Skills Laboratory: How to extract a maxillary canine in dogs

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Teeth with gross or radiographic evidence of pulp necrosis are candidates for either endodontic therapy or extraction. Discoloration due to intrinsic tooth staining, tooth fracture with pulp exposure, radiographic evidence of a wide pulp cavity compared with the rest of the dentition, and abnormal lucencies surrounding the tooth apex are all consistent with pulp death and necrosis. In cases of severely fractured teeth or gross or radiographic changes or in cases in which there are financial constraints or extended anesthetic concerns, extraction may be the only viable alternative to root canal therapy. Efficient removal of the comparatively large root of the maxillary canine tooth requires a mucoperiosteal flap. Closure of the defect after extraction is facilitated by proper flap construction.

EQUIPMENT

Proper equipment is imperative when performing surgical extractions. A high-speed delivery system is necessary. Round carbide burs or crosscut tapered fissure burs allow for the removal of vestibular bone and the creation of a mesial and distal groove. Diamond taper or flame burs contour bone after tooth removal. Other necessary instruments include a scalpel handle with a No. 15 blade, a periosteal elevator, Metzenbaum or iris scissors, and 4-0 absorbable suture material with a cutting needle.

Dental radiography equipment is essential in all extractions, and preoperative and postoperative radiography should be performed in every case. Regional nerve blocks are performed to maximize intraoperative patient safety and provide postoperative analgesia. (See How to perform four oral regional nerve blocks in dogs and cats.)

Hemorrhage control is generally not a concern because a high-speed water-cooled hand piece allows good visualization during most of the procedure. However, gauze may be used to blot the incision line to aid in elevation.

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MUCOPERIOSTEAL FLAP ELEVATION

Step 1

After performing the infraorbital regional nerve block and achieving an appropriate level of anesthesia,1,2 lift the upper lip adjacent to the maxillary canine tooth to expose the proposed surgical site. To help expose the site, you can place the patient in dorsolateral recumbency and use an atraumatic lip retractor. The attached gingiva (white arrow) and the lighter colored unattached gingiva or alveolar mucosa (black arrow) can now be visualized. The line of demarcation between the two is called the mucogingival line.

References

1. Beckman BW, Legendre L. Regional nerve blocks for oral surgery in companion animals. Compend Contin Ed Pract Vet 2002;24:439-444.

2. Beckman B. Skills Laboratory: Regional nerve blocks for oral surgery in dogs and cats. Vet Med 2012;107(1):30-34.

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Step 2

Start a vertical releasing incision dorsally, extending ventrally to the central diastema between the canine tooth and the third incisor. Extend the incision to create an envelope flap within the sulcus to the second or third premolar tooth (arrows). Carefully place multiple stab incisions rather than a continuous single incision to decrease the chances of tearing the flap.

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Step 3

Use a scalpel as a lever to carefully release 1 to 2 mm of gingiva and periosteum around the entire periphery of the attached gingiva.

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Step 4

Extend the release started with the scalpel by using a periosteal elevator. Apply firm pressure to the bone, and move the elevator simultaneously forward and slightly side to side to expose the bone adjacent to the maxillary canine tooth root efficiently and safely.

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Step 5

Use the periosteal elevator to retract the flap, exposing the bone for removal later.

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Step 6

Identify the buccinator (white arrows), a thin muscle that runs parallel and palatal to the alveolar mucosa and is adjacent to the apical extent of the vertical releasing incision.

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Step 7

Use Metzenbaum or iris scissors to separate the buccinator from the mucosa by using blunt dissection.

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Step 8

Once separated, incise the buccinator midflap caudally to the level of the first premolar. This incision releases the flap to move coronally to allow for a tension-free closure.

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BONE REMOVAL

Step 9

Use a large round carbide bur (No. 2, 4, or 6) or a crosscut tapered fissure bur on a high-speed hand piece to remove vestibular bone. Crosscut burs (depicted in the figures) can decrease procedure time but are best used in experienced hands. Round burs are perfectly acceptable and may help to avoid excessive bone removal. It is important to depress the foot pedal completely when operating any high-speed hand piece to maximize the efficiency of the equipment and minimize the wear.

Apply light pressure to the hand piece, and use a light sweeping motion to paint away the vestibular bone. Start at the coronal extent (see photo above) of the bone and expose the tooth root from the mesial to the distal aspect moving apically (see photo below).

The apical extent of removal depends on how firmly seated the tooth is within the alveolus. For example, a maxillary canine tooth with a comparatively wide periodontal ligament space in a young, mature dog requires removal of about 40% to 60% of the overlying alveolar bone. However, radiographic evidence of ankylosis or resorption would likely require bone to be removed further apically, approaching 100%.

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Step 10

Once the desired volume of vestibular bone is removed, use either a small round carbide bur (No. 0 or 2) or a crosscut tapered fissure bur to create a groove within the bone outlining the mesial (see photo above) and distal (see photo below) extent of the tooth root. Extend this groove palatally 2/3 to 3/4 of the vestibulopalatal width of the tooth. Further extension in a palatal direction risks communication with the nasal cavity. The mesial and distal grooves are carried to the apical extent of vestibular bone removal. This step further releases the alveolar attachment and provides a site for placement of the luxator.

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LUXATION AND EXTRACTION

Step 11

Place a winged luxator, 4 to 7 mm in width depending on the patient's size, into the mesial groove at the coronal portion of the root. Once firm purchase exists between the tooth and the bone, torque the luxator in a left-to-right or clockwise direction. Exert firm pressure for 15 seconds.

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Step 12

Place the luxator into the distal groove opposite the mesial placement, and torque it in a right-to-left or counterclockwise direction. Again, maintain firm pressure for 15 seconds. If adequate bone has been removed, adequate mobility now exists for Step 13. If mobility is minimal or nonexistent at this point, repeat luxation or remove additional bone apically.

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Step 13

Place extraction forceps on the crown of the tooth. Orient the forceps so that the best engagement is achieved; this orientation will vary depending on the forceps and the tooth's size. For the most predictable success and to minimize root fracture, pull firmly and progressively with a slight twist. Erratic, jerky movements are much less effective than slow continuous retractive force.

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CLEAN AND CLOSE

Step 14

Once tooth removal is accomplished, inspect the area visually and tactilely to detect rough or sharp bone margins. Gently contour and smooth the entire circumference of the alveolar bone, including the marginal palatal bone. A diamond taper or flame bur on a water-cooled high-speed hand piece is ideal for this purpose. Then lavage the alveolus with saline solution to eliminate any bone or tissue debris and visually inspect it. Perform dental radiography to confirm the absence of bone or tooth remnants within the remaining alveolus. A blood clot is allowed to reform within the alveolus. Bone grafting materials are available as adjuncts or as alternatives to the blood clot.

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Step 15

Use a periosteal elevator to elevate 1.5 to 2 mm of attached gingiva coronal and mesial to the alveolus to facilitate suture placement.

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Step 16

Use scissors to straighten the gingival margin before suturing.

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Step 17

To close, use a simple interrupted suture pattern 2 to 4 mm apart from distal to mesial with 4-0 absorbable suture material. Slight elevation of the palatal mucosa interdentally may be needed to ensure needle placement and eliminate mucosal tearing when the needle is passed.

RECOVERY AND PROGNOSIS

The patient may be sent home the same day to recover from the extraction with instructions for the owner to administer analgesics for four days. Additionally, the dog should wear a protective collar for two weeks.

Dehiscence is rare and generally results from patient maceration from pawing or rubbing the face. The prognosis for healing without complications is excellent.