Periodontal Disease
Periodontal comes from the Greek peri-, meaning around, and odous, meaning
tooth.
The crown,
which is covered with enamel, is above the gum line, or
gingiva.
Underneath 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 cats older than 4 years have periodontal disease.
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.
Causes
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. Proliferating bacteria, food particles and saliva accumulate at the
gum line, forming a slimy substance called plaque
on the teeth. 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, bone marrow depression, weight loss and poor physical condition in affected animals.
Susceptibility
Species, age, breed and anatomy all influence an animal's susceptibility to
periodontal disease. 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.
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 Actinomyces
and Peptostreptococcus species, deplete the oxygen supply and produce
toxins that pave the way for more virulent gram-negative anaerobes, such as
Bacteroides. 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
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 14 days, may be necessary to treat osteomyelitis
involving the alveolar bone, which is commonly associated with dental disease.
Antibiotics are also used alone to treat early periodontal disease. For a cat
with halitosis, antibiotics should be used with scaling to block the
progress of periodontal disease. Scaling should always be recommended.
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® AQUADROPS®
(clindamycin hydrochloride) Liquid and CLAVAMOX® (amoxocillin trihydrate, clavulanate potassium) Drops overviews.
See the Glossary
on this site for the definition of all highlighted words.
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.
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