Tooth extraction

Chapter 13


Tooth extraction




Indications


While there are some absolute indications (i.e. no other treatment option exists) for extraction, there are often alternative treatments available (e.g. endodontic therapy and restoration of a complicated crown fracture), which would allow a tooth to be maintained. Alternative treatment is recommended for strategic teeth, i.e. the permanent canines and large posterior teeth, but only if they are periodontally sound. However, treatment by extraction is always preferable to leaving pathology untreated.


Common conditions that generally require extraction include the following.




Extensive destruction of dental hard tissue


Extensive destruction of dental hard tissue occurs with dental caries and odontoclastic resorptive lesions. Teeth with caries can be treated either with restoration alone or in combination with endodontic therapy if the pulp is also affected. In advanced caries, however, most of the crown has been destroyed and only the root(s) with inflamed or necrotic pulp tissue remain in the alveolar bone. These root(s) must be extracted to avoid periapical pathology.


Resorptive lesions are detailed in Chapter 11. The current treatment recommendation for most teeth affected by resorptive lesions is extraction. However, if there is no radiographic evidence of endodontic involvement and the roots are seen to be undergoing replacement resorption, crown amputation and flap closure is justified, but this procedure requires long-term postoperative radiographic monitoring.



Persistent primary teeth


Persistent primary teeth, i.e. primary teeth that are still in place when their permanent counterparts start erupting, may interfere with the normal eruption pathway of the permanent counterparts, resulting in the development of malocclusion. The primary incisors and canines are the most common teeth that persist. Apart from the risk of a malocclusion developing, periodontal complications are likely. Hair and other debris become trapped between the primary and permanent homologous pair and accelerate plaque-induced periodontal breakdown. Persistent primary teeth should generally be extracted early in the animal’s life (ideally at around the time that the homologous permanent tooth is erupting), to reduce the likelihood of a malocclusion developing and prevent periodontal complications.



Malocclusion


Orthodontic techniques are available to correct/modify malocclusion of the permanent dentition, such that pain-free function is achieved. However, there will be owners who will not be able to afford these, usually multistage, procedures. Alternatively, the patient may not be suitable for more than a single elective anesthetic. Ethical considerations also play a role in deciding how best to treat a malocclusion. In many circumstances, extraction of maloccluding teeth, and/or their antagonist tooth, will enable adequate function.


Primary teeth involved in malocclusion should be extracted before the eruption of their permanent counterparts (i.e. at 6–8 weeks of age). This is called ‘interceptive orthodontics’. It will allow the upper jaw and mandible to develop to their full genetic potential independently before the permanent dental interlock forms. Interceptive orthodontics will prevent dental interlock-induced malocclusion from developing. However, if the developing malocclusion is of skeletal origin, the value of interceptive orthodontics is negligible since the permanent teeth will form the same incorrect interlock.








Choice of extraction technique


The choice of either a closed or an open technique will depend on several factors. The most important are:



Preoperative radiographs are mandatory to evaluate the tooth morphology and extent of pathology necessitating the extraction.


Situations where an open extraction technique is absolutely indicated (i.e. the tooth cannot technically be removed using a closed technique, since alveolar bone must be removed to free the root) include:



Situations where an open technique may facilitate extraction include:



With the exception of teeth affected by advanced periodontitis, I generally use an open extraction technique. It enables visualization of the periodontal ligament space (instrument placement can thus be more precise and the extraction is less traumatic to adjacent tissues) and healing is more predictable. Human patients report less postoperative discomfort following an open technique than a closed technique. The same is probably true for our patients.



Extraction techniques



General considerations


Extraction of teeth is a surgical procedure. While it is not possible to achieve a sterile environment in the oral cavity, the mouth should be clean before extraction is performed. All teeth should be scaled and polished and the mouth rinsed with a chlorhexidine solution.


It is essential to know the normal anatomy of the oral cavity to prevent iatrogenic damage, e.g. severing neurovascular structures, which would result in sensory deficits and hemorrhage. Good visibility simplifies the procedure greatly. A good light source is essential. In addition, use the three-way syringe to clean the mouth out frequently during the procedure. Use water only or water and air to clean away debris, followed by air only to dry the tissues. The air spray should be used sparingly (brief bursts) to avoid soft-tissue emphysema. Suction is extremely useful and strongly recommended. Extraction is easy if the periodontal ligament space can be visualized and consequently instruments applied at the correct location. Contrary to common belief, tooth extraction requires no force. It is best achieved by planned placement of instruments and carefully working around the whole circumference of the tooth cutting the periodontal ligament, thus releasing the tooth.


As already mentioned, preoperative radiographs are mandatory to assess the extent of the pathology and identify morphologic abnormalities. The clinical findings in combination with preoperative radiographs allow selection of the best extraction technique for each tooth. Intraoperative radiographs are recommended if the procedure is not proceeding as planned. Finally, adequacy of the extraction should be verified with postoperative radiographs.


Equipment and instrumentation requirements for extraction are detailed in Chapter 1. A new extraction instrument, called the ‘Extraktor’ has recently been developed (Fig. 13.1). The Extraktor has been specifically designed to fit the shape of canine and feline tooth roots, thus optimizing the forces used. It can be used to exert apical pressure and cut the periodontal ligament. It can also be used for leverage. The Extraktor can be used both as a luxator (cutting in an apical direction) and as an elevator (exerting horizontal leverage). In addition to these modes of action, the Extraktor, because of its sharp lateral edges, can be used to cut laterally, sliding around the tooth to cut the periodontal ligament. This mode of use is unique to the Extraktor. The correct use of the Extraktor is critical for success. The technique is a modification of traditional techniques using luxators and elevators and will be detailed in this chapter. Correct use always entails amputating the tooth crown to allow the Extraktors to fit snugly to the root surface. If performed correctly, the Extraktor technique results in minimally traumatic extraction in a reasonable time period.



Some guidelines for the use of dental luxators, elevators and Extraktors:




Closed extraction



Single-rooted teeth


Teeth suitable for this technique are any single-rooted teeth e.g. incisors in the dog and cat, 1st premolars in the dog, upper 2nd premolars in the cat, and mandibular 3rd molars in the dog. It can also be used for canine teeth with extensive bone loss due to severe periodontitis.



Procedure – using luxators and elevators:



1. Cut the gingival attachment around the whole circumference of the tooth using either a No. 11 or 15 scalpel blade in a handle or a sharp luxator (Fig. 13.2).



2. Select a luxator of the appropriate size. Its concave surface should equal the curvature of the root being extracted. This is often a larger size than initially estimated. The instrument is held with the handle along the palm of the hand and the index finger resting on the shaft, with the tip of the finger close to the cutting end (Fig. 13.3). The fingertip functions as an emergency stop should you slip, thereby avoiding iatrogenic damage to surrounding structures. With an average-sized hand, this will leave the end of the handle resting against the wrist, where it can be gripped with the other fingers. This grip prevents the excessive force which can be applied if the handle end rests in the center of the palm, forming a straight line of force from the elbow!



3. The luxator is advanced into the gingival sulcus at a slight angle to the tooth, i.e. following the surface of the tooth, and pressed into the periodontal ligament space (Fig. 13.4). If the luxator is not inserted into the gingival sulcus in the described fashion, it is likely to slide over the margin of the alveolar bone and raise the gingiva off the bone. This will lacerate the gingiva rather than break periodontal ligament fibers!



4. The luxator is worked, applying gentle apical pressure, into the periodontal ligament space around the whole circumference of the tooth (Fig. 13.5). The sharp luxator will cut the periodontal ligament fibers. Once sufficient space has been created between the tooth and the alveolar bone, an elevator can be used. Some clinicians prefer to perform the whole extraction using luxators of increasing size, i.e. do not switch to elevators. This is acceptable procedure as long as the luxators are used in the correct fashion, i.e. in an apical direction, without rotation, to cut the periodontal ligament fibers. Luxators should not be rotated, as this will damage the fine end of the instrument.



5. The elevator (gripped in the hand in the same way as a luxator) is also worked circumferentially around the tooth, with a steady gentle rotational pressure held at each point for 10–15 s to fatigue the deeper periodontal fibers. Hemorrhage will be created at the same time, which adds hydraulic pressure to the process of breaking down the fibers. The other hand should be used to support the jaw and prevent any undue stress on the jawbone. In addition, the thumb and index finger of the other hand should be placed on the buccal and palatal/lingual aspect of the tooth root (around the alveolus of the tooth). This will allow tactile feedback as well as minimize iatrogenic damage should slippage occur with the elevator. As the periodontal ligament fibers break and the tooth begins to loosen, the elevator can be pushed further apically, and rotated more. It is essential to work around the whole circumference of the tooth. It is tempting to concentrate elevation at the points where the tooth is most mobile. The opposite should be performed, i.e. the elevator should be worked more in positions where the tooth is least mobile. When the tooth is loose in its socket, it is tempting to use extra force to speed up the extraction. Try to avoid this, as it usually results in fracture of the root, which then needs to be retrieved.


6. When the tooth is loose, it can be drawn out of the socket with fingers or forceps. In my experience, the use of dental forceps usually results in fracture of the apical portion of the root. I do not use them or recommend their use. However, if they are used, make sure that the forceps are applied as far apically as possible on the root and use gentle rotational force applied in a back and forth manner along the long axis of the tooth.



Procedure – using Extraktors:



1. Cut the gingival attachment around the whole circumference of the tooth using either a No. 11 or 15 scalpel blade in a handle (Fig. 13.2B) or a sharp Extraktor (Fig. 13.2C).


2. Amputate the tooth crown at the cemento-enamel junction.


3. Select an Extraktor of the appropriate size. Its concave surface should equal the curvature of the mesial and distal surface of the root being extracted. This is often a larger size than initially estimated. The instrument is held in the same way as a luxator or elevator (Fig. 13.3).


4. The Extraktor is advanced into the gingival sulcus at a slight angle to the tooth, i.e. following the surface of the tooth, and pressed into the periodontal ligament space (Fig. 13.4).


5. The Extraktor is worked, applying gentle apical pressure, into the periodontal ligament space at the mesial and distal surfaces of the tooth root (Fig. 13.5). The instrument is also encouraged to slide buccally and palatally/lingually (Fig. 13.6) to cut periodontal ligament fibers around the whole circumference of the tooth. The spoon-shaped Extraktor is sharp at its apical termination but also on part of its lateral wings and will thus readily slide bucally and palatally/lingually. Extraktors are also of sufficient metal thickness to allow some rotation (unlike luxators).


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Oct 9, 2016 | Posted by in GENERAL | Comments Off on Tooth extraction

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