Figure 1: A ½ surgical carbide round bur is used to create a moat around a root tip and to create a window in the bone lateral to the root. Note the tongue depressor on the lingual surface of the tooth to protect the sublingual tissue and the use of thumb forceps to retract the flap and avoid soft tissue damage from the bur.Photo courtesy John Lewis It’s been approximately six years since I discussed in my column the approach to what may be the most common complication of dental extractions: retained root tips.1 Does the subtle “snap” heard during elevation of a tooth send shivers down your spine? I am here to tell you the snap happens to all of us. However, when you learn how to deal with it, it’s no longer scary. Some of the veterinarians who attend our CE wet labs devote a large portion to creating and retrieving broken root tips to practice their approach in a stress-free environment. I encourage you to try to change your mindset when performing extractions. Next time you hear that snap, remember this is a common complication. In fact, instead of calling it a “complication,” let’s call it an “opportunity”—an opportunity that provides visualization of the remaining root structure without the bulky crown being in your way. This outlook is easier to embrace when you’ve learned a relatively foolproof plan to remove stubborn root tips. In this column, I’ll describe my approach toward removal of root tips. Radiographs are worth the investment First, I’ll make a recommendation: if you do not have the ability to perform dental radiographs, it’s time to make the investment. Dental radiography will allow you to predict which tooth roots will break when you attempt to remove them. If there is loss of the periodontal ligament space (the black line that separates the tooth and its surrounding bone), there is likely ankylosis of the root. Think of ankylosis as a spot-welding of the tooth to its surrounding bone, resulting in one of three scenarios: 1) occasionally, the crown-root segment will be retrieved intact despite ankylosis, 2) a portion of the ankylosed root will stay attached to the bone as the coronal portion of the root is retrieved, or 3) the ankylosed bone will be delivered attached to the root. The latter scenario occurs most often when the thin layer of bone on the palatal surface of the maxillary canine tooth is ankylosed to the tooth. Sometimes, elevation of the root is accompanied by bone, which can also disrupt the thin layer of nasal epithelium that separates the alveolar bone from the nasal cavity. Dental radiography also allows for preoperative diagnosis of hypercementosis of the roots. Cementum is the hard tissue covering the root surface. As a patient ages, more cementum may be laid down on the outer surface of the root, particularly in older cats. Hypercementosis is actually a histological diagnosis, but when you see the radiographic appearance of a bulb on the apical portion of a root, hypercementosis is likely playing a role. This makes extractions challenging since the apical widening of the root may prevent delivery of the root even if a window is created lateral to most of the root structure. The bulb on the end of the root is analogous to the proverbial hand that barely fits through a small hole to grab something; once the hand forms a fist, it can no longer be pulled back through the same opening. Being able to identify ankylosis or hypercementosis on radiographs prior to surgical exodontics will temper expectations of the operator. In fact, after you have looked at enough dental radiographs, you can fairly accurately predict which roots will break off, eliminating the surprise of the “snap” when it happens. Having access to dental radiography will also allow you to know when there is no root to retrieve. Especially common with cats, but also occurring in dogs, root replacement resorption can be so profound that the entire root may be resorbed, giving the radiographic appearance of a “ghost root”—a wispy radiographic remnant of the root structure, with a density approximating that of the surrounding bone rather than the normally much dense root when compared to the surrounding alveolar bone. Evaluating for root replacement resorption is important. Without dental radiographs, you may be trying to remove a root that is no longer present, which may result in iatrogenic mandibular fracture, especially when speaking of the mandibular canine teeth in cats. When a root tip fractures during surgical extraction, the first step in its retrieval is obtaining greater exposure. If a pedicle flap has not already been raised, extend releasing incisions far enough apically to allow for full exposure of the bone containing the root tip. After raising a mucoperiosteal flap, remove bone lateral to the root tip with a small round bur, such as a ½ round surgical length carbide bur on a water-cooled high-speed handpiece, which allows for subtle removal of bone lateral to and circumferentially around the tooth root. There is a ¼ size of round carbide bur, which is the smallest round bur available, but finesse should be used when utilizing this bur, as it may fatigue, and the head of the bur may detach from the shaft. A small bur is important, as root tips are adjacent to tooth roots of other teeth and near neurovascular structures, which, if encountered, the small bur will cause less damage and less bleeding than a larger round bur. After a window of bone has been removed from the lateral surface of the root, a thin moat is created circumferentially around the root with the bur to allow for a dental elevator or root tip elevator to be placed into the periodontal ligament space on the lingual/palatal surface of the root.2 With gentle lateral pressure, the root is displaced from its alveolus and delivered through the lateral bone window. Root tip forceps or a small pair of needle drivers may be helpful to grab onto the root tip once loose. Care should be taken to avoid pushing the root tip into the mandibular canal or the nasal passage. If this happens, it should be retrieved at that time or referred to a specialist for future removal. This complication can be avoided if forces are generated laterally instead of in the direction of the root apex. One instrument that works great in my hands to retrieve roots that have a moat created around them is the small end of an EX-9 periosteal elevator. Holding the instrument like a pencil, the thin, disc-like elevator can be placed on the palatal/lingual surface of the root, and a gentle twist allows for delivery of the root from the bone window created lateral to the root tip. Always take a postoperative radiograph to document the root has been removed. Other tools Two other tools I have been using lately to decrease the chance of root breakage are: 1) dental luxators, and 2) piezosurgical unit. Although I was exposed to the use of dental luxators almost 20 years ago, I have a newfound love for a new set of interchangeable dental luxators that are super thin and act like miniature scalpel blades within the periodontal ligament space. Thin piezosurgical tips can act as a piezotome to free up the periodontal ligament and increase the chances of the root being retrieved intact. Use of the high-speed handpiece can result in significant bleeding, especially if a large bur is used or if not being careful in the apical portions of the root when creating the bone window or the moat. If significant bleeding happens, pack the area with a gauze sponge, take a deep breath, and apply digital pressure for three minutes. Avoid the temptation to remove the gauze to check the status of the bleeding every 30 seconds. Make a mental note of what area of the moat the bleeding arose from and avoid using the bur in that area after the bleeding subsides. John Lewis, VMD, FAVD, DAVDC, practices dentistry and oral surgery at Veterinary Dentistry Specialists and is the founder of Silo Academy Education Center, both located in Chadds Ford, Pa. References 1 https://www.veterinarypracticenews.com/how-to-remove-stubborn-tooth-roots/ 2 Woodward TM. Extraction of fractured tooth roots. J Vet Dent 2006; 23(2): 126-129.
