Effects of Diets, Treats, and Additives on Periodontal Disease

Teeth help increase the surface area of food by making individual pieces of food smaller, thus allowing for better mixing of food with the lubricating saliva before the bolus of food is swallowed. The teeth are held in position by the periodontium, which is made up of the gingiva, periodontal ligament, alveolar bone, and cementum. When the periodontium becomes infected or inflamed because of plaque bacteria and the host’s response to the bacterial insult, periodontal disease (gingivitis and periodontitis) is the result.¹

Periodontal Disease

Gingivitis (inflammation of the gingiva) is the less severe form of periodontal disease and can be treated with proper oral hygiene.

Periodontitis affects the gingival and nongingival components of the periodontium, resulting in tooth attachment loss, gingival recession, root exposure, furcation exposure, pocket formation, and bone loss. Clinical signs vary widely (BOX 1). Treatment depends on the severity of periodontal disease and may range from professional dental cleaning, closed periodontal therapy (root planing, gingival curettage), administration of antiseptic and anti-inflammatory medications, open periodontal therapy (improved access to diseased tissues after creation of a flap), and complex flap and bone grafting procedures to extraction of nonsalvageable teeth.

In an otherwise healthy patient, periodontal disease can lead to bacteremia, but it is rapidly cleared by the reticuloendothelial system.² Thus, routine use of systemic antibiotics is discouraged and required only for selected patients with conditions that could worsen during or after a dental or oral surgery procedure (e.g., established organ disease, immunosuppression). In addition to bacteremia, periodontal disease can lead to the chronic release of inflammatory mediators, immune complexes, and byproducts of bacterial and cellular degradation into the blood and lymph vessels, which could produce direct or immune-mediated organ pathology (e.g., liver, kidney, and myocardium in dogs).¹

Preventing or Managing Periodontal Disease

To be able to make appropriate recommendations, the veterinary professional should always ask clients about any home oral hygiene that they may perform for their pet; their pet’s chewing habits and diet; and which, if any, chewing objects they offer their pet.³ As mentioned, there are many professional treatment options for periodontal disease; this article focuses on products available to help clients prevent or manage periodontal disease at home.

Home Oral Hygiene

No discussion of oral health would be complete without mentioning home oral hygiene, a critical component of oral health maintenance. Plaque is soft enough to be brushed or wiped off; however, if allowed to accumulate for 2 to 3 days, plaque becomes mineralized to form calculus (tartar), which resists removal by tooth brushing or mastication (although some dental diets and chews may remove some calculus via the process of chewing). Thus, to remove plaque before it mineralizes, toothbrushing needs to be done daily or at least every other day.⁴ Pet-specific toothbrushes are available; some are angled to assist in brushing the caudal teeth. Cats and small dogs often prefer finger brushes. Regardless of what type of brush is used, the bristles of the brush must be soft. Other products that can be used to remove plaque from the tooth surfaces include medicated wipes, gauze, and cotton-tipped applicators. Pet dentifrices (pastes or powders) are also available and come in many flavors; some are more abrasive for working on calculus and others contain enzymes to reduce plaque.⁵

Products for Improving Oral Health

Products that reduce plaque and calculus buildup include dental diets; chews, treats, and toys; and drinking water or food additives.⁶ Oral rinses, gels, and toothpastes are also effective but fall outside the scope of this article. The Veterinary Oral Health Council (VOHC; vohc.org) is an entity of the American Veterinary Dental College and awards a seal of acceptance to products that meet pre-set criteria for mechanically and/or chemically controlling plaque and/or calculus deposition in dogs and cats. Clients often educate themselves through the Internet, and they can be confident that the marketing claims are credible for products that have been awarded the VOHC Seal of Acceptance. However, VOHC is not a regulatory agency, and submission of clinical trial results to the VOHC on behalf of a company is voluntary. Furthermore, VOHC does not determine the safety of a product but requires assurance by the company that a product is safe and meets all applicable regulatory requirements.⁵

Dental Diets

A study in Australia compared the oral health of domestic cats eating commercially available canned and dry diets with that of feral cats whose diets consisted of small mammals, birds, reptiles and insects. Researchers found that calculus accumulation was more severe in the domestic cats but prevalence of periodontal disease did not differ significantly between the 2 groups.⁷ For reasons of food safety, pets should generally not be fed raw meat or unpasteurized dairy products.⁵

In terms of food texture, another study found that compared with soft and mixed (dry and soft) food, dry food had a positive influence on the oral health of cats and dogs, decreasing the occurrence of mandibular lymphadenopathy, accumulation of dental deposits, and development of periodontal disease.⁸ Oral health also improved significantly in cats and dogs fed a commercial dry diet compared with those fed a home-prepared diet.⁹ Cats fed large kibbles had significantly less gingivitis and calculus than did cats fed small kibbles.¹⁰ Specially engineered dry kibble with added polyphosphates or chlorhexidine provides the mechanical and chemical actions, respectively, to prevent or retard plaque and calculus formation. Long fibers within a large kibble oriented in one direction help to keep the kibble from crumbling when a dog or cat bites into it. This design allows the kibble to mechanically scrape the sides of the teeth as they penetrate it.^11,12

Chews, Treats, and Toys

Dental chews and treats given daily have been shown to reduce plaque and calculus accumulation, gingivitis, and bad breath in dogs.^13-15 Rawhides in particular seemed to have a protective effect against periodontal disease; this effect was more obvious in dogs fed dry food only.¹⁶ Note, however, that there have been some reports of potential rawhide contamination with Salmonella. The inclusion of polyphosphates or chlorhexidine may further improve the effectiveness of a chew or treat.¹⁷ However, the decisive factor in maintaining oral health in dogs seems to be the abrasiveness of the product rather than the activity of the added chemical.¹⁸ Studies in cats demonstrated that the daily addition of a dental treat to the dry diet resulted in significantly less plaque and calculus accumulation on tooth surfaces.^19,20 The size and shape of any chew, treat, or toy should be matched with the chewing habits of the pet. Chewing objects should not be too hard because very hard materials can fracture teeth.²¹ Inappropriate items include plastic bones made of hard nylon, cow hooves, antlers, rocks, large ice cubes, and wooden sticks. Meat bones (cooked and uncooked) are also too hard and carry the risk of esophageal obstruction and gastrointestinal perforation. Tennis balls are very abrasive to teeth because they collect tiny particles of dirt and sand and will wear down the crowns, leading to pulp exposure.⁵

Food and Water Additives

Some plaque or calculus-retarding agents can also be added as a liquid to the drinking water or as a powder to the food.²² Pet owners generally should avoid products with unsubstantiated or unreasonable claims (e.g., “no more brushing of teeth needed,” “replaces general anesthesia for dental cleanings”).

Despite the value of the above-mentioned products (diets, chews/treats, water/food additives), none replaces thorough oral examinations (including periodontal probing and dental radiography) and dental cleanings (including root planing and gingival curettage) performed by trained veterinary professionals. The gold standard for the management of periodontal disease is diagnosis and treatment under general anesthesia, followed by home oral hygiene (daily toothbrushing and proper nutrition). Anesthesia-free dental cleaning done by untrained persons may be cosmetically pleasing to some pet owners, but it provides a false sense of accomplishment by making parts of the crowns look good while neglecting the subgingival areas of the teeth where periodontal disease is active.⁵ A painful mouth will make for a noncompliant pet and may cause the client to give up completely on toothbrushing and other home oral hygiene measures. Thus, it is often best to start with professionally cleaned teeth and healthy gums, which will be hugely motivating to the client and far more beneficial to the pet (FIGURE 1).⁵

Figure 1. Images showing a dog’s teeth before (A) professional dental cleaning.

Figure 1. Images showing a dog’s teeth after (B) professional dental cleaning. Showing such images to clients can inspire them to start daily toothbrushing as part of their pet’s home oral hygiene.

Watch our SPARK! video on Dr. Ellen Lowery, DVM, PhD, MBA, Director of the Veterinary Oral Health Council, speaking about how the VOHC provides quality assurance for plaque and tartar retardation for pets using nutritional products.