Extraction Techniques and Complications in the Dog and Cat

Sandra Manfra Marretta, DVM, Diplomate ACVS, AVDC
University of Illinois

Dental problems occur frequently in dogs and cats. Based on the type and severity of the lesion extraction of the diseased tooth may be indicated. Utilization of state-of-the-art dental equipment, proper perioperative pain management and appropriate extraction techniques can provide a better approach to dental extractions in the dog and cat.

The recent development of state-of-the-art veterinary dental equipment can provide the veterinary practitioner with a better approach for extracting difficult teeth. Proper perioperative pain management and new surgical techniques minimize intraoperative trauma and postoperative pain.

Perioperative Pain Management

Perioperative pain management is an extremely important part in the management of patients requiring dental extractions.¹ Proper perioperative pain management permits the patient to eat soft food even after multiple extractions with minimal discomfort. Perioperative pain management includes the administration of appropriate preoperative analgesics, including various narcotics, meditomidine, butorphanol and nonsteroidal antiinflammatory drugs providing preemptive analgesia. Regional nerve blocks can also provide preemptive analgesia. Local blocks prior to extractions also provide preemptive analgesia. Postoperative analgesics include various narcotics, butorphanol, and nonsteroidal antiinflammatory drugs such as carprofen.

State-of-the-Art Veterinary Dental Equipment

Dental extractions are most efficiently performed using state-of-the-art dental equipment. This includes dental radiographic equipment, a high-speed fiberoptic handpiece, magnification devices, and appropriately sized sharp hand instruments including dental elevators, periosteal elevators, curettes, root tip picks and extraction forceps.

Simple Extraction

A simple extraction refers to the extraction of a small single-rooted tooth, such as an incisor. An appropriate-sized dental elevator is placed in the gingival sulcus to sever the attachments of the gingiva around the tooth. The elevator should be advanced apically between the alveolar bone and the root. The periodontal ligament can be torn by rotating and holding the elevator 90 degrees for 15-second intervals. A dental extraction forceps can then be placed on the crown to rotate the tooth and remove it from the alveolus.

Multi-Rooted Extraction

Multi-rooted teeth include the premolars and molars which may be difficult to extract when only one root is affected with the other roots firmly attached to the alveolar bone. Most roots are embedded in the alveolar bone at divergent angles which further anchors the tooth into the surrounding bone. Sectioning of a multirooted tooth into two or three segments converts the procedure into multiple simple extractions. A tapered fissure bur on a high-speed handpiece is an efficient technique for sectioning teeth. The furcation is located prior to sectioning the tooth. This can be done by elevating the gingiva with a periosteal elevator. The bur is placed at the furcation and directed through the crown. The segments of the tooth are then independently extracted.

Complicated or Surgical Extraction

A complicated or surgical extraction technique is generally reserved for dog�s teeth that are difficult to extract because of their large root structure including the canine teeth, mandibular 1^st molars and the maxillary 4^th premolars.

Numerous steps are involved in the performance of a surgical extraction. The initial step is creation of a mucoperiosteal flap. Careful and adequate elevation of the mucoperiosteal flap is important for gaining access to the underlying buccal alveolar bone so that during the procedure the gingiva is not perforated. The next step involves location of the furcation and sectioning of a multi-rooted tooth. The buccal alveolar bone is then removed as needed to provide an efficient controlled technique for delivering large rooted teeth. Excessive removal of buccal bone should be avoided particularly when extracting mandibular teeth because this causes unnecessary weakening of the mandible. Elevation and extraction of each segment is accomplished by gently placing the dental elevator into the periodontal space advancing the elevator apically and gently rotating and holding the elevator for 10-15 seconds around the entire gingival sulcus until the segment can be easily extracted with an extraction forceps. An alveoloplasty is performed prior to closure to give the extraction site a smooth boney contour decreasing postoperative pain that may be associated with sharp edges of bone beneath the mucoperiosteal flap. A small dental curette is placed in the alveolus to remove any necrotic debrie, calculus or bone fragments and the alveolus and flap are flushed prior to closure. The mucoperiosteal flap is repositioned and sutured in place. If there is tension on the mucoperiosteal flap when attempting to close a surgical extraction site the tension can be released by incising the inner most layer of the flap, the inelastic periosteum, at the apical portion of the flap. Incision of the periosteum will permit tensionless apposition of the flap and prevent postoperative dehiscence.

When performing a mucoperiosteal flap for the surgical extraction of the maxillary 4^th premolar several structures should be carefully avoided. When making the mesial (rostral) portion of the incision the infraorbital artery, vein and nerve should be avoided as they exit the infraorbital canal immediately rostral to the periapical bone of the mesiobuccal root of the maxillary 4^th premolar. These structures can be avoided by digitally retracting them dorsally and not extending this incision too far apically. When making the distal (caudal) part of the incision the parotid and zygomatic salivary duct papillae should be visualized and avoided.

There are two approaches for the surgical extraction of the mandibular canine teeth including the labial and lingual approach.² The labial approach utilizes a mucoperiosteal flap located on the labial aspect of the tooth while a lingual approach utilizes a lingually located flap. Equal amounts of alveolar bone are present buccally and labially so there is no advantage of one technique over the other with regard to bone removal. The mental artery, vein and nerve exit through the mental foramen located near the labial aspect of the apex of this tooth. A lingual approach would avoid potential damage to these structures.

Extraction of Teeth with Odontoclastic Resorptive Lesions

A new technique for removal of teeth with advanced feline odontoclastic resorptive lesions has been described. Whole tooth extraction is generally considered to be the treatment of choice for teeth with advanced feline odontoclastic resorptive lesions. Feline teeth affected with advanced odontoclastic resorptive lesions are often weakened, have a brittle crown and have radicular ankylosis. These factors make extraction of these teeth difficult, time-consuming, and traumatic, and often results in significant postoperative pain. An alternate technique reported by DuPont recommends crown amputation with intentional root retention for advanced feline resorptive lesions.⁶³ Utilization of this technique requires preoperative dental radiographs to rule out evidence of endodontic pathosis, which would appear as periapical lysis. Teeth with endodontic pathosis or periodontal pocketing must be treated by extraction rather than crown amputation with intentional root retention. Also cats affected with ulceroproliferative disease are not candidates for this technique. These cats require that all root structure and possibly the surrounding alveolar bone be completely removed.

After radiographing feline teeth with advanced odontoclastic resorptive lesions and ruling out the presence of endodontic pathosis and periodontal pocketing a very small envelope flap is created with a small feline periosteal elevator. Two small interproximal gingival incisions located mesial and distal to the affected tooth are made using a #12a or #15 blade. The gingiva is minimally elevated from the tooth and marginal alveolar bone with a small feline periosteal elevator. The gingiva is retracted and protected with the end of a small flat elevator while the crown of the affected tooth is amputated with a small round bur on a high speed handpiece with sterile water flush at or slightly below the level of the alveolar crest. Sharp bony projections are smoothed with the bur and the gingiva is closed with a single simple interrupted 4-0 absorbable suture. The DuPont technique is superior to conventional extraction techniques in feline teeth with advanced odontoclastic resorptive lesions because these teeth often lack a distinct periodontal ligament space, have ankylosis of the roots to the surrounding bone and have severe resorption of the root itself making extraction of the entire root difficult for the clinician, often extremely painful for the patient and almost impossible because of the lack of anatomic division between the root and alveolar bone. Immediately following the performance of the DuPont technique cats are less painful and if the technique is performed properly on appropriately screened teeth the cats remain asymptomatic.

References

1.  Holmstrom SE, Frost P, Eisner ER. Anesthesia and pain management in dental and oral procedures. In: Holmstrom SE, Frost P, Eisner ER,Veterinary Dental Techniques for the Small Animal Practitioner, 2^nd ed., 1998, 481-496.

2.  Smith MM. Lingual approach for surgical extraction of the mandibular canine tooth in dogs and cats. J Am Anim Hosp Assoc 32:359-364, 1996.

3.  DuPont G. Crown amputation with intentional root retention for advanced feline resorptive lesions - a clinical study. J Vet Dent 12:9-13, 1995.