Oral and Dental Disease Flashcards
Define Anodontia?
All of the teeth are absent.
Define Oligodontia?
Six or more of low normal tooth number is absent.
Define Hypodontia?
Less than six of the normal number teeth is absent; this might be associated with genetic
abnormalities and is often encountered in lines or families. Permanent teeth develop as a
side bud from the tooth bud that formed the deciduous tooth, it is very likely that if a deciduous tooth is absent, that succedaneous teeth will also be absent. This is not applicable to
permanent teeth that have no deciduous precursors
Define Supernumerary teeth?
This describes teeth that are present in larger numbers than in other normal dentition and
especially the permanent dentition of brachycephalic breeds, supernumerary premolars
are not uncommon.
What can supernumerary teeth lead to?
Often leads to crowding and associated plaque stagnation.
Early onset periodontal disease can be expected in these areas and strategic extraction to prevent this is indicated.
Define Gemination?
Supernumerary teeth develop if a single tooth germ divides into two creating two very similar looking teeth. If this division does not happen completely the result is a tooth that is
partly divided. This often presents as a tooth with a single root but with a double (or bifid)
crown. Radiography is necessary to investigate such teeth.
Discuss tooth fusion?
If two adjacent tooth germs fuse.This results in a larger tooth, that might appear to have a
double crown. (Also bifid crowns) On visual inspection this could closely resemble the appearance of germination. With tooth fusion, the number of teeth will be less than expected
in the normal dentition
Discuss tooth Concrescence?
Concrescence is a condition of teeth where the cementum overlying the roots of at least two teeth join together. It is a developmental anomaly of the teeth, wherein roots fuse, with no evidence of periodontal space between two or more normal teeth below the cementoenamel junction. It usually involves only two teeth.
This
can happen before or after eruption and could be a consequence of crowding
Define Macrodontia?
This describes a tooth that appears larger than normal.
Define Microdontia?
This describes that appears to be smaller than normal and occasionally affects the maxilla
third incisor on dogs. Often radiography is required to distinguish these teeth from retained
deciduous teeth.
Define supernumerary roots?
Additional roots do occur on teeth that usually has two roots only. About 10% of maxillary
third premolars in dogs have a third root. Radiography confirms the presence of a third
root and without radiography extraction of these teeth could be incomplete with one of the roots retained.
Discussed fused roots?
One or more roots of a tooth with multiple roots could fuse. This is another tooth shape
that if not confirmed by radiography could complicate extraction.
To get enamel hypoplasia what stage of embryonal development is affected?
Amelogenisis
What cells produce enamel?
ameloblasts
The formation of enamel by ameloblasts that form the inner layer of the enamel
organ can be affected by changes that occurs during the formation stage. The first stage
of amelogenisis is the?
Formation of the organic matrix that later becomes mineralised by
the deposition of calcium hydroxyapatite crystals.
The enamel of permanent teeth in dogs are formed before the eighth week post partum. This helps us understand the cause of enamel hypoplasia which is?
Enamel defects that are caused by either malformation of the organic
matrix or hypo-mineralisation, could either affect individual teeth or bands of enamel of different teeth at the same stage of development. Trauma to developing tooth buds often affects the enamel of a single or a few teeth in the same area. Pyrexia or infection with epitheliotropic viruses (distemper virus) usually affects multiple teeth.
It is generally
accepted that teeth with enamel hypoplasia might have the dentine exposed but the
enamel that remains covering the coronal dentin, could just be?
thinner
Teeth affected by hypo mineralisation might appear quite normal at eruption. The purely
mineralised enamel is more porous and brittle and stains more readily. These teeth are often affected by extrinsic staining. The purely mineralised, chalky enamel rapidly wears
away during normal use and depending on the degree of damage could eventually expose
the underlying dentin.
It might therefore be possible to distinguish these two lesions (enamel hypoplasia vs enamel hypomineralisation) how?
If they were noticed very soon after eruption of the affected teeth. Once the mineralised enamel had worn away,
histopathology is often the only way to differentiate between these two conditions.
Their shape and number of roots of any tooth is determined by?
Hertwig’s root sheath.
Conditions similar to those causing enamel defects could also affect the number and
shape of?
Roots that are formed during this time.