Oral and Dental Disease

Question 1

Define Anodontia?

Answer 1

All of the teeth are absent.

Question 2

Define Oligodontia?

Answer 2

Six or more of low normal tooth number is absent.

Question 3

Define Hypodontia?

Answer 3

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

Question 4

Define Supernumerary teeth?

Answer 4

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.

Question 5

What can supernumerary teeth lead to?

Answer 5

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.

Question 6

Define Gemination?

Answer 6

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.

Question 7

Discuss tooth fusion?

Answer 7

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

Question 8

Discuss tooth Concrescence?

Answer 8

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

Question 9

Define Macrodontia?

Answer 9

This describes a tooth that appears larger than normal.

Question 10

Define Microdontia?

Answer 10

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.

Question 11

Define supernumerary roots?

Answer 11

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.

Question 12

Discussed fused roots?

Answer 12

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.

Question 13

To get enamel hypoplasia what stage of embryonal development is affected?

Answer 13

Amelogenisis

Question 14

What cells produce enamel?

Answer 14

ameloblasts

Question 15

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?

Answer 15

Formation of the organic matrix that later becomes mineralised by
the deposition of calcium hydroxyapatite crystals.

Question 16

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?

Answer 16

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.

Question 17

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?

Answer 17

thinner

Question 18

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?

Answer 18

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.

Question 19

Their shape and number of roots of any tooth is determined by?

Answer 19

Hertwig’s root sheath.

Question 20

Conditions similar to those causing enamel defects could also affect the number and
shape of?

Answer 20

Roots that are formed during this time.

Question 21

What is Amelogenisis imperfecta?

Answer 21

Amelogenesis imperfecta (AI) is a congenital disorder which presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel (ameloblastin, enamelin, tuftelin and amelogenin) as a result of abnormal enamel formation via amelogenesis.

People with amelogenesis imperfecta may have teeth with abnormal color: yellow, brown or grey; this disorder can affect any number of teeth of both dentitions. Enamel hypoplasia manifests in a variety of ways depending on the type of AI an individual has (see below), with pitting and plane-form defects common. The teeth have a higher risk for dental cavities and are hypersensitive to temperature changes as well as rapid attrition, excessive calculus deposition, and gingival hyperplasia. The earliest known case of AI is in an extinct hominid species called Paranthropus robustus, with over a third of individuals displaying this condition.

Question 22

What is Amelogenisis imperfecta?

Answer 22

This genetic condition causes abnormalities in all or most of the teeth of affected individuals. These teeth could be small, abnormally formed, discoloured and abnormally grooved
and fissured. Many of these teeth will either be the partly erupted or un-erupted.

Question 23

What breeds of dog are more prone to Amelogenisis imperfecta?

Answer 23

Ectodermal dysplasia occurs in some dog breeds like the Mexican Hairless and Chinese
Crested. In these breeds this is linked to an autosomal dominant gene. The malformation
of teeth in these breeds are also accompanied by defects in skin and hair development

Question 24

Discuss dilacerated roots?

Answer 24

Teeth affected by this condition shows acute angles to the apical aspects of some of the
tooth roots. Without dental radiography preoperatively, the surgeon would be unaware of
this complication and this would potentially complicate the extraction and often lead to root
fracture during extractions.

Question 25

Discuss convergent roots?

Answer 25

In affected teeth, the roots tend to be angled towards each other rather than the normal divergent position. This is another condition that if not indicated by pre-extraction radiography, that would complicate extraction unnecessarily.

Question 26

What is Dens-en-dente/Dens-Invaginalis?

Answer 26

in these teeth folding and invagination of the enamel into the pulp chamber occurs during crown formation, prior to mineralisation. The changes to the shape of these crowns could be either very obvious or very inconspicuous. The roots of these teeth could also be affected and except in extreme cases, radiography is required to make the diagno

Question 27

What are teeth with Dens-en-dente/Dens-Invaginalis more susceptible to?

Answer 27

Teeth with crowns deformed in this way, are far more susceptible to the formation of endondontic or periodontal disease. Endodontic treatment of affected teeth is often not possible because of the significant abnormalities in the pulp canal and the presence of pulp stones and extraction is usually their only option.

Question 28

When should deciduous teeth exfoliate?

Answer 28

As a general rule there should not be a deciduous and a permanent member of any tooth present in the mouth at the same time. This implies that the deciduous tooth should not remain after more than about three quarters of the crown of the succedaneus tooth crown had emerged.

Question 29

What are the implications of persistent deciduous teeth?

Answer 29

The implication of persistent deciduous teeth is that it may interfere with the normal eruption path of the permanent tooth. This displacement of the permanent tooth could cause malocclusion and persistent deciduous teeth are considered the most important cause of malocclusion.

Question 30

The extraction of deciduous teeth that are causing or threatening to cause a displacement of permanent a tooth is called?

Answer 30

Intercepted orthodontics and can be very effective method to prevent malocclusion.

Question 31

What other problems do persistent deciduous teeth cause?

Answer 31

Persistent deciduous teeth also cause crowding and a close proximity of the deciduous and permanent teeth, causes areas of severe plaque stagnation and this leads to formation of localised or focal periodontal disease, that affects both the deciduous and permanent teeth.

Question 32

What should be done with deciduous teeth that remain and have no permanent tooth to replace it?

Answer 32

Deciduous teeth that are not replaced by a permanent one, could remain in the mouth and mature like a permanent tooth. These teeth are almost invariably smaller and the roots more slender and even if it matured normally, remains more fragile than a permanent tooth. If radiography confirms no resorption of the roots of deciduous teeth and there is no permanent replacement, there is no real indication to extract these teeth. It does however remain possible that spontaneous resorption of such deciduous tooth roots could occur.

Question 33

What should happen with unerupted teeth?

Answer 33

Visibly absent teeth, should be investigated to establish the situation. It is possible that some retained teeth could form dentigerous cysts. These cystic structures form by the accumulation of fluid between the inner enamel epithelium of the crown of an uninterrupted tooth.

Question 34

What is an embedded tooth?

Answer 34

These teeth have formed normally but for unexplained reasons have not erupted normally.

Question 35

What is an impacted tooth and what are the treatment options?

Answer 35

These retained teeth fail to erupt because of the obstruction of the normal eruption path, by either adjacent teeth or soft tissue. Radiography is essential to establish the position of these teeth. Extraction of the impacted tooth or of a less important teeth obstructing this process, is usually indicated. Regular radiographic monitoring could be sufficient if unerupted teeth without any associated cystic change, is diagnosed in mature patients. If soft tissue causes an obstruction, exposure of the tooth by removal of the tough gingival tissue could be a good treatment option. This procedure is described as operculectomy.

Question 36

If soft tissue causes an obstruction to a tooth eruption, exposure of the tooth by removal of the tough gingival tissue could be a good treatment option. This procedure is described as?

Answer 36

Operculectomy

Question 37

To be classified as a true cyst, a space needs to be lined by?

Answer 37

Epithelium

Question 38

Dentigerous cysts are the most common odontogenetic cysts that occur in dogs but is rarely seen in?

Answer 38

cats

Question 39

Dentigerous cysts are always associated with?

Answer 39

An unerupted tooth and often affects the first mandibular or maxillary premolars.

Question 40

What breeds are more commonly associated with dentigerous cysts?

Answer 40

Brachycephalic breeds are more frequently affected.

Question 41

What is the pathophysiology of a dentigerous cyst?

Answer 41

During normal eruption the reduced enamel epithelium that covers the crown and is attached to the neck of the tooth, fuses with the oral epithelium. If this process does not occur, fluid might accumulate between the tooth crown and this epithelial membrane. The slowly expanding mass causes destruction of the surrounding bone and also causes resorption of tooth roots in contact with a cyst.

Question 42

If left untreated what can happen with a dentigerous cyst?

Answer 42

If left untreated the bone destruction could eventually lead to pathological fracture.

Question 43

When treating an dentigerous cyst what must be done?

Answer 43

During surgery to treat this condition the epithelium lining of the cyst should be removed completely. Neoplastic metaplasia of this lining is possible and even though extremely rare, it is advisable to submit some of the cyst lining for histopathological examination.

Question 44

What is the Clinical approach to visibly absent teeth?

Answer 44

Teeth that are visibly absent justifies further investigation these teeth could either be lost through fracture periodontal disease or extraction, or it is that such teeth never developed. The most significant cause of visibly absent teeth, is retained teeth. Significant proportion of retained teeth are associated with the formation of cystic change.

Question 45

What is an Odontoma?

Answer 45

These expanding masses are non-neoplastic and could be better described as a hamartoma. The latter of overgrowth of cells in an abnormal body position. A definitive diagnosis can usually be made based on radiographic appearance. Biopsy is only indicated if the latter is inconclusive. A compound odontoma shows radiographic evidence of tooth-like structures called denticles. In complex odontomas, the structures are not easily distinguished as tooth-like. Odontomas will slowly expand so surgical excision is advisable, but no significant surgical margins are required.

Question 46

What is a Feline Inductive Odontogenic Tumour (OM/FIO)?

Answer 46

This is a rare tumour that occurs in young cats. It is benign but locally invasive. It is radiographically characterised by a rapidly expansile radiolucent lesion at the rostral aspects of either the maxilla or mandible

Question 47

What is Macroglossia?

Answer 47

In patients affected by this condition the tongue appears to be abnormally large. This can either be a true enlargement or oversized tongue, or it could also be that the tongue is large in relation to an altered jaw conformation, “normal” in brachycephalic dog breeds.

Question 48

What is Microglossia?

Answer 48

The tongue is smaller than normal, so called “bird tongue”. The edges of these smaller tongues are curved inwards and upwards and affected juveniles have great difficulty in suckling normally.

Question 49

What is Ankyloglossia?

Answer 49

In this condition the tongue appears to be more firmly attached to the floor by mouth by means of a shorter than normal lingual frenulum. This is not an uncommon problem in humans and is often referred to as tongue-tied.

Question 50

Discuss hairy tongues?

Answer 50

In breeds like spaniels and labradors, hair sometimes becomes embedded in the central raphe of the tongue. This foreign material causes localised irritation and inflammation. Removal of the hair from this area improves the situation but sadly it will usually reoccur very rapidly. Recent studies have found that heterotrophic hair shafts can actually form along the median raphe of the tongue. In these cases, there is no inflammation associated with the hair.