Paediatric tooth morphology

Question 1

What are the quadrants of primary dentition

Answer 1

5 (UR), 6(UL), 7(LL), 8(LR)

Question 2

What does contra lateral tooth mean

Answer 2

Teeth of the same series
ex. upper right canine with upper left canine

Question 3

What is the difference between primary and permanent dentition

Answer 3

The primary incisors are smaller in both their crown and root proportions

The primary molars are wider mesiodistally than the permanent premolars which take there place.

Primary molars crowns are more bulbous

The primary teeth are usually whiter in colour due to enamel being thinner

Question 4

What are gingival cysts

Answer 4

Small collections of keratin white appear as white spots in gingiva. Not a concern for dentists just useful to recognise

Question 5

What is congenital epulis

Answer 5

A growth in the mucosa. (benign tumour of oral cavity) Not concerning im children unless interfeering with feeding

Question 6

What are natal or neonatal teeth

Answer 6

Teeth present before or shortly after birth. Usually the primary incisors developed in an ectopic position. Only removed when threatening airway (not attached so could fall out) or giving problems with feeding in which case they might be smoothed down

Question 7

What does an eruption cyst appear like

Answer 7

Small fluid fild sac within the gum. Sometimes blue colour due to blood within the folicle. These often resolve naturally

Question 8

When do teeth start forming

Answer 8

During week 5 of intra-uterine life (IUL)

Question 9

When does hard tissue formation of primary teeth begin

Answer 9

Week 13 of intra-uterine life

Question 10

When would the root formation of a maxillary central incisor be completed

Answer 10

When a child is around 33 months (3 years)

Question 11

When is the crown of maxillary second primary molars (55 65) completed

Answer 11

At 11 months after birth

Question 12

when do the primary second molars usually erupt

Answer 12

Bewteen 25-33 months

Question 13

When are the second primary molar roots fully formed

Answer 13

By around 47 months

Question 14

What often causes defects in primary dentition

Answer 14

Systemic disturbances during calcifiction (complicated pregnancy or problems at birth)

Question 15

How much of the crowns of each tooth are calcified by birth

Answer 15

½ of central incisors

¹/3 of lateral incisors

Tip of primary canines

½ of first primary molars

¹/3 of second primary molars

Tip of cusps of first permanent molars

Question 16

What causes tooth eruption

Answer 16

The exactbiology has not been explained but a force must be generated to propel the tooth through the bone and gingival tissue. In the case of the permanent dentition the primary tooth root must also be removed in some cases

Question 17

What are some possible theories behind tooth eruption

Answer 17

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 18

What role does the dental follicle play in tooth eruption

Answer 18

Follicle is activated to initiate osteoclastic activity in the alveolar bone ahead of the tooth and clear a path for tooth eruption (unsure what signals this)

Question 19

Once a path for tooth eruption is acheived what is the role of osteoclasts

Answer 19

There is no osteoclastic activity once the path is cleared

Question 20

When does tooth eruption stop

Answer 20

When the tooth comes into contact with something (i.e opposing arch)
-Continues throughout life to compensate for vertical growth of the jaws and tooth wear

Question 21

When is primary dentition usually complete

Answer 21

2.5/3 years

Question 22

What tooth has a prominent mesiobuccal tubercle

Answer 22

Upper first primary molar (D or 4)

Question 23

Which tooth has a transverse ridge

Answer 23

Upper right second molars (E or 55)

Question 24

Which primary tooth has 3 buccal cusps

Answer 24

Lower right second primary molar (E or 85)

Question 25

Why do primary teeth roots tend to flare and flatten

Answer 25

To allow room in between for the developing permanent tooth crowns

Question 26

What are the differences of the hard tissue in primary and permanent teeth

Answer 26

Coronal dentine is much thinner in primary teeth along with the enamel with has a consistent thinner depth of primary teeth and doesnt vary

Question 26

What is anthropoid or primate spacing

Answer 26

Spacing mesial to upper deciduous canine
(52 —> 53)

Spacing distal to lower deciduous canine.
(73 —–> 74)

Question 27

What is the usual leeway space caused by the primary molars

Answer 27

Usually 1.5 mm per side upper and 2.5 mm per side lower

Question 28

When does mixed dentition begin

Answer 28

When the first permanent tooth erupts and ends when the last primary tooth is exfoliated (6-11 years)

Question 29

What is often the last tooth to erupt

Answer 29

Permanent canine

Question 30

What is often the last primary tooth to fall out

Answer 30

Primary upper canine

Question 31

What is the eruption sequence of permanent teeth

Answer 31

UPPER:
6,1,2,4,5,3,7,8

LOWER:
6,1,2,3,4,5,6,7,8

Question 32

How long does it take for a permanent root to complete apexogenesis from eruption

Answer 32

3 years (1.5 in primary)