It is prudent for cat owners to keep a regular check of their cat's mouth and seek veterinary attention if they notice anything amiss. Things to look for include;
Some common dental problems cats encounter include
Gingivitis is a general term for inflammation of the gums (gingiva). It may be localised to one tooth, or may be widespread affecting numerous teeth.
Gingivitis is the mildest form of periodontal disease. Infection and inflammation spreads from the gums to the ligaments and bone that support the teeth. Left untreated, loss of support causes the teeth to become loose and eventually fall out. 
Symptoms include bad breath, drooling, red or swollen gums, gums which bleed easily.
Your veterinarian will perform an examination of your cat's mouth for signs of gingivitis such as a build up of tartar, red and inflamed gums, bad breath.
Full mouth x-rays may be recommended to determine the extent of the disease.
This depends on how far advanced the gingivitis is. Early cases of gingivitis which haven't progressed far may possibly be treated at home with regular dental cleaning. Descaling to remove tartar build up will be performed in more advanced cases.
If addressed immediately, gingivitis is reversible, if it is left to progress to periodontal disease, damage is irreversible.
Endodontic disease refers to any inflammation of the pulp, known as pulpitis. Pulpitis can be reversible or irreversible. In the case of reversible pulpitis, once the cause of inflammation is removed, the pulp returns to it's healthy state. Left untreated, irreversible pulpitis occurs, resulting from severe inflammation of the pulp, which is extremely painful. Over time, the pulp becomes necrotic (dies), and pain subsides.
Symptoms include pain, discoloured (grey) tooth, abscess with swelling and or a drainage tract, reluctance to eat.
Treatment involves either root canal or extraction.
Periodontal disease (also known as gum disease) is the most common oral disease to affect cats.
Plaque is a sticky 'biofilm' composed mostly of bacteria (predominantly streptococcus) which forms on the teeth. If proper dental care isn't followed, over time, plaque, saliva, minerals and food debris mineralise, causing tartar (also known as calculus). Tartar is yellowish in colour and is seen along along the gum (gingiva), where it meets the teeth. This leads to inflammation of the gums. At this stage, proper treatment can reverse the problem. Left untreated the tartar begins to collect under the gum line. Toxins produced by the bacteria in the plaque can irritate the gums, which in turn stimulates an inflammatory response, it is a combination of toxins released by the bacteria, and the inflammatory response which causes destruction of the supportive structures (gingiva, alveolar bone, cementum and periodontal ligament). Gums separate from the teeth, forming pockets (spaces between the teeth and gums) that become infected.
Tooth abscesses can be caused by advanced dental disease, FORL and tooth fractures all of which can introduce bacteria to the roots of the teeth leading to the formation of an abscess.
Symptoms of tooth root abscess include reluctance to eat, bleeding from the nose and facial swelling. Left untreated the infection may spread to other parts of the oral cavity, possibly causing a drainage wound on the face.
Diagnosis is made upon visual examination and dental x-rays. Treatment involves tooth extraction, flushing of the affected area and antibiotics.
Feline ondoclastic resorptive lesions (FORL)
Also known as resorptive lesions, feline resorptive lesions, neck lesion, cavities, cervical line lesions and invasive resorptions, these painful lesions are one of the most common dental problems in cats. There are three types of lesion;
- Internal resorptive lesions
- External ondoclastic resorption
- Cervical line erosions
It is estimated that 20 to 67% of cats have one more more of these lesions. 
Lesions usually begin under the gingival margin and are caused by odontoclasts which are cells who's role is to absorb the bone and roots of deciduous (baby) teeth. In the case of FORL, these cells reabsorb the adult teeth.  Lesions typically occur under the gumline, making early identification difficult. Premolars are most often affected. Your cat will display extreme sensitivity if these lesions are touched.
Symptoms often include salivation, reluctance to eat, cherry red gums.
Diagnosis is via visual examination of the teeth and dental x-rays and the use of a dental probe.
Treatment depends on the severity. There are 5 classifications for lesions with stage 1 being the mildest and stage 5 the most severe. In mild cases, your veterinarian will apply a fluoride varnish or sealant on the teeth. More severe cases will require extraction of the affected tooth/teeth.
The cause of FORLs isn't known, therefore there is currently no way to prevent the condition.
Also known as lymphocytic-plasmacytic gingivitis-stomatitis-pharyngitis (GSPC), stomatitis is a common disease causing chronic inflammation and ulceration of the soft tissues in the mouth. There is no definitive cause but it is felt to be multifactoral with an immune mediated component, possibly representing a hypersensitivity to oral bacterial antigens.  Other possible factors include oral irritants, some viruses, immunodeficiency diseases, metabolic diseases, drug reactions etc.
Symptoms include reluctance to eat, anorexia, weight loss, bad breath, excessive salivation, gums which bleed easily.
Stomatitis is diagnosed by the appearance of the affected tissues.
Oral biopsy may be performed to determine if the lesions are caused by other diseases such as neoplasia (cancer) or eosinophilic granuloma complex. Biopsy should reveal a dense infiltration of lymphocytes and plasma cells.
X-ray may be performed to check the condition of the dental roots and bones. Stomatitis often affects the molars and pre-molars more than the canines and incisors.
Stomatitis is very difficult to treat and response to many treatments are poor. If the cause can be identified, then specific therapy can be aimed at treating or managing the problem, as indicated.
Professional cleaning of the teeth under anaesthesia is necessary, as periodontal disease may cause or at least contribute to stomatitis.
Antibiotics given long term may be of benefit.
Cats unresponsive to treatment may require extraction of all teeth behind the canines to provide long term relief. This may sound extreme but your cat will get along just fine without these teeth with the assistance of a softer diet.
Daily cleaning of your cat's teeth at home is required to keep plaque under control.
 Cat Health Encyclopedia - Edited by Lowell B. Ackerman.
 Recognition of Feline Oral Lesions
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