Understanding Dog Underbites: Causes, Effects, and Treatment Options

Proper bite alignment supports healthier chewing, fresher breath, and fewer oral injuries.

By Anjali Sayee

Created on Aug 29, 2025

Proper bite alignment supports healthier chewing, fresher breath, and fewer oral injuries.

Understanding Underbites in Dogs: What Is Canine Malocclusion?

Many dog owners notice that their petâs lower jaw or teeth jut out farther than their upper jaw, giving the dog a signature “bulldog smile.” This dental difference is called a dog underbite or, medically, class-3 malocclusion. While often considered just a cosmetic quirk, underbites can have important implications for canine oral health, comfort, and overall quality of life.

What Is an Underbite (Canine Malocclusion)?

A canine underbite occurs when the lower front teeth extend in front of the upper front teeth when the mouth is closed. In veterinary dentistry, this is classified as a class-3 malocclusion or “mandibular prognathism.” This condition alters the alignment and occlusion (bite) of the dog’s teeth, in contrast to the natural scissor bite found in most dogs.

Scissor bite: Upper incisors overlap the lower incisors.
Reverse scissor bite (underbite): The lower incisors are in front of the upper ones.

This arrangement can be normal for some breeds, but in others, it signals dental or skeletal problems that may cause discomfort or injury.

What Causes Underbites in Dogs?

The primary cause of underbites in dogs is genetics. Certain breeds, especially those with shortened facial bones (brachycephalic breeds), are predisposed to this condition. Other causes can include developmental abnormalities, retained baby teeth, injuries to the jaw during growth, or misaligned jaw bones.

Genetic Factors

Brachycephalic breeds (with broad, short skulls) are most often affected.
Inheritance: Underbites are often passed down from parents to offspring.

Developmental & Environmental Causes

Retained deciduous (baby) teeth interfering with normal adult tooth eruption.
Jaw trauma or injuries sustained during puppyhood.
Developmental disorders affecting bone or tooth growth.

Dog Breeds Prone to Underbites

Underbites are common (even expected) in certain breeds. This is due to their unique jaw and skull structure bred for specific aesthetic or functional purposes.

Breed	Underbite Prevalence
Bulldogs (English, French)	Very Common / Breed Standard
Boxers	Common
Pugs	Common
Shih Tzus	Common
Pekingese	Common
Boston Terriers	Common
Cavalier King Charles Spaniels	Somewhat Common

For many of these breeds, a degree of underbite is natural and not a health concern unless it leads to complications.

Symptoms and Signs: When Is a Dog’s Underbite a Problem?

Though some dogs live without issues, an underbite can cause significant oral health and functional problems. Watch for:

Difficulty eating or chewing.
Dropping food from the mouth.
Excessive drooling.
Mouth pain: yelping, whimpering when eating, or pawing at the face.
Bad breath (halitosis).
Mouth injuries: sores, ulcers, or bleeding from trauma to soft tissues.
Behavior changes during eating, reluctance to eat, or sudden food aversion.

If these symptoms are present, veterinary assessment is critical to prevent escalation of oral health complications.

Complications and Health Risks Associated with Underbites

The severity and consequences of an underbite largely depend on how the teeth meet and the impact on the surrounding tissues.

Tooth-on-tooth wear: Abnormal or premature wear leading to inflamed tooth pulp (pulpitis) or even tooth death.
Trauma to soft tissues: The dog’s misaligned teeth may cause ulcers, sores, or injuries to the gums, lips, or the roof/floor of the mouth.
Overcrowding of upper teeth: Jaw size discrepancy can cause severe crowding and twisting of the upper jawâs teeth, predisposing the dog to gum disease.
Difficulty closing the mouth; possible impact on breathing.
Periodontal (gum) disease: Food particles and bacteria become trapped in abnormal positions, accelerating plaque build-up.

Not all underbites require intervention. The need for treatment depends on whether the dog is in pain, unable to function normally, or at risk of chronic dental or oral disease.

Diagnosing Canine Malocclusion

Veterinarians use a combination of physical examination and dental radiographs (X-rays) to judge the extent and impact of an underbite. They check:

Bite alignment and jaw symmetry
Evidence of discomfort, tissue trauma, or tooth wear
Presence of retained baby teeth or fractured teeth
Signs of periodontal disease

Severe or complicated cases may be referred to a board-certified veterinary dentist for advanced evaluation and treatment planning.

Treatment and Management: When Should an Underbite Be Treated?

Not every dog underbite needs correction. If a dog can comfortably eat, drink, and perform normal activities without injury or pain, the condition may simply be monitored over time.

When Is Treatment Needed?

The underbite causes pain, trauma, or injury (e.g., lacerations, ulcers, persistent bleeding).
Teeth interfere with the dog’s ability to eat, close their mouth, or breathe normally.
There is active or risk of progressive gum or bone disease.
There is tooth crowding or malposition leading to rapid tooth decay or infections.

Main Treatment Options for Canine Underbites

Veterinary dentists may use one or a combination of these interventions:

Tooth extraction: Removing teeth causing chronic trauma or severe misalignment.
Orthodontic appliances: Special bite plates, retainers, or even dental braces to gradually correct alignment.
Crown height reduction and restoration: Filing and capping teeth to relieve painful contact if appropriate and to preserve function.
Root canal treatment: For teeth with pulp damage where the goal is to relieve pain and preserve the tooth.
Surgical correction: Used rarely and only in severe bone deformities or traumatic injuries.

The choice of treatment depends on the dogâs age, overall health, the severity of malocclusion, and the ownerâs goals. The priority is always to restore a comfortable, functional, and pain-free mouth.

Home Care and Preventing Dental Problems in Dogs with Underbites

Good dental hygiene and careful monitoring are essential for dogs with underbites, especially if their bite is abnormal. Hereâs how pet owners can help:

Brush your dogâs teeth daily with a veterinarian-recommended brush and toothpaste.
Use safe, vet-approved dental chews to limit tartar build-up.
Switch to soft or moistened foods if chewing is difficult; avoid hard kibble or tough chews for dogs undergoing orthodontic treatment or with recent dental extractions.
Monitor your dogâs mouth and eating habits for changes suggesting pain or difficulty (e.g., suddenly avoiding food or scratching at the mouth).
Schedule regular veterinary dental check-ups and professional cleaning as recommended.

Always consult a veterinarian before changing your dogâs diet or dental routine, especially if your pet has a known underbite or oral health issue.

Living with a Dog That Has an Underbite

For many dogs, an underbite is little more than a unique facial characteristic. With proper care, most can live healthy, happy livesâeven with pronounced malocclusion. However, it is important for owners to:

Recognize early warning signs of pain or dysfunction (difficulty eating, excessive drool, mouth odor, changes in behavior).
Understand that routine dental exams and cleanings are especially important for dogs with abnormal bites.
Be open to veterinary recommendations if interventions are needed to prevent injury, infection, or discomfort.

Frequently Asked Questions (FAQs) about Underbites in Dogs

Q: What causes an underbite in dogs?

A: An underbite is most commonly genetic, especially prevalent in brachycephalic breeds such as Bulldogs, Boxers, and Pugs. Other causes may include jaw injuries, retained baby teeth, and developmental abnormalities.

Q: Are all underbites in dogs a problem?

A: No. For many breeds, a mild underbite is normal and not a health concern. Treatment is only necessary if it leads to pain, eating difficulties, or oral injuries.

Q: How do I know if my dogâs underbite needs veterinary attention?

A: Look for signs like trouble eating, excessive drooling, pawing at the mouth, sores, or foul breath. Any of these warrant a veterinary check-up.

Q: What treatments are available for dogs with problematic underbites?

A: Treatment options include tooth extraction, orthodontic devices, crown height reduction, and in some severe cases, surgery. The goal is always to restore comfortable function and prevent ongoing damage.

Q: Can I prevent underbites in my dog?

A: While genetic factors canât be changed, early veterinary examination of puppiesâespecially those in high-risk breedsâmay catch retained baby teeth or developmental issues that can sometimes be addressed before they cause permanent problems.

Conclusion

Dog underbites, or class-3 malocclusions, are commonâespecially in certain breeds. While not always a cause for concern, they can lead to oral health problems ranging from mild discomfort to severe pain and disease. Dog owners should be vigilant, practice excellent dental care, and consult a veterinarian promptly if health issues arise.

References

Author

Anjali Sayee

Anjali is an Associate Editor at StyleCraze with 7 years of experience specializing in hairstyles, hair care, and skin care. She has authored over 300 articles and offers expert advice on hair styling techniques, effective skin care routines, and tips for maintaining healthy hair and skin.

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