Does your pet have a dry mouth?

By Robert Devlin, DVM

Dog drool can be a great source of laughter as seen in the movie Beethoven and in the Tom Hanks movie, Turner and Hooch, where it flew everywhere!  Dogs with big jowls who drool excessively can both be funny and a source of frustration, dogs with a poor salivary condition called dry mouth, also known as xerostomia, can be a serious medical condition that can have a huge impact on dental health. A healthy quality and quantity of saliva helps to keep the mouth clean and healthy.  When the quality or quantity of saliva is compromised, bacteria can build up in the mouth and cause bad breath, gum disease, and tooth decay. 

NORMAL SALIVARY PRODUCTION ACTIVITY

Digestion 

Salivary production is as important for dogs as it is for people.   Dog saliva, like human saliva, contains amylase which helps in early digestion of starches.   While the level of amylase in dog saliva is lower than humans, it exceeds the carnivorous wolf by comparison.   It is thought that the dog developed increased amylase activity due to its proximity with humans. (Pajic, et al, 2019) 

Lubrication 

A large contribution of dog saliva is simply to moisten the food and allow ease of swallowing.   Almost all animals would have a much harder time swallowing if not for saliva.  The water in saliva moistens the food while the mucus component makes it more slick for a combination effect to decrease oral and throat abrasions from food and helps ease its passage down the esophagus to the stomach.    

Solubilization 

The water in dog saliva also dissolves food particles carrying them to the taste buds allowing your pet to taste the food you provide to them.   While many dogs appear to eat heartily, the palatability of food and the dog’s sense of taste is key to their desire to eat.  Saliva helps make this happen!  

Evaporative cooling 

In contrast to humans who have sweat glands all over their body, dogs predominately have sweat glands only on their foot pads.   To compensate for this, dog’s pant.   By moving air in and out of lungs they utilize water through evaporative cooling to help regulate their body temperature.  This system works well most days, but dogs can be at risk for heat stroke especially on hot humid days when water doesn’t evaporate well.   Likewise, dogs with a “dry mouth” have decreased ability to cool themselves down.   

Washing effect for teeth and oral cavity 

Saliva, produced by the parotid, submandibular, mandibular glands, helps bathe or flush the teeth and gums helping to minimize plaque formation.   This flushing effect also helps decrease bad breath and reduces potential periodontal disease.  

Mild wound healing properties 

Dog saliva has been found to contain histatins, which guard against infection and nerve growth factors that help with healing.   So, some licking can be cleansing and help with healing, but excessive licking can actually be detrimental and should be discouraged. 

WHAT ARE THE SIGNS THAT MY DOG HAS DRY MOUTH?

Dry mouth can present as sticky or dry gums with what can be described as ropy saliva.  Unfortunately, the dryness is associated more with the water component of saliva so the ropiness is a result of excess mucus.  Many dogs have bad breath and some even have trouble swallowing and eating food.  Dry mouth can also be associated with severe dental disease and a dry or cracked tongue.   If your dog has any of these issues you should work with your veterinarian to identify the cause and look at treatment options to help your pet feel better and be healthier.   

WHAT CAUSES DOGS TO GET DRY MOUTH?

Xerostomia can be caused by several factors including: 

Dehydration 

Dehydrated animals can present with a dry mouth, sunken eyes, and skin that does not snap back when gently lifted.  Animals should always have access to plenty of fresh water, especially during the hot summer months as dehydration can be life threatening and can lead to overheating and possible death.   Bowls and water dispensers should be cleaned regularly so mold and algae don’t build up causing the pet to not want to drink.  

Medications 

As with people, some medications can decrease the water component of saliva resulting in a dry mouth.  Some major classes of medications that have shown a propensity for dry mouth are:  

• Antihistamines 
• Decongestants 
• Atropine 
• Behavioral medications 
• Diuretics  
• Sedatives 

Of course, there are many more individual medications that have been shown to cause dry mouth or react in certain breeds to initiate an immune reaction causing dry mouth. 

Immune system disorders 

Some dogs have an auto immune response where the dog’s immune system attacks the salivary glands.   This prolonged immune system attack can eventually lead to a dry mouth.   To help alleviate the auto-immune system response your veterinarian my prescribe medications that lower the immune response.   These medications may include: 

• Steroids 
• Cyclosporine 
• Other immunosuppressants 

By lowering the immune response on the salivary gland, many times, it can return to function and once again produce the necessary saliva to help the dog have a healthier mouth. 

Radiation therapy 

Oral or neck tumors necessitating radiation therapy may also adversely impact the production of saliva.  The impact of the radiation to the salivary glands may be permanent or temporary depending on dosage of the radiation to the normal tissue.   Radiation therapy is while not frequent in veterinary medicine is becoming more frequent and understanding the potential impacts and ways to support your pet is critical. 

Nerve Damage  

While rare, nerve damage can also result in dry mouth.   Typically, two forms of nerve damage have been seen: 

• Damage to the nerves supplying the salivary glands – this can be the result of direct trauma, surgeries or even tumors that impinge on the nerves.   A minority of cases may return to function if caught early or mild trauma, but many may have a permanent impact.  Unless the issue is on both sides of the mouth the non-affected side may have normal salivary gland function.  Support and plenty of access to water may help minimize any clinical signs. 
• Dysautonomia – First diagnosed in 1983 in the UK it is a progressive degeneration of the nerves affecting multiple areas of the nervous system.  Unfortunately, the cause of the disease is unknown and has a 92% mortality rate.  To date, this rare disease has been diagnosed generally in the mid-western US in predominately outdoor dogs with median age affected being 3 years of age.   Aggressive supportive treatments are recommended but no specific treatment is known. 

HOW CAN I SUPPORT MY DOG IF I SEE SIGNS OF DRY MOUTH

If you see signs of dry mouth in your dog the first thing to do is contact your local veterinarian to have your dog examined.   He/she may recommend an alternative medication or treat your pet for any specific issues.   Again, ensuring your pet has access to plenty of fresh water is a key aspect to minimizing clinical signs.     

Products specifically designed to help alleviate dry mouth 

If your pet can benefit from additional support, products like Oratene® Brushless Oral Care can help. Oratene   is specifically designed to boost salivary defenses and keep teeth clean and mouth healthy.  t It contains multiple enzymes to balance oral flora, including the LP3 Enzyme System to decrease the bacteria and odors associated with increased plaque caused by dry mouth. Additionally, Oratene contains the enzymes dextranase and mutanase, which work synergisticallyto breakdown the plaque biofilm and make it water soluble and unable to bind to the tooth.  Oratene is available in Breath Freshener Spray, a Water Additive and a Brushless Toothpaste Gel.