Tooth extraction can be very challenging and is rarely a simple procedure. A successful extraction is when the entire tooth is removed with the minimum of trauma to the adjacent, remaining tissues (and the operator). To achieve the best success rate requires:
Knowledge of tooth root morphology.
Correct choice of technique.
Having the appropriate equipment.
Practice and patience.
The operator needs to be familiar with the normal shape and number of roots of all the teeth. Be aware that abnormalities such as extra roots or abnormally shaped roots (e.g., hooks) are not uncommon. For a reminder of what is the normal root pattern, refer to a dental textbook, Dentalabels®, dental charts, Visimodels®, or a dry skull.
In the cat and dog, the routine technique for extraction is to loosen (luxate) and extract (elevation) each tooth root individually. In all cases, the crowns of 2 and 3 rooted teeth need to be sectioned to produce single root pieces prior to extraction. The roots of multi-rooted teeth are usually divergent and therefore have different paths of withdrawal. Using a dental drill to section the crown enables cutting that is accurate, quick, and causes minimum trauma to adjacent tissues.
The first step is to locate the furcation, which is generally directly below the main cuspal point of the crown. To confirm the location, it can be felt with a probe as a concavity or seen by slightly reflecting the gum margin with an instrument or the air syringe. The tooth should be cut from the furcation at gum level and up through the crown using a fissure bur in a dental handpiece. The cut may need to then be extended below gum level to achieve complete crown division. Test the division by wedging an elevator between the sectioned crown and observing slight movement of the crown parts in opposite directions. It may be helpful to also reduce the crown height prior to luxation.
Sectioning 3 rooted teeth (upper carnassial teeth and the upper molar teeth in dogs) can only be achieved by using fissure burs in dental handpieces. Accurate positioning of the cuts requires proper knowledge of tooth morphology.
Usually the crowns are sectioned by vertical cuts. In large teeth the crown height may be greater than the bur length. In these teeth, it is better to angle the cut to go through a part of the crown of less height. This also means the cutting requires less effort.
CUTTING THE GINGIVAL ATTACHMENT
As part of the severing of the tooth’s attachment, the gingival attachment of the tooth should be cut around the entire circumference. This can be done by running a scalpel blade around the gingival sulcus/pocket and cutting down the root surface to crestal bone. The gingival attachment can also be cut using a sharp dental elevator at the time of luxation. If the gingival attachment is not cut there will be unnecessary disruption and trauma to the soft tissues as the tooth is extracted.
ROOT LUXATION AND REMOVAL
Luxation is the loosening of the tooth in the socket by progressive severing of the periodontal ligament fibres. A Couplands elevator of the appropriate size, or a similar instrument is used. The elevator is inserted behind the gingiva at an acute angle to the tooth root until it hits crestal bone. The instrument tip is now wedged between the root and bone and gently rotated (not levered) to move the tooth laterally. The pressure is built up gradually and then held for five seconds to stretch and break the periodontal fibres. The elevator is then relocated at different sites around the tooth and the procedure repeated until the tooth root becomes loose. Patience and controlled force are needed, not brute strength. The force should be applied as low down the root as possible when extracting teeth. Slipping, when using an elevator, is often because the tooth moves. You should support the jaw with your other hand and have a thumb and finger on either side of the tooth being extracted. Using the air/water syringe during extraction to rinse away blood and keep it at bay can be very helpful as it enables the progress of root luxation to be seen clearly.
ROOT ELEVATION AND EXTRACTION
In tooth extraction in dogs, the tooth can completely extracted using the elevator but usually it is simpler to finish the extraction using extraction forceps. The final periodontal fibres are broken by slightly rotating the root in the socket. As the roots of teeth in the dog are neither straight nor round in cross section, they will not rotate more than a degree or two. When the root will turn a little in both directions the forceps can then be used to pull the tooth from the socket. The beaks of the extraction forceps should fit the root and make a 4-point contact. The root should always be gripped as low down as possible to reduce the torque on the root and the risk of breakage.
In cat tooth extraction, the forceps can be employed earlier and to greater effect to luxate the tooth. Once the root is moving, the forceps can be used to rotate the tooth in the socket. Teeth roots in cats tend to be straight and circular in cross section and so allow greater rotation. Care should be taken not to crush the tooth with the forceps or to allow forces lateral to the long axis of the root. Feline tooth root apices are often bulbous. Once the root is quite loose it is withdrawn by “popping” the bulbous apex through the narrower socket above.
SURGICAL EXTRACTION OR OPEN EXTRACTION TECHNIQUE
A surgical extraction technique is indicated for removal of all canine teeth and root fragments. Some people prefer this approach for the extraction of multiple adjacent teeth. A surgical extraction involves raising a gingival flap and removing some bone to facilitate extraction. All veterinary surgeons should be familiar with a surgical extraction procedure. A description of this technique can be found in the BSAVA Manual of Small Animal Dentistry (2nd ed.) and other good texts.
The idea is that the root is drilled out using high-speed dental drills. This is not a proper extraction technique and should only be employed as a technique of last choice. Root atomisation is frequently necessary for feline teeth roots with odontoclastic resorptive lesions when the root is ankylosed or resorbed. It is better to leave a small piece of root tip rather than over drill and cause damage to adjacent structures such as the inferior alveolar canal or the maxillary sinus. There is insufficient follow up information available to know whether this is actually an acceptable procedure.
TREATMENT OF THE SOCKET
Once the tooth has been extracted, the aim is to promote the best healing of the socket. Sharp bony projections and non-viable bone pieces should be removed. Any non-viable soft tissue should also be removed. The socket should be gently curetted to remove any granulation tissue. There are pros and cons for suturing the gingiva. It should be considered whether the suturing or packing of a socket aids healing and reduces postoperative pain or hinders these factors due to the extra tissue manipulation and the presence of “foreign” material. Suturing is indicated when there is excessive tissue mobility. Extraction sockets heal very well naturally and the author feels that minimal intervention is best. The best way to promote healing and minimise post extraction pain is by gentle and proper extraction techniques. The amount of postoperative pain correlates to the degree of trauma to the adjacent bone and soft tissues during extraction.
Extraction may be made more difficult by root abnormalities (such as excess curvature or hooks) or root ankylosis. Complications usually result from incorrect technique or insufficient care in its execution and include:
Iatrogenic damage to adjacent tissues.
Fractured roots and remnant root tips.
Displaced root fragments, especially the palatal root or the upper carnassial tooth or in the cat, mandibular premolar roots.
Fistula, usually oronasal fistula, after extracting the upper canine tooth in dogs.
Delayed or complicated healing.
This condition has not been well reported in animals. It is well recognized in people when there is a marked increase in pain about three days after extraction. It is associated with loss of the blood clot from the socket and exposure of the bony surface. It is thought to occur in animals, especially if excessive force was used during the extraction. The animal begins exhibiting signs of pain and possibly pyrexia a few days after the dental extraction. Treatment is with antibiotics. In people, the socket is cleaned and packed with an obtundant and antiseptic dressing.
WHEN CAN A ROOT FRAGMENT BE LEFT?
The ideal is to avoid the situation by correct technique. Unless the fracture is considerably below bone level, it may still be possible to remove the root remnant by further use of elevators or other instruments. A surgical extraction technique will allow the removal of root remnants deep in the bone. A root fragment cannot be left if it has associated infection or pathology. It can be argued that the potential complication from leaving a small piece of root tip (which is not infected) is sufficiently small as to make the trauma of removal unjustified. This may be so but should not be used as a general excuse. A radiograph should be taken and the animal’s records clearly marked to indicate the position of the root fragment. Where possible a follow-up radiograph should be obtained to monitor in case of developing pathology.
POST EXTRACTION CARE
The owner should be advised not to feed soft sticky food, which will pack in the sockets. Normal food should be fed and soft, not sticky, food only used if necessary. Usual oral hygiene should be recommenced immediately. Topical application of chlorhexidine preparations can be used for a short period if there is an objection to tooth brushing. Tough chew toys should be withheld for about a week when sutures have been placed
Analgesia should be given prior to extraction(s) and additional follow up analgesia considered. The amount of pain will depend on the difficulty of the extraction, the number of extraction sites and the individual patient. A course of antibiotics is not routinely indicated after tooth extraction. Antibiotics should be used when there is a specific reason for their requirement.
Ideally, extraction kits should be prepared and sterilised ready for each situation. Many of the instruments or the particular pattern of a certain instrument will be according to the personal preference of the operator. The author would use:
Basic Extraction Kit
1. Full dental drill unit (including 3 in 1 syringe).
2. Luxator (s) (size according to size of teeth).
3. Elevators. For dogs; Couplands No. 1 and No. 3. For cats; Super Slim elevators.
4. Tooth forceps (pattern 76N).
5. Gauze swabs.
Possibly supplemented by bone rongeurs and a suture kit.
Surgical Extraction Kit
1. Basic extraction kit.
2. Periosteal elevator (Goldman Fox or Molt).
3. Scalpel handle and No. 15 blade.
4. Tissue forceps.
5. Needle holders.
6. Resorbable suture material with a swagged on needle ( 4/0 chromic gut or Monocryl).