mechanism of tooth eruption

Question 1

teeth need to become functional

Answer 1

1) to be in mastication
2) however some factors can disrupt this path of eruption

Question 2

what can cause impaction

Answer 2

1) not enough space for eruption
2) jaw did not grow enough (genetics and environment)

Question 3

movements of teeth

Answer 3

1) pre-eruptive
2) eruptive
3) post-eruptive

Question 4

pre-eruptive

Answer 4

1) movements of deciduous and permanent tooth germs within tissues of the jaw before eruption
- bodily movements and eccentric growth
2) permanent molar tooth germs which have no predecessors, develop from the backward extension of the dental lamina

Question 5

eruptive tooth movement

Answer 5

1) move into position in the bone into the functional position in occlusion
2) intraosseous and extraosseous phases
- molecular signals will help
- reduced enamel epithelium
3) similar mechanism to deciduous teeth

Question 6

posteruptive tooth movement

Answer 6

1) movements to accommodate growing jaw
2) those to compensate for continued occlusal wear
3) those to accommodate interproximal wear

Question 7

passive eruption

Answer 7

1) lengthening of the clinical crown due to gingival recession and loss of attachment

Question 8

influence on eruption

Answer 8

1) root growth
- not much contribution
2) main factors
- signals from dental follicle
- alveolar bone remodel
- formation of the PDL

Question 9

reduced enamel epithelium

Answer 9

2) ameloblasts, stratum intermedium, stellate reticulum, outer EE

Question 10

role of dental follicle

Answer 10

1) signaling between REE and dental follicle
2) remarkable consistency of eruption times
- enamel epithelium is programmed as part of functional life cycle
3) CSF-1 and TGF-beta1
4) EGF and IL-1alpha

CORONAL REGION (needs to go up)
5) MCP-1 and CSF-1
- attracting monocytes and differentiation into macrophages and osteoclasts
6) more RANKL and less OPG
7) osteoclastogenesis
- bone resorption

APICAL REGION
1) RUNX2 and BMP2
- deposition of trabecular bone in that areas
- osteoblast activation

Question 11

gubernacular cord and canal

Answer 11

1) eruption - coronal region
2) gubernacular canal connects dental follicle to oral epithelium
- teeth can find its path

Question 12

periodontal ligament

Answer 12

1) fibers have traction power
- fibroblasts
- myofibroblasts (contractile properties)
2) compressing and stretching PDL leads to bone remodeling

Question 13

junctional epithelium

Answer 13

1) from REE
2) attached to toot hand forms a seal between the oral cavity and underlying tissue
3) the connective tissue is lost and two epithelia fuse
- enamel organ over the tooth breaks down to form an epithelium lines canal through which the tooth erupts

Question 14

shedding of the teeth

Answer 14

1) as the permanent teeth increase in size, they erupt and the deciduous teeth and resorbed
2) they usually develop lingually to deciduous teeth

Question 15

premolars

Answer 15

1) between the wide roots of deciduous

Question 16

dental tissue resorption

Answer 16

1) resorption of dental hard tissue is achieved by cells with a histologic nature similar to that of osteoclasts
2) odontoclasts derive from monocytes and migrate from blood vessels to the resorption site

Question 17

memorize exfoliation and eruption times

Answer 17

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Question 18

eruption problems

Answer 18

1) mechanical obstruction x genetic anomalies
2) impaction
3) abnormal eruption path / ectopic dental eruption
4) ankylosis
5) primary failure of eruption
- posterior open bite