A splash of prevention

Dr. Candace Grier-Lowe demonstrates how to brush a dog’s teeth using her pet Lola as a model. Photo: Debra Marshall.

My cat has terrible breath. I try to follow the veterinarian’s orders by brushing her teeth, but she’s pretty feisty – even at 17 years old. A few scratches later, and with me dripping in sweat, I usually have to give up. But there might be a simpler alternative: my pet may be able to get a healthier mouth from her drinking water.

It’s an option that Dr. Candace Grier-Lowe, assistant professor at the Western College of Veterinary Medicine (WCVM), has been investigating in the past couple of years. During her veterinary dentistry residency, she conducted a study looking at the effectiveness of a water additive for reducing plaque and calculus in pets.

Plaque – a soft mixture of bacteria, sugar and proteins – is the main component of periodontal disease, a local infection of the periodontal tissues. According to Grier-Lowe, calculus also plays a role in the development of periodontal disease.

“Calculus is the hardened and mineralized form of plaque. It acts as a rough surface for plaque to adhere to,” she explains, noting that it also provides a place for plaque to hide below the gum line.

Periodontal disease is the most frequently diagnosed disease in all ages of dogs. “I would say about nine out of 10 patients that we see in the WCVM’s Veterinary Medical Centre for routine procedures and yearly exams and vaccines have some type of periodontal disease,” says Grier-Lowe.

Xylitol: plaque fighter?
While periodontal disease can be treated by surgical extraction of affected teeth, effective preventive care is the best defense. Pet stores and veterinary clinics sell numerous home dental care products, many of which are labelled as useful against plaque and calculus build-up.

Grier-Lowe decided to put one of these products, a water additive called Breathalyser^®, to the test. “Many vets recommend it,” says Grier-Lowe. “And we get questions from pet owners every day about it so I wanted to see if the product actually made a difference in a dog’s mouth.”

The product’s key ingredient is xylitol – a natural sugar often found in human oral hygiene products. Xylitol reduces cavities in people by killing the common cavity-causing bacteria, Streptococcus mutans.

“The bacteria absorb the xylitol but can’t use it to satisfy their energy needs,” explains Grier-Lowe. “This ultimately leads to their death.”

Although cavities in dogs and cats are fairly uncommon, the idea is that xylitol works similarly to reduce the bacteria population.

Grier-Lowe’s study, funded by Nestlé Purina, was completed as part of her combined residency and Master of Veterinary Science (MVetSc) degree program. She started developing the project in 2009 and the clinical trials – which lasted seven months – began in September 2010.

Test-driving Breathalyser^®
First, Grier-Lowe started recruiting healthy dogs for her investigation. The participants also had to be between two and six years of age and medium to large breed with no missing teeth or existing periodontal disease.

Because of the project’s nature, pet owners were instructed to not do anything that could disrupt the build-up of plaque and calculus such as brushing their dog’s teeth, handling their dog’s mouth and giving their pet anything they could potentially chew such as bones, sticks and toys. These demands resulted in a small sample size of only seven dogs.

The dogs were given the same diet and tap water with a two-week start-up period so the animals could get used to the food before the experiment began. Each dog underwent a complete dental cleaning under anesthesia to attain a dental score of zero – meaning no plaque or calculus in the mouth at all.

Then the dogs were randomly assigned to one of two groups. The treatment group received the Breathalyser^® while a control group got a placebo – a substance that had all the same physical characteristics as the plaque-fighting water additive.

After three months, the dogs returned to the WCVM to have their teeth graded for plaque and calculus. Following a two-week rest period where they only received food and untreated tap water, the dogs had another dental cleaning. Next, Grier-Lowe repeated the experiment with each dog switched to the opposite group.

The study’s data showed a 5.3 per cent decrease in plaque and a 14.9 per cent decrease in calculus. While the reduction in calculus was significant, the reduction in plaque was not. One dog actually ended up with more plaque build-up during the Breathalyser® treatment, causing the results to be skewed.

“The dogs weren’t supervised 24/7 so it’s hard to know if they chewed on anything that may have interfered with the results,” Grier-Lowe explains. “If I had to do it all over again, I’d want a more controlled environment for these dogs and a much larger sample size.”

Although her results don’t completely confirm the effectiveness of this product, Grier-Lowe does believe it’s worthwhile to use – especially for pet owners having difficulty brushing their pet’s teeth.

“Daily brushing is the gold standard for preventing periodontal disease, but I know that this isn’t easy for some owners,” she says. “If Breathalyser^® can help increase compliance when it comes to dental care, then great.”

However, Grier-Lowe would like to see further research into this product.

“All current research into xylitol as an additive in dental care products has focused on its effectiveness against S. mutans in a human’s mouth,” she says. “But what about its usefulness against common bacteria in the normal oral flora of a dog? S. mutans isn’t common in dogs’ mouths. Ideally, we need to expose the normal oral bacteria from a dog to xylitol in a microbiology lab to know what it’s doing.”

Robyn Thrasher of Edmonton, Alta., is a second-year veterinary student at the WCVM. Robyn is producing stories about the veterinary college’s clinical services, research program and its researchers as part of her summer job in research communications.