Shedding

shedding of deciduous teeth

1. Menatalla M. Elhindawy

2. SHEDDING Definition. Factor affecting shedding. Histology of shedding. Pattern of shedding. Abnormalities in shedding.

3. Definition To give off, discharge, or expel from the body of a plant or animal, slough off, or lose as part of the normal processes of life. It is a physiological process for elimination of deciduous teeth by resorption of their roots prior to eruption of their permanent successors.

4. Factor affecting shedding 1. L ocal factors Pressure from the erupting successional tooth plays an important role in shedding . Growth of the face and jaws and Enlargement of the masticatory muscles probably increase the forces applied over the deciduous teeth. Pressure + Enlargement = Loss of Supporting Tissue Tooth Exfoliation Accelerated.

5. Factor affecting shedding 2. Genetic factors Apoptosis in the periodontal ligament fibers. The initiation of root resorption may be inherent developmental process.

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7. H istology of shedding Resorption of the hard tissue “ odontocalst ” Resorption of the soft tissue: Pulp. Periodontal ligament.

8. Histology of shedding ODONTOCLASTS Derived from blood monocytes , migrate to the resorption site and fuse to form multinucleated cells. Are cells with same histological nature of osteocalsts . They have ruffled border and sealing zone . They have the ability to resorb the pre-dentine.

9. Histology of shedding

10. Histology of shedding PULP response. While the root is being resorped ; coronal pulp appears normal with odontoblasts line the pre-dentine. Once the root resorption is almost completed the odontoblasts degenerate, mononuclear cells migrate form pulpal bl. v. and fuse forming odontoclasts .

11. Histology of shedding PULP response. Just before exfoliation, the odontocalsts migrate away from the dentine surface and the remaining pulp tissue secreats cement like tissue . The tooth is shed with some pulpal tissue intact .

12. Histology of shedding PERIODONTAL LIGAMENT response . Fibroblasts of the P L exhibit sings of interface with cytotoxic alteration as well as apoptosis . These changes leads to abrupt loss of the P L.

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14. Pattern of shedding The pattern of shedding is symmetric in both Rt and Lt sides. The lower E shed before the upper E . Girls teeth shed before that of boys . Sequence of shedding in the mandible follows anterior to posterior order; while in the maxilla the 1 st molar shed before the canine .

15. Pattern of shedding

16. Pattern of shedding Anterior teeth For all deciduous anterior teeth resorption initiated at the lingual side of the root. With subsequent movement and relocation of the teeth in the growing jaws, the growing permanent tooth becomes directly below the deciduous one. The resorption become apically .

17. Pattern of shedding Anterior teeth

18. Pattern of shedding Posterior teeth For deciduous molars, root resorption initiated on the inner surface where the permanent premolars initially developed. Later the premolars come to lie beneath the deciduous molars . Farther resorption at the apices then occur. The shift in position may account for the intermittent nature of the resorption.

19. Pattern of shedding Posterior teeth

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21. Clinical considerations Abnormalities of shedding Retained deciduous teeth. Submerged deciduous teeth. Remnants of deciduous teeth. Pre-deciduous teeth.

22. Abnormalities of shedding 1. Retained deciduous teeth. Deciduous teeth that persist beyond their shedding time is known as retained deciduous teeth. Most common in upper B and lower E . Usually due to congenital missing or impaction of permanent ones ankylosis due to trauma. Appears normal and persist for a while till resorption occurs due to heavy masticatory forces.

23. Abnormalities of shedding 1. Retained deciduous teeth.

24. Abnormalities of shedding 2. Submerged deciduous teeth. Ankylosed deciduous teeth mostly due to trauma. No active eruption and become at a lower level than the other teeth “ SUBMERGED ”. Mostly in lower E. The permanent become either impacted or out of alignment . Submerged tooth should be removed allowing the permanent one to erupt

25. Abnormalities of shedding 2. Submerged deciduous teeth.

26. Abnormalities of shedding 2. Submerged deciduous teeth.

27. Abnormalities of shedding 3. Remnants of deciduous teeth. Roots of the deciduous teeth specially molars which interfere with the eruption path . Usually due to more diverged roots of the deciduous teeth and the smaller the premolar size .

28. Abnormalities of shedding 4. Pre-deciduous teeth. Known as rootless or natal teeth . Rare condition in the newborn infants. It is dangerous cause it may be inhaled as it is rootless so not fixed to the body. May cause eruption cyst . Cause discomfort to the mother during lactation .

29. Abnormalities of shedding 4. Pre-deciduous teeth.

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