Dental disease in rabbits and guinea pigs

The dental disease is the most common chronic health problem in pet rabbits and guinea pigs, and the dental disease is one of the most preventable. The rabbit or guinea pig that is fed the right diet, with the right hay, in the right amount, is the rabbit or guinea pig that has a healthy dental system throughout the life. The rabbit or guinea pig that is fed the wrong diet, or the right diet in the wrong amount, is the rabbit or guinea pig that develops the dental disease that is endemic in the species. The dental disease is, in most cases, a nutritional disease. The dental disease is a diet disease. The dental disease is preventable.

This article is going to walk you through the dental disease in rabbits and guinea pigs — the unique continuous-tooth biology of these species, the most common dental problems, the early signs that owners commonly miss, the surgical and management interventions, the long-term care, and the four mistakes that turn a preventable problem into a chronic crisis. I am an avian and exotic pet consultant, and the dental disease is one of the most common reasons I see rabbits and guinea pigs in consultation. The cases that go well share a common feature: the owner has understood the dental biology, has provided the right diet, has recognized the early signs, and has brought the pet in promptly for intervention. The cases that go poorly share a different common feature: the owner has not understood the dental biology, has provided the wrong diet, has missed the early signs, and has brought the pet in when the dental disease is advanced and the prognosis is guarded.

I want to be clear at the start: the dental disease in rabbits and guinea pigs is not the same as the dental disease in dogs and cats. The dental disease in rabbits and guinea pigs is a continuous-growth, malocclusion, and spur-formation problem that requires a different understanding, a different prevention, and a different treatment. The owner who applies dog-and-cat dental concepts to the rabbit or guinea pig is the owner who is missing the point. The rabbit and guinea pig dental system is unique, and the unique system requires a unique approach.

The continuous-tooth biology

The rabbit and the guinea pig have a unique dental system. The teeth of the dog and the cat are closed-root (the teeth stop growing once they reach the adult size), and the dental disease in the dog and the cat is primarily a periodontal disease (the disease of the supporting structures of the teeth) and a calculus-and-caries disease (the buildup of calculus and the formation of cavities). The teeth of the rabbit and the guinea pig are open-root (the teeth grow continuously, throughout the life), and the dental disease in the rabbit and the guinea pig is primarily a malocclusion-and-spur-formation problem (the misalignment of the teeth and the formation of sharp points on the molars).

The growth rate of the rabbit's and guinea pig's teeth is 2–3 mm per week, and the growth is balanced by the wearing of the teeth through the chewing action. The wearing is accomplished by the long-strand hay (the timothy hay for the adult, the alfalfa hay for the young), and the hay is the primary wearing agent. The pellets, the vegetables, and the fruits do not provide the same wearing action, because the pellets, the vegetables, and the fruits are soft and do not require the same chewing effort.

The malocclusion develops when the wearing is not balanced with the growth. The teeth grow longer than they are worn, the teeth develop sharp points (spurs) on the molars (the spurs form on the lingual side of the lower molars and the buccal side of the upper molars), the spurs cut into the tongue and the cheeks, the pet stops eating because of the pain, and the pet develops the cascade of problems (the weight loss, the GI stasis, the secondary infections) that is the dental disease.

The most common dental problems

The dental disease in rabbits and guinea pigs takes several forms, and the form depends on the underlying cause, the species, the age, and the genetic predisposition.

Acquired malocclusion (the most common). The most common dental problem in rabbits and guinea pigs. The malocclusion develops when the wearing is not balanced with the growth, and the malocclusion produces the spurs on the molars, the elongation of the incisors, the overgrowth of the cheek teeth, and the cascade of secondary problems. The acquired malocclusion is, in most cases, a diet-related problem (the diet is too low in hay, too high in pellets, too low in the long-strand fiber that the teeth need). The acquired malocclusion is also common in the older rabbit or guinea pig that has lost the dental alignment through years of wear.

Congenital malocclusion (the genetic problem). The congenital malocclusion is a genetic problem that is present from birth, and the congenital malocclusion is most commonly seen in certain breeds of rabbits (the dwarf breeds, the lop breeds) and in certain breeds of guinea pigs (the Abyssinian, the Peruvian). The congenital malocclusion produces the misalignment of the incisors and the molars from a young age, and the congenital malocclusion requires regular dental intervention (the filing or the extraction of the affected teeth) throughout the life.

Incisor overgrowth. The overgrowth of the incisors is often the first sign of the dental disease that the owner notices. The incisors grow longer than they should, the incisors protrude from the mouth, the pet has difficulty eating (especially the foods that require the incisors — the carrots, the apples, the hay stems), and the pet starts to lose weight. The incisor overgrowth is a sign of the underlying malocclusion, and the incisor overgrowth is the reason for the vet visit that leads to the diagnosis.

Molar spurs. The molar spurs are the sharp points that develop on the molars as the malocclusion progresses. The spurs on the upper molars point outward (toward the cheeks), the spurs on the lower molars point inward (toward the tongue), the spurs cut into the soft tissue, the pet has pain, the pet stops eating. The molar spurs are the most common reason for the "off-feed" presentation in the rabbit or guinea pig, and the molar spurs require veterinary intervention (the filing of the spurs under anesthesia).

Tooth root elongation and abscess formation. The advanced dental disease produces the elongation of the tooth roots (the tooth roots extend into the jaw, the nasal cavity, or the eye socket), and the elongated roots produce the secondary problems (the dental abscesses, the nasal discharge, the eye discharge, the facial swelling). The tooth root elongation and the abscess formation are the late-stage dental disease, and the late-stage disease is the disease that is the most difficult to treat and the most expensive to manage.

The early signs that owners commonly miss

The early signs of the dental disease in rabbits and guinea pigs are subtle, and the early signs are commonly missed. The owner who recognizes the early signs is the owner who brings the pet in for intervention before the disease is advanced. The owner who misses the early signs is the owner who brings the pet in when the disease is advanced and the prognosis is guarded.

The subtle weight loss. The pet is losing weight gradually, but the weight loss is not obvious to the owner. The owner should be weighing the pet weekly (a kitchen scale works for the rabbit, a smaller scale for the guinea pig), and the weight loss of more than 5% of body weight in a month is a red flag.

The change in food preferences. The pet that used to love the carrots or the apple is now refusing the carrots or the apple. The change in food preferences is often the first sign of the dental pain, because the harder foods (the carrots, the apple) require the chewing action that the painful teeth do not allow.

The change in stool size or quantity. The rabbit or guinea pig that is eating less is producing less stool, and the stool is smaller. The owner who is monitoring the stool production (the number of fecal pellets per day, the size of the fecal pellets) is the owner who notices the change. The change in stool is often the first objective sign of the reduced food intake.

The "messy" eating. The pet is dropping food from the mouth while eating, the pet is eating more slowly, the pet is favoring one side of the mouth, the pet is producing more saliva (the chin or the chest is wet). The "messy" eating is the sign of the dental pain, and the "messy" eating is the sign that the pet needs a vet visit.

The wet chin or the wet chest. The increased salivation (the hypersalivation or "slobbers") is a sign of the dental pain, and the wet chin or the wet chest is the visible sign of the hypersalivation. The wet chin is a classic sign of the dental disease, and the wet chin is a sign that the owner should not ignore.

The change in behavior. The pet is less active, is less social, is hiding more, is less interested in the surroundings. The change in behavior is often a sign of the chronic pain, and the change in behavior is the sign that the owner should bring the pet in for a vet visit.

The tooth grinding. The pet is making a grinding sound with the teeth (different from the normal purring-type grinding), the grinding is loud, the grinding is persistent. The tooth grinding is a sign of the dental pain, and the tooth grinding is a sign that the pet needs intervention.

The owner who is monitoring for these signs is the owner who catches the dental disease early. The owner who is not monitoring is the owner who catches the dental disease late.

The diagnostic workup

The vet visit for the suspected dental disease includes a thorough physical exam (with attention to the face, the jaw, the teeth that are visible), an oral exam (under sedation or anesthesia, with the use of an otoscope or a specialized mouth gag to visualize the molars), and imaging (skull radiographs or CT scan, with attention to the tooth roots, the jaw, the nasal cavity, the eye socket).

The imaging is essential for the diagnosis of the advanced dental disease. The visible portion of the teeth is only a small part of the tooth, and the tooth root elongation and the abscess formation are not visible without imaging. The skull radiographs or the CT scan is the diagnostic test that identifies the extent of the disease and the appropriate treatment.

The diagnostic workup is the foundation of the treatment. The owner who agrees to the imaging is the owner whose pet has the right treatment plan. The owner who declines the imaging is the owner whose pet has the wrong treatment plan.

The treatment options

The treatment options for the dental disease depend on the extent of the disease and the specific problem.

Molar filing (the floating). The most common treatment. The molar spurs are filed down with a dental burr, and the filing is performed under anesthesia. The filing is not a permanent fix — the spurs will regrow within 4–12 weeks, and the filing needs to be repeated regularly. The frequency of the filing depends on the severity of the disease (some rabbits need the filing every 4–6 weeks, some need it every 3–6 months).

Incisor trimming or extraction. The incisor overgrowth is treated with regular trimming (the incisors are trimmed with a dental burr, every 4–6 weeks) or with extraction (the incisors are surgically removed, and the rabbit or guinea pig can eat normally without the incisors). The extraction is a permanent fix, and the extraction is appropriate for the rabbit or guinea pig with the severe incisor overgrowth that cannot be managed with the regular trimming.

Tooth extraction (the molar). The extraction of a molar is a major surgical procedure, and the extraction is reserved for the molar that is severely diseased (abscessed, fractured, severely elongated). The extraction is performed by an experienced exotic vet, and the extraction requires careful post-operative care.

Abscess treatment. The dental abscess is treated with surgical debridement (the abscess is opened, the infected material is removed), with long-term antibiotics (the antibiotics are given for weeks to months, based on the culture and the sensitivity), and with the addressing of the underlying cause (the tooth that produced the abscess is extracted or treated).

Pain management. The dental pain is managed with analgesics (meloxicam is the most common, given orally or by injection). The pain management is essential for the pet to start eating again, and the pain management is an important part of the treatment plan.

The dietary correction. The dietary correction is the long-term fix. The pet is transitioned to the hay-based diet (with the timothy hay for the adult, the alfalfa for the young, and the appropriate pellets for the life stage), and the diet is the foundation of the long-term management. The dietary correction does not reverse the existing malocclusion, but the dietary correction prevents the malocclusion from progressing, and the dietary correction supports the wearing of the teeth that the long-term management requires.

The long-term management

The dental disease in rabbits and guinea pigs is a chronic condition that requires chronic management. The long-term management includes:

• Regular vet visits. The vet visit every 3–6 months (or more frequently for the severe cases) for the physical exam, the oral exam, the imaging as needed, and the treatment as needed.

• Regular dental filing. The dental filing every 4–12 weeks (depending on the severity) to manage the molar spurs.

• The dietary correction. The hay-based diet, with the appropriate pellets and the fresh vegetables, and the avoidance of the high-starch, low-fiber treats that contribute to the dental disease.

• The weight monitoring. The weekly weigh-in, with the trend recorded in a log, and the weight loss of more than 5% in a month is a red flag that requires the vet visit.

• The environmental enrichment. The hay-based enrichment (the hay in a hay rack, the hay in a hay bin, the hay in multiple locations around the enclosure) provides the continuous wearing action that the teeth need.

The long-term management is the difference between a rabbit or guinea pig that is living well with the dental disease and a rabbit or guinea pig that is in a chronic cycle of dental filings, weight loss, GI stasis, and vet visits. The commitment to the long-term management is the commitment to the quality of life of the pet.

The four mistakes that turn a preventable problem into a chronic crisis

Mistake 1: Feeding a pellet-based diet instead of a hay-based diet. The most common mistake. The owner fills the bowl with pellets, the rabbit or guinea pig fills up on the pellets, the rabbit or guinea pig does not eat enough hay, and the teeth do not wear enough. The malocclusion develops. The fix is to limit the pellets (1/4 cup per 5 lbs of body weight per day for the adult rabbit, the appropriate amount for the guinea pig), and to provide the hay unlimited.

Mistake 2: Missing the early signs of the dental disease. The second most common mistake. The owner misses the subtle weight loss, the change in food preferences, the change in stool size, the wet chin. The pet is brought in only when the dental disease is advanced. The fix is to monitor the pet weekly (weight, food preferences, stool), and to bring the pet in at the first sign of the dental problem.

Mistake 3: Declining the imaging at the diagnostic visit. The third mistake. The vet recommends the imaging, the owner declines (the cost, the anesthesia concern), and the treatment is based on the visible disease only. The treatment does not address the underlying disease (the tooth root elongation, the abscess formation), and the disease progresses. The fix is to agree to the imaging, to get the full diagnosis, and to start the appropriate treatment.

Mistake 4: Not committing to the long-term management. The fourth mistake. The dental filing is performed, the pet improves, the owner stops the regular vet visits, the disease progresses, the pet is brought in when the disease is advanced. The fix is to commit to the long-term management, with the regular vet visits and the regular dental filings, for the life of the pet.

The bottom line

The dental disease in rabbits and guinea pigs is the most common chronic health problem, and the dental disease is one of the most preventable. The right diet (the hay-based diet, with the appropriate pellets and the appropriate fresh vegetables) is the foundation of the prevention. The right monitoring (the weekly weigh-in, the food preference observation, the stool monitoring) is the foundation of the early detection. The right intervention (the prompt vet visit, the imaging, the dental filing, the long-term management) is the foundation of the management.

The rabbit or guinea pig that is well-managed is a pet that is living well with the dental disease, that has a good quality of life, and that has a long-term relationship with the owner. The rabbit or guinea pig that is poorly managed is a pet that is in a chronic cycle of suffering. The difference is the management. The management is the framework above. The framework, applied with consistency, is the right prevention.

The owner who is committed to the hay-based diet, the weekly monitoring, the prompt vet visits, and the long-term management is the owner who has a rabbit or guinea pig that is thriving. The owner who is not committed is the owner who has a rabbit or guinea pig that is suffering. The difference is the commitment. The commitment is the framework above. The framework, applied with consistency, is the right prevention.

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About the author

Ravi Patel is an avian and exotic pet consultant with a focus on the husbandry, welfare, and clinical management of small mammals, with a particular interest in the dental and gastrointestinal health of rabbits, guinea pigs, and other herbivorous small mammals. He has worked with private owners, exotic pet rescues, and zoological collections across temperate North America and South Asia, and writes regularly on the day-to-day realities of keeping small mammals healthy and engaged. He is a strong advocate for the hay-based diet and the weekly monitoring that are the foundations of small mammal dental health.