Dental Abnormalities Flashcards
What abnormalities can occur during the initiation stage of tooth growth?
Interference with this trigger for tooth formation, could lead to ADONTIA (absence of teeth)
or HYPODONTIA (reduced number of teeth)
It is also possible that additional (supernumerary) teeth are formed during the initiation
phase.
What abnormalities can occur during the bud stage of tooth growth?
Abnormalities in the shape of the tooth bud could cause MACRODONTIA or MICRODONTIA.
What abnormalities can occur during the cap stage of tooth growth?
Abnormalities that occur during this stage of crown formation, can cause invagination of
the crown into itself causing tooth like structures to develop within the tooth. This is a
rare condition and is called dens in dente. Teeth affected in this way are more prone to
endodontic disease
What other abnormalities can happen during cap stage?
Fusion of two adjacent tooth buds can form one larger tooth. This is confirmed by the
fact that there would be one less tooth than expected in this quadrant.
Germination is a partial or complete split of a single tooth bud to form two crowns
(mirror images of each other). Teeth affected in this way therefore appears to have a
double crown, with a single/partly split root.
What other abnormalities can happen during Apposition and Maturation
stage?
Enamel hypoplasia
Enamel hypomineralisation
Iatrogenic damage (e.g removal deciduous teeth)
Enamel hypomineralisation results in the reduced quality of enamel. This incompletely
mineralised enamel is more prone to staining. This condition can occur because
of?
Infection with epithelio-tropic viruses (e.g. distemper virus) but also by episodes of
pyrexia that occurred during amelogenisis or dentinogenisis
What is Oligodontia?
Fewer than the normal number of teeth. This can also be described as hypodontia.
Any teeth that are visibly absent should be?
Further investigated. These teeth could only be described as absent or missing if
radiographic confirmation that the tooth is not retained (unerupted). Visibly absent tooth
could therefore either be lost (fractured, extracted or lost because of advanced
periodontitis), never developed, or retained (unerupted). Any retained teeth can
possibly develop dentigerous cysts
What is an impacted tooth?
The normal eruption of impacted teeth are obstructed by other teeth.
These teeth are therefore also retained.
What are Supernumerary teeth?
These are extra teeth. These teeth can cause crowding and should be extracted if it causes such problems.
What are Persistent deciduous teeth?
Describes deciduous teeth that remain in the mouth after the permanent teeth have erupted. This can cause deviation of erupting permanent teeth and is a major cause of malocclusion. The expected close proximity between a
permanent and persistent deciduous tooth, causes plaque stagnation in these areas
and subsequent focal periodontal disease. Early extraction of these deciduous teeth are indicated
What is Macrodontia?
Teeth that are abnormally large
What is Microdontia?
Teeth that are abnormally small
What is a Peg tooth?
An abnormally shaped simple tooth with a single cone shaped crown and a single root.
What are supernumerary roots?
This describes a tooth root in addition to the normal
expected roots. This is identified by radiography and an important reason for
preoperative dental radiography.
What is Gemination?
Affected teeth have bifid/split crowns and indicate an incomplete
separation (into two separate teeth) during tooth development. This can be distinguished radiographically and there would therefore be an extra/supernumerary
crown than the anticipated normal number.
What are dilacerated roots?
This indicates a sharp angulation in a tooth root. Another
important radiographic finding to plan extractions.
What is a pulp stone?
This is an abnormal structure (dentin) with in the pulp canal and have implications for endodontic treatment.
What is normal occlusion?
Ideal occlusion can be described as perfect interdigitation of the upper and lower teeth. In the dog, the ideal tooth positions in the arches are defined by the occlusal, inter-arch and interdental relationships of the teeth of the archetypal dog (i.e. wolf). This ideal relationship with the mouth closed can be defined by the following:
Maxillary incisor teeth are all positioned rostral to the corresponding mandibular incisor teeth.
The crown cusps of the mandibular incisor teeth contact the cingulum of the maxillary incisor teeth.
The mandibular canine tooth is inclined labially and bisects the interproximal (interdental) space between the opposing maxillary third incisor tooth and canine tooth.
The maxillary premolar teeth do not contact the mandibular premolar teeth.
The crown cusps of the mandibular premolar teeth are positioned lingual to the arch of the maxillary premolar teeth.
The crown cusps of the mandibular premolar teeth bisect the interproximal (interdental) spaces rostral to the corresponding maxillary premolar teeth.
The mesial crown cusp of the maxillary fourth premolar tooth is positioned lateral to the space between the mandibular fourth premolar tooth and the mandibular first molar tooth.
Normal Occlusion in a Dog:
Normal Occlusion in a Cat:
Normal occlusion in cats is similar to dogs.
Maxillary incisor teeth are labial to the mandibular incisor teeth, with the incisal tips of the mandibular incisors contacting the cingula of the maxillary incisors or occluding just palatal to the maxillary incisors.
Mandibular canine teeth fit equidistant in the diastema between the maxillary third incisor teeth and the maxillary canine teeth, touching neither.
The incisor bite and canine interdigitation form the dental interlock.
Each mandibular premolar tooth is positioned mesial to the corresponding maxillary premolar tooth.
The maxillary second premolar tooth points in a space between the mandibular canine tooth and third premolar tooth.
The subsequent teeth interdigitate, with the mandibular premolars and first molar being situated lingual to the maxillary teeth.
The buccal surface of the mandibular first molar tooth occludes with the palatal surface of the maxillary fourth premolar tooth.
The maxillary first molar tooth is located distopalatal to the maxillary fourth premolar tooth.
What is a Class I malocclusion?
This is described as neutrocclusion at as a normal jaw length is present but a single or a few teeth are abnormally orientated
What is a Rostral cross bite?
One or more mandibular incisors occludes labial to the maxillary incisors or one or more
maxillary Incisors are displaced lingually or occludes on the lingual aspect of the
mandibular Incisors.
What is Mesioversion?
Mesioversion
Displacement of the maxillary canine teeth in a mesial direction. This most commonly
occurs in Shetland sheepdog and could cause displacement of other teeth and possibly
entrapment of the lip. This breed predisposition indicates a genetic underlying cause.
Extraction or orthodontic movement of these teeth or crown reduction with vital pulp
treatment, can be considered and breeding from affected animals should be
discouraged.
What are base narrow mandibular canines?
In cases where the the lower jaw is in fact more narrow, severe crowding of the
mandibular Incisors should be present. This should be distinguished from linguoversion
of mandibular canines. Both of these conditions could cause impingement of mandibular
canine teeth on the hard palate or gingiva.
What is Linguoversion?
With this conformation, the mandibular canines are more upright and can affect either
one or both of these teeth. This usually leads to impingement of these mandibular
canines on the opposing palate.
What is a class 2 malocclusion?
Mandibular distocclusion also described earlier as mandibular brachygnatism.
This indicates that the mandibles are shorter than normal. (Or that the upper jaw is too
long.) This could cause traumatic occlusion by either deciduous or permanent
mandibular canine teeth
What is class 3 malocclusion?
Mandibular mesiocclusion or previously mandibular prognathism. In these cases the
lower jaw are relatively long (or the upper jaw to short.)
In the latter two conditions it is more likely that the facial bones are either too long or too
short.
