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==Introduction==
==Introduction==
Incisor overgrowth is common in rabbits. It is either primary or secondary depending on the cause.<br>
Incisor overgrowth is common in rabbits. It is either primary or secondary depending on the cause.<br>
Primary overgrowth occurs early in life as a consequence of inherited skeletal malocclusion (maxillary brachygnathism resulting in a relative mandibular prognathism). <br>
'''Primary''' overgrowth occurs early in life as a consequence of inherited skeletal malocclusion (maxillary brachygnathism resulting in a relative mandibular prognathism). <br>
Secondary overgrowth usually occurs in rabbits 1 year or older as a result of [[Cheek Teeth Malocclusion – Rabbit|cheek tooth overgrowth]]. This is the most common cause of incisor malocclusion in the rabbit.<br>
'''Secondary''' overgrowth usually occurs in rabbits 1 year or older as a result of [[Cheek Teeth Malocclusion – Rabbit|cheek tooth overgrowth]]. This is the most common cause of incisor malocclusion in the rabbit.<br>
Trauma to the teeth or head can also result in incisor pathology.<br>
Trauma to the teeth or head can also result in incisor pathology.<br>
Incisors have been shown to grown up to 5mm/week if not in contact, and disease progression can be rapid if no action is taken.
Incisors have been shown to grown up to 5mm/week if not in contact, and disease progression can be rapid if no action is taken.
==Clinical Signs==
==Clinical Signs==
Signs are similar to those seen with [[Cheek Teeth Malocclusion – Rabbit#Clinical Signs|cheek teeth malocclusion]], including:
Signs are similar to those seen with [[Cheek Teeth Malocclusion – Rabbit#Clinical Signs|cheek teeth malocclusion]], including: ptyalism and wet fur around the chin, weight loss, poor hair coat, [[Clagged Vent – Rabbit|clagged vent]], ileus, epiphora and visible overgrowth, twisting, splaying or slant of the incisors.
==Diagnosis==
==Diagnosis==
==Treatment==
==Treatment==
It must always be remembered that [[Cheek Teeth Malocclusion – Rabbit#Treatment|treatment of the cheek teeth]] is usually also required.<br>
It must always be remembered that [[Cheek Teeth Malocclusion – Rabbit#Treatment|treatment of the cheek teeth]] is usually also required.<br>
Incisors can ben trimmed on a regular basis (every 3-4 weeks) or complete extraction can be performed.
Incisors can be '''trimmed''' on a regular basis (every 3-4 weeks) or '''complete extraction''' can be performed.
===Incisor trimming===
===Incisor trimming===
This is best done using a dental drill but good clippers may have to be employed if a drill is not available (this leads to a much higher risk of iatrogenic damage to the teeth).
This is best done using a '''dental drill''' but good clippers may have to be employed if a drill is not available (this leads to a much higher risk of iatrogenic damage to the teeth).
#The teeth should be cut horizontally at the estimated desired length
#The teeth should be cut horizontally at the estimated desired length
#The bur can be used to apply a bevel to the incisal edges and to remove sharp edges
#The bur can be used to apply a bevel to the incisal edges and to remove sharp edges
#Gently cut the periodontal membrane with a 20G hypodermic needle bent to suit the socket (hence the previous radiograph), holding the socket steady. Arnolds and Veterinary Instrumentation market a special ligament cutter called the Crossley elevator for this, but it doesn’t suit the curvature of every tooth.
#Gently cut the periodontal membrane with a 20G hypodermic needle bent to suit the socket (hence the previous radiograph), holding the socket steady. Arnolds and Veterinary Instrumentation market a special ligament cutter called the Crossley elevator for this, but it doesn’t suit the curvature of every tooth.
#Keep cutting the ligament until the tooth is visibly and palpably loose. Concentrate on the inside curvature, the lateral and mesial surfaces of the teeth, as these are where the periodontal ligament is strongest. This takes quite a long time and is most difficult on the lingual/caudal aspect of the tooth. It is a good idea to work from tooth to tooth and back again, loosening several teeth at once.
#Keep cutting the ligament until the tooth is visibly and palpably loose. Concentrate on the inside curvature, the lateral and mesial surfaces of the teeth, as these are where the periodontal ligament is strongest. This takes quite a long time and is most difficult on the lingual/caudal aspect of the tooth. It is a good idea to work from tooth to tooth and back again, loosening several teeth at once.
#TAKE YOUR TIME! Do not attempt to extract the tooth until it is loose enough or you will break the root and there will be problems with infections or regrowth afterwards.
#'''Take your time!''' Do not attempt to extract the tooth until it is loose enough or you will break the root and there will be problems with infections or regrowth afterwards.
#When adequately loosened, push the extracted incisor back into its socket for about ten seconds to traumatise the deep germinal tissue and prevent regrowth.
#When adequately loosened, push the extracted incisor back into its socket for about ten seconds to traumatise the deep germinal tissue and prevent regrowth.
#Remove the tooth carefully in the curved direction indicated on the radiograph, or follow your observation of the layout of the socket on clinical examination. Use your fingers – not a forceps. Do NOT twist the tooth in its socket as you would with a dog's or cat's incisors. You must not risk breaking the tooth.
#Remove the tooth carefully in the curved direction indicated on the radiograph, or follow your observation of the layout of the socket on clinical examination. Use your fingers – not a forceps. Do '''not''' twist the tooth in its socket as you would with a dog's or cat's incisors. You must not risk breaking the tooth.
#If you do break the tooth, consider culture and antibiotic sensitivity of the socket. And prepare the client for the fact that the tooth may grow back and the whole procedure will have to be repeated especially as the “new” tooth probably won’t grow in a direction compatible with a comfortable mouth!
#If you do break the tooth, consider culture and antibiotic sensitivity of the socket. And prepare the client for the fact that the tooth may grow back and the whole procedure will have to be repeated especially as the “new” tooth probably won’t grow in a direction compatible with a comfortable mouth!
#Repeat the procedure with the four maxillary incisors. In spite of their insignificant size, take the same care with the peg tooth as you did with the major incisors.
#Repeat the procedure with the four maxillary incisors. In spite of their insignificant size, take the same care with the peg tooth as you did with the major incisors.
#Follow-up diet should contain fibre as if the incisors were still present except that greens may have to cut in strips. Incisor-less rabbits can cope well with eating.
#Follow-up diet should contain fibre as if the incisors were still present except that greens may have to cut in strips. Incisor-less rabbits can cope well with eating.
<br>
<br>
Any teeth may re-grow even when removed entire. It is more likely when the pulp is not extracted with the tooth. If the pulp remains in the socket it is best left and a second extraction procedure performed at a later date.
Any teeth may '''re-grow''' even when removed entire. It is more likely when the pulp is not extracted with the tooth. If the pulp remains in the socket it is best left and a second extraction procedure performed at a later date.
==Prevention==
==Prevention==
Provision of grass or hay (Timothy) and edible branches (apple and pear twigs) will provide adequate abrasion for the normal wear of incisors and cheek teeth. Supplemental foods such as concentrates or muesli-type food should not be necessary. <br>
Provision of '''grass or hay''' (Timothy) and edible branches (apple and pear twigs) will provide adequate abrasion for the normal wear of incisors and cheek teeth. Supplemental foods such as concentrates or muesli-type food should not be necessary. <br>
(Note: Trees that bear single-stoned fruits may have unacceptable amounts of cyanide in the bark so don’t offer peach, plum or cherry, for example)
(Note: Trees that bear single-stoned fruits may have unacceptable amounts of cyanide in the bark so don’t offer peach, plum or cherry, for example)
==References==
==References==
Crossley, D (2010) [http://www.vetdent.eu/cpd/cpd.html Online CPD] <br>
Crossley, D (2010) '''[http://www.vetdent.eu/cpd/cpd.html Online CPD]''' <br>
Gorrel, C (2004) Veterinary Dentistry for the General Practitioner, Elsevier Health Sciences
Gorrel, C (2004) '''Veterinary Dentistry for the General Practitioner''', ''Elsevier Health Sciences''
[[Category:Rabbit Dentition]]
[[Category:Rabbit Dentition]]
[[Category:To Do - Review]]
[[Category:To Do - Review]]