DENTISTRY
Persistent primary teeth are diagnosed when the
primary and secondary teeth are present in the same
alveolus. This results when the normal resorption of
primary teeth fails to occur due to malposition of the
secondary tooth, causing the secondary teeth to erupt
next the primary teeth. A retained deciduous tooth
occurs where there is a primary (deciduous) tooth
without an accompanying secondary (adult) tooth
visible either clinically or radiographically (Figures 2A-
2E).
Figure 2D. Radiographic confirmation of the persistent right
maxillary third incisor.
Figure 2A. A persistent right maxillary canine. Note the swelling
around the primary and secondary canine.
Figure 2E. Persistent primary left mandibular second and fourth
premolars.
Persistent primary teeth may overcrowd the dental arch,
moving the secondary teeth to abnormal locations,
causing oral discomfort. Double sets of roots may also
prevent the normal development of the alveolus and
periodontal support around each permanent tooth,
resulting in early tooth loss. Malpositioned, primary
mandibular canine teeth result in mesioversion (lingual
displacement) of the permanent mandibular canine
teeth causing traumatic occlusion of the hard palate
(Figures 3A and 3B).
Figure 2B.
When a delayed approach is taken to determine
whether the persistent primary tooth will exfoliate, the
secondary adult tooth often becomes permanently
malpositioned, requiring orthodontic movement,
crown reduction or extraction. It is for this reason that
the “wait and see” approach isn’t recommended.
Just say 'no' to a trim
Figures 2B and 2C. Persistent primary maxillary canines and the
right third incisor.
Some breeders trim the primary canine crowns in
hopes that they’ll shed early and possibly prevent
orthodontic problems. Trimming, also known as
deciduous tooth crown reduction, isn’t recommended
because it results in pulp exposure, causing the animal
pain and risking the development of the surrounding
permanent teeth.
Issue 04 | AUGUST 2017 | 31