Periodontitis in dogs: disease of the tooth-supporting tissues

Overview

A tooth's supporting structures include the gum, cementum covering the root, periodontal ligament and surrounding jawbone. Gingivitis is inflammation confined to the gum tissue, without loss of tooth attachment. Untreated gingivitis can progress to deeper periodontitis.

Up to 80% of dogs have some degree of periodontal disease by two years of age. This broad disease category includes both gingivitis and periodontitis. The figure therefore does not mean that all these dogs have already lost bone supporting their teeth.

In UK patient records from 784 practices in 2016, periodontal disease was recorded in 2,797 dogs.

This represented 12.52% of dogs during the year. The proportion calculated from patient records may underestimate the true frequency of disease.

Causes

The disease begins with bacterial plaque accumulating on teeth and the body's inflammatory response. Plaque is a soft layer containing oral bacteria, substances from saliva and food particles, among other components. The bacteria organise into a biofilm attached to the surface.

Oxygen decreases in thick plaque, favouring bacteria that live without oxygen. Plaque beneath the gumline is a key factor maintaining inflammation in periodontitis. The body's inflammatory mediators damage bone and other tissues around the root. Bacteria and their metabolic products also contribute to bone damage.

Tartar is mineralised, or hardened, plaque. Minerals in saliva help plaque left in place to harden. The hard deposit shelters bacteria. Bacteria within a biofilm resist antimicrobial effects better than free-floating bacteria.

The normal oral bacterial population is not entirely harmful. Some bacteria may limit the numbers of microbes that harm the tooth-supporting tissues. Plaque continually reforms on tooth surfaces and between teeth.

Risk factors

Periodontal disease is more common in small dogs. Increasing age also raises the likelihood of disease. Crowded teeth and thin surrounding bone predispose to damage of the supporting tissues. Misaligned teeth can create surfaces where plaque readily collects.

In the UK patient records, Toy Poodles had adjusted odds of a periodontal diagnosis 3.97 times those of crossbreeds. Greyhounds also had increased odds, at 2.58 times those of crossbreeds. The comparison concerned dogs receiving veterinary care in the UK.

In short-muzzled dogs, rotated and crowded teeth can complicate oral health. However, an association between a short muzzle and increased disease risk does not apply to every breed.

Diabetes and Cushing's disease can predispose to disease of the oral tissues. Poor nutritional status is another risk factor. Alongside inherited characteristics, oral hygiene and concurrent diseases affect disease development.

Typical symptoms

Early oral disease may cause no obvious outward signs.

Signs you may notice at home include:

• Bad breath associated with a build-up of oral bacteria.

• Red, swollen or easily bleeding gums around the teeth.

• Drooling or rubbing the mouth with a paw or against surfaces.

• Slower eating and dropping food from the mouth before eating it.

• Reduced appetite or reluctance to chew previously favoured toys.

• Withdrawing from the family or unusually aggressive behaviour.

Gum recession can expose the tooth root. In advanced disease, a tooth may become loose or fall out. White-looking tooth crowns do not rule out hidden periodontal disease.

Complications and consequences

Destruction of the periodontal ligament and jawbone permanently weakens tooth support. Progressive disease can cause long-term pain before the tooth falls out. Deep damage around an upper canine tooth can create an opening between the mouth and nasal cavity.

Periodontitis reaching the root tip can also damage the tooth's pulp. Saving such a tooth may require both periodontal treatment and root canal treatment. Disease can recur after treatment if oral hygiene at home does not change.

The outlook for a tooth being retained depends on how much supporting tissue remains. In advanced PD4 disease, the prognosis for retaining the tooth is guarded.

Diagnosis at the vet

Examination extends beneath the gumline

The vet takes a history and checks the dog's general health before a dental procedure. An awake mouth examination may reveal tartar, bite abnormalities and broken or discoloured teeth. Its accuracy also depends on how readily the dog allows the mouth to be examined.

Blood tests may be taken before anaesthesia to assess health. Further tests, such as an ECG, are added when needed. Missing and extra teeth and foreign objects stuck in the mouth are also assessed while the dog is awake.

A detailed examination of the tooth-supporting tissues is performed under general anaesthesia. Teeth are examined individually and findings recorded on a dental chart. A periodontal probe is gently passed between the tooth and gum. Each tooth is measured at six sites so that localised deep damage is not missed.

Normal canine gingival sulcus depth is usually 1–3 mm. Tooth mobility and the areas where roots divide in multi-rooted teeth are also assessed. Full-mouth intraoral dental X-rays show the roots and surrounding bone. The tongue, palate and other oral soft tissues are also checked for abnormalities.

A biopsy from an abnormal oral mass can be sent for histological examination. Gingivitis persisting despite cleaning requires investigation of other factors maintaining it. An autoimmune disease or oral inflammation associated with kidney disease may occasionally be responsible.

Attachment loss determines the stage

PD1 means gingivitis without attachment loss. In early periodontitis, or PD2, less than 25% of attachment has been lost. In PD3, the loss is 25–50%. In PD4, more than 50% has been lost.

Treatment

Cleaning and, when needed, tooth extraction

The vet chooses treatment according to the amount of tooth attachment lost. Plaque and tartar are removed above and below the gumline under anaesthesia. Tooth surfaces are polished after cleaning. The cosmetic result of removing tartar in an awake dog does not treat ongoing disease below the gumline.

Alongside ultrasonic equipment, hand instruments can be used to remove tartar. Polishing smooths small scratches made on the tooth surface during cleaning. Finally, the area below the gumline is flushed to remove loosened material and polishing paste.

Deep periodontal pockets require cleaning of the root surface and inflamed pocket. Pockets deeper than 5–6 mm may need the gum to be surgically opened for adequate cleaning. In selected bone defects, membranes or bone grafts supporting tissue regeneration may be used. A loose tooth with a poor prognosis is often best removed.

A fistula between the mouth and nose requires extraction of the affected tooth and closure of the opening. Removing the tooth allows diseased soft tissue and bone to heal. Dogs can enjoy a good quality of life even without teeth.

Pain relief and consideration of antibiotics

Pain relief continues at home when needed, as directed by the vet. An antibiotic does not replace removal of plaque, tartar and unhealthy teeth. Routine treatment does not usually require antibiotics. In special circumstances, the need for antimicrobial treatment is assessed individually.

Vital functions are monitored during the procedure and recovery. Falls in temperature and blood pressure are anaesthetic risks considered during dental procedures. A heart murmur may warrant further cardiac investigation before anaesthesia is planned.

A breathing tube keeps the airway open until the dog is swallowing and resting on the breastbone. Body temperature and, when needed, fluid support are managed during recovery. Monitoring of vital functions continues until the dog is awake.

Prevention

Daily tooth brushing removes soft plaque and helps prevent gingivitis. Plaque left in place for more than two days can mineralise into tartar. Ordinary brushing cannot remove tartar that has already formed.

Choose toothpaste intended for dogs. Detergents and fluoride in human toothpaste enter a dog's digestive tract when swallowed. Hard bones and hooves can fracture teeth. Ordinary dry kibble may not clean teeth adequately.

Research evidence can be used to assess the effectiveness of dental diets and chews in reducing plaque or tartar. Mouth examinations during puppyhood can identify retained baby teeth causing crowding and bite abnormalities. Severe crowding can sometimes be reduced by extracting selected teeth.

Where a permanent tooth appears missing, an X-ray distinguishes a truly absent tooth from an unerupted one. Good management of metabolic disease such as diabetes also forms part of preventing periodontitis. Tissue damage from biting cage bars or chewing stones is addressed by changing these habits.

A protective coating applied to tooth surfaces may reduce plaque accumulation. It does not replace oral hygiene at home or professional dental care. A baby tooth can sometimes remain stable if no permanent replacement has developed.

Important for dog owners

Vigorous brushing of a painful, inflamed mouth can increase discomfort and make later training harder. Introduce brushing gradually and reward your dog. Training can progress from touching the lips to touching the gums, tasting toothpaste and finally using a brush.

For most dogs, thorough brushing of the outer tooth surfaces is the most important part of home care. The tongue rubs the inner surfaces, which usually collect less plaque. Home brushing maintains oral health between professional treatments.

Handling the mouth may feel unpleasant to a puppy during teething. Avoid negative brushing experiences at this stage. A baby tooth remaining beside a permanent tooth can push the new tooth out of position.

Record changes in eating, chewing, breath and behaviour for the consultation. Mention previous dental procedures and other diseases. On discharge, ask for written instructions on feeding, wound monitoring and starting brushing, as well as the timing of the next examination.

A follow-up visit can check healing after extractions or other oral surgery.

Frequently asked questions

Is periodontitis the same as gingivitis?

Gingivitis means gum inflammation without loss of tooth attachment. In periodontitis, inflammation has progressed into the deeper tooth-supporting tissues. Gingivitis can resolve with thorough plaque removal. Periodontitis may instead require treatment of deep pockets or tooth extraction.

Can a dog have toothache while still seeming bright?

Yes, oral disease can be painful without obvious expressions of pain. Pain may show as slower eating or reluctance to chew favoured toys. Withdrawal or unusual irritability can also be associated with mouth problems. A superficial look inside the mouth does not always reveal the underlying cause.

Is removing tartar without anaesthesia enough?

Cleaning visible surfaces while the dog is awake mainly improves the teeth's appearance. Inflammation below the gumline can remain untreated. A detailed examination involves periodontal probing and dental X-rays under anaesthesia. Treatment choice depends on the severity of the supporting tissue damage found.

Will an antibiotic cure periodontitis?

An antibiotic is not used as the sole treatment for periodontitis. Plaque, tartar and, when needed, unhealthy teeth are removed from the affected mouth. Routine dental procedures do not usually require antibiotics. Any special need for medication is assessed according to the dog's other diseases and findings.

How will a dog cope if teeth need to be removed?

After an unhealthy tooth is removed, the surrounding tissues can heal. A dog can cope and enjoy a good quality of life even without teeth. After surgery, pain is managed at home as prescribed by the vet. A veterinary follow-up examination can confirm healing.