. for these teeth. There is no study documenting the hMonocryl 2–0 cutting needle, Medex Supply, Santa Monica, long-term success of this procedure in horses; how- CA.

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