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Surgical tooth extractions (Proceedings)
Before any mention of surgery is made pain management must be addressed.
Before any mention of surgery is made pain management must be addressed. The days of ignoring pain are over and if the oral surgeon desires successful outcomes various pain management techniques must be used. These include:
• medical management (presurgical and postsurgical medications)
• regional nerve blocks
• local nerve blocks.
These issues are discussed in Chapter One and the reader is referred to this information before any attempt is made at surgery.
Perhaps the best procedure to resolve the majority of diseased teeth problems presented to the veterinary dentist is extraction. Clearly there are a multitude of procedures available to preserve teeth, but patient and owner selection are paramount for success. Dental extraction's solve disease problems and should be considered when the goal is to create a healthy mouth. After all, tooth loss is the end result of most diseases in the mouth with subsequent return to health.
Extraction of diseased and malformed teeth is an essential part of veterinary oral surgery.
Indications for extraction include:
• end stage periodontal disease
• end stage endodontic disease
• severe malocclusions
• retained deciduous
The reason for extraction is the relief of pain and suffering. As discussed earlier animals mask their oral pain giving the clinician the false impression of health. If the animals are to be helped it is essential extraction be considered an intergal part of therapy.
The old saying "Its as tough as extracting teeth" need not be the case for the dental surgeon. Extracting teeth is no more difficult than other procedures as long as the following principles are understood:
1. the top ⅓ of the alveolar bone surrounding the tooth has ⅔ of the holding power
2. periodontal fibers are not designed to withstand slow continuous torque
3. multirooted teeth are transformed into single rooted teeth
4. gingival preservation in paramount
5. complete extraction of root confirmed by radiograph
6. closure of alveolus to maintain blood clot.
The techniques of extraction include surgical and nonsurgical procedures. Non surgical extraction are those accomplished with simple elevation and traction. Typically these are teeth that are lost during the intubation stage of anesthesia or left on the surgeons sleeve as attempts are made to exam the mouth while the animal is awake. The periodontium is replaced with fibrous scar tissue as the disease progresses while supporting bone loss occurs furthering the weakening of the supporting structures. Mobile teeth are poor candidates for salvage with conventional prophylaxis techniques and extraction is generally the best option. Salvage procedures include bone regeneration, periodontal splinting and aggressive home care. These are intensive procedures best done by a veterinary dentist with advanced training.
Non Surgical Extraction's
Prior to any attempts at extraction dental radiology is imperative. Without adequate visualization of tooth root and bone structure extraction planning is greatly compromised. Veterinary dental radiology techniques are well described in other textbooks and the reader is referred to the suggested reading list if unfamiliar with dental radiology.
Non surgical extraction's are performed by placing gentle traction on the affected tooth with dental forceps, or needle holders. Extreme caution must be employed when toy breed dogs are presented with excessive bone loss in the distal mandible for pathologic fractures are common. Many dogs with "egg shell" mandibles are successfully treated if proper protocols are followed
Radiographs of the involved teeth are mandatory prior to extraction to define the amount of bone loss present Radiographs will also reveal preexisting pathologic fractures. Sectioning teeth to isolate each root is also mandatory to allow rotational forces to be used rather than leveraging forces.
Following successful extraction bone augmentation therapy is performed. The alveolus is gently debrided removing excessive fibrous tissue (not risking fracture) down to bone. Once cleaned the alveolus is filled with osteoinductive materials such as perioglass (Concil), impregnated resins (HTR) or the newer materials such as bone morphogenic materials (Emdogain). After filling, the alveolus is closed using 4-0 or 5-0 absorbable suture material (PDS II). Home care includes antibiotic therapy (clindamycin or clavamox), pain management (butorphenol), and soft diet. In extreme cases small muzzles are used for two weeks post op to discourage the dog from rough play and to maintain occlusion. Healing is generally uneventful.
Complications occur if there is insufficient bone left to support normal muscle tone or other factors are at play (neoplasia, mycosis, metabolic disease, uncooperative animals, or noncompliant owners.) Each complication is addressed individually. If the failure results from too little bone present salvage procedures are directed at maintaining function and health. These procedures are discussed in Chapter —. The other causes of failure should have been anticipated with preoperative blood work, history, physical exam, and interoperative dental radiology. The standard protocol should include histopathologic examination on any abnormal tissue found in the mouth during a dental procedure. While a pathologic fracture may result following a procedure having identified a neoplasm will save time and energy and help define treatment options. When in doubt BIOPSY.
Surgical extraction's are performed on nonmobile teeth with normal or near normal attachment levels. These teeth are often described as "solid" and instill great anxiety in the veterinarian attempting extraction without adequate training or instrumentation.
The indications for extraction include:
• endodontically compromised teeth
• endstage periodontitis of one root of a multirooted tooth
• feline odontoclastic resorptive lesion ("neck lesion")
• plaque intolerant animals
The techniques for surgical extraction closely adhere to the principles of extraction. The techniques include:
1. preoperative intraoral dental film
2. flap creation
3. removal of crestal bone (osteoplasty)
4. isolation of roots (sectioning)
5. elevation of roots
6. radiography (pre and post extraction)
7. alveolplasty (if required)
Each step is equally important and short cuts generally end up as surgical adventures. Adventures belong in movies, not the dental operatory.
As with nonsurgical extraction's dental radiographs are taken preoperatively to assess in extraction planning. In the least the radiographs helps document the need for extraction making the procedure defendable in a court of law. At best it guides the surgeon in placing flaps, coronal sectioning angles and elevation points.
Following radiographs the next step is the creation of a surgical flap. Since the last step is closure the surgeon must plan ahead when cutting tissue to preserve as much attached gingiva as possible. If attached gingiva is lost closure becomes difficult. In addition, maintaining the placement of gingiva following closure is critical. If the closure breaks down healing is by second intention and "dry sockets" are a real possibility. Flap design is important.
Extraction flaps are created using the following guidelines:
• incisions through attached gingiva and mucosa are on a diagonal diverging apically
• incisions are placed on the jugga of the mesial and distal adjacent tooth root
• dental papilla are incised
• periosteal elevators are used to reflect attached gingiva and oral mucosa
Regardless of the species the above guidelines are employed. Figure ( ) represents the incision sites for a maxillary fourth premolar. After the incisions are made a molt periosteal elevator (or equivalent) is used to peel off the attached gingiva from the bone. Care is used to prevent shredding the gingiva (especially in felines) during this step. Molt periosteal elevators are spoon shaped instruments with a sharp cutting surface on a round edge. As the attachment is cut the rounded edge deflects the tissue away from the bone atraumatically. When done properly the attached gingiva and mucosa are in one piece without perforations
Crestal Bone Height Reduction
Once the attached gingiva is deflected the crestal bone is cut with a round or pear shaped bur. Enough bone is removed to significantly weaken the holding power of the periodontium. A good rule of thumb is to remove one third of the crestal bone in an apical direction. Generally the buccal or labial surfaces are the only areas that require reduction. On rare occasion the palatal or lingual surfaces also require reduction. Occasionally a notch is cut on the mesial and distal edges of the tooth in the crestal bone to allow a "purchase" with the root elevator.
Isolation Of Roots
One of the key steps in extraction's is the sectioning of teeth. Because tooth roots diverge in animals extracting them as one unit is nearly impossible. By cutting the crown through the furcation areas the veterinary dentist is able to extract each root on an individual basis. The three rooted teeth (maxillary 4th premolars and molars) require two cuts, the remaining multirooted teeth require a single cut. Figure ( ) represents the cutting angles for teeth to be extracted. The choice of bur is left to the oral surgeon. The author discourages the use of diamond wheels or crosscut fissure burs and encourages the use of round or pear shaped burs.
Elevation Of Roots
The hallmark for this step is patience. More extraction adventures occur from impatience than any other cause. Periodontal fibers are designed to withstand sharp, repetitive forces (much like those of mastication) and not those of slow continuous torque. The idea behind elevation is just that - elevation, not prying, gouging, crunching, or punching. The proper use of an elevator is the application of rotational forces placed on the tooth in an effort to lift the tooth out of its alveolus. Because the periodontal fibers break slowly, bundle by bundle, the forces are applied for 20 to 30 seconds at a time. The elevator is reapplied at a different location on the tooth and the forces are again applied for 20 to 30 seconds (The Thirty Second Rule). The advantage of "slowing down" is that apical bleeding occurs into the alveolus helping to "push" the tooth out of its home. The hydraulics can be quite powerful and this phenomena should be used. If there is insufficient purchase on the tooth a bur is used to cut a notch in adjacent bone to provide sufficient space for the elevator blade to fit between bone and tooth.
After sufficient bone removal and elevation the tooth root should become mobile. Other forces that can be applied are rotational. Small dental forceps (or better yet needle holders) are used to grasp the tooth crown and then rotate the tooth on its long axis. The same principle of patience is used in that the tooth is rotated to the point of resistance and held for 20 to 30 seconds. The rotation is reversed and again held for 20 to 30 seconds. By using slow continuous forces the fibers are torn and the tooth becomes loose enough for gentle traction to remove it from its socket.
Once in a career (the reason becomes very obvious as the resulting hemorrhage is quite impressive and difficult to control). Enough radicular bone is removed until the tooth root has been successfully removed. Such problems as root ankylosis can necessitate full length removal of bone before the tooth root can be completely removed.
After the roots have been successfully removed the alveolus is treated with an alveolar augmentation agent (as previously discussed) then closed with 4-0 or 5-0 absorbable suture material. For patient comfort and knot security simple interrupted inverted sutures are used to secure the attached gingiva and oral mucosa. The releasing incisions are closed in a similar manner. The finished site should be smooth with only single strands of suture material visible
Mandibular First Molars
Mandibular first molars can be a challenge to extract if the principles of extraction are ignored. The key is radiography and patience. Dental radiographs will reveal existing or impending pathologic fractures and root malformations (dilacerations). The surgical techniques are essentially the same as maxillary 4th premolars. Releasing incisions for flaps are placed on the labial surface of adjacent tooth roots both mesially and distally starting through the attached gingiva and diverging apically about one half the length of the root. The dental papilla is incised and the attached gingiva and oral mucosa separated from the mandible. The soft tissue is peeled away from the mandible on the lingual surface usually with releasing incisions. Again, the goal is to displace the soft tissue from the bone in one piece and not in shreds.
Following flap creation a small round bur or pear shaped bur is used to lower the crestal bone to at least the level of the furcation. This is done both labially and lingually. Care is used to keep the soft tissue away from the bur. Next, the bur is used to section the tooth starting in the furaction and proceeding coronally just mesially to the table surface of the distal root.
If needed, a groove is cut around the tooth root to allow placement of the elevator tip. This allows the tip to make a "purchase" on the tooth crown to aid in the displacement of the tooth root in its alveolus. If this groove is not cut it becomes exceedingly difficult to properly elevate the tooth from the mandible.
In cases with significant bone loss the elevators are not used, instead needle holders or small forceps are employed to apply gentle rotational torque to the tooth root. This is critical if the surgeon wishes to avoid an iatrogenic fracture during extraction. The rotational forces are applied first in one direction, held for thirty seconds, the changed to the opposite direction, held for thirty seconds and repeated. This step is repeated until the periodontal fibers are broken and gentle traction extricates the tooth. If the tooth has significant anklyosis (as seen radiographically) the surgeon may need to circumferentially cut around the tooth root with a small round or diamond bur. Care must be taken to avoid the mandibular canal. Penetration not only creates visual impairment of the extraction site (bleeding) but inflicts lingering pain as the mandibular nerve is disturbed. Face pawing is a common sign when inadequate pain control is used.
Closure of the alveolus is similar to the upper 4th premolars. The releasing incisions are closed with 4-0 or 5-0 absorbable sutures using a simple interrupted inverted knot pattern. The goal is to close the soft tissue over both alveoli to preserve the blood clot and prevent food impaction then dry socket formation. If healing is by second intention (delayed) the process can be quite painful. Worst case scenario is the development of osteomyelitis. This complication requires aggressive therapy and is discussed elsewhere.
When performed properly healing is uneventful and the animals experience minimal discomfort.
Maxillary Canine Teeth
The upper canine teeth are the least difficult to extract when proper surgical techniques are employed. The steps are similar to the previous descriptions with special care given to avoid oral nasal fistula formation. The major complication occurs in cats with the resultant extraoral occlusion of the mandibular canine. This occurs in cats that have a tendency to be prognathic and the upper canine tooth is holding the upper lip off the buccal plate. Unfortunately not all cats learn to flip their upper lip over the lower canine and trauma to the upper lip margin can occur. Resolution of this problem ranges from crown reduction and vital pulpotomy to extraction of the mandibular tooth.
Extraction of the upper canine tooth starts with a radiograph. This reveals any abnormalities that may need to be addressed and helps eliminate surgical surprises. Releasing incisions are made over the lateral incisor and first premolar directed apically and diverging. Next, the diastemas between the lateral incisor and canine and canine and premolars are incised along the alveolar ridge. As before, a molt periosteal elevator used used to reflect the attached gingiva and oral mucosa off the buccal plate. And as before, great care is used to not shred the tissue.
Once reflected, a small round bur or pear shaped bur is used to cut a relief site on the buccal plate over the tooth root. As a rule, about one third of the tooth's buccal plate can be removed without any complications. Its easiest to bur along the mesial and distal surface of the root then cross over the root connecting both sides. It is not necessary to bur deeply in that the buccal plate is thin (.5 to 1mm) and over burring weakens the tooth root leading to root fracture during extraction. In addition to the buccal side some animals need to have a purchase groove cut into the palatal side of the tooth. Generally this needs only be 1 - 3 mm in depth.
An elevator is placed on the palatal side of the tooth and the crown is gently displaced buccally. Next, the elevator is placed mesially, then distally and gentle elevation is applied to the crown. The "Thirty Second Rule" is used with patience being a virtue. If needed, forceps are used to gently grasp the tooth and rotate the crown buccally. If the crown is rotated palatally there is a risk the apex will perforate the alveolar septal bone ensuring oral nasal fistula formation. The best force to use is gentle traction following the contour of the root..
Closure is routine. If the alveolus is large hemostatic agents such as Gelfoam(R), Concil(R), HTR(R) are used to pack the void minimizing postoperative bleeding.
Mandibular Canine Teeth
Lower canine teeth in felines and small dogs represents the greatest likelihood of extraction misadventures (discussed later). The key to successful extraction is understanding the mandibular symphysis is cartilage and that the root structure of the canine tooth can represent 70 percent of the jaw volume. Successful extraction of the lower canines is accomplished by preserving supporting bone lingually and as much as possible labially.
Dental radiographs will determine the amount of available bone and the degree of ankloysis present. This is especially important in geriatric felines. Failure to radiograph mandibles is the major reason for extraction nightmares.
The first surgical step in a routine mandibular canine extraction is creating a releasing incision of the alveolar ridge from the distal surface of the canine extending to the labial ventral surface of the first premolar. The next incision starts at the jugga of the lateral incisor and extends apically and distally through the labial frenulum to the level of the mental foramen. Next, a molt periosteal elevator is used to create a full thickness extraction flap separating the attached gingiva and oral mucosa from the labial surface of the mandible. The molt is used to also separate the adjacent oral mucosa from the lingual side of the canine tooth to allow placement of a dental bur. When finished the top one half of the labial surface of the mandibular canine root and approximately 2mm of the lingual bone is exposed. A number two round surgical bur is used to remove approximately one third of the alveolar bone on the labial surface (being careful to avoid the mental foramen). Next, the bur is used the removed approximately 1 mm of bone to a depth of 2mm on the lingual surface. This furrow allows placement of a dental elevator and gives purchase to the working tip.
Extraction forces include labial, mesial, and distal displacement. In addition, forceps can be used to provide rotational forces (the safest force to use on this tooth). The area of greatest retention on the lower canine is the dorsal surface mesial to the first molar. If this bone can be manually removed with elevators or burred with a number two bur the retention forces are greatly reduced. Especially in small animals with fragile mandibles the best technique is to surgically removed the dorsal component described then use rotational forces. If prying or gouging forces are used there is great risk for iatrogenic fracture. Difficult extraction's are best met with patience and surgical burs. More harm is done with aggressive prying than aggressive burring. Rotational forces are held for a minimum of 30 seconds in each direction. The sequence is repeated for two to three minutes then a resting period allow for alveolar hemorrhage which helps displace the tooth. By slowing down the whole process is speeded up and a successful extraction is realized.
Once the tooth is removed closure is by simple interrupted inverted sutures. Generally there is great apposition of the labial mucosa to the mandible and the lower lip is esthetically repositioned. In giant breed dogs the alveolus is filled with Gelfoam or any other hemostatic agent. Healing is usually uneventful
In geriatric animals with severe anklyosis an option to consider is the Dupont techniques (described later). This technique does have caveats and radiology is essential.
The extraction techniques for the feline oral cavity are essentially the same as the canine species except that all structures are smaller and abit more brittle. Because cats are plagued with feline odontoclastic resorptive lesions the veterinary dentist is faced with teeth that facture easily. The best way to manage this is surgical exposure of the extraction site and circumferential removal of bone from the tooth root to be removed. This technique allows the oral surgeon to tease the tooth root out of the alveolus in one piece. If tooth root separation occurs a small round bur is used to enlarge the alveolus to gain access to the fragment.
Retention of tooth roots frequently occurs as a result of incomplete tooth extraction or endstage odontolclastic resorption. In either event dental radiographs of the affected arches are taken to determine the location of the retained roots. Surgical extraction and alveoloplasty of the retention sites is performed.
The first step is pain control. Local nerve blocks are performed prior to surgical intervention. Preoperative medications include butorphenol with or without acepromazine. Post operative pain control is a continuation of preoperative medication without acepromazine. Fentanyl patches are a consideration when oral administration of pain medication is difficult or impossible.
The surgical incision is made directly over the affected arch both mesial and distal. A molt periosteal elevator is used to reflect the attached gingiva to the respective labial and lingual direction. When finished surgical exposure allows the visualization of all the involved alveoli on the affected arch. Prior dental radiographs dictate which alveoli are curretteted and which alveoli have retained roots. Alveolar curettage involves using a number two round bur and carefully debriding the alveolar wall back to healthy bone. Magnification is essential to evaluate the completeness of necrotic bone removed. When finished the alveolus should have clean walls with a blood clot remaining. Retained roots are removed as previously described. Follow up dental radiographs will confirm the complete removal of retained tooth roots.
The keys to successful extraction of feline teeth are patience, equipment, and technique. As the proverb states "Haste makes waste." Slow down and do the steps correctly and the operative time will be greatly shortened. In addition, have the correct equipment. This is not an area for Black & Decker drills and hack saw blades. If the practice is not equipped with the proper instrumentation and radiography refer the cat to a veterinary dentist. The client and animal will be grateful
Extraction misadventures result from:
• failure to visualize tooth (xray and surgical exposure)
• too much horizontal force
• too much vertical force
• too much rotational force)
• too much grasping force
• insufficient bone removal
• failure to isolate each root
The consequences of a misadventure is increased operative time to complete the extraction and further trauma to the animal. If tooth roots are left in the animal most will abscess and be lost through inflammation. If complications occur the oral surgeon is at risk for legal consequences with financial implications. All of these problems can be avoided if the oral surgeon follows each step and does not cut corners.
If a tooth root does fracture from the root the surgeon should be able to remove it if proper instrumentation is available. To remove a root tip the surgeon reradiographs the retained tooth root tip to determine its size and structure. Next, a small round or pear shaped bur is used to circumferentially cut around the root tip to allow for placement of a root tip elevator. Usually the alveolar wall must be enlarged just enough to make space for the bur then elevator. In most instances this is not a problem but care must be used in small breed dogs, cats and other animals with significant horizontal bone loss. Over enthusiastic use of the bur when extracting an upper fourth premolar may result in penetration of the infraorbital canal. The oral surgeon makes this mistake and NO knots.
This technique has been described as the pulverization of tooth roots with a bur. In cases of endstage ondontoclastic resorption in felines extraction is better accomplished with root tip picks and fine blade elevators. Merely twirling a round bur in the alveolus gives very little tactile feel of what is tooth root and what is bone. Significant collateral damage plus inadequate root removal are two common outcomes. Normal root structure is best removed using the above described techniques. Burring out normal tooth roots is rarely complete and frequently results in the continuation of the inflammatory process.
If atomization is used radiographs are mandatory both preoperatively and postoperatively to document complete removal of tooth root. Incomplete tooth root removal is considered malpractice if the veterinarian records the teeth as being extracted.
This technique involves the coronal amputation of the tooth to be extracted and leaving the root in place. The gingiva is closed over the root and the soft tissue is allowed to heal.
Again, the caveat is the extent of periodontal and endodontic disease present. If the tooth root is not completely healthy leaving it in place will result in the continuation of the inflammatory process. This will result in continuation of the presenting problems and an unhappy client and pet. To avoid this problem careful radiographic inspection with magnification of the root structure will determine candidates for the Dupont technique. In general, this technique should be reserved for the geriatric animal with noninflammed roots where anesthesia time is critical. In all other cases conventional surgical extraction is the best option.