1. PHYSIOLOGIC TOOTH MOVEMENT─ ERUPTION AND SHEDDING 高雄醫學大學 兒童牙科 陳弘森 07-3121101-7008, 7020 hosech@kmu.edu.tw

2. Eruption  Movement of a tooth through the jaw into the oral cavity.

5. Pattern of tooth movement 1. preeruptive movement 2. eruptive movement 3. posteruptive movement

6. Histology of tooth movement  Preeruptive phase  Eruptive phase  Posteruptive phase

7. Preeruptive phase  Bodily movement  Excentric growth bony remodeling osteoclast

11. Eruptive phase  Root formation  Periodontal ligament  Dento-gingival juction

15. Posteruptive phase  Condylar growth  Jaw bone growth

18. Direction of tooth movement  Axial  Drifting  Tilting  Rotating

22. Tooth eruption mechanism  The push mechanism  The pull mechanism

23. Push mechanism  Root growth (Pierce 1887)  Vascular pressure (Constant 1900)  Bone growth (Brash 1928)  Cellular proliferation (Eidmann 1923)  Dental follicle

24. Pull mechanism  Collagen maturation (Thomas 1967)  Fibroblasts (Ness 1967)

26. Eruption rates  Mouse  Guinea pig 200-1100 μ m/day  Rabbit  Human 140 μ m/day (5 μ m/day)

27. Clinical consideration  Early eruption  Delayed eruption  Impacted

35. Shedding(exfoliation)  Gradual removal of roots and alveplar bone

38. Shedding of teeth odontoclasts pressure

39. odontoclasts Cementoclas Dentinoclast

40. Histology of shedding  Odontoclasts Large multinucleated cell Cytoplasm of vacuole Dense mitochondria Brush border surface Acid phosphatase

41. Odontoclasts resorption bay (Howship’s lacunae) brush border (ruffled border ; microvilli ) acid phosphatase

47. Root resorption  resorption period  rest period  repair period

53. Clincal consideration  Remnants of deciduous tooth  Retained deciduous tooth  Submerged deciduous tooth

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