Developmental Anomalies: Background to Tooth development

Question 1

When are the first signs of tooth development initiation?

Answer 1

6 weeks

Question 2

Which tissue initiates tooth development?

Answer 2

Epithelium initially has the odontogenic potential, then the ectomesenchyme

Question 3

What are the components of the stages of the tooth germ?

Answer 3

• Enamel organ
• Dental papilla
• Dental follicle

= tooth germ

Question 4

What is hypodontia?

Answer 4

Missing teeth as result of them failing to develop

Question 5

What is anodontia?

Answer 5

Total lack of teeth in one or both dentitions

Question 6

What is oligodontia?

Answer 6

Rare condition where more than 6 primary or permanent teeth

Question 7

What is the hypodontia aetiology?

Answer 7

• Considered likely to be genetic
  autosomal dominant inheritance pattern in some families
  mutations in the MSX1 gene on chromosome 4
• Occasionally environmental insult or combination of both
• Sometimes linked to single-gene disorders
• associated with certain syndromes
  trisomy 21 (down syndrome)
  ectodermal dysplasia

Question 8

What are mesiodens?

Answer 8

in the midline; usually peg shaped teeth

Question 9

What are supplemental teeth?

Answer 9

look like a normal tooth

Question 10

describe conical supernumeraries

Answer 10

• if not inverted, there is a good chance they will erupt
• if not impeding eruption of other teeth, can be monitored until erupted
• if inverted, they may migrate superiorly towards nose

Question 11

describe tuberculate supernumeraries

Answer 11

Don’t tend to migrate but may impede eruption of adjacent teeth

Question 12

describe microdontia

Answer 12

• includes peg shaped teeth
• Females > Males
• Lateral incisors most affected

Question 13

Describe macrodontia

Answer 13

• double teeth
• dens in dente (aka dens invaginatus)
• talon cusps

Question 14

fusion

Answer 14

abnormal shaped tooth resulting from fusion of two separate tooth germs

Question 15

gemination

Answer 15

• two teeth develop from one tooth germ
• look abnormally wide
• appear similar clinically and radiographically

Question 16

describe dens in dente

Answer 16

• “A tooth within a tooth”
• localised area of the crown is folded inwards
• Important to pick up at clinical examination because:
• can result in an area of caries, leading to pulpitis and periapical infection
• often difficult/impossible to treat endodontically

Question 17

describe amelogenesis imperfecta

Answer 17

• spectrum of hereditary defects in the function of ameloblasts and mineralisation of enamel matrix
• affects both primary and permanent dentitions

Question 18

amelogenesis imperfecta several classifications but simply

Answer 18

• hypoplastic type (think, but hard enamel; normal bond strength)
• hypomineralised type (full thickness enamel, but very soft; impaired bond strength)

Question 19

amelogenesis imperfecta what are other associated dental defects

Answer 19

• Pulp calcifcation
• Taurodontism
• Delayed eruption
• Gingival overgrowth
• Skeletal anterior open bite

Question 20

dentinogenesis imperfecta (5 main clinical problems)

Answer 20

• Poor aesthetics
• chipping & attrition of enamel
• exposure of dentine
• poor oral hygiene, gingivitis and caries
• pain and infection, pulpal necrosis

Question 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

Question 25

Question 26

Question 27

Answer 27