Page 119 - ONLINE PROCEEDING BOOK WSAVA 2017
P. 119

Following  ap creation, buccal bone is removed to a point approximately 1⁄2 the length of the root. Next,
the tooth is sectioned. The mesial roots are separated from the distal by starting at the furcation and cutting coronally. Next, the mesial roots are separated by sectioning in the depression between the palatal and buccal roots. Another way to visualize this is to follow the ridge on the mesial aspect of the tooth. When performing this step, a common mistake is not fully sectioning the tooth. The furcation is fairly deep, so make sure that you have it fully sectioned by placing an elevator between the teeth and twisting gently. If fully sectioned, the pieces will move opposite each other easily.
Following these steps, extraction proceeds as described in the last lecture for single rooted teeth
Mandibular  rst molar
In canine patients, these extractions are further complicated by a groove on the distal aspect of
the mesial root. In addition, the mesial root is often curved. Finally, in small breed dogs, there is commonly a signi cant hook at the apex. Moreover, this tooth is the most common place for an iatrogenic mandibular fracture and it is possible to damage the mandibular nerve and vessels. This is much more likely in small and toy breed dogs, because the roots of these teeth are much larger in proportion to the mandible than large breeds. Bony resorption can signi cantly weaken the bone and predispose to a mandibular fracture. It is advised to
warn clients of these potential complications. Dental radiographs are required to demonstrate the level of remaining bone. Finally, consider referral for these extractions (or possible root canal therapy).
The  rst step when extracting this tooth is to create
a gingival  ap. Classically this is was full  ap with one
or two vertical releasing incisors. However, this author  nds that an envelope  ap is suf cient in virtually
all cases. Following  ap creation, buccal bone is removed. Next, the tooth is sectioned and the extraction proceeds as for single rooted teeth
Maxillary Canine
Maxillary canines are a very challenging extraction due to the signi cant length of the root. In addition, the very thin (less than 1-mm) plate of bone between the root and the nasal cavity often results in the creation of an oronasal  stula.
Vertical incisions are usually necessary for exposure and closure. At least a distal incision should be performed, and performing a mesial and distal incision will allow for increased tissue for closure.
The distal releasing incision is typically created at the mesial line angle of the  rst premolar. An exception exists if the  rst premolar is very close to the canine. In this case, carrying the horizontal component to the mesial
An Urban Experience
line angle of the second premolar is recommended. This is to allow suf cient exposure for bone removal, as the root curves back to over the second premolar.
If a mesial incision is performed, it should be in the diastema between the canine and third incisor. Classically it was made at the line angle of the canine or third incisor. However, in this author’s opinion, the mesial line angle of the canine does not allow suf cient exposure and there is no reason to risk damaging the third incisor and increase surgical trauma. It is critical to fully incise the interdental gingiva to avoid tearing the  ap. This is particularly challenging in the area mesial to the canine. Make sure to cut all the way to the bone. Following the creation of the vertical incisions, the  ap is carefully elevated. If it is not elevating fairly easily, ensure that the interdental tissue is fully incised.
Once the  ap is raised, approximately 1⁄2 of the buccal bone is removed. Make sure to remove some of the mesial and distal bone as the tooth widens just under the alveolar margin.
After the bone removal, elevate the tooth carefully. Do not torque the crown too much bucally as this will lever the apex into the nasal cavity. Once the tooth is elevated to
a point of being very loose, it can be carefully extracted with forceps. The bone is then smoothed with a coarse diamond bur.
Closure is initiated with fenestration of the periosteum. When this is performed the tissue should stay in position over the defect. If it does not, tension is present and
the  ap will dehisce. It is critically important to relieve all tension if an oronasal  stula is present. Close the  ap starting at the corners to avoid having to start over if it does not close correctly.
Mandibular canine
These are quite simply the most dif cult extraction in veterinary dentistry. This is due to the length and curve of the root, the hardness of the mandible, and the minimal bone near the apex. Furthermore, extraction
of this tooth will greatly weaken the jaw and further predispose the patient to an iatrogenic fracture either during or after surgery. This tooth often holds the tongue in, and therefore it is not uncommon for the tongue to hang out following the extraction. Finally, the patient loses the function of the tooth. Therefore, it is strongly recommended to avoid extraction of this tooth. Referral for root canal therapy is a much better solution, if possible.
Some authors recommend a lingual approach to this extraction since less bone needs to be removed as to tooth curves lingual apically. However, this author prefers the standard buccal approach. This is because superior exposure is afforded and the  exible buccal mucosa allows for easier closure.
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