I think anyone who’s ever been around a dog recognizes that their mouths usually stink pretty bad. “Doggie breath” is an endearing term for halitosis, or foul breath, and it’s extremely common. While technically speaking, there are a few different causes (including dogs guilty of recreational coprophagy), by far the most common cause of “doggie breath” is dental disease. And specifically periodontal disease, which is in fact the most common exam finding when dogs go to the vet. If you were to go to the dog park on any given day of the week and look in some dog mouths (I’m vaccinated against rabies so I have no compunction about doing this), you’d have a very high chance (upwards of 80%) of finding evidence of periodontal disease. It’s about the same for cats, but there aren’t any cat parks that I’m aware of (this might be the closest thing?).

Periodontal disease in dogs and cats is complicated, so without going too far into the weeds, what you need to know is that it’s related to plaque buildup and affects pretty much all of our dogs and cats (wild canids get it too, sorry appeal-to-nature-folks). There is a whole residency training program and professional association of veterinary dentists who tackle the complicated cases. For most dogs and cats though, typical plaque buildup can be treated with a dental cleaning by a veterinarian in general practice. The process is actually almost exactly the same as for people and involves: scaling, polishing, x-rays (radiographs), probing, and charting. We do these routinely on otherwise healthy pets, because in addition to making the animal feel better (periodontal disease is inflammatory and painful), there are systemic effects that are likely detrimental to health.

There is a big caveat in doing a dental cleaning in animals though, and it is this: it must done under anesthesia. The obvious reason is, that unless you’re a masochist, nobody likes going to the dentist. And when animals think “I don’t like this”, and people have to perform a procedure that requires the dexterity of a model-ship builder (e.g. placing a fine tipped ultrasonic scaler in the tiny gap between the teeth and the gums), it’s pretty much impossible to accomplish anything with the animal wiggling, squirming, or even thrashing and trying to bite. Not to mention that they have no idea that they’re benefitting, so they are usually terrified and feel like they’re in the movie The Running Man. Anesthesia lets the animal sleep through the procedure without remembering anything scary, and lets the veterinarian and technicians assess and clean the teeth thoroughly. Although anesthesia is necessary for success, most pet owners are put off for a couple of reasons, (1) they’re scared of the risk of anesthesia, and (2) it makes things more expensive.

Anesthesia for healthy pets is actually pretty safe though , with a mortality rate of about 0.05 to 0.15%. It is higher than for people (for comparison, the US anesthetic mortality rate for people is about 0.001%, or 50-150 times better than for dogs), but it’s still very rare for anything to go wrong. And the benefits of a healthy mouth do outweigh the risks for most pets with moderate to severe dental disease. As for the cost, that’s always going to depend on a number of factors such as what their veterinarian charges and what value the owner puts on dental care. If we consider the cost of a dental cleaning to be an investment in improving a pet’s health and quality of life, that makes it worth it to some people.

Most pet owners are aware their pet’s teeth are a problem. There is (fortunately) a proven solution: a standard dental cleaning. However, (unfortunately) many of them are afraid of this treatment because they lack important information (i.e. the benefits and low risk). What steps into this gap? SBM readers will know right away: pseudoscience! Heroically diving into this chasm of doubt and apprehension are a number of entrepreneurs willing to provide a service that purportedly fixes the problem: clean the teeth without anesthesia, and to do it for way less money! You can find these services all over the place (not only AFD but also a bazillion pet dental care products, very few of which are scientifically tested; if you’re looking for which have some evidence behind them, the nice people at the Veterinary Oral Health Council have done the work for you) and there are a number of names and acronyms for them, but for now we’ll call them anesthesia free dentals (AFD for short, I thought about Dental Anesthesia Free Treatment but that seemed mean).

What is AFD?

Here’s what happen during these services: someone removes visible tartar off of teeth, then they take money from pet owner, and pet owner leaves feeling like they just saved a bunch of money and avoided a risky procedure. “My vet is such a jerk for suggesting that we knock Mr. Fuzzybottom out to clean her teeth! Now her teeth are perfectly clean! Why are they so greedy?” And to most people, the teeth do look better, because the crowns of the teeth don’t have any gross brown gunk on them anymore, which is what they think the benefit of a tooth cleaning is. What does not happen during this procedure though, is any tangible benefit to the pet. There is an important reason for this, and that is because the vast majority of inflammation (and thus pain and detrimental health effects) is underneath the gumline.

Look at the gums of a dog who’s just had an anesthetic free dental, the crowns look pretty good, but the gums are bright red due to persistent gingivitis. That’s because in an awake animal, it’s usually extraordinary difficult to clean that space (and impossible if using better equipment like ultrasonic scalers and polishers that use water irrigation). The owners have just paid to have a cosmetic procedure performed and are now even less likely to do an actual dental cleaning. Worst of all, the animal just had to sit there while somebody scraped their teeth, and they don’t get any benefit from the procedure. If I haven’t made it clear, you have to get below the gumline to benefit the animal. When we talk dental cleanings in dogs and cats, we’re generally talking about the subgingival and periodontal spaces, which are (you guessed it) below the gumline. Good luck getting there when the pet is awake.

That has not stopped people from marketing and selling AFD services. There are licensed veterinarians who provide the service, despite the American Veterinary Medical Association and the American Veterinary Dental College (among many others) taking official positions against the practice. Whether or not these people are doing it because they truly believe in its efficacy, or because the demand leads to profit, who knows? The people selling AFD services run the gamut from mobile dog groomers to well-respected veterinarians. There are even national brands emerging who incorporate their techniques into existing veterinary clinics. One such example is Pet Dental Services Inc., a company that has stepped into the fray to provide AFD cleanings with the flimsy veneer of scientific and professional authority.

Pet Dental Services has an 11-step AFD process that they’ve created and are willing to incorporate into your local veterinarian’s practice. I guess a process with 12 steps was already being used (hmmm, maybe that’s why they left out anesthesia?)? Anyway, don’t be fooled by the officialty of counting strides, nor the equally authoritative acronym-izing of the service (it’s called a “Professional Outpatient Preventative Dentistry”, or POPD). They claim their service is different from most AFD care, since it’s under the supervision of a licensed veterinarian, they even have a button on their website to “report an unlicensed cleaning”, presumably someone providing a similar service but not under the direct supervision of a licensed vet. They claim that they are “the only company proven safe & effective through a double blind study conducted with dental specialists”.

This is extremely misleading.

The company has a “report”, although I think to call it a scientific study is inaccurate, and calling it “double-blinded” is delusional. There are a lot of problems with the report, even if we give them a pass on the blinding: the fact that it’s published in an unreliable journal (“unreliable” is generous, see the Skeptvet’s assessment of the IVC Journal), doesn’t have any board-certified veterinary dentists involved (but, for reasons unknown, has three human dentists as co-authors), and is full of splleing erorrs. It has the superficial appearance of being a scientific study, but it really does not hold up to even half-hearted scrutiny (which I’m happy to provide).

Here’s what they did: researchers took a dozen cats and a dozen dogs, did an AFD on them including charting dental lesions, then put the animals under anesthesia and had a veterinarian do a standard oral exam (including periodontal probing, full mouth x-rays, and checking for calculus under the gingiva). The first and second assessments were compared in terms of the pathologic findings. They claim that they were able to perform the procedure on all patients, that there was no residual subgingival calculus (remember that’s the important stuff that we really care about), and that there were no complications from the procedure. They are using this study to tout the procedure’s efficacy and safety.

Their conclusions are not even a stretch, they are a yoga move only achievable by teleportation. This is a really bad study. There are so many problems with its design, measurements, and even the conclusions reported that it presents almost no meaningful information. It reeks of bias like a Gilroy festival.

Can you perform a dental cleaning on awake pets?

The researchers stated that 100% of the animals allowed the technique. The most obvious, glaring, enraging problem is that they conveniently (their word, not mine, but my italics) selected the patients who underwent the procedure. They included only animals who would allow them to complete the procedure, so of course they all allowed it. This is not the general population of dogs and cats, and anyone that’s ever tried just to brush a dog’s teeth should be suspicious of this number. I would guess that only a small percentage of pets out there would allow this to be done to them, and that there would be a lot of injuries (to people and animals) if this was tried on every pet with dental disease. They also completely gloss over the fact that animals with advanced dental disease would absolutely require anesthesia for full assessment and treatment.

Also, despite their perfect compliance, they stated that during the AFD, the technician “recommended radiographs for 100% of the patients and recommended anesthetic dental treatment for 15 out of the 24 (62.5%) patients”. Anesthesia is required for radiographs, so 100% of the dogs undergoing this procedure would have required anesthesia. Huh? How is this evidence that an anesthesia free dental is effective? They also stated that 88% of patients had radiographic findings, which is a majority I believe [double checks with a second grader], yeah, it’s a majority! So if you don’t do an AFD, there’s an 88% chance that you’ll miss radiographic evidence of disease, and if you do an AFD, there’s a 100% chance that you’ll get a recommendation for radiographs. And that’s in your 100% hand-picked population of pets with mild dental disease.

The combination of cherry-picking patients to include and then apparently recommending that all of them get an anesthetic dental anyway seems like poor evidence that this procedure is worth anything. But for sake of argument, if you could do this on most pets and they didn’t end up needing anything that would require anesthesia, can you effectively clean the teeth?

Do you remove the subgingival plaque and tartar (or, does it actually work?)

This is the nitty-gritty, meat and potatoes, brass tacks question. If we give the researches a pass on their generous patient selection and ignore that they are recommending anesthesia for every pet after this procedure, did they measure any reasonable benefit? You’d assume they would have some pretty objective data showing that all of the subgingival plaque and tartar was removed. Actually, you might not assume that after getting this far in the paper, but that’s what they should have done. Instead they had the veterinarian use compressed air to peek under the gingiva and say if there was any residual tartar. And the veterinarian said there wasn’t. That’s it. No control group of pets who’d had a dental under anesthesia (or hadn’t gotten any treatment). No objective measurements of subgingival plaque and tartar (they could have used thiol strips or a disclosing agent). Just the veterinarian, who wasn’t blinded because every animal had the AFD done to them, looking and saying that they didn’t see any tartar. Do we take their word for it? Maybe if the rest of the study was watertight, but I have my doubts. And yet this finding is touted as conclusive proof of how effective their technique is.

Looking through the rest of the paper, the researchers confusingly report that lesion identification was much higher in the AFD than when the veterinarian was performing a standard dental. They explain this by saying AFD probably over-diagnosed pathology because the technicians performing it didn’t know what they were doing, but there’s no control for differently trained observers. Maybe the technicians are over-diagnosing because it’s really hard to probe the mouth in an awake animal. There’s also some hand-wringing about how this service must be done under the supervision of a veterinarian and that it’s not a replacement for dental cleanings under anesthesia, but then use it to market the effectiveness of not using anesthesia for dental care. They also try to explain away the high rate of radiographic findings by pointing out that half of the animals with findings had had an anesthetic dental within the last two years, a subtle attempt to discredit standard dental care. But since most people don’t provide any meaningful dental care for their pets at home, two years is plenty of time to develop radiographically significant disease. Plaque formation starts within a day of a dental cleaning, and without daily tooth brushing, these numbers don’t seem surprising at all. If you don’t believe me, stop brushing your teeth or going to the dentist for two years and get back to me.

Conclusion: AFD cannot be declared effective

I completely disagree with the authors’ conclusion that their study showed AFD works and that it’s safe. This is not evidence that AFD works, and promoting it as rigorous science on the front page of their website is deceptive to consumers. I hope that my veterinary colleagues will take a critical look at this study and not just glance at it superficially. Fortunately the major veterinary organizations are taking a stand against these practices. There is a wide range of AFD providers out there, from the outright illegal practice of AFD without the supervision of a veterinarian, to the medically questionable ones done under a veterinarian’s care. Pet Dental Services appears to be flashing scientific credentials, but there’s no there there. If they can do a better study that shows real world applicability and doesn’t mislead the public, it will be important and helpful. To be fair, the company has stated that they are working on a study that fixes all of the problems in the original. I have my doubts, but I’ll be happy to take a look when it comes out. Their current paper appears to be just a marketing tool though, and unfortunately I think it will lead some pet owners to avoid actual dental cleanings and possibly even distract them from the importance of home dental care (i.e. brushing).

Posted by Greg Bishop

Greg Bishop is a veterinarian in Southern California who works mainly with dogs and cats. As a fan of the SBM blog, he sees the enormous amount of bad science and information in the field of veterinary medicine as an opportunity, not a problem! But also a problem.