Tooth eruption is defined as

“ The movement of a toot h from its site of develop

ment within the alveolar process to its functional position in oral cavity,”

Massier and Schour, 1941

Active

Eruption

&

Passive

Eruption

Stage of tooth eruption

• Pre-eruptive• Intraosseous movement

• Eruptive mucosal penetration preocclusal eruption

• Post-eruptive

Pre-eruptive stage

•Deciduous teeth

•Permanent teeth

Eruptive stage

Post-eruptive stage

1. accommodation for growth

2. compensate for occlusal &

interproximal wear (mesial

drift)

3. supraeruption

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Factors consideration in tooth eruption

• development of periodo ntium, root, pulp, alveol ar bone• speed of eruption• events during eruption

– eruptive pathway: gubernacular canal

– 3D movement– inheritable position

Development of Dental Follicle

• cementoblasts

• periodontal ligament

• alveolar bone

Reduced

Enamel Epithelium

Gubernacular canalGubernacular cord

Eruptive Pathway

FORCES of Tooth Eruption

•Root Formation

•Pressure ( Pulp and

Hydrostatic )

•Periodontal Ligament

•Bone Remodeling and Dental

Follicle

Root growth

• relation of root growth and eruptive movement: Carlson (1944)

• remove HERS

• supraeruption

• rootless tooth :Gowgiel 1961, 1967

Pulp growth

• Antimitotic drugs inhibit mitotic activity

of pulp cell :Sicher (1962)Ness & Smale (Sicher (1962)Ness & Smale (

1959)1959)

• Vitamin D deficiency & overdose: Bryer

Hydrostatic pressure

• King & Bryer -> sympathetectomy

• Main (1961) -> Hypotensive drugs

• Hassel & McMinn (1972) -> measure

fluid pressure

Periodontal Ligament

• Berkovitz & Thomas (1969) -> root resection• Michaeli et al (1982) -> degenerate PDL• Ness (1967) -> PLF • Bellows et al (1983) -> PLF

dental

follicle• Control resorption and formation of bone around tooth germ: Cahill & Mark 1974,1980,1983,1987

• no dental follicle, no eruption

• PDL , alveolar bone and cementum are derivative of Dental Follicle

Bone remodeling

• Apposition & resorption of bone

• Vit A and D def. Bone growth

• Metal and Acrylic replica:Marks & Cahill (

1984)

Molecular biology of Bone Remodeling

• Influx of monocytes at the onset of eruption

• appearance of osteoclasts

• signaling molecules

signaling molecules

• CSF-1

• EGF

• IL-1

• TGF alpha

• TGF beta-1

Problem ?????

• In vitro / in vivo

• nature of experimental animal ……extrapolation

• experimental design…isolate single system

Multifactorial

Conclusion of FORCES of Tooth Eruption

(However, “Dental Follicle” Activity & Bone Remodeling have the Highest Potential)

1. Timing of Eruption

2. Unerupted Tooth (Embedded)

3. Tooth Impaction

4. Position of newly Erupted Successor

s

5. Dental Treatment Consideration on

Newly Erupted Tooth

6. Denture and Supra-Erupted Tooth

( Of Deciduous Teeth )

Mono-Phyodontism

Di-PhyodontismPoly-Phyodontism

Pattern of Shedding

•Resorption of roots– anterior/posterior

•Shedding of crown

Cause of shedding

• Pressure from permanent teeth

• loss of bone…weakening of supporter

• trauma and inflammation…occlusal stress, caries .. Etc.

- Gubernacular Canal

- Osteoclasts

- Odontoclasts

- PerioDontal Ligament

Histology of Sheding

Clinical Application

• Remnants of Deciduous Teeth

• Retained Deciduous Teeth

• Submerged Deciduous Teeth