Steven E. Holmstrom, DVM, DAVDC
Veterinarians are often called upon to extract teeth. This paper will discuss the indications, methods, equipment and techniques to perform exodontia.
Indications for Exodontia
While the goal in Veterinary Dentistry is to save teeth, it sometimes becomes necessary to extract them. Indications are fractured teeth, periodontal disease that is not treatable, orthodontic disease, dental crowding, and chronic ulcerative conditions. In addition to additional fees, clients may be come emotionally disturbed over the loss of teeth. The doctor should advise his or her clients of alternative types of therapy prior to treatment, for once the tooth is extracted, it is final!
State law regarding extractions varies from jurisdiction to jurisdiction. In all areas, if extraction is permitted by persons other than a veterinarian, the extraction must be performed under the supervision of a veterinarian. In some areas regulations are in conflict. As an example, in California, Registered Veterinary Technicians are permitted to extract teeth. However, California law forbids Registered Veterinary Technicians from performing surgery. Many extractions are surgical (when teeth are sectioned, alveoplasty performed and gingival flap procedures performed, etc). This presents a conflict for the technician. The American Veterinary Dental College, has evaluated and considered the duties of the veterinarian, registered veterinary technician, and non-licensed individuals in practice. As a result, a position statement has been developed that states that extraction services should be provided only by a veterinarian. A copy of the position statement is available at http://www.avdc.org/.
Instruments for Exodontics
Because there are a variety of sizes of teeth, one needs a variety of sizes of dental elevators. To add to the confusion, a variety of manufacturers use a variety of names and numbering systems to identify their instruments. The 301, 301s and 301ss elevators are small, delicate elevators. The 301s is especially useful in extracting feline teeth and the 301ss elevators are even smaller. The 301 series also has been modified by notching the back side of the instrument, creating a fork to assist in preventing the instrument from sliding off alveolar crests. The 301ss would be effective in elevating incisors. The 301s would be effective in elevating incisors, small canines and premolars. While the 301 would be effective in elevating cat canine teeth. Generally select the elevator that best fits the contour of the tooth to be extracted.
The Heidbrink root tip pick, HB10/11, and Miltex 76 are root tip picks useful in elevation and for extracting retained root tips. They also can be used to cut the gingival attachment off of the tooth prior to displacement with dental elevators.
Smaller extraction forceps have been designed for cat teeth. They have more parallel jaws, increasing the surface contact and are much more effective than the human incisor forceps formerly used in veterinary dentistry. It is best to use a spring-loaded forceps.
Magnification & Lighting
One frustrating aspect of the extraction of roots is the limited access and poor visibility. These problems may be decreased by the use of magnification (3 power) and head lamps.
Sterilization of Equipment
Since extraction is a surgical procedure and the instrument penetrates tissue, sterile instruments should be used. While it is true that the tissue surrounding the tooth is already infected, it is inappropriate to add different species of bacteria to the infection. Chemical disinfectants may be effective, but they take time to work, and must be thoroughly washed off prior to use. Sharp instruments may become dull by chemical sterilization. Some metals will weaken. Gas sterilization techniques are less hazardous to the instrument. Autoclaving techniques use a combination pressure and steam heat to sterilize instruments. Sterilization must be monitored, either by the use of chemical strips that turn colors when the proper sterile conditions have been achieved or by biological monitors which check for bacterial growth after sterilization.
There are three ways of removing a tooth from its socket. These are the force, elevation and surgical techniques. The force technique fractures bone (and tooth root) and causes more trauma than necessary and is discouraged. Elevation stretches and tears the periodontal ligament fibers by insertion of the elevator into the alveolus and using it as a wedge. A rotational motions rather than "teeter-totter" motions should be used. The tooth is eased out of the socket rather than using brute strength. The key to this approach is to be patient. All of the root should be removed, except in the rare circumstance where more damage would be the result of root retrieval. The surgical technique creates a flap, removes the buccal plate of bone and removes the root through the opening created in the buccal wall.
A step-by-step approach in exodontic technique is important. Keep in mind the object - to remove the tooth as atraumatically as possible. You may not need to use each of these techniques for every extraction. Nor is the order necessarily followed each time. Combinations of vertical and horizontal extraction may be used.
Single root teeth are the incisors, canines, and first premolar. The first step in tooth extraction is to sever the gingival attachment. A No 11 or 15c scalpel blade, root tip pick or dental elevator is most commonly used. Work all the way around the tooth. "Be patient!" Occasionally it may be helpful to use a round or pear shaped bur on a high-speed handpiece to separate the ligament. Be sure to use plenty of water to keep the tissues cool, otherwise, bone necrosis may occur, secondary to thermal injury.
The Vertical Rotation force occurs when the elevator is used parallel to the root. Once the free gingiva has been severed, begin to work an elevator, whose curve approximates that of the tooth, into the space between the tooth and the alveolus. It is helpful to place a slow, gentle, steady pressure on the tooth rather than quick, rocking motions. The slow steady pressure (holding the pressure on each side 5–15 seconds) will break down the periodontal ligament so that the tooth exfoliates easily.
Placing the elevator perpendicular to the crown and tooth root in the interproximal space employs the horizontal extraction position. Pressure is placed on the tooth to be extracted by a coronal rotation of the instrument. Care should be taken not to luxate the tooth that is acting as a fulcrum. When the periodontal ligament breaks down, hold onto the tooth with extraction forceps for easy removal. To increase the speed of healing, the socket and associated gingiva should be disinfected by curettage and irrigation. Finally the gingiva is sutured using 4-0 suture material. The author prefers using MonocrylTM as it will dissolve or become untied and fall out within several weeks.
It is almost always easier to section multi-root teeth before extracting them. After splitting, remove each section as if you were extracting a single root tooth. Once the crown has been split, each individual root is treated like a separate tooth and extracted. The only difference in this technique is that adjoining roots may be used as a fulcrum for the extraction before and after the root has been elevated. A high-speed handpiece with a 701 bur works best. Generally, it is best to expose the furcation and start sectioning the tooth from the furcation towards the crown. The incision through the crown can go directly up from the furcation, splitting the crown in half. Alternatively, the incision can be angled toward a crown developmental fissure, sectioning the crown unequally.
All premolars except the first premolar (1 root) and the maxillary fourth premolar (3 roots), should be sectioned by using a high speed bur to cut between the tip of the crown and the furcation. The maxillary fourth premolar first molar and second molar should be separated between the furcations and the crown of each of the three roots. This will create three separate tooth segments that can be elevated one at a time.
Surgical Extractions are performed by making releasing incisions on the mesiobuccal and distobuccal line angles of adjacent teeth. These releasing incisions are joined by an intrasulcular incision that follows the gingival margin. The periosteum and gingiva is elevated off the bone with a periosteal elevator, to create a full-thickness gingival flap. The buccal plate of bone over the tooth is removed with a high-speed bur and irrigation. The root is removed and the flap is closed over the alveolar socket.
Radiographs taken postoperatively allow the practitioner to verify that the entire tooth has been extracted. Radiographs create a permanent record of the procedure.
The trauma and possible pain to the patient caused by the disease condition or the procedure creates the need for the consideration of pain medication administered either by the injection of a local anesthetic, parenteral injection, oral medication, skin patch or a combination of two or more methods.
Complications may occur while extracting teeth. Occasionally, roots or root tips remain. The roots may be difficult to extract. With any extraction procedure, dental radiology may be helpful in making sure that all of the root tissue has been removed. Occasionally, complications occur and roots or root tips remain. The preferred treatment in this situation is to create a flap and elevate the tooth buccally. Another complication of extraction that occurs most often in untrained hands is collateral damage to other oral or extra oral structures. Perforation or orbital contusion of the eye with sharp dental instruments has resulted, secondary to the lack of training and care, when extracting the maxillary fourth premolar or first molar. Even slippage off the mandible while elevating premolar or molar teeth can cause injury to the patient or operator.
Using proper instrumentation and extraction technique makes the extraction simpler, safer and easier on the patient and practitioner. Multirooted teeth should always be sectioned prior to extraction to prevent the likelihood of fractured root segments. Difficult extractions can be accomplished by gingival flap surgery to facilitate atraumatic elevation of the root in a buccal direction. Postoperative radiographs and pain control help document what has been done, and provide the patient with a relatively painless procedure.