Dental development and abnormalities

Question 1

What are some features of the primary dentition?

Answer 1

Spacing, anthropoid spaces, Class III tendency (may be edge to edge), anterior open bite, buccal crossbite, flush distal plane.

Question 2

What are the anthropoid spaces and where are they located?

Answer 2

Spaces in the primary dentition that accommodate for the larger permanent incisors.

Upper arch - between B and C; Lower arch - between C and D.

Question 3

What can thumb sucking or use of a pacifier cause?

Answer 3

Anterior open bite.

Question 4

What are some common features of the mixed dentition?

Answer 4

Spaced incisors, proclined 21 12, distal inclined upper laterals, 6s in class II, ugly duckling stage.

Question 5

What is the leeway space?

Answer 5

The difference in combined widths of the C, D and E, and their permanent successors. This space allows for the 6s to erupt into a class I occlusion.

Question 6

What is the leeway space in the maxilla?

Answer 6

1.5mm.

Question 7

What is the leeway space in the mandible?

Answer 7

2.5mm.

Question 8

What are some features of the permanent dentition?

Answer 8

Upper MB cusp in buccal groove of lower 6, no rotation, spacing or crowding, flat occlusal plane, mild curve of spee.

Question 9

What are the main differences between primary and permanent teeth?

Answer 9

Primary teeth are smaller, whiter, have thinner enamel, more bulbous molars, wider contact points, increased pulp to crown ratio, larger pulp horns, and splayed roots.

Question 10

What is hypodontia?

Answer 10

Partial anodontia; the lack of one or more teeth.

Question 11

Which teeth are most commonly missing?

Answer 11

8s, then upper 2s, then 5s.

Question 12

What is severe hypodontia?

Answer 12

6 or more teeth missing.

Question 13

Which syndromes are associated with hypodontia?

Answer 13

Cleft lip and palate, Down syndrome, ectodermal dysplasia.

Question 14

What characterises ectodermal dysplasia?

Answer 14

Hair - fine, dry, sparse; Skin - dry, perioral lesions; Sweat glands - absent; Teeth - hypodontia, small, conical.

Question 15

What are supernumerary teeth?

Answer 15

Extra teeth.

Question 16

What are the 4 different types of supernumerary teeth?

Answer 16

Conical, tuberculate, supplemental, odontome.

Question 17

What are tuberculate supplemental teeth?

Answer 17

Have more than one tubercle or cusp.

Question 18

What are supplemental supernumerary teeth?

Answer 18

An extra tooth exactly the same as the normal tooth.

Question 19

What are odontomes?

Answer 19

Tumours of odontogenic origin.

Two types - compound composite and complex composite.

Question 20

What are compound composite odontomes?

Answer 20

Resemble teeth.

Question 21

What are complex composite odontomes?

Answer 21

Disorganised mass of tissue.

Question 22

What are some problems with supernumerary teeth?

Answer 22

No eruption, delayed eruption, rotation.

Question 23

What is microdontia?

Answer 23

Abnormally small teeth.

Question 24

Which teeth are most commonly affected by microdontia?

Answer 24

Maxillary lateral incisors.

Question 25

Which abnormality is microdontia associated with?

Answer 25

Hypodontia.

Question 26

What is the treatment of microdontia?

Answer 26

Crown or extraction + ortho.

Question 27

What is an accessory cusp?

Answer 27

Talon cusp.

Question 28

What issues can accessory cusps cause?

Answer 28

Rarely causes issues in molars, can interrupt occlusion on anterior teeth.

Question 29

What is the treatment of accessory cusps?

Answer 29

Dependent on extent; Nil, fissure sealants, selective grinding, sectioning and pulpotomy.

Question 30

What is invagination - dens in dente?

Answer 30

Invagination of enamel giving the radiographic appearance of a tooth within a tooth.

Question 31

What is the treatment of dens in dente?

Answer 31

Fissure sealant, RCT, extraction.

Question 32

What is taurodontism?

Answer 32

Multi-rooted teeth characterised by abnormally short roots and abnormally large pulp chamber.

Question 33

What is molar incisor hypomineralisation?

Answer 33

Developmental condition causing enamel hypomineralisation of 6s and 1s.

Question 34

What are the causes of MIH?

Answer 34

Unknown, thought to be an event during enamel development (from birth until 1y) including fever, malabsorption, systemic illness.

Question 35

What is the treatment of MIH?

Answer 35

1s - composite, microabrasion; 7s - seal, PMC, onlay, extraction.

Question 36

What causes fluorosis?

Answer 36

Excess ingested fluoride during tooth development.

Question 37

How does fluorosis present?

Answer 37

Mottling, hypoplasia.

Question 38

What is the treatment for severe fluorosis?

Answer 38

Microabrasion.

Question 39

What is amelogenesis imperfecta?

Answer 39

Hereditary condition affecting the matrix or mineralisation of enamel.

Question 40

What are the clinical features of amelogenesis imperfecta?

Answer 40

Different clinical features depending on which genes are affected; teeth may be hypoplastic or hypomineralised.

Question 41

What is dentinogenesis imperfecta?

Answer 41

Hereditary condition affecting dentine formation.

Question 42

What are the features of dentinogenesis imperfecta?

Answer 42

Dentine exposure due to early enamel loss, dentine is blue grey, attrition, pulp exposure.

Question 43

How does dentinogenesis imperfecta present radiographically?

Answer 43

Bulbous crowns, short and thin roots, large pulps.

Question 44

What is the treatment of dentinogenesis imperfecta?

Answer 44

PMC, extraction.

Question 45

What are natal teeth?

Answer 45

Present at birth.

Question 46

What are neonatal teeth?

Answer 46

Erupt within 1 month of birth.

Question 47

What is the treatment of neonatal/natal teeth?

Answer 47

Reassure; extract if risk of inhalation or significantly affecting feeding.

Question 48

What are some possible causes of delayed eruption?

Answer 48

Supernumerary, dilaceration, cyst, impaction, premature loss of primary teeth, Down's syndrome, endocrine.

Question 49

How can dilaceration cause delayed eruption?

Answer 49

Can occur in primary tooth due to trauma and can displace the permanent tooth germ or damage it.

Question 50

How can premature loss of primary teeth affect eruption?

Answer 50

Scar tissue can form which can affect eruption.

Question 51

What can cause infraoccluded primary molars?

Answer 51

Ankylosis.

Question 52

What is the treatment of infraoccluded primary molars?

Answer 52

If successor present, leave to exfoliate; if no successor, composite onlay.