Periodontal disease

Early disease is gingivitis: reddened, inflamed gums, often with plaque and calculus. As periodontitis develops there is gingival swelling and bleeding, gum recession, deepening periodontal pockets, exposure of the root furcation, chronic pain, tooth mobility and eventually tooth loss. Staging relies on probing and intraoral radiographs under anaesthesia: mild disease is gingivitis without attachment or bone loss, moderate disease has 25-50% attachment loss with 4-6 mm pockets, and advanced disease exceeds 50% attachment loss with pockets of at least 6 mm.

Periodontal disease is chronic inflammation and progressive destruction of the tissues that hold the teeth: gingiva, periodontal ligament and alveolar bone. It is now understood as a dysbiosis of the mouth's own microbial community rather than a single infection. Plaque accumulates, gingivitis develops, and the healthy flora dominated by aerobic and facultative bacteria gives way to anaerobic, proteolytic species such as Porphyromonas gulae, Prevotella, Treponema denticola and Tannerella forsythia, which rise with severity. P. gulae carries fimbrial adhesins and gingipain-type proteases that damage epithelial adhesion proteins. The host inflammatory response then drives attachment loss, periodontal pockets, alveolar bone resorption and finally tooth loss.

It is one of the commonest oral conditions of dogs and is also common in cats. Prevalence estimates disagree with study design and diagnostic criteria: one review cites about 80% of dogs and cats affected by age four and 44-63.6% of dogs with periodontitis, a Mexican paper cites up to 90% in dogs, yet its own radiographic survey of 184 randomly selected dogs found periodontitis in 30.4% and gingivitis in 78.8%. Prevalence rises with age and falls with body weight; toy and small breeds are most susceptible, as their crowded teeth sit in relatively little alveolar bone. Lack of home dental care is a predisposing factor, and soft food has been linked to plaque, though large surveys have not shown dry food to protect.

Gingiva, periodontal ligament, alveolar bone, teeth (crown, root, furcation), jaw bone; bloodstream spread linked to kidneys, heart and liver

Daily tooth brushing to delay plaque build-up; a dental prophylaxis programme with professional plaque removal; chewing. Probiotic and postbiotic products are under study.

Gingivitis is reversible, but it can progress. Untreated periodontitis can destroy jawbone, and bacteria entering the bloodstream may contribute to kidney, heart or liver disease. Scaling and antibiotics alone give only temporary relief.