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An Urban Experience
The  ap for this extraction is generally triangular with just one distal vertical  ap. A horizontal incision is created along the arcade to the mesial line angle of the  rst premolar. Then a distally divergent vertical incision is created. Next, the  ap is carefully elevated and the buccal bone is removed to a point about 1/3 of the way down the root. More bone can be removed if necessary, but be careful with creating a larger  ap or taking more bone as the mental nerve and artery exit approximately 3/4 of the way down the root. The tooth is then carefully elevated and extracted. Debridement and closure is as above.
Extraction of retained roots
Root fracture is a very common problem in veterinary dentistry. While it seems that removal of retained root tips is a daunting task, with proper technique and training it can be fairly straightforward. The  rst step is to create
a gingival  ap. Depending on the anticipated amount of exposure necessary to retrieve the fragments, this can either be an envelope  ap or a full  ap with one or two vertical releasing incisions.
Following  ap creation, buccal cortical bone is removed with a carbide bur to a point somewhat below the most coronal aspect of the remaining root. If necessary, the bone can be removed 360 degrees around the tooth, but this author tries to avoid this aggressive approach.
Once the root(s) can be visualized, careful elevation with small, sharp elevators is initiated. Once the tooth is mobile, it can be extracted normally. After radiographic con rmation that the tooth is fully extracted, the bone is smoothed and the defect closed.
Oronasal  stula repair
In most cases, the single layer mucogingival  ap technique is suf cient to repair ONFs, especially when done correctly the  rst time. This is the most common surgical treatment used to repair ONFs and therefore will be presented here.
The single layer mucogingival  ap is created with either one or two vertical incisions. Depending on the size and location of the  stula as well as presence of the offending tooth, a horizontal interdental incision may also be necessary for successful repair. Proper design of the mucogingival  ap will allow maximum exposure of the area for extraction of the tooth (if necessary), debridement of the  stula, and critically important tension-free closure.
Incisions are created with a number 15 or 11 scalpel blade. As described previously, the vertical incision(s) were classically started at the line angle of the teeth. A line angle is a theoretic corner of a tooth. When repairing an ONF associated with a maxillary canine tooth, the distal incision is made at the mesial line angle of the
 rst premolar, and the mesial incision is started at the
mesial line angle of the canine (if present). However, it
is not necessary to cut over to a line angle if there is a diastema. If the tooth is already absent, the incisions are made at the mesial and distal edges of the  stula.
When making  ap incisions, adequate pressure should be placed to ensure full thickness of the soft tissue is incised down to the bone. Any vertical incisions should be created slightly divergent as they proceed apically. Divergent incisions allow for adequate blood supply for the newly created pedicle  ap. It is important to choose the location of the incisions to ensure that sutured margins will have adequate bony support and will not lie over a defect.
The mucogingival  ap is gently elevated off the bone using a periosteal elevator.
Approximately 2-3mm of palatal mucosa is also gently elevated/lifted off the palatal bone so that fresh epithelial edges are created. Any margins of the  ap associated with the oronasal  stula should be debrided using a LaGrange scissors or coarse diamond bur to remove 1-2mm of tissue, leaving fresh epithelial edges.
A coarse diamond bur on a high-speed handpiece is used to smooth the edges of the remaining maxillary bone (if necessary) and to remove any epithelial remnants between the  stula and the nasal cavity.
As with any closure in the oral cavity, the key to success is to ensure there is no tension on the incision line. Fenestration of the inelastic periosteum (see previous section on surgical extractions) is performed to increase the mobility of the  ap and allow for a tension free closure. This is accomplished by a combination of sharp and blunt dissection with a LaGrange scissors to ensure the overlying mucosa is not damaged.
The gingival  ap is then placed over the defect so that
it remains in position without being held. Once this is accomplished (i.e. no tension is present), the  ap is ready to be sutured into place.
Further reading: Niemiec BA: Dental Extractions Made Easier. Practical Veterinary Publishing. Tustin CA www.

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