Periodontitis in dogs: clinical signs

Introduction

Periodontitis is an inflammatory disease of the deeper supporting structures of the tooth (periodontal ligament, cement and alveolar bone) caused by microorganisms. The inflammation is accompanied by irreversible resorption of the connective tissue and bone that anchors the tooth in the alveolus, leading to insertion loss.^1,2

Periodontitis in dogs: characteristics

Periodontitis in dogs is part of the periodontal disease (PD) complex and is a result of the evolution of gingivitis. Unlike gingivitis, which is characterised by the presence of reversible inflammation of the gingival epithelium and connective tissue, periodontitis is an irreversible process.^1,3,4

The American Veterinary Dental College has identified four stages of PD based on the severity:

• The first stage is the presence of gingivitis.
• The remaining three are different stages of periodontitis: 
• Initial periodontitis (periodontal insertion loss < 25%).
• Moderate (insertion loss 25–50%).
• And advanced periodontitis (insertion loss > 50%).⁴

Prevalence

Periodontitis is more prevalent and severer in smaller dogs, although it may also occur in large breeds, such as Greyhounds and Basset Hounds. Although the prevalence is thought to increase with age, it may already be present at very early ages in certain breeds.^1,4,5 A study in Yorkshire terrier dogs showed that 98% of the dogs assessed (n = 49) already showed evidence of mild periodontitis in at least one tooth at 37 weeks of life. The teeth affected earliest were the canines, followed by incisors, premolars and molars.⁶

Dogs with gingivitis are highly likely to develop periodontitis in the affected teeth if the problem is not reversed:

• A study in Miniature Schnauzers concluded that 98% suffered progression in less than 15 months and was faster in older dogs.7
• In Labradors with gingivitis followed for 2 years, 56.6% developed periodontitis.⁴

Factors to consider in its development

The presence of bacterial plaque plays an important role in the development of periodontitis in dogs. However, other factors must influence the progression of the disease, because not all dogs with plaque develop periodontitis on all the affected teeth. These factors include tooth malposition, the type of diet, a lack of dental hygiene, and low resistance to infection.^1,4

Unlike in humans, gram-negative bacteria are more prevalent in dogs without periodontal disease and gram-positive bacteria are predominant in cases of periodontitis. It has been suggested that periodontitis is not due to new the appearance of pathogenic species, but rather because of a change in the proportions of Gram-negative microbiota.⁸

The action of these pathogens triggers the release of vasoactive agents (endotoxins, chemotactic peptides, toxic proteins and organic acids) that induce the a host response involving the production of cytokines (IL-1β, IL-8), prostaglandins and TNF-α, and leading to varying degrees of inflammation ranging from mild gingivitis to destructive periodontitis.^3,4

Periodontitis in dogs: clinical signs

The signs of periodontitis include halitosis, ptyalism, anorexia, gum discolouration, gingival bleeding, increased tooth mobility, periodontal and periapical abscesses, osteomyelitis, pathological fractures, oronasal fistulas, nasal discharge, and sneezing.^1,2

Treatment of periodontitis 

The basis of treatment for periodontitis in dogs is to control the plaque. To this end, the first step is to perform dental cleaning under general anaesthesia. Patients with progressive or severe periodontitis may require mucogingival surgery and open scaling, but in certain cases accepting that the best option for the patient may be removal of the affected tooth.⁴

Antibiotics were traditionally recommended prior to anaesthesia and for the following 7–10 days.¹ However, this measure has been questioned recently.⁸ If antibiotics are considered necessary, cefazolin (30–60 minutes before the procedure) could be a good option. Antibiotic therapy is not usually indicated after the intervention.⁸

Exceptions to this recommendation are cases of ulcerative stomatitis, very severe gingivitis with spontaneous bleeding that requires gingival suturing, or performing a clean surgical procedure in another location during the same anaesthetic procedure.³ Chlorhexidine gluconate should be administered before starting the procedure.²

It should be noted that without further care bacterial plaque adheres to the tooth surface within 24 hours of cleaning, periodontal pockets are re-infected within 2 weeks and in less than 6 weeks they have reached the same depth as before cleaning.²

This means that home dental treatment is essential for controlling periodontitis in dogs. Regular tooth brushing is considered the most effective means of mechanically removing plaque. Correctly formulated chewable treats can also contribute to improved dental health.

Oral sprays, rinses and water additives, by contrast, do not generally serve this purpose.²

Conclusions

Periodontitis is a commonly encountered disease process in general consultations and can have significant consequences for the patient’s health. Considering it is an irreversible but controllable process, it is important to make an early diagnosis and establish appropriate management guidelines. Which is why it is essential to involve owners in the maintenance of correct oral hygiene when dogs are still young and conduct regular examinations of the oral cavity, preferably under anaesthesia.

References

1.     Albuquerque C, Morinha F, Requicha J, et al. (2012). Canine periodontitis: the dog as an important model for periodontal studies. Vet J; 191: 299–305.

2.     Niemiec B, Gawor J, Nemec A, et al. (2020). World Small Animal Veterinary Association Global Dental Guidelines. J Small Anim Pract; 61: E36-E161.

3.     Harvey C. (2022). The relationship between periodontal infection and systemic and distant organ disease in dogs. Vet Clin North Am Small Anim Pract; 52: 121–137.

4.     Wallis C, Holcombe LJ. (2020). A review of the frequency and impact of periodontal disease in dogs. J Small Anim Pract; 61: 529–540.

5.     O'Neill DG, Mitchell CE, Humphrey J, et al. (2021). Epidemiology of periodontal disease in dogs in the UK primary-care veterinary setting. J Small Anim Pract; 62 :1051-1061.

6.     Wallis C, Pesci I, Colyer A, et al. (2019). A longitudinal assessment of periodontal disease in Yorkshire terriers. BMC Vet Res; 15:207.

7.     Marshall MD, Wallis CV, Milella L, et al. (2014). A longitudinal assessment of periodontal disease in 52 Miniature Schnauzers. BCM Vet Res;10:166. 

8.     Davis EM, Weese JS. (2022). Oral microbiome in dogs and cats: dysbiosis and the utility of antimicrobial therapy in the treatment of periodontal disease. Vet Clin North Am Small Anim Pract.; 52: 107–119.