Periodontal comes from the Greek peri-, meaning around, and odous, meaning tooth.
Dog and cat teeth all have the same basic structure. The crown, which is covered with enamel, is above the gum line, or gingiva.

Dental ServicesUnderneath the enamel of the crown is the dentin, which extends below the gum line to form the tooth’s root. The inner portion of the dentin is the pulp chamber, or root canal. It contains the blood and nerve supply for the tooth.

Below the gum line, the dentin is covered by a thin layer of cementum, which is attached to the tooth socket by dense connective tissue known as periodontal ligaments. The gingiva, part of the mucous membrane of the mouth, attaches to underlying alveolar bone, which anchors the tooth in the jaw.

Veterinarians see periodontal disease more often than any other infection in veterinary practice. Between 75% to 80% of dogs aged 2 years and older are affected, and periodontal disease is the leading cause of tooth loss in dogs.

Periodontal disease begins as gingivitis, an inflammation of the gingiva, or gums. Gingivitis is reversible if treated promptly. Left unchecked, the condition advances to periodontitis and affects the periodontal ligaments and alveolar bone.

Awake Dentals

TLC Animal Hospital offers anesthesia-free dental care to dogs and cats. Ask our veterinarians for more details.


Halitosis, or bad breath, is often the first sign that an animal has periodontal disease. Because halitosis is common, this sign of disease often causes no concern to owners. In fact, halitosis associated with early gingivitis is so common that many owners don’t recognize their dog’s bad breath as abnormal.

Proliferating bacteria, food particles and saliva accumulate at the gum line, forming a slimy substance called plaque on the teeth. Plaque is the perfect growth medium for bacteria. If plaque is not removed, it mineralizes and hardens into calculus, or tartar, which is very hard to remove.

Tartar encourages bacterial growth, and bacteria eventually invade the sulcus, the crevice between the gingiva and the tooth’s root. The gingiva regresses, and as periodontal structures detach from the root, periodontal pockets form. These pockets may be 4 mm to 8 mm deep, weakening the tooth’s support and exposing its roots. Finally, the tooth loosens and falls out.

Periodontal abscesses and bacteremia, which can be the result of neglected periodontal diseases, can lead to heart problems, liver and kidney failure, and bone marrow depression. Weight loss and poor physical condition are evident in affected animals.


Species, age, breed and anatomy all influence an animal’s susceptibility to periodontal disease. Dogs are more prone to periodontal disease than cats. Older animals are more susceptible than younger ones. In general, periodontal disease is more severe in older animals because it has been causing irreversible damage over a number of years. Older animals with multiple health problems are more likely to suffer from periodontal disease.

Breed Factor

In dogs, breed also affects the animal’s susceptibility to periodontal disease. Brachycephalic (short-headed or broad-headed) breeds, such as pugs, bulldogs and boxers, are particularly vulnerable. Because of their pushed-in faces, they often have malocclusion, which hampers mechanical cleaning of the teeth as the dog eats. The smaller, crowded jaws of toy breeds also make them susceptible to periodontal disease. Breeds with longer jaws, such as Dobermans and collies, benefit from the cleaning action of chewing and are therefore more resistant to periodontal disease.

Other Factors

Tooth anatomy also makes some teeth more vulnerable to periodontal disease. Molars, which have multiple roots, are more susceptible than canines and incisors, which have single roots. Exposure of the furcation, where the roots fork, indicates advancing disease. The tooth surface facing the cheek, called the buccal surface, is more commonly diseased than the lingual surface, which faces the tongue. Food particles, saliva and bacteria are more likely to accumulate on the buccal surface.

Tooth location affects periodontal disease, too. The fourth premolar is a likely candidate for disease because a nearby salivary gland secretes chemicals and minerals, causing a buildup of tartar. Teeth in the maxilla, the upper jaw, are more often affected than teeth in the mandible, the lower jaw.

Bacterial Involvement

As periodontal disease progresses from gingivitis to periodontitis, the bacterial population shifts from gram-positive, aerobic streptococci and staphylococci to gram-negative, anaerobic bacteria. Synergy between different bacteria promotes infection. The pioneering aerobes consume large amounts of oxygen, producing an ideal environment for anaerobes. Gram-positive anaerobes, such as Actinomycesand Peptostreptococcus species, deplete the oxygen supply and produce toxins that pave the way for more virulent gram-negative anaerobes, such as Bacteroides and Fusobacterium species. Finally, gram-positive anaerobes release stimulating factors that enhance the growth of gram-negative anaerobes.

Classification of Periodontal Disease

A simple system classifies periodontal disease as early, moderate or advanced.

Early periodontal disease

  • Periodontal pockets and beginning bone loss
  • Start of permanent loss of tooth-supporting tissues

Moderate periodontal disease

  • Ulceration of gingiva due to bacterial toxins
  • 50% of bone lost at canine and large fourth premolar roots
  • Slight tooth mobility

Advanced periodontal disease

  • More than 50% of supporting bone lost
  • Substantial tartar buildup
  • Pus and loose central lower incisors
  • Teeth will be lost without immediate treatment


Prevention, as always, is the best strategy. A preventative oral health program includes proper diet, regular home-care tooth brushing and regular tooth cleaning by a veterinarian. Feeding hard, dry food instead of soft, moist food will help prevent disease. Regular scaling, to remove plaque and tartar, prevents gingivitis from progressing to periodontitis. Dental health should be discussed with owners at the first examination of a new puppy or kitten. Of course, some owners may be unable or unwilling to brush their pet’s teeth, and some pets are uncooperative.

Surgical Intervention

Root planing is necessary when pockets develop and crown scaling is no longer effective in controlling periodontal disease. The veterinarian scrapes off any calculus and tartar attached to the root inside the periodontal pocket and then scrapes the inside layer of the gingiva to expose fresh, bleeding tissue in the hopes that it will reattach to the root. To correct deep periodontal pockets, part of the free gingiva may need to be removed.

Antibiotic Therapy

Antibiotics play an important role in the treatment of dental disease. Antibiotic use is considered mandatory when

  • severe oral ulceration is present
  • preserving as many teeth as possible in severe periodontitis
  • animals have systemic disease, metabolic instability or compromised immune systems
  • tooth scaling is combined with another surgical procedure
  • osteomyelitis, a bone infection, is present
  • capping of the pulp chamber is required

Antibiotics are often started as many as 5 days before the dental procedure and continued for 5 days after. Their use can prevent bacteria that are dislodged in the mouth from entering the bloodstream and infecting the kidney, liver or heart. Long-term therapy, as long as 28 days, may be necessary to treat osteomyelitis involving alveolar bone, which is commonly associated with dental disease.

Antibiotics are also used alone to treat early periodontal disease. For a dog with halitosis, antibiotics should be used with or scaling to block the progress of periodontal disease.
In treating early or advanced periodontal disease, the antibiotic should

  • be effective against the major aerobic and anaerobic periodontal disease-causing bacteria found in the mouth
  • penetrate periodontal tissues, both soft tissues and bone
  • be safe
  • allow convenient administration

Antibiotic Options

For more information on antibiotic options, please visit the ANTIROBE® (clindamycin hydrochloride) Capsules and CLAVAMOX® (amoxicillin trihydrate, clavulanate potassium) Drops overviews.

When ANTIROBE was tested in clinical trials, vomiting and diarrhea were occasionally observed.

CLAVAMOX is contraindicated for use in animals with a history of allergic reaction to any of the penicillins or cephalosporins. Safety of use in pregnant or breeding animals has not been determined.