Selected Canine Malocclusions:
RostralCrossbite,Mesioversion of Maxillary Canines, and
Linguoversion of Mandibular Canines
Malocclusions in the canine mouth need to be diagnosed
and addressed by the general practitioner because they
can cause soft tissue trauma, dental trauma,dysphagia, and
excessive tartar and calculus build up. Treatment may be
by exodontic, orthodontic, or coronoplasty dependent on
the malocclusion, skill of the practitioner, and available
funds of the owner. Three common malocclusions will be discussed;
rostralcrossbite, mesioversion of maxillary canines,
and linguoversion of mandibular canines.
Rostral or anterior crossbite occurs when one or more of
the mandibular incisors have reversed occlusal orientation
with their maxillary counterparts which can be dental
or skeletal in origin. Normally, the mandibular incisor
occludes palatally to the maxillary incisor at the cingulum
of the maxillary incisor. If anterior crossbite is the only
malocclusion (all other occlusal parameters normal) it may
be assumed that the causative agent was trauma, nutrition,
disease, or retention of deciduous teeth and not genetic.
The importance of genetics is that it is considered unethical
to treat animals orthodontically if they are reproductively
intact. The most common orthodontic method of correction
is by the use of the Maryland
This, and most orthodontic work, is usually referred to
a veterinary dentist. Interceptive exodontics can be done
by the general practitioner if the anterior crossbite is
discovered while the deciduous teeth are present. The deciduous
incisors are removed to break the dental interlock and enable
the "short maxilla" to out-grow the mandible.
Mesioversion or rostral displacement of the maxillary canine,
also called "lance canine", is thought to be the
result of retained deciduous teeth and Shetland sheepdogs
seem to be predisposed to this condition and as such, the
breeding of Shelties with lance canine should be greatly
discouraged. This malocclusion can lead to the attrition
of the enamel on the mesial aspect of the maxillary canine
and the distal aspect of the mandibular canine often leading
to endodontic involvement. Once again, it is important to
watch for evidence of eruption of the permanent maxillary
canines (5-7 months). A dental rule of thumb is that deciduous
teeth should be extracted as soon as the permanent teeth
are erupting, even if they are lose. Orthodontic
treatment is available.
Linguoversion of lingual displacement of the mandibular
canine commonly referred to as "base narrow canines"
is common in doliocephalic dogs and is thought to be the
result of retained deciduous teeth. This malocclusion can
be insidious, in that it is easily missed by casual observance
by owner and practitioner alike. These animals often present
with dysphagia if the problem goes unnoticed or uncorrected.
The base narrow canines can damage the palate, cause pain,
and possibly oronasalfistuli. They also may contact the
maxillary canines and cause attrition. There are three main
procedures to correct this problem. The first is removal
of the base narrow canines. This can be difficult and the
possibility of mandibular fracture during the extraction
can be daunting. The second is blunting of the mandibular
canines and pulpotomy. The pulpotomy and sealing of the
canal must be done to keep the tooth vital and eliminate
endodontic involvement. This procedure may have to be repeated
if the canine tooth erupts further. The third is orthodontic
treatment by a veterinary dentist, this can be a very involved
route to take. If the correct space (between the lateral
incisor and the maxillary canine) is not wide enough to
allow proper dental interlock it must be corrected prior
to movement of the mandibular canines by another orthodontic
In conclusion, dental malocclusions are often underdiagnosed
or ignored pathology. Understanding and treating these
conditions can lead to healthier patients and happier owners.
The sooner the malocclusion is diagnosed, the shorter the
treatment time will be. You are encouraged to refer cases
to a veterinary dentist where applicable, but you must know
enough about the problem to be sincere to the client when
recommending often very expensive treatments.
- William J.Aylward,BS, Class of 1996
- Edited by H.L.Thacker,DVM,PhD
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