DISEASE SUMMARY PAGE

Congenital Incisor Abnormalities in Rabbits

Radiograph showing congenital incisor malocclusion. Click here for full page view with caption Rabbit skull. Click here for full page view with caption

Summary Information
Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease summary
Alternative Names  
Disease Agents
  • Congenital. (B601.18.w18, B614.13.w13, J60.6.w3)
    • Absence of second incisors (peg teeth) has been reported in domestic rabbits and occasionally in wild individuals. There are no apparent ill-effects from this abnormality. (B614.13.w13)
      • This can occur as a dominant or recessive inherited feature. (J213.6.w2)
    • Supranumerary peg teeth; these are much rarer than absence of peg teeth. (B614.13.w13)
    • Hereditary mandibular prognathism leading to incisor malocclusion; this is an autosomal recessive trait with incomplete penetrance. (B601.18.w18, B614.13.w13)
      • This is more common in Netherlands dwarf (B600.7.w7) dwarf breed (B601.18.w18, J60.6.w3) and lop-eared breeds. (J60.6.w3)
    • Normally, the incisors wear one another, causing attrition so that these continually growing teeth remain at an appropriate length. If occlusion does not occur, overgrowth results. (B452.14.w14)
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description
  • The absence of peg teeth, or presence of supranumerary peg teeth, may be an incidental finding when the mouth is examined. (B614.13.w13)
  • With hereditary mandibular prognathism, incisor malocclusion is visible very early - in kits as young as three weeks old. (B614.13.w13)
    • Initial blunting of the cutting edges of the incisors.
    • Lower incisors positioned with their tips against the main upper incisors (they should be against the peg teeth) or anterior to the upper incisors.
    • Overgrowth of both upper and lower incisors, with the upper incisors curling within the mouth and the lower incisors protruding forward from the mouth.
      • Hair or food may be matted round the overgrown teeth. (J60.6.w3)
    • Upper incisors may pierce the buccal or gingival mucosa; mucosal ulceration or abscess formation may occur.
    • Impaired closure of the mouth.
      • Normal molar wear may be impeded.
    • Difficulty in eating.
      • Weight loss and emaciation may result.
    • Difficulty in engaging in normal coprophagy, leading to soiling of the perineal area.

(B614.13.w13, J4.155.w7, Th16.1.w1)

Further Information
Diagnosis
  • Clinical signs and findings from visual examination of the mouth. (B614.13.w13, J15.19.w3)
    • With hereditary mandibular prognathism, initially, edge-to-edge occlusion of the main maxillary and the mandibular incisors (in the normal rabbit, the mandibular incisors should rest against the peg teeth), later more obvious tooth lengthening and abnormal tooth growth. (B614.13.w13)
    • Age of the rabbit: abnormalities are present in the young rabbit. (B614.13.w13, J15.19.w3)
    • The incisors have sound enamel - shiny and smooth, tinged slightly yellow and with a vertical groove running down each tooth (compared to dull, whiter teeth, without the normal vertical groove, and often with horizontal ribbing, seen in acquired incisor abnormality). (J15.19.w3)
  • Radiographical examination of the head. (B614.13.w13)
    • With hereditary mandibular prognathism, overall skull length is reduced and length of the maxillary diastema is reduced, while mandibular length is normal. (B614.13.w13)
Treatment
  • No treatment is necessary for absence of peg teeth or presence of supranumerary peg teeth. (B614.13.w13)
  • For incisor malocclusion due to mandibular prognathism, repeated shortening of the incisors or removal of the incisors. (B614.13.w13, J4.155.w7, J15.19.w3)
    • Surgical removal of the incisors (J15.19.w3)
      • See: Extraction of the Incisors in Rabbits
      • Note:
        • Rabbits are able to eat adequately without their incisors, so long as hard foods (e.g. carrot, apple, broccoli) are chopped or grated. Food will be prehended with the lips. (B600.7.w7, J15.19.w3, J60.6.w3)
        • Rabbits are less able to groom without their incisors. (B600.7.w7)
        • Removing the maloccluded incisors will not prevent development of abnormalities of the cheek teeth. (J15.19.w3)
    • Incisor trimming followed by partial pulpectomy and pulp mummification (B452.14.w14) 
      • Reduce the lower incisors to a length which exposes the pulp.
      • Perform a partial pulpectomy
      • Control haemorrhage if needed by gentle application of the wider end of a paper point to the amputated pulp tissue; if necessary (rare), apply a haemostatic agent.
      • Fill the pulp cavity with a mummifying material such as a paraformaldehyde-based product used for mummification of primary human pulp tissue. (B452.14.w14)
      • Apply a sublining and use composite filling material as a permanent filling.
        • It is important to ensure that the material used is sufficiently soft to wear normally against the opposing teeth. (B452.14.w14, V.w125)

      (B452.14.w14) 

    • Incisor shortening using powered dental burrs or saws. (J15.19.w3)
      • This can be carried out in the conscious rabbit, or with the rabbit sedated or anaesthetised, which may allow better shaping of the incisors. (J15.19.w3)
      • Use an adapted syringe case or wooden tongue depressor to protect the soft tissues during the procedure. (J15.19.w3)
      • After use of powered equipment, cool the teeth using a cold wet swab.
      • The procedure will have to be repeated periodically. (J15.19.w3)
    • Incisor trimming using nail clippers (J15.19.w3)
      • This is the traditional treatment for overlong rabbit incisors. (B600.7.w7, J60.6.w3)
      • This is not ideal but is cheap and quick. (J15.19.w3)
      • It is not possible to produce good tooth alignment or shaping of the occlusal surface. (B601.18.w18, J15.19.w3)
      • There is a risk of the tooth splitting when clipped, exposing the pulp cavity. (J15.19.w3, J60.6.w3)
      • It is common for incisors to fracture longitudinally if cut with clippers. (B601.18.w18)
      • Clipping may leave sharp edges on the teeth. (J15.19.w3)
      • Forces applied during clipping may be painful for the rabbit and may damage the germinal tissues of the tooth. (B601.18.w18)
      • This procedure will have to be repeated every few weeks. (J15.19.w3) every 4-6 weeks (B600.7.w7)
Prevention
  • Do not breed from affected rabbits. (B600.7.w7)
Associated Techniques
Host taxa groups /species
Disease Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referees Molly Varga BVetMed DZooMed MRCVS (V.w125)

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