THE SECRET WORLD OF THE FELINE MOUTH Paul Q. Mitchell, DVM, DAVDC
Introduction Feline dentistry is a field with many frustrations and many unanswered questions. There are still mysteries surrounding the major feline oral diseases such as Stomatitis and Tooth Resorption. Though the etiologies and hence, the definitive treatments for these perplexing conditions elude us at this point, one thing is certain: these are painful conditions! Cats have truly unique problems and they often demand a unique approach to the diagnosis and treatment of those problems. Intraoral radiography and smaller more delicate instruments are essential for assessing and treating the feline mouth. Using basic information and skills about oral and dental disease can help your feline patients have the best oral care possible. Intraoral Radiology Radiology is a vital tool in veterinary dentistry, especially in cats to assist in diagnosis, treatment planning, and monitoring of oral disease.1 Being able to radiographically examine oradental structures helps to determine if abnormalities exist, including variations in development (missing or aberrant teeth) or acquired diseases that may affect the bone and tooth structure (periodontitis, endodontic abscess or tooth resorption.)2 When determining the possible treatment for problems such as tooth resorption, endodontically compromised teeth and periodontal disease, radiology can help the practitioner make a more accurate assessment. Preoperative radiographs can help monitor extractions by revealing abnormal root structures, impacted teeth, and ankylosed or resorbing root material. Post-operative films check treatment success. Endodontics requires several films during the procedure to evaluate routine treatment and reveal complications. Chronic Alveolitis / Osteitis Individuals with chronic periodontal disease may exhibit some osseous changes. This is especially prominent in the maxillary canines of older patients, where a large, bulbous alveolus is often accompanied by an extruding tooth. It looks like the body is trying to rid itself of an annoying tooth, and if you have to assist in its removal, do so with care. Extraction of the tooth is typically easy, but closure of the gingiva can be quite challenging. Raise a gingival flap, do alveoloplasty to recontour the bulge of bone, and suture without tension. Feline Stomatitis When the gingiva is inflamed and it does not resolve following prophylaxis and home care, progressing to a severe chronic inflammatory condition afflicting the entire oral cavity, Stomatitis is often diagnosed. Extensive ulcerative and proliferative gingiva and mucosa with signs of excessive salivation, halitosis, decreased appetite and weight loss are often accompanied by histological presence of lymphocytes and plasma cells, as well as a frequent polyclonal hypergammaglobulinemia.3 The term Stomatitis is used to cover a wide range of inflammatory oral conditions, and each patient should be treated individually depending on the extent of their disease and response to treatment. While a generalized stomatitis may have a variety of possible contributing factors, including Gram-negative anaerobes, calici virus, FIV or FeLV and other chronic diseases, complete patient assessment will help in treatment planning. Any of these inflammatory processes should always be treated with a complete dental prophylaxis and associated home care (as much as the patient will allow). Antibiotics to help control the plaque bacteria are often employed in both immunosuppressive diseases and hyperresponsive immune syndromes, but should not replace oral hygiene. Diagnosis of the viral infections will help determine a prognosis, and general supportive care with adequate nutrition and supplementation is desired. Monitoring of root and bony pathology with radiographs helps keep the practitioner informed of ongoing progression. The various signs pointing to the possible immune dysfunction (hypergammaglobulinemia, plasma cells and lymphocytes) of the specific stomatitis syndrome leads to the presumption that the excess activity of the body's immune system itself is contributing to the extensive damage. Those individuals tend to be "plaque intolerant" and yet complete plaque avoidance is seldom possible. Non-surgical therapy has historically included
corticosteroids for immunomodulation and/or antibiotics for bacterial control. Care should be taken with these regimens, as they are not great long-term solutions and the owner should be informed of any possible side effects. Other immune modulators, as well as hypoallergenic diets, have been tried, with varying results on an individual basis. In many severe cases, caudal or full mouth extractions are often necessary. Where multiple extractions have not completely resolved the problem, laser therapy has been used as well, with anecdotal information about the effectiveness. The practitioner must keep in mind that not all cases are currently curable or even controllable. Tooth Resorption One frequent finding in cats is the presence of tooth resorption (previously referred to as feline odontoclastic resorptive lesions or FORLs). While the exact pathogenesis and etiology are not known, these defects tend to start at or just below the gingival margin.4 The premolars and molars are most commonly involved, on the lingual or the buccal surface. The presence of reddened gingiva growing onto the crown of a tooth should be a warning sign of a possible lesion hidden underneath.. The process seems to be progressive, often including many teeth in different stages of involvement and can be exquisitely painful. Extraction is the treatment of choice in almost all cases of recognizable tooth resorption with communication to the oral cavity. Radiographs are essential to reveal advanced root lesions, some that may be more severe than external signs indicate, and to lead the practitioner to the correct extraction technique. Feline Extractions To be able to perform feline dentistry well it is necessary to extract cat teeth with precision and delicacy. Even the healthiest of cat teeth are fragile and easily broken, not to mention those teeth weakened by resorption. To provide feline patients with the best possible oral surgical care, it is necessary for the veterinarian to constantly improve upon delicacy, precision, finesse and patience. Though there are finer instruments, intraoral radiography and magnification available, surgical technique still plays the most important part in success. Feline extractions should not be performed without intraoral radiography. It is only with accurate visualization of the root structure and surrounding bone integrity that proper treatment decisions can be made. So much of the success of an extraction depends upon the condition of the root and the condition of the bone and periodontal ligament that constrain it. Without this information the dental operator is only guessing at the best course of action and in some cases may be headed down a very unrewarding path. If a tooth with tooth resorption has a root that is resorbing, then that tooth may actually be better off treated by amputation of the crown with intentional retention of the resorbing root(s). A study has shown that with proper case selection, crown removal, alveoloplasty, and suturing, problems were seldom encountered with these resorbing roots.5 In these situations it is necessary to remove all of the enamel and smooth the alveolar crestal bone with a round ball bur on a high-speed handpiece as well as properly suturing the gingiva with an appropriate flap. Another great aid to feline extraction is the use of magnification. Enlarging the teeth and illuminating them properly will greatly enhance any oral surgery to be performed. Magnification comes in many types of eyewear at varying costs. It is not necessary to spend $1000 to improve the work that was previously done with the unaided eye, but quality of optics, clarity of the image and depth of field are better with the higher end magnifications and surgical loupes. There is also a range of magnification powers available, but it is generally recommended to stay within 2X to 3.5X for veterinary dentistry. Finer, smaller instruments are necessary to perform quality feline dental extractions. Many instrument manufacturers are now carrying these root elevators, periosteal elevators, root tip picks and dissecting scissors that were previously not available to the veterinary market. It is so important to have instruments that are not mere adaptations from human dentistry, but rather instruments that are purpose built for the smaller, more delicate teeth of cats. Cat teeth in most cases demand more deliberate attention to surgical extraction technique than do dog teeth. Mucoperiosteal flap creation, buccal alveolar bone removal, multirooted tooth sectioning, root elevation and flap closure all require a more exacting touch to perform successfully. More precise instrumentation
will help, but all throughout the extraction process the operator must treat the fragile root or roots with care to prevent further complications, such as root fractures. Perhaps the biggest reason that feline tooth roots break is that too much force is applied too far coronally. To alleviate this problem there is no more helpful instrument than the high-speed handpiece. Feline extractions should not be attempted without a high-speed handpiece and a round ball bur. This is an indispensable instrument for the precision removal of bone, sectioning of multirooted teeth and shaping of the coronal tooth. While alveolar bone removal and tooth sectioning are similar in cats to that which is performed in dogs, the deliberate shaping of the crown is something optional in dogs, but nearly essential in cats. It must always be remembered that the judge of success of the tooth extraction process is not the condition of what is removed, but rather the condition of what remains within the mouth. To spare the oral cavity and the dental operator as much trauma as possible the teeth may be altered in almost any way that facilitates their removal. By reducing the crown height of cat teeth as well as removing the cervical bulge of the crown, it is possible to create a tooth shape that is easier to extract. The resultant tooth permits easier direct access to the periodontal ligament space with the root elevator, while at the same time preventing leverage force on the crown. If roots do break, as they often will, the urge to use the high-speed handpiece to “drill out” or atomize the root(s) must be subdued. Atomization typically does one of two things; it either removes too little of the retained root, leaving root shards to potentially cause future problems, or it removes too much material, including the surrounding bone. If the periapical bone is removed in the mandible, there is a great risk of damaging the neurovascular bundle running within the mandibular canal. If the periapical bone is removed in the maxilla, there is a great risk of entering the nasal cavity and creating an oronasal fistula. When a root fractures the immediate reflex of the operator should be to take a mental step back and obtain an intraoral radiograph to assess the amount and location of the remaining root material. The high-speed drill should be used, but for removal of more buccal bone in an apical direction. The flap can be retracted further apically while the additional buccal bone is removed to gain better visualization and isolation of the retained root tip. Once the root tip has been careful exposed, a fine-tipped instrument known as a root tip pick may be used to carefully tease the root tip away from the alveolar walls. The root tip pick is much more delicate than a root elevator and it forces the operator to use more finesse. It should be used similarly to the nut picks used to retrieve broken bits of nut from inside walnut shells. The force of the pick should be up an out of the alveolus, instead of the apical pressure that a root elevator requires. The operator must guard against forcing a retained root tip further apically into the mandibular canal or nasal cavity. Patience is often rewarded with a whole root tip delivery from the alveolus, assuring the operator that the root removal is complete. References 1. Robinson, J. Gorrel, C. Oral examination and radiography. Manual of Small Animal Dentistry (D.A. Crossley, S. Penman, eds.). BSAVA, Gloucestershire, UK. 1995; pp 35. 2. Verstraete FJM et al. Diagnostic Value of full-mouth radiography in dogs. AJVR; 59(6): 686-691; 1998 3. Lyon KF. Feline LPS associated with Monoclonal gammopathy and Bence-Jones proteinuria. J Vet Dent, Mar 1994; 11(1): 25-28. 4. Okuda A, Harvey CE. Etiopathogenesis of feline dental resorptive lesions. In: Harvey CE, ed. Feline Dentistry. Vet Clin North Amer Small Anim Pract. 1992; 22: 1385. 5. DuPont G. Crown amputation with intentional root retention for advanced feline resorptive lesions: a clinical study. JVD 1995; 12: 9-13.