Dental disease in rabbits and rodents

Question 1

What are rabbits teeth?

Answer 1

• Elodont (open root)
• Hypsodont (long crown)
• Grow continuously
• formula = 2/1 0/0 3/2 3/3 = 28

Question 2

What is normal dental anatomy of rodents?

Answer 2

• 1 pair of upper incisors that grow continuously
• Sciuromorphs = only incisors grow continuously (squirrels, prairie dogs)
• Myomorphs = only incisors grow continuously (Rats, hamsters, gerbils)
• Hystricomorphs = all teeth grow continuously (guinea pigs, chinchillas, degus)
• formula = 1/1 0/0 1/1 3/3

Question 3

What are risk factors of dental disease?

Answer 3

• Diet - lack of fiber / abrasive food
• Congenital malocclusion
• Reduced chewing time / cycles
• Trauma
• Metabolic demands - pregnancy, lactation
• Hypovitaminosis D

Question 4

How do you stage dental disease?

Answer 4

1. Normal dentition and occlusion
2. Root elongation
3. Malocclusion - loss of bone density + abnormal dental growth
4. Cessation of dental growth - loss of germinal tissue
5. Abscess formation + osteomyelitis

Question 5

What are clinical presentation of dental disease?

Answer 5

• Anorexia
• selective appetite
• Weight loss
• low BCS
• unkept haircoat
• Gut stasis
• Excessive salivation
• Contact dermatitis on chin, lower neck and front paws
• Typical of molar overgrowth = Epiphora and dacryocystitis, Abscesses – mandibular, maxillary, retrobulbar
• Typical of incisor overgrowth = Obvious overgrown incisors, Abrasions, wounds around lips

Question 6

What is general approach to managing dental disease?

Answer 6

• Review husbandry - cage design, material, sources of trauma
• Review diet - species dependent -
• Hay + grasses – normal dental wear in rabbits / Hystricomorph rodents
• Controlled amount of pellets
• Remove seeds, muesli mixes, sugary treats, etc
• Regular health checks = 4-6 months
• Medical management
• Surgical/dental procedures

Question 7

What can be used for multimodal analgesia in dental disease?

Answer 7

• NSAIDs - meloxicam
• Opioids - methadone, buprenorphine
• Gabapentin

Question 8

How do you treat incisor malocclusions?

Answer 8

Rabbits =
* Crown reduction under GA (high speed burr)
- can grow 3mm/week, repeat every 4-6wks
* Incisor extraction under GA - RADIOGRAPHS first

Rodents =
* Only crown reduction under GA

Question 9

What are complications with incisor extractions?

Answer 9

• Risk of incisor regrowth if part of germinative root left behind
• Fracture if using nail clippers / cutting pliers - DO NOT

Question 10

What is dacryocystitis? CS? Dx? Tx?

Answer 10

• Occlusion of lacrimal duct by overgrown upper molars / inflammation
• CS = contact periocular dermatitis, recurrent / chronic eye discharge
• Dx = radiographs + CS
• Tx = long term meloxicam, Ab eyedrops, Lacrimal duct flush

Question 11

What are different Tx options for molar malocclusion?

Answer 11

• Crown and spurs reduction under GA
• Long term medical management with Meloxicam – chronic periapical pain
• Periapical abscesses =
  1. Abscess marsupialization – usually impossible to remove abscess as a whole mass
  2. Extraction of affected molars
  3. Enucleation in case of retrobulbar abscesses
  4. Antibiotics (ideally based on C&S) for minimum of 6-8 weeks
  5. “Lance & flush” useless in these cases

Question 12

How is abscess marsupialization surgery carried out?

Answer 12

1. Circumferential skin incision over abscess
2. Remove as much of the abscess capsule as possible – send a sample for C&S
3. Suture the abscess capsule to surrounding skin
4. Debride/remove abnormal bone
5. Extract any affected molars (intra-orally or through the abscess capsule)
6. Pack abscess cavity with bactericidal material (e.g. antibiotic impregnated beads)
7. Healing by 2nd intention

Question 13

What is the main sign of retrobulbar abscesses? Ddx? Tx?

Answer 13

• Exophthalmia
• Ddx = intra-ocular disease (glaucoma), retrobulbar neoplasia
• Tx = marsupialization, dental extractions, frequently requires enucleation

Question 14

What are specific problems with chinchillas?

Answer 14

• Periodontal disease =
  -v common
  -food/hair impaction between crowns
  -periodontal pockets
  -tooth resorption
  -removal of impacted material + cleaning periodontal spaces
  -Local + systemic ABs
• Dental caries - v common
  -associated w periodontal disease
  -remove affected dental tissue

Question 15

What are specific problems with guinea pigs?

Answer 15

• Macrodontia (large teeth)
  -Enlargement of teeth width
  -Irregular dental surface
  -Irregular periodontal space
  -Irregular alveolar bone
  -Irregular pulp cavity
  -Dental pain
• Temporo-mandibular joint luxation / subluxation - accompanies other dental overgrowth problems

Question 16

What are specific problems of degus, prairie dogs?

Answer 16

• Elodontomas, pseudodontomas
  -neoplasia / hyperplasia of dental roots
  -Usually affects upper incisors
  -URT signs (obstruction)
  -Can affect other rodent species
  -Require extensive surgery for Incisor extraction + Rhinostomy to create a permanent opening