Surgical approach to root tip retrieval (Proceedings)
Extractions in dogs and cats are categorized as simple and surgical. Simple extractions are performed where alveolar bone removal is not necessary to facilitate successful extraction. Examples include deciduous teeth, mobile teeth and incisors. Surgical extractions are utilized to minimize anesthesia time and decrease operator fatigue. Proper technique includes creation of a mucoperiosteal flap to expose the alveolar bone and subsequent root exposure to facilitate extraction. This also allows for debridement of diseased bone and soft tissue. Keep in mind that a mobile tooth means that surrounding tissue is diseased and must be removed. Therefore a surgical approach is often necessary.
One common indication for extraction is the fractured or intrinsically stained tooth where endodontic therapy is not feasible or desired. With the exception of most incisors these generally require a surgical approach. A tooth compromised from periodontal disease may be mobile however even mobile teeth can result in root fracture if careful technique is not utilized. Slow sustained luxation is paramount in maintaining root integrity throughout the extraction process. Successful extractions are more of an art than a science. Knowledge of root anatomy of different teeth in the dog and the cat, diligent practice and preoperative radiography are paramount in avoiding root fractures during extraction. Even then root fractures are inevitable in some cases.
Surgical extractions make up a wide majority of oral surgery procedures routinely done in practice. Indications are few and relatively specific. Familiarity with periodontal anatomy and mucoperiosteal flap design is paramount when performing these procedures.
Surgical technique should be followed to ensure optimal outcome and to avoid potential complications. The best way of avoiding root tip retrieval is prevention by utilizing proper technique.
Envelope flaps should be used when possible; however vertical releasing incisions may be used to provide additional visualization and exposure when needed. Soft tissue manipulation should be as atraumatic as possible. Mucosa may be manipulated with fingers or a retention suture eliminating the need for repeated crushing trauma with thumb forceps. Sharp periosteal elevators are required to maximize mobilization of the periosteum from the underlying bone. Once attached gingiva is removed the remaining alveolar mucosa is easily elevated exposing the juga.
The volume of vestibular bone removed depends upon the tooth type and the relative health of the periodontal tissue. Bone removal should start at the marginal bone and move apically. Large round burs are ideal and size is dependent upon patient and tooth size. Manipulation of the flap with a periosteal elevator aids in apical retraction and protects the tissue from the bur. Smaller round burs or in larger patients, crosscut tapered fissure burs may then be utilized to remove bone adjacent to the tooth root to create a “moat” for luxator placement. Winged elevators can then be used to lever the tooth against the bone facilitating extraction. Luxators should remain engaged for 15 seconds to allow adequate time to fatigue the periodontal ligament. Once mobile, extraction forceps are utilized in a cork in a wine bottle approach to complete tooth removal.
Why do roots fracture during extraction? The answer is generally improper technique and operator inexperience however compromised roots often fracture. Ankylosis, root resorption, malformation and previous traumatic root compromise are examples where root tip retrieval becomes necessary in many cases.
The approach to root tip retrieval is additional exposure in most cases. Additional exposure on the vestibular aspect of the root is the most common. Take for example surgical extraction of a maxillary fourth premolar. A mucoperiosteal flap is utilized to partially expose the vestibular roots. Unfortunately the mesial root fractures and 2 mm of the apical root is left within the bone. Periosteal elevation may be needed to expose additional bone apically. Additional bone can then be removed and a small round bur utilized to outline the tooth by creating a mote in the surrounding bone. What is left is a root that has bone only on the palatal side and generally extraction is by simple luxation.
A second approach to root tip retrieval is via circumferential bone removal. This is sometimes necessary when vesitibular bone removal would result in significant compromise as might be the case in the mandibular first molar in a small breed dog or the cat (especially the distal root in this species) Vestibular bone is often very thick consequently a small round bur may again be utilized to create a mote 360 degrees around the tooth. Depth of the bone removal depends on radiography and experience to avoid entry into the mandibular canal.
Root tips can be forced into the mandibular canal, nasal cavity and maxillary sinus. Removal at this point should only be attempted by a very experienced practitioner and is likely best referred. Referral should be immediate to ensure simple access and visualization. If the alveolus is allowed to close retrieval becomes much more difficult.
Following successful extraction the alveolus is curetted to remove diseased soft tissue, bone and other debris and then flushed with saline. A blood clot is left within the extraction site or in some cases a synthetic bone substitute may be used to fill the void. A postoperative radiograph is obtained to ensure complete removal of root and bone from the alveolus. The marginal gingiva is freshened leaving normal mucosa and the defect closed with simple interrupted sutures placed 2-3 mm apart.
Root tip retrieval requires operator experience, proper technique and the right equipment. Everyone that chooses to provide proper dentistry services should be comfortable extracting root tips. Avoidance is desirable however the inevitability of fracture behooves us to be skilled in removal of root tips when root fracture occurs. The lecture will outline proper extraction and root tip retrieval principles and techniques in a case format.