Boy et al, Developmental structural tooth defects in dogs Flashcards

Frontier 2016 - Grossely Steenkamp

1
Q

What can you see in this image ?

A

Enamel changes - typical for focal enamel hypoplasia FEH

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2
Q

what is Turner’s hypoplasia?

A

Enamel hypoplasia

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3
Q

What is the most common type of dog tooth abnormality seen in private practice?

A

Enamel hypoplasia

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4
Q

What is this image ?

A

Focal enamel hypoplasia
restoration of EH
Turners tooth

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5
Q

What is this image?

A

Focal enamel hypoplasia
Turners tooth( if 1 tooth is affected )

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6
Q

Most common cause of EH ?

A

Environmental:
trauma - bite wound in 1st 8 to 10 weeks of life ***
infection
chemicals- fluoride

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7
Q

what is this and what happened ?

A

EH - extreme form
Trauma to developing tooth germ cause structural disturbance of AB layer with complete change of developing tooth crown

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8
Q

what is this ?

A

EH or Turners tooth

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9
Q

What causes diffuse enamel hypoplasia DEH?

A

Systemic diseases, direct infection of active enamel producing AB

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10
Q

Amelogensis imperfecta AI - What causes it and how does it present?

A

AI hereditary type of EH
Genetics
Affects all deciduous teeth and or permanent teeth

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11
Q

What are the 3 types of AI?

A

Hypoplastic type - defective matrix secretion by AB
Hypocalcified type - defective mineralization of the matrix
Hypomature type - enamel crystal growth during maturation is defective due to ineffective enamel protein removal

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12
Q

What is internalized discoloration?

A

extrinsic stains gets incorporated in the tooth substance

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13
Q

How does internalized discoloration in extrinsic type of discoloration happen?

A

 due to structural enamel defects either through developmental abnormality of acquired defects following tooth wear, GR, caries, restorative material

Chromogens ( compound that forms colored compounds by oxidation) enter porous defects or open dentinal tubules  discoloration which cannot be removed by scale and polish

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14
Q

what can cause extrinsic staining of the tooth?

A

extrinsic staining: 1) staining of enamel due to pigmentation deposits on enamel surface
2)

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15
Q

how many causes of staining exists?

A

intrinsic and extrinsic staining

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16
Q

what is the cause of intrinsic staining on enamel

A

influenced by thickness and structural properties of enamel -influences the scattering and light absorption of light within the enamel

there is a local and a systemic cause

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17
Q

what are the local causes of intrinsic discoloration ?

A

pulp necrosis, pulpal hemorrhages, pulp tissue remnants after RCT,  deposition of hemoglobin related pigments in dentin

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18
Q

What are the systemic causes of intrinsic discoloration?

A

drug related discoloration tetracycline, metabolic fluorosis , genetic: porphyrins and hyperbilirubinemia deposits as a by product hemolysis , structural defect as AI, dentinogenesis imperfecta abnormal dentin structure- not enough support to enamel fractures

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19
Q

What is dentinogenesis imperfecta?

A

abnormal dentin structure- not enough support to enamel fractures

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20
Q

Tetracycline staining

A

Permanent yellow to brown discoloration to areas of the tooth that was in the process of matrix mineralization and maturation
Do not give to pregnant bitches or puppies <6 months of age
Irreversible staining but does not affect the dental hard tissue structure
Doxycycline – staining less dramatic

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21
Q

list 4 developmental abnormalities

A

Germination, twinning, fusion, concrescence

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22
Q

Another term for germination

A

schizodontism

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23
Q

What is germination?

A

A single tooth germ tries to develop divide into 2 separate teeth

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24
Q

Which teeth are mostly affected by germination? and which dog breed?

A

incisors, canines, premolar teeth,
mainly Boxers

25
Q

what is true germination?

A

2 halves of joined crown are anatomically similar. mirror image with a groove that extends between 2 teeth through incisal edge of crown

26
Q

gemination affects deciduous or permanent dentition in animals?

A

permanent dentition

27
Q
A

Gemination

28
Q

Describe fusion

A
  • 2 separate tooth buds unite at the crown and /or roots before hard tissue formation is complete
29
Q

What is this image ?

A

Fusion with 201, 202 -with double tooth

30
Q

how many root canals does fused teeth have ?

A

usually have separate root canals

31
Q

What is concrescence?

A

Union of 2 or more fully formed teeth by only their cementum without dentin or enamel involvement

32
Q

What is this image ?

A

Concrescence between canine and supernumerary tooth . shared only cementum bridge but not dentin or other hard dental tissue

33
Q
  • True concrescence ( developmental)
A

trauma or crowding with abnormal resorption of interproximal bone and cementum deposition between adjacent roots

34
Q
  • Acquired concrescence ?
A

inflammation induced hypercementosis

35
Q

Another name for Dens invaginatus DI

A

dens in dente

36
Q

Dens invaginatus DI

A

Tooth crown surface invaginates into developing tooth pulp before mineralization

37
Q

What is this image?

A

dens invaginatus

38
Q

there are 3 types of dens invaginatus

Which one is the most uncommon in dogs?

A

 Type 1 = invagination in the crown only not extend beyond CEJ
 Type 2= invagination extends beyond CEJ – into root canal and ends as a blind sac
 Type 3= invagination extends through the root or lateral surface to form additional opening or foramen but with no communication to existing pulp canal

Type 3 is most uncommon

39
Q

What is dilaceration ?

A

 Developmental abnormality of a sharp bent curve along root or crown of a tooth

40
Q

what is this image?

A

Dilaceration of the crown

41
Q

What is this image?

A

Dilaceration of the roots

42
Q

What is dilaceration ?

A

 Developmental abnormality of a sharp bent curve along root or crown of a tooth
 Degree of curvature – varies from 20 to 90 degrees

43
Q

what is the difference between dilaceration and root angulation?

A

root angulation is is a more gradual change in developmental direction of developing tooth

44
Q

in dogs dilaceration is found which condition?

A

X linked hypohidrotic ectodermal dysplasia

45
Q

How is dilaceration formed ?

A

 Acute mechanical trauma with intrusion of deciduous tooth and permament physical damage to tooth
o Mineralized and harder part of developing tooth is displaced and softer non mineralized part and continues developing

46
Q

What are enamel pearls?

A

 Small nodules of enamel <4 mm located on root surface of tooth close or at CEJ

47
Q

What are enamel pearls made out of?

A

 Core of dentin covered by enamel- may contain a pulp chamber

48
Q

where is commonly found?

A

bi or trifurcation of molars
rare on incisors

49
Q

what does neural crest cells from?

A

ectomesenchyme which is important for teeth development

It does not from enamel and some of the cementum

50
Q

Odontogenesis is initiated by ….

A

Formation of a band of thick oral epithelium which give rise to dentinal laminae, thin down growths of epithelium extending from the overlying epithelium into developing jawbone

51
Q

what does the enamel organ consist of?

A

Enamel organ consists out of OEE, IEE, SR

52
Q

amelogenesis can be divided into 2 forms

A

o Hypoplasia of enamel due to incomplete or disruptive enamel matrix production
o Hypoplasia because of inadequate matrix mineralization

53
Q

Eruption time ranges for different types of teeth in the dog

A

 Incisors 12 to 16 weeks
 Canines and premolars 16 to 24 weeks
 Molars 20 to 32 weeks

54
Q

What does HERS consist of and what is its role ?

A

HERS - Consists of OEE and IEE
Outlines the future root and responsible for shape, length, size, number of roots

55
Q

What is the Bell stage?

A

 Bell stage  histological differentiation develops – enamel organ develops into outer enamel epithelium OEE, inner enamel epithelium IEE, stellate reticulum SR, ameloblast and odontoblast differentiate

56
Q

What is the cup stage ?

A

 epithelial cells from a cap over condensed ectomesenchyme dental papilla and origin to the dental follicle
o The ectomesenchyme & odontogenic epithelium surrounds it  tooth germ or dental organ
o The tooth germ continues to proliferate until it looks like a bell

57
Q

What is the age of dental hard tissue formation in permanent teeth in the dog?

A

hard tissue formation of all permanent teeth occurs starts about from early birth to 8 weeks and local infection /trauma in developing canines and max 4th PM as late as 12 weeks of age

58
Q

What happens if there is any interference during odontogenesis ?

A

 Any interference of odontogenesis result in structural abnormalities of enamel and gross anatomy of tooth