Tooth abscesses refer to painful pockets or capsules filled with pus found on the rabbit’s teeth or mouth (oral cavity) caused by mainly bacterial infections and other predisposing factors.
They are very common in these pets and they tend to grow on the gum areas, i.e., they are common on the mandibles (lower jaws) or maxilla (upper jaws or cheeks).
In some instances, they can grow on the nasal cavity (the sinuses), behind eyes (or around eyes – periorbital abscesses), or neck and when found here, they often have a poor prognosis.
Causes of dental abscesses
Primarily, they are caused by several bacteria, both aerobic and anaerobic species with the Pasteurella multocida being the most often identified.
Other bacteria that cause them include Pseudomonas aeruginosa, Staphylococcus aureus, Bacteroides sp., Proteus sp., Fusobacterium sp., Peptostreptococcus sp., other Pasteurella sp., among others.
Besides the above, there are other predisposing factors that often aid these bacteria to enter and canonize the soft tissues in the oral cavity and hence your bunny ends with these abscesses. These factors include the following:
Cuts, laceration, and puncture of the mucosal membrane
These injuries may be due to trauma from feeds or teeth defects which may create gateways for bacteria entry. Also, overgrown or elongated premolars or molar may damage tongue and cheek tissues, opening a gateway for bacterial infection.
Finally, do not forget that incisor malocclusion may also be a cause of trauma and consequently lead to infections that may abscesses.
Tooth diseases and problems
The odontogenic or jaw abscess may be due to dental disease which is common in these pets. These will range from systemic disease such as those that alter calcium levels may affect the teeth, tooth decay, congenital problems, among others and they are often associated with facial abscesses as one of their complications. 
Also, the Inflammation of dental pulp tissue may cause tooth death and the dead tooth often become a site for infection and hence abscesses may be formed.
Finally, oral wounds caused by any other factor can also give way for a bacterial infection which will later form abscesses around the wound or spread to other parts.
A weakened immunity makes rabbits vulnerable to various causative bacterial infections and this can be due to stress, excessive use of oral or topical steroids, and so on.
Since the rabbit’s teeth are every growing, diet low in fiber, those that less abrasive or those rich in carbohydrates, may also be a contributing factor to this problem as they fail to wear down teeth and may encourage some dental diseases and decay.
Rabbit abscess under the chin (lower jaw), maxilla or on nose cavity and eye
If they are on maxilla your pet may have abscesses behind eyes and on nasal cavity, i.e., the tooth root problems on the maxilla (upper jaw) may invade the retrobulbar space which is behind the eye or the nasal cavity causes abscesses in these areas.
When behind eyes, your rabbit will have symptoms such as the eye-bulging outside its socket, tear duct blockages and watery eyes (tear or discharges from eyes). On the other hand, if the nasal cavity is invaded, nasal congestion, discharge, and so on may be noted.
Finally, when dental root problems on the lower jaw cause them, i.e., rabbit abscess under the chin, they will be characterized by the presence of lump on the lower jaw that can be felt.
Symptoms to expect
The symptoms to expect will depend on the severity and the exact location of the abscess. We have already seen the possible symptoms you expect in case the abscess is behind the eyes or in the nasal cavity.
Some of the general symptoms that may be noted include the following:
- Loose teeth
- A rabbit’s face swollen on one side or jaw.
- Unwillingness to eat or preferring soft foods.
- GI stasis in cases where your bunny does not eat
- Rhinitis if it is in the nasal cavity
- Weight loss in extreme cases
- Pain signs such as a hunched posture, lethargy, hiding, depression, being less active and so on.
- A swollen oral cavity tissue
- Lumps on the lower jaw
- Overgrown teeth including elongated incisors and cheek teeth
- Under or overbite
- Strong odor from the rabbit’s mouth and facial areas.
Your vet will look at various signs of any dental disease including the swollen mouth and rule out any other condition that may have symptoms like those of dental abscesses.
He may also consider palpating your bunnies jaws especially the mandibles to check for any lump-like capsules or swelling as well as consider dental and skull radiograph to help detect any abscesses next to bones which are often immovable and hard to detect.
Also, an endoscopic oral exam may be recommended to help identify the exact place where the abscess is and a draining point under anesthesia.
Finally, your vet will get a sample of the pus for culture to help him or her identify which bacterial organisms are involved. This is vital for him or her to correctly decide on which medications will be most appropriate for these pets.
Treatment could be outpatient if not so severe unless they are large or there are infected wounds. Some causes may require non-steroid anti-inflammatory to help reduce pain for a longer time.
Being thick-walled, antibiotics may not be able to penetrate rabbit abscesses and draining may be a challenge because “ purulent material in rabbits is therefore thick and dense making it more difficult to drain when the abscess is lanced” 
Unlike abscess in other animals such as cats and dogs, those on rabbits hard drain or rupture on their own. Instead, “they tend to puncture the bone of the rabbit, often requiring surgical treatment”  since they have a thick fibrous wall. They also lack a lysosome enzyme that could digest the walls of the capsule enclosing the abscess.
During surgery, often done from outside through their skin, the infected tissue may be removed including any non-vital teeth that have been affected or bones that have undergone necrosis. During surgery, thorough cleaning is required which might go to the underlying bone since these abscesses are always deep.
Marsupialization and wound packing (with various things including antibiotic-impregnated beads) may be used to manage healing after surgical removal of the abscess. This will help heal the resultant wound.
Hospitalization for monitoring may be recommended after surgery and your vet will prescribe the required pain killers and antibiotics to help manage resultant symptoms as well as treat any bacterial infections.
Managing dental abscesses
To begin with, provide well-balanced diets with high fiber to reduce tooth decay and wear them down (avoid overgrown teeth) and let your vet reevaluate this pet after a few months and check if there are any abscesses.
For instance, ensure there is enough amount of grassy hay. Go for good brands of hay such as Small Pet Select 2nd Cutting “Perfect Blend” Timothy Hay, Kaytee Timothy Hay or Standlee Premium Western Forage Timothy Grass.
Furthermore, provide your bunnies with the recommended amounts of leafy greens. Chew toys and safe chew items may also help wear down your rabbit’s teeth and boost their health.
Non-invasive treatment of tooth abscesses
Some researches  have concluded that the use of dual-acting penicillin G or Benzylpenicillin is effective in dealing with most of the bacteria that cause cranial abscesses when offered subcutaneously (and not even to the vein) as giving them orally will cause not only dysbiosis but also enterotoxemia.
Your vet will advise you on their use as well as some stabilizers such as benzathine or local anesthesia such as Procaine.
Challenge of cranial abscesses
They always present a big challenge since some of them may have bacteria that are from your pet’s stomach, getting to the mouth through cecotrophy.
Using antibiotics to kill them may also kill the good bacteria in the gut causing dysbiosis.