Boy et al, Developmental structural tooth defects in dogs

Question 1

What can you see in this image ?

Answer 1

Enamel changes - typical for focal enamel hypoplasia FEH

Question 2

what is Turner’s hypoplasia?

Answer 2

Enamel hypoplasia

Question 3

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

Answer 3

Enamel hypoplasia

Question 4

What is this image ?

Answer 4

Focal enamel hypoplasia
restoration of EH
Turners tooth

Question 5

What is this image?

Answer 5

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

Question 6

Most common cause of EH ?

Answer 6

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

Question 7

what is this and what happened ?

Answer 7

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

Question 8

what is this ?

Answer 8

EH or Turners tooth

Question 9

What causes diffuse enamel hypoplasia DEH?

Answer 9

Systemic diseases, direct infection of active enamel producing AB

Question 10

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

Answer 10

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

Question 11

What are the 3 types of AI?

Answer 11

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

Question 12

What is internalized discoloration?

Answer 12

extrinsic stains gets incorporated in the tooth substance

Question 13

How does internalized discoloration in extrinsic type of discoloration happen?

Answer 13

 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

Question 14

what can cause extrinsic staining of the tooth?

Answer 14

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

Question 15

how many causes of staining exists?

Answer 15

intrinsic and extrinsic staining

Question 16

what is the cause of intrinsic staining on enamel

Answer 16

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

Question 17

what are the local causes of intrinsic discoloration ?

Answer 17

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

Question 18

What are the systemic causes of intrinsic discoloration?

Answer 18

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

Question 19

What is dentinogenesis imperfecta?

Answer 19

abnormal dentin structure- not enough support to enamel fractures

Question 20

Tetracycline staining

Answer 20

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

Question 21

list 4 developmental abnormalities

Answer 21

Germination, twinning, fusion, concrescence

Question 22

Another term for germination

Answer 22

schizodontism

Question 23

What is germination?

Answer 23

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

Question 24

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

Answer 24

incisors, canines, premolar teeth,
mainly Boxers

Question 25

what is true germination?

Answer 25

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

Question 26

gemination affects deciduous or permanent dentition in animals?

Answer 26

permanent dentition

Question 27

Answer 27

Gemination

Question 28

Describe fusion

Answer 28

* 2 separate tooth buds unite at the crown and /or roots before hard tissue formation is complete

Question 29

What is this image ?

Answer 29

Fusion with 201, 202 -with double tooth

Question 30

how many root canals does fused teeth have ?

Answer 30

usually have separate root canals

Question 31

What is concrescence?

Answer 31

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

Question 32

What is this image ?

Answer 32

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

Question 33

* True concrescence ( developmental)

Answer 33

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

Question 34

* Acquired concrescence ?

Answer 34

inflammation induced hypercementosis

Question 35

Another name for Dens invaginatus DI

Answer 35

dens in dente

Question 36

Dens invaginatus DI

Answer 36

Tooth crown surface invaginates into developing tooth pulp before mineralization

Question 37

What is this image?

Answer 37

dens invaginatus

Question 38

there are 3 types of dens invaginatus Which one is the most uncommon in dogs?

Answer 38

 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

Question 39

What is dilaceration ?

Answer 39

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

Question 40

what is this image?

Answer 40

Dilaceration of the crown

Question 41

What is this image?

Answer 41

Dilaceration of the roots

Question 42

What is dilaceration ?

Answer 42

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

Question 43

what is the difference between dilaceration and root angulation?

Answer 43

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

Question 44

in dogs dilaceration is found which condition?

Answer 44

X linked hypohidrotic ectodermal dysplasia

Question 45

How is dilaceration formed ?

Answer 45

 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

Question 46

What are enamel pearls?

Answer 46

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

Question 47

What are enamel pearls made out of?

Answer 47

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

Question 48

where is commonly found?

Answer 48

bi or trifurcation of molars rare on incisors

Question 49

what does neural crest cells form?

Answer 49

ectomesenchyme which is important for teeth development It does not from enamel and some of the cementum

Question 50

Odontogenesis is initiated by ....

Answer 50

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

Question 51

what does the enamel organ consist of?

Answer 51

Enamel organ consists out of OEE, IEE, SR

Question 52

amelogenesis can be divided into 2 forms

Answer 52

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

Question 53

Eruption time ranges for different types of teeth in the dog

Answer 53

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

Question 54

What does HERS consist of and what is its role ?

Answer 54

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

Question 55

What is the Bell stage?

Answer 55

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

Question 56

What is the cup stage ?

Answer 56

 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

Question 57

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

Answer 57

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

Question 58

What happens if there is any interference during odontogenesis ?

Answer 58

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