The Science Behind Dental Homecare Products
World Small Animal Veterinary Association Congress Proceedings, 2019
K. Istace, RVT
Mayfield Animal Hospital, Edmonton, AB, Canada

There are hundreds of products on the market, each advertising itself as the best, most effective, and easiest to use item ever designed in the history of pet care. Every day, more products appear on the market. How are we as Veterinary Technologists to know how each works, which of them work, which will be readily accepted by pets, and which will be used consistently by pet owners?

No matter a product’s hype, most dental home care products fall under one (or more) of these categories:

1.  Mechanical removal of plaque and calculus

2.  Chemical control of calculus formation

3.  Antimicrobial agents

4.  Barriers against plaque attachment

1. Mechanical

Mechanically remove or prevent the accumulation of plaque and tartar.

Toothbrushes—should be soft-bristled, not medium or hard

  • Can be designed for pets or for humans, as long as the size of the head is appropriate to the patient’s mouth
  • Plastic or nylon “fingerbrushes” are more useful for training than for actual brushing. Try to get owners to graduate to bristled brushes.
  • Rotating “spin” brushes are a favorite for many large-breed dogs
  • Special round head brushes are available for cats
  • Pets who won’t tolerate a brush in their mouth may tolerate the owner’s finger wrapped in gauze or a rag
  • Can be used with or without pet toothpastes

Diets—scrub plaque and calculus from teeth during chewing

  • Large kibble size ensures each piece must be chewed, not swallowed
  • Some have a special texture allowing teeth to sink into the kibble, scrubbing the entire surface of the tooth (but not under the gumline)
  • May be coated with a chemical agent (see Chemical Control below) to reduce calculus formation
  • Must be at least 25% of the pet’s total diet to provide expected results
  • Only clean teeth which grind food (not incisors or canines)

Treats—use mechanical abrasion from a wide variety of ingredients to scrub plaque and tartar from teeth

  • May also contain antimicrobial agents (see Antimicrobials below)
  • Are a source of calories, but not the main source of calories, in a pet’s diet
  • Designed to be effective while allowing the pet to eat its regular diet
  • Only clean teeth which grind food (not incisors or canines)
  • Very hard treats can cause tooth fractures

Chew Aids—meant to be consumed, but not a significant source of calories

  • Use mechanical abrasion from a wide variety of ingredients to scrub plaque and tartar from teeth
  • Pet receives psychological satisfaction and boredom relief from chewing
  • May also contain antimicrobial agents (see Antimicrobials below)
  • Some can cause digestive upset
  • Must be used under supervision as can cause choking or intestinal blockage
  • Very hard or compressed chew aids can cause tooth fractures

Chew Toys—non-consumable items

  • Wide variety of materials: rubber, rope, nylon, natural bones, tennis balls
  • Some can cause tooth fracture
  • Fuzz from tennis balls can cause tooth abrasion and pulp exposure
  • May have holes for treats or food to increase chewing compliance

2. Chemical Control

Chemical compounds called polyphosphates bind the calcium in saliva, decreasing the mineralization of plaque into calculus. When sprayed onto the surface of diets, treats, or chew aids, these chemicals reduce the formation of tartar, even on non-chewing teeth. They don’t remove plaque, which is the true cause of periodontal disease, but may increase the efficacy of mechanical plaque removal methods such as toothbrushing.

Another agent which inhibits calcium precipitation into calculus is xylitol, but as it also inhibits the growth of plaque bacteria, it will be discussed further in Antimicrobials.

3. Antimicrobials

Antimicrobial agents used to control plaque.

Chlorhexidine gluconate—chemical antiseptic rinse which combats both Gram-positive and Gram-negative bacteria, as well as some fungi and viruses.

  • Is bacteriostatic and bactericidal
  • Disrupts the cell membranes of microorganisms
  • Prevents plaque, gingivitis, and halitosis
  • Binds to tissues in the oral cavity and is released over a period of up to 12 hours
  • Can escalate calculus formation by increasing the mineralization of plaque
  • Can cause tooth staining
  • Products containing chlorhexidine should be kept out of the eyes (can cause corneal ulcers) and ears (can cause deafness at high concentrations)

Lactoperoxidase, lactoferrin and lysozyme—3 enzymes which are often marketed together as the “Triple Enzyme System.”

  • Some products contain only one or two of these enzymes
  • Decrease plaque by killing bacteria, fungi and viruses by disrupting cell membranes or depriving them of iron
  • Also fight free radicals
  • Found in toothpastes and treats

Mutanase and dextranase—enzymes which disrupt the glycan bonds in plaque, making it water-soluble and unable to adhere to teeth.

  • Found in oral gels, rinses, and water additives

Papain—enzyme which reduces the buildup of salivary glycoproteins in the mouth, reducing plaque formation.

Zinc—has antiseptic activity against both Gram-positive and Gram-negative bacteria

  • Decreases bacterial growth, plaque formation, and gingivitis
  • Usually found in oral gels and liquids which are rubbed, sprayed, or brushed onto the teeth, as well as some drinking water additives

Ascorbic acid (vitamin C)

  • Essential for wound healing, collagen production, and fighting free radicals, among other functions
  • May provide unfavourable conditions for bacterial growth
  • Found in oral gels, rinses, and water additives

Xylitol—a natural sugar alcohol that is also used in human products such as chewing gum to reduce plaque formation and gingivitis.

  • Inhibits bacterial growth, forms extracellular polysaccharides which make plaque less adhesive to teeth, and decreases the precipitation of calcium into calculus.
  • Use is controversial in animals, particularly in dogs, because of concerns about xylitol causing severe hypoglycemia and liver failure. It has also been anecdotally reported as causing hemorrhagic gastroenteritis in dogs. Though the dose of xylitol in pet dental products is much less than should ever be able to cause these effects [suggested use: 5–10 mg/kg/day, toxic dose: 150 mg/kg/day (Note: one stick of chewing gum may have as much as 1000 mg xylitol!)], some veterinarians are still reluctant to recommend its use. However, it seems to have no ill effects in cats, and has been shown to be effective in reducing plaque, calculus, and halitosis, and increasing gingival health.
  • Found in drinking water additives
  • Well accepted by pets, requires no particular effort on the part of the owner

4. Barriers

These are waxy polymers that electrostatically adhere to tooth enamel. Because the wax is attached to the surface of the teeth, plaque is prevented from attaching. The teeth must be free of plaque and calculus in order for the product to adhere properly to the enamel, so it’s best used following a professional dental cleaning. Also, a thick layer of ‘professional’ wax must be applied first in the hospital, then the owner is sent home with a thinner version that is to be applied once or twice weekly. The reason for this is that the wax is sloughed off in microscopic layers during normal salivation and chewing. The initial ‘professional’ wax contains many more layers than the home care version, whose weekly reapplication is meant to replace the lost layers.

Miscellaneous Agents

Antioxidants (acanthocyanins, vitamins) and EFAs—can increase the immune response to oral bacteria

  • Essential fatty acids such as omega 3 can aid in reducing inflammation in the oral cavity

Chlorine dioxide—oxidizes the sulphur compounds that contribute to halitosis

  • May help reduce gingivitis
  • Found in drinking water additives

CoQ10—an antioxidant which has been shown to improve gingival health in humans when ingested

  • No veterinary studies so far

Alcohol—used in human products such as mouthwash to reduce plaque

  • Have been linked to oral cancers in humans
  • Can cause GI irritation if swallowed
  • A small study of dogs showed efficacy against gingivitis, though no long-term safety studies have been done

Acetic acid—may inhibit plaque transformation into calculus similarly to polyphosphates.

Veterinary Oral Health Council

The best way to be sure that a product you are recommending is safe and effective is to look for the VOHC seal of approval. Products are awarded the VOHC Seal of Acceptance following review of data from trials conducted according to VOHC protocols. No product is required to undergo testing, and it is a voluntary, expensive, and time-consuming process. What this means is that a product may be effective, but its manufacturers may not have chosen to pursue clinical trials and submission to the VOHC. However, a product with the VOHC seal of approval is known to be effective when used as directed. A continuously updated list of VOHC-approved products is available at


Speaker Information
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K. Istace, RVT
Mayfield Animal Hospital
Edmonton, AB, Canada

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