Cecilia Gorrel United Kingdom
“Surgical Extraction” is defined as a technique where a muco-periosteal flap must be raised and alveolar bone removed in order to remove the whole tooth root.
There are often alternative treatments to extraction. Alternative treatment is recommended for strategic teeth (generally, permanent canine and large posterior teeth) that have a healthy periodontal status. Treatment by extraction, however, is always preferable to leaving pathology untreated.
Common indications for surgical extraction include:
Periodontally sound upper and lower canines, which are affected by fracture or involved in a malocclusion.
Teeth that are affected by ankylosis.
Root remnants where the remaining root fragments are embedded deep within the alveolus.
Roots with bizarre morphology.
Multiple-rooted tooth that has no loss of crestal bone.
TECHNIQUE FOR SURGICAL EXTRACTION OF TEETH
Pre-extraction radiographs to check root morphology and get a more complete picture of the pathology necessitating the extraction are mandatory. Surgical extraction should be performed in a clean environment. So, periodontal therapy (supra- and sub-gingival scaling, root planing and crown polishing) should be performed before starting the extraction.
An upper canine tooth will be used as an example for surgical extraction. Differences in extraction technique for other teeth will be highlighted.
Cut the epithelial attachment around the canine and extend the incision rostrally to the 3rd incisor (103/104) and distally to the 2nd premolar (106/206) using a No. 11 or No. 15 blade.
Cut a releasing incision at the rostral and distal ends of the initial incision to just beyond the muco-gingival line. Make the releasing incisions slightly divergent to ensure that the base of the flap is broader than the edge.
Use a “wax spatula” type periosteal elevator to lift the gingiva and mucosa from the bone overlying the canine root. Extend the releasing incisions if necessary.
To remove the buccal bone plate overlying the root, use an appropriately sized round burr with water irrigation/cooling. It is usually not necessary to remove bone to the apex, only to two-thirds of the root length. A size 2 or 4 burr is best for cats, a size 6 for dogs and size 8 for giant breeds. Water-cooling and irrigation is mandatory otherwise bone will be thermally damaged and a sequestrum may later form. Bone can readily be differentiated from tooth; bone has a greyish colour and bleeds, cementum/dentine is white and avascular.
Use the round burr to create a trough or gutter between the tooth root and the alveolar bone on the rostral and distal root surfaces. Try to remove bone and not drill into the root surface, or the tooth may fracture during elevation.
Place an elevator in one of the troughs and rotate the elevator along its long axis. This action will rotate the tooth along its long axis. The aim is to break down the palatal periodontal fibres and those of the root tip, but avoid levering the root tip into the nasal cavity. The elevator is rotated to stretch the fibres, and held for 10–30 seconds at a time, repeating each side until the tooth becomes loose, and can be easily removed.
The burr is used to smooth the edges of the alveolus. If the socket is filled with debris, this should gently be flushed out prior to closure. Ensure a clean clot forms in the socket.
The flap should be sutured over the socket, such that there is no tension on any of the sutures. If necessary, bluntly dissect the flap sub-mucosally towards the lip margin in order to gain more tissue. Ensure that the edge of the palatal mucosa is free by gently inserting the periosteal elevator between the bone and soft tissue. Use simple interrupted sutures and an absorbable suture material with a swaged on needle. Proper placement of releasing incisions should ensure that all edges at the time of repair are supported by bone. If it is not possible to fully close the flap without tension, then leave an opening, which will heal by granulation.
The upper canines will be the teeth most often extracted surgically, but mandibular canines, if periodontally sound, will also require surgical extraction due to their wide root compared with the diameter at the cemento-enamel junction and the curvature of the root. Sound mandibular canine roots should only be extracted with good reason since the root accounts for 50% of the rostral mandibular bulk. Their removal, together with alveolar bone, considerably weakens the rostral mandibular ramus and fractures may occur. Endodontic therapy and restoration of a periodontally sound but fractured lower canine is preferable to extraction.
If using a buccal approach, care must be taken to avoid damage to the neurovascular bundle exiting the mental foramen while raising the flap. A lingual approach is possible but gives poor visualisation for the procedure. To preserve mandibular strength, remove as little bone as possible—just to the point of maximum root. It is possible to obtain small curved luxators to follow the root curvature and minimise the amount of bone removal required.
Upper 4th Premolars And Lower 1st Molars in The Dog
These teeth, if affected by periodontitis, are usually removed by sectioning and non-surgical extraction. But if the teeth are periodontally sound, then surgical extraction is indicated. The flap for the upper 4th premolar (108/208) extends from the middle of the 3rd premolar (107/207) to the distal edge of the 1st molar (109/209), with the releasing incision made from the distal end of the first incision. This avoids damage to the infraorbital foramen, dorsal to the 3rd premolar (107/207). The flap for the lower 1st molar (309/409) usually only needs to extend to the adjacent teeth, with the releasing incisions at each end diverging as they pass through the mucogingival line. Buccal bone can be removed to expose the furcation in order to section the tooth into its constituent root/crown units. Further removal of alveolar crest bone will facilitate entry of elevators into the periodontal space without interference from the prominent enamel bulge on these teeth. If ankylosis is present, most of the buccal bone plate will need to be removed. (Use caution when removing large amounts of buccal bone as the upper 4th premolar mesiolateral root lies against the infraorbital canal and the lower 1st molar root tips are adjacent to the mental canal.)
Historically, feline premolars have been every veterinary surgeons nightmare due to the ease with which they fracture during extraction. This leaves roots, with or without pieces of crown attached, which must be removed. Although it might be tempting to leave these roots and hope they will resorb or the gingiva will grow over them, this is negligent. Remaining tooth fragments may cause a great deal of pain and act as a source of inflammation, possibly resulting in stomatitis.
Feline upper premolars can usually be removed non-surgically, but if ankylosis is present, the surgical techniques described above can be used. In the mandible, a modified technique aimed at preserving alveolar bone is recommended. This method can be adapted to the removal of most feline multiple rooted teeth.
The technique is to raise a small gingival flap, both buccally and lingually, followed by the removal of just enough alveolar crestal bone to expose the furcation. A small round burr, size 2 usually, is used to make two cuts from the furcation at 45 degrees, one distally, and one rostrally. These cuts will remove the bulk of the crown leaving only a small point of crown on each individual root. The next stage is to use either a size 2 or size 4 round burr to remove the cancellous bone between the two roots. The depth should be the same as the root length, and in the mandible, not long enough to enter the mandibular canal. If in doubt, measure the distance on your radiographs. Each root is then only supported by bone on three sides and a small luxator or elevator can be eased into the space created by the burr and the roots can be loosened and removed.
Retained Deciduous Maxillary Canine Teeth
Surgical extraction can be indicated here due to the long narrow root that is prone to fracture if a non-surgical approach is used. Follow the technique as above for a permanent tooth but use care to avoid damage to the permanent canine.
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