Primary tooth morphology

Question 1

What are early problems that can affect children even before they are born

Answer 1

• gingival cysts
• congenital epulis
• natal or neonatal teeth
• eruption cysts

Question 2

What are gingival cysts also known as

Answer 2

epstein’s pearls or bohns nodules

Question 3

what do gingival cysts look like? Are they a problem?

Answer 3

small white ‘pearls’

Question 4

What does a congenital epulis look like? What happens to them? Are they a problem?

Answer 4

a massive red bulge out of the mucosa.

will shrink as child grows or can be removed. Not dangerous

Question 5

What problems can natal or neonatal teeth cause?

do they tend to be removed?

Answer 5

can be mobile and cause ulcers, not got as strong roots. Sometimes are taken out if a big interference but otherwise not.

Question 6

What does an eruption cyst look like? What causes it? Is it a problem?

Answer 6

a blue blob on the mucosa, blood has got in there, no it will resolve

Question 7

what is the notation of an upper right second primary molar?

What is really important about primary tooth notation

Answer 7

5,5
or
upper right E

never use numbers and letters together

Question 8

When do teeth start to form?

Answer 8

week 5 of intrauterine life

Question 9

When does hard tissue start to form

Answer 9

week 13 of iul

Question 10

What are the calcification dates of the maxilary central incisor

Answer 10

start cal 13-16 weeks iul
crown complete 1.5 months after birth
eruption 8-12 months
root complete 33 months

(see welbury text page 12)

Question 11

What is the chronology of the maxilary second primary molar

hard tissue formation, crown formation, eruption, complete root formation

Answer 11

hard tissue formation 16-23 weeks iul
crown formation complete at 11 months after birth
eruption between 25-33 months
complete root formation 47 months

Question 12

How might the process of calcification cause defects in primary teeth

Answer 12

• systemic disturbances during calcification can lead to defects in the enamel which was forming at that time
• defects in the primary dentition (which are not hereditary) are most likely the result of a difficult pregnancy for the mother/ birth complications

Question 13

How much of central incisors are calcified at birth

Answer 13

1/2

Question 14

How much of lateral incisors are calcified at birth

Answer 14

1/3

Question 15

How much of primary canines are calcified at birth

Answer 15

the tip

Question 16

How much of first primary molars are calcified at birth

Answer 16

1/2

Question 17

How much of second primary molars are calcified at birth

Answer 17

1/3

Question 18

How much of permanent molars are calcified at birth

Answer 18

tip of cusps

Question 19

what are the possible theories behind tooth eruption

Answer 19

• cellular proliferation at the apex of the tooth
• localized change in blood pressure/ hydrostatic pressure
• metabolic activity within the PDL
• resorption of the overlying hard tissue

Question 20

why does resorption of the overlying hard tissue occur

Answer 20

due to enzymes in the dental follicle

Question 21

what does the dental follicle look like on a radiograph?

Answer 21

a dark halo round the unerupted tooth

Question 22

what process is essential for the process of tooth eruption

Answer 22

remodelling

however, it is not necessary for the tooth to erupt to cause resorption of bone

Question 23

what role does the dental follicle play in tooth eruption

Answer 23

is activated to initiate osteoclastic activity in the alveolar bone ahead of the tooth and clear a path for tooth eruption
(once crestal bone has been breached the follicle is likely to play a lesser role)

Question 24

how does eruption occur

Answer 24

• occur gradually
• stops when the tooth comes into contact with something-usually the tooth of the opposing arch
• continues throughout life to compensate for vertical growth of the jaws and tooth wear

Question 25

what is the order of eruption (general rules)

Answer 25

lowers before uppers except lateral incisors central incisor, lateral incisor, first primary molar, canine, second primary molar ABDCE 12435

Question 26

what is the eruption dates for the lower central incisor

Answer 26

4-6 months

Question 27

what is the eruption dates for the lateral incisors

Answer 27

7-16months

Question 28

what is the eruption dates for the 1st molars

Answer 28

13-19 months

Question 29

what is the eruption dates for the canine

Answer 29

16-22 months

Question 30

what is the eruption dates for the 2nd molar

Answer 30

15-33 months

Question 31

teeth of the same series normally erupt between x of their contra lateral tooth

Answer 31

3 months

Question 32

when is primary dentition normally complete by

Answer 32

2.5 - 3 years

Question 33

what is more predictable - eruption of primary or permanent dentition

Answer 33

permanent dentition

Question 34

how do the crowns of primary teeth differ from the crowns of permanent teeth

Answer 34

- the primary incisors are smaller in both their crown and root proportions - the primary molar are wider mesiodistally than the permanent premolars which take there place - primary molars crowns are more bulbous - primary teeth are usually whiter

Question 35

what is the defining feature of an upper 1st primary molar

Answer 35

prominent mesiobuccal tubercle

Question 36

what is the defining feature of the lower 1st primary molar

Answer 36

prominent mesiobuccal tubercle

Question 37

what is the defining feature of the upper 2nd primary molar

Answer 37

transverse ridge

Question 38

what is the defining feature of the lower 2nd primary molars

Answer 38

three buccal cusps (like first permanent molar)

Question 39

how do the roots differ between primary and permanent teeth

Answer 39

- primary teeth tend to have narrower roots - primary molars have longer and more slender roots than permanent molars - roots tend to flare apically to allow room in between for the developing permanent tooth crowns

Question 40

how does the pulp differ between primary and secondary teeth?

Answer 40

- the pulp chambers of the primary teeth are relatively large in proportion to the crowns that surround them - the pulp horns of primary teeth extend high occlusally, placing them closer to the enamel than the pulp of permanent teeth - hence pulpal exposure on cavity preparation is more likely

Question 41

how do the root canals differ between primary and secondary teeth?

Answer 41

tend to be ribbon shaped with multiple interconnecting and accessory canals (clinically impossible to clean completely)

Question 42

how does the hard tissue differ between primary and secondary teeth?

Answer 42

- the thickness of the coronal dentine is much thinner than in permanent teeth - the enamel of the primary teeth is relatively thin and has a consistent depth

Question 43

why do we want anterior spacing in the primary dentition

Answer 43

to prevent crowding in permanent dentition

Question 44

what is anthropoid or primate spacing

Answer 44

spacing mesial to upper deciduous canine | spacing distal to lower deciduous canine

Question 45

what is leeway space

Answer 45

extra mesio-distal space occupied by the primary molars which are wider than the premolars which will replace them - 1.5mm per side on uppers - 2.5mm per side in lowers

Question 46

how does facial growth affect occlusion

Answer 46

downward and forward growth of the facial portion of the skull

Question 47

when is the mixed dentition stage

Answer 47

from the eruption of the first permanent tooth to the exfoliation of the last primary tooth ages 6-11 roughly

Question 48

what is the eruption sequence of permanent teeth

Answer 48

uppers 1st permanent molars then front to back except canines (61245378) lowers 1st permanent molars then front to back (61234578) lowers before uppers except second premolars

Question 49

lower teeth tend to erupt before upper teeth except x

Answer 49

second premolars

Question 50

crowding in the upper arch usually leads to the exclusion of what tooth

Answer 50

upper canine

Question 51

crowding in the lower arch usually leads to the exclusion of what tooth

Answer 51

second premolars

Question 52

how do primary incisors occlude

Answer 52

upright

Question 53

how do permanent incisors occlude

Answer 53

proclined

Question 54

when is the 'ugly duckling phase'

Answer 54

transient spacing of the upper 1's may occur due to the close proximity of their roots to the erupting 2's and 3's

Question 55

how long after eruption does it take for the permanent tooth root to complete apexogenesis

Answer 55

3 years

Question 56

how long after eruption does it take for the primary tooth root to complete apexogenesis

Answer 56

1.5 years