teeth shedding of the teeth dheedding.ppt

afsedfwe

1. Shedding of teeth
ProfesorDr. AkramYousifYasear
College of Dentistry
University of KerbalaIraq

2. Shedding
•The normal physiological process by which the
deciduous teeth are removed to allow the
succeeding permanent teeth to take their
functional position in the mouth.
•The loss of deciduous teeth is mainly due to
the resorption of their roots.
•Commences earlier in girls than in boys.

3. Shedding of primary teeth
A six year old girl's deciduous teeth, which are beginning to fall out.

4. Rules of “sixes” in dental development
6 weeks old in utero: beginning of dental development
6 months old: emergence of the first primary tooth
6 years old: emergence of first permanent tooth
Source: http://www.columbia.edu/itc/hs/dental/d9903/lectures/lecture4.pdf

5. Mechanism of shedding
•Pressure of the succeeding permanent teeth.
•Increase in force of mastication
•Action of odontoclast( cementoclast for the
cementum and dentinoclast for the dentin)
•Action of osteoclast which resorbe bone
•PDL is resorbed by fibroclast

6. Source: http://www.columbia.edu/itc/hs/dental/d9903/lectures/lecture4.pdf

7. Essentials of Oral Histology and Embryology. James Avery, 2
nd
edition

8. Shedding of
anterior
teeth

9. Shedded crown

10. Eruption for secondary tooth and
shedding for posterior deciduous

11. Cells responsible for shedding

12. Shedding of Teeth
1.Osteoclast/bone remodeling
2.Odontoclast (cementoclast; dentinoclast)
3.Resorption of soft tissues
Pressure from successional teeth
Odontoclast
Figure Source: Dr. Sandra Meyers

13. Osteoclastsare bone resorbing cells derived form monocyte-
macrophage lineage
Giant multinuclear cells with 4-20 nuclei
Osteoclasts resorbhard tissue by separating mineral from the
collagen matrix through the action of hydrolytic enzymes
Resorption occurs at the ruffled border which greatly increases
the surface area of the osteoclast in contact with bone
Hard Tissue resorption:
1. Extracellular phase
2. Intracellular phase

14. Resorption in dentin

15. Odontoclast in a process of resorption
of dentin

16. PDL resorbed by fibroclast

17. Note the collagen fiber fragments
inside the fibroclast (Head arrows)

18. Osteoclast resorbing the bone

19. Shedding of anterior teeth

20. Shedding of posterior teeth

21. Clinical consideration
•Remnants of the root of deciduous teeth
•Retained deciduous teeth
•Submerged deciduous toth

22. Retained Primary teeth

23. Submerged primary teeth
Hyper or supra eruption

24. Impacted maxillary canine

25. Impacted mandibular third molar