Structure and Function of the Tongue, Teeth and Mouth in Cats
Disorders of the tongue may occur as isolated conditions, or may be involved with other disorders of the mouth. When the tongue is diseased, the animal may be reluctant to eat, may show abnormal chewing movements, may drool excessively, and have a foul odor or bloody discharge from the mouth.
What Are Some Diseases of the Tongue, Teeth and Mouth?
Glossitis is inflammation of the tongue. It may occur alone, or be associated with a generalized inflammation of the soft tissues of the mouth (stomatitis), inflammation of the gums (gingivitis), or of the lips (cheilitis). Causes of glossitis and stomatitis in the cat include the ingestion of foreign bodies (e.g. sewing needles, string, rubber bands), exposure to chemicals and caustic agents, and irritating plants. Infectious diseases, particularly the viruses that cause upper respiratory infections, can cause inflammation and ulceration of the tongue. These viruses include feline herpesvirus-1 and feline calicivirus.
Ulcerations can develop on the tongue in association with systemic diseases such as kidney failure and certain cancers of the body. Ulcerations can also occur with a peculiar disease of cats called eosinophilic granuloma or rodent ulcers. Collagen degeneration and the infiltration of white blood cells called eosinophils lead to ulceration of the tongue, lips and gums. The cause of this disease is not entirely understood.
Tumors or neoplasia may also occur on the tongue. The most common tumor of the tongue in cats is a malignant cancer called squamous cell carcinoma. Other types of tumors are rare, but include lymphosarcoma, and mast cell tumor.
Trauma may also occur to the tongue. Injuries may include burns, lacerations, puncture wounds, bite wounds, etc.
A number of dental diseases occur in the cat. Such diseases may involve only the tooth, only the gums, or the supporting tissues of the teeth. Signs associated with dental disease include a foul odor to the breath (halitosis), difficulty chewing, pain upon chewing, discoloration of the teeth or gums, discharge or bleeding from the gums or mouth, and deformity of the teeth.
Abnormal numbers of teeth and retained deciduous may occur. Brachycephalic cats with very short, blunt faces may have fewer teeth and shorter jaws that other cats. Retained deciduous teeth are baby teeth that fail to fall out on their own. Any baby tooth that persists beyond six months of age is considered abnormal.
Periodontal disease is the development of plaque or tartar on the teeth, with secondary inflammation of the gums (gingivitis) and other supporting structures (periodontitis). Dental plaque is a yellow/gray/green substance that coats the surface of the tooth. It is composed of bacteria, proteins from saliva, and various other substances. Plaque is a major problem for animals because they do not routinely brush their teeth. Untreated plaque leads to infections around the teeth and potentially the loss of affected teeth.
Resorptive lesions are small holes that develop in the crowns of the teeth of cats. The hole usually starts where enamel meets cementum, right at the gum line. The hole may enlarge until enamel and dentin are lost, and pulp is eventually exposed. These small holes or resorptive lesions may result in loss of the tooth, gingival infections and pain. They occur most often in older cats, and some affected cats are positive for the feline leukemia virus.
Tooth root abscesses can occur in any tooth, but are usually associated with the premolar or molar teeth. They occur more often in upper teeth, than in lower teeth. They are characterized by the accumulation of pus around the root of the tooth. When upper teeth are involved swelling may occur on the face, just beneath the eye. If the abscess ruptures to the outside, a small draining hole may be seen on the face.
Trauma to the teeth is common in some animals. Some teeth become broken or cracked. Other teeth wear down over years of continuous use. Abrasions may also occur from chewing sharp objects. Clinical signs associated with dental trauma vary, depending upon whether the pulp cavity is exposed. Exposure of the pulp cavity is often painful.
The most common disorders of the mouth include stomatitis and tumors. Disorders of the salivary glands also affect the mouth. Clinical signs associated with these conditions including difficulty eating, reluctance or refusal to eat, halitosis, drooling, bleeding from the mouth, retching or gagging, pawing at the face, rubbing the face, fever and lethargy, and sometimes nasal discharge.
Stomatitis is an inflammation of the oral mucosa (lining of the mouth) and other soft tissues of the mouth. It has many potential causes, including all the causes of glossitis outlined above. Bacterial (e.g. spirochetes) and viral (e.g. feline leukemia virus, feline immunodeficiency virus) infections may cause stomatitis. Some bacteria that are normal residents of the mouth may take advantage of inflammation in the mouth to create significant infections. In addition, cats may develop a peculiar disease called lymphoplasmacytic stomatitis that arises for unknown reasons. It produces a chronic inflammation in the mouth characterized by the infiltration of white blood cells (lymphocytes, plasma cells) into the soft tissues.
Tumors of the mouth are often malignant in cats and usually involve the soft tissues of the mouth. Tumors of the bones of the mouth are also possible, but occur less often.
A ranula is a swelling that develops under the tongue from the formation of a cyst of the sublingual salivary gland. The swelling may become large and inflamed, causing the tongue to be pushed upwards or to the side. The cat may have difficulty eating, may drool or exhibit excessive licking, and may act painful when the mouth is opened or manipulated.
What Types of Diagnostic Tests Are Used to Evaluate the Tongue, Teeth, and Mouth?
Veterinarians use a number of different tests to evaluate the tongue, teeth and mouth. A thorough oral examination using an external light source is the single most important test in evaluating structures in the oral cavity. Many times tranquilization or even anesthesia is necessary for a thorough evaluation of all of the oral structures. Oral examination is followed by a thorough physical examination in order to detect other signs of illness or organ involvement.
Depending upon the clinical signs, the age and overall health of the cat, and the findings on oral and physical examination, other specific tests may be recommended by your veterinarian. Tests designed to evaluate disorders of the tongue, teeth and mouth include the following:
Swabs of the mouth may be taken for cytology (microscopic examination) and bacterial staining and culture. Tests may also be performed to detect certain viruses and fungal agents.
Blood samples may be submitted for a complete blood count to search for signs of infection, for a biochemistry profile to look for evidence of other organ diseases, and for certain infectious diseases such as feline leukemia virus and feline immunodeficiency virus.
X-rays of the skull, jaw, and teeth may be helpful. Such X-rays require that the animal be placed under general anesthesia.
Biopsies of abnormal tissue, masses may be required to reach a definitive diagnosis.
Some lesions are only diagnosed with surgical removal and exploration of the abnormal area in the mouth.