physiologic tooth movement─ eruption and shedding 高雄醫學大學 兒童牙科 陳弘森...
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PHYSIOLOGIC TOOTH MOVEMENT─ ERUPTION AND SHEDDING
高雄醫學大學 兒童牙科陳弘森
07-3121101-7008, 7020hosech@kmu.edu.tw
Eruption
Movement of a tooth through the jaw into the oral cavity.
Pattern of tooth movement
1. preeruptive movement
2. eruptive movement
3. posteruptive movement
Histology of tooth movement
Preeruptive phase Eruptive phase Posteruptive phase
Preeruptive phase
Bodily movement Excentric growth bony remodeling osteoclast
Eruptive phase
Root formation Periodontal ligament Dento-gingival juction
Posteruptive phase
Condylar growth Jaw bone growth
Direction of tooth movement
Axial Drifting Tilting Rotating
Tooth eruption mechanism
The push mechanism The pull mechanism
Push mechanism
Root growth (Pierce 1887) Vascular pressure (Constant 1900) Bone growth (Brash 1928) Cellular proliferation (Eidmann 1923) Dental follicle
Pull mechanism
Collagen maturation (Thomas 1967) Fibroblasts (Ness 1967)
Eruption rates
Mouse Guinea pig 200-1100 μ m/day Rabbit Human 140 μ m/day
(5 μ m/day)
Clinical consideration
Early eruption Delayed eruption Impacted
Shedding(exfoliation)
Gradual removal of roots and alveplar bone
Shedding of teeth
odontoclasts pressure
odontoclasts
Cementoclas Dentinoclast
Histology of shedding
Odontoclasts
Large multinucleated cell
Cytoplasm of vacuole
Dense mitochondria
Brush border surface
Acid phosphatase
Odontoclasts
resorption bay (Howship’s lacunae)
brush border (ruffled border ; microvilli )
acid phosphatase
Root resorption
resorption period rest period repair period
Clincal consideration
Remnants of deciduous tooth Retained deciduous tooth Submerged deciduous tooth
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