We all have seen it. That yellow nasty buildup on a dog’s teeth. The medical term to describe this build up is calculus (not the one where you have to do some math if you’re wondering). Now Researchers from Brazil and Norway have proven in a controlled study that eating raw bones is actually an excellent way to remove “established” calculus in dogs. In other words, bones can reverse existing buildups regardless of how nasty they are.


One of the many cases presented to vet clinics with severe calculus formation. This is a very advanced stage but vets still see similar cases frequently.


Dogs commonly suffer from oral diseases. One of the most common oral diseases is a condition called periodontal disease, which starts as inflammation of the gum. If the disease is not caught early it progresses to cause looseness of the tooth. The consequences are familiar to many dog owners. The typical scenario ends with a dental procedure where your dog goes under anaesthesia for his teeth/tooth to be pulled out and an expensive bill to pay if the teeth become loose.

 Fear no more! Feeding raw bones is actually an excellent way to remove “established” calculus in dogs. In other words, supplementing your dog’s diet with bones can remove e

xisting calculus and help reverse the condition if you have not reached the point of no return yet.

The anatomy of the dog's tooth


To understand how the reversal process works, first we need to understand how the calculus forms. Plaque initially establishes on the tooth’s enamel (the visible white outer part of the tooth). Without appropriate chewing or tooth brushing, there are no mechanical forces that will remove the plaque. This leads to it becoming thicker and maturing. As minerals present in the saliva mixes with food materials, the thin layer of plaque mineralises to form the yellow calculus. This process happens faster in dogs because of their saliva’s alkaline pH (~7.5) which provides a favourable environment for mineralisation and calculus formation.   

 The widely fed dry and canned food do not control or help plaque formation as they have no abrasive power to keep the teeth clean. Some researchers believe that kibble is actually contributing to the problem.

What the researchers did in this study it that their compared the effect of chewing on bovine raw cortical or ‘compact’ bone (CB) from femur diaphysis (lower part of the bone), to bovine raw ‘spongy’ bone (SB) from the femoral epiphysis (top part of the bone), to reduce established calculus in adult Beagle dogs.  

The structure of beef femur bone

The study was conducted using eight healthy adult around 3 years old. With 4 males and 4 females involved. The dogs had never undergone professional dental cleaning and did not receive any regular tooth brushing or food containing chemicals (sodium polyphosphates) to prevent dental calculus accumulation. The researchers first gave the dogs a piece of CB daily for 12 days. Any remaining bone piece was taken away each day before offering a new piece. The second study with the spongy bones started 7 months after finishing the first study to allow buildup of new dental calculus in the dogs. The second study lasted longer, 20 days, to see if a longer period could further improve the results.

Fresh bones were supplied from a commercial slaughterhouse. The researchers chose raw bovine femur for the study because of its large and uniform size and its suitability for cutting into appropriate pieces. From practice, it is known that some owners give pieces of raw bovine femur, obtained from butchers or supermarkets, to their dogs. The bones were cut into ~5 cm (2”) long to minimize the chance being swallowed whole by the dogs. The bones were stored at −18°C and thawed at room temperature before being offered to the dogs. The beagles were fed twice daily with a non-dental dry commercial diet

To document and asses the findings, images were obtained on days 0, 1, 3, 7, 9 and 12.  The researches then integrated images over each other (overlay) using fancy computer software to compare progress.


A gradual removal of calculus formation took place, with 70.6% reduction happening over 12 days when the compact bone was given. After the first study, a 7-month period of no treatment followed, which allowed a significant dental calculus buildup in a similar pattern to that initially seen in the first study. At day 12, an average of 81.6% reduction was seen in all dogs receiving the spongy bone. On day 20, the dogs’ teeth were virtually clean and had only 4.7% of the teeth area covered by calculus (coming down from almost 40% of their teeth covered). What is really interesting that for the entire experimental period, no complications; such as pieces of bones stuck between the teeth, dental fractures or intestinal obstructions were observed.

Australian Veterinary Journal
Volume 94, Issue 1-2, pages 18-23, 26 JAN 2016 DOI: 10.1111/avj.12394



The study is well-controlled and representative of what happens in real life. What is surprising is the speed at which kibble diet causes calculus build up after cleaning. In 7 months almost 40% of the teeth surface was covered with calculus on average! Just by adding a piece of femur to the diet a huge change in the dental health of these dogs happened.

Owners feeding raw bones have been seeing similar results for a while now, with some believing that feeding RMBs is the best way to prevent dental disease. Some even cannot imagine why a dog would get any calculus buildup in the first place. Given that dental surgical procedures are one of the most common (and costly) procedures in the veterinary practice, spreading the word to friends who do not give raw bones as part of their dog’s diet is important. Now that we have a clear scientific paper, with clear visual proof, no one has an excuse.

If you are not a fan of cutting bones, you can check our handy guide on which bone suits your dog best: 



How to quickly reduce tartar buildup on your dog's teeth by 80% ?

Researchers from Brazil have finally showed in a controlled clinical trial what owners feeding raw swear is real!

Posted by RawChoice on Saturday, March 5, 2016