tooth eruption

Question 1

what is intra-osseous eruption?

Answer 1

eruption of tooth through bone via formation and resorption of an eruption pathway

Question 2

What is the difference between modelling and remodelling?

Answer 2

In bone modelling resorption and formation are happening at different surfaces whereas in remodelling they are occurring at the same site.

Question 3

what is pre-occlusal eruption?

Answer 3

movement of crown in to functional position where it meets opposite tooth

Question 4

Why is the theory rejected that teeth erupt through apical pushing force from developing root?

Answer 4

teeth without roots can still erupt.

Question 5

What it the vascular/tissue hydrostatic pressure theory of eruption?

Answer 5

blood pressure or hydrostatic pressures in PDL and pulp may force eruption. Thought to play a part in supra-osseous eruption

Question 6

What is the evidence for vascular/tissue hydrostatic pressure theory?

Answer 6

1. Tooth moves proportional to arterial force
2. Proteoglycans in PDL have osmotic effect and our increased in PDL during eruption
3. experimental changes to PDL vasculature has predictable effects on eruption

Question 7

Name the other theories of eruption?

Answer 7

1. PDL fibroblast contraction
2. Formation and renewal of PDL
3. Alveolar bone modelling

Question 8

what is the importance of Formation and renewal of PDL in eruption?

Answer 8

important for movement of tooth in to occlusal plane and ORTHODONTIC MOVEMENT

Question 9

Why is PDL unlikely to be involved in intra-osseous eruption?

Answer 9

PDL does not form from dental follicle until intra-osseous eruption is complete.

dental papilla fibres are not attached to alveolar bone or correctly oriented in occlusal direction

Question 10

Which hormones are thought to be involved in eruption?

Answer 10

GH and thyroxine

Question 11

Name an example in which physical factors can affect tooth eruption?

Answer 11

thumb sucking

Question 12

What is required for triggering bone modelling during intra-osseous eruption?

Answer 12

DENTAL FOLLICLE

Question 13

What proof is there that formation of eruption pathway is partly under genetic control not just local?

Answer 13

even if the tooth is prevented from erupting the eruptive pathway will still form in bone.

Question 14

Which molecule produced in the dental follicle is key to osteoclastogeneis in eruptive bone modelling?

Answer 14

CSF

Question 15

What is osteoclastogenesis?

Answer 15

formation of osteoclasts

Question 16

What are the events in osteoclastogenesis?

Answer 16

1. Dental follicle releases CSF-1, MCSF-1, MCP-1
2. Influx of mast cells
3. mast cells fuse and form osteoclasts
4. CSF upregulates RANK
5. Osteoclasts activated via binding of RANKL on to osteoclast RANK receptor

Question 17

What inhibits osteoclast formation?

Answer 17

OPG

Question 18

What is the effect of bisphosphonate on eruption?

Answer 18

decreased eruption

Question 19

Where and why does bone formation occur during eruption?

Answer 19

Root apices. Thought to force tooth to move in coronal eruption

Question 20

Which molecule is responsible for osteogenesis in eruption?

Answer 20

BMP-2

Question 21

Define primary failure of tooth eruption?

Answer 21

cessation of tooth eruption BEFORE emergence in to oral cavity. NOT due to physical barrier, abnormal position or systemic cause

Question 22

What genetic disorders may prevent tooth eruption?

Answer 22

1. osteopetrosis.
2. cleidocranial dysplasia (delayed eruption and hyperdontia)
   3.

Question 23

How does cleidocranial dysplasia lead to defective eruption?

Answer 23

1. prevents osteoblast differentiation
2. delayed RANKL induction
3. defective osteoclastogenesis
4. altered dental follicle paracrine signalling
5. increased bone density

Question 24

Tractional force required for tooth eruption, true or false?

Answer 24

FALSE