Primary incisor malocclusion is most common in young rabbits.  If incisor malocclusion is the only problem in young rabbits, it is likely to have a genetic origin (Verstraete, FJ et al, Dentistry in Pet Rabbits Compendium Sept 2005).  In small rabbit breeds, there is often a disparity on jaw length.  The maxilla is short, in relation to the mandibles.  This condition may be called maxillary brachygnathism.  In these animals, the jaw length discrepancy prevents normal incisor occlusion and wear.  The upper incisors elongate and curl inward.  The lower incisors elongate and protrude in a dorsofacial orientation.  The result is variable degrees of soft tissue trauma as shown in the above photos. 

In older rabbits, incisor malocclusion is often secondary to cheek teeth malocclusion.  This is often related to dietary problems that do not promote normal occlusal wear.  As the cheek teeth elongate, the bite opens and allows for incisor malocclusion and elongation.

Incisor malocclusion may also be a result of injury to incisor teeth.  Fractured teeth may result from trauma such as a fall, or tooth entrapment in a cage.  Iatrogenic injury from teeth clipping can also result in tooth fracture.  Fractured teeth may grow in an abnormal orientation and in some cases, the teeth become non-vital (die).  The fractured tooth will not occlude with the opposing incisor, and elongation may occur with malocclusion development. 

Incisor malocclusion is a life threatening condition that must be addressed.  These animals have difficulty, or an inability to prehend and masticate food.

Treatment

Trimming these teeth does little to resolve the malocclusion.  Periodic trimming is required on a 4-9 week schedule.

The need for frequent trimming becomes inconvenient and expensive for most clients.  Dental extraction of the incisors offers a more permanent solution.