A brief description of Tooth Shedding taken from Ten Cates and James Avery Text books

1. Shedding of Teeth

2. Objectives
At the end of this chapter the student should be able
to understand the different phases of tooth eruption
and also the shedding of primary teeth.
Sub topics
1.Introduction
2.Causes of shedding of teeth
3.Events in shedding of teeth

3. Shedding of primary teeth
Shedding is the exfoliation of primary teeth followed by
physiologic resorption of their roots
The permanent anterior teeth develop lingually to the
deciduous teeth.
When the deciduous anterior exfoliate the roots resorb
lingually and most of the pulp chamber remains intact.

4. The premolars develop between the divergent roots of the
deciduous molars.
Resorption of interradicular dentin and cementum takes
place with some resorption of pulp chamber in exfoliating
deciduous molars
Shedding of deciduous teeth follow a fixed pattern.
The pattern of shedding is the same as the pattern of
eruption of permanent teeth.

5. There are three causes of shedding of teeth
1.Loss of root
2.Loss of bone
3.Increased force

6. 1.Loss of root
As the permanent teeth grows it exerts pressure which
induces the differentiation of osteoclasts and odontoclasts.
Odontoclast cause the resorption of dental hard tissues of
the root.
They are similar to the osteoclasts in histology and
function.

7. 2. Loss of bone
 As root resorption continues the supporting structures
of root are weakened and the modifications in alveolar
bone follows.
 Loss of bone further loosens the root attachment.
 Osteoclasts are responsible for the bone resorption.
 During the process of resorption the pressure of the
erupting tooth is first directed towards the bone.
 After this area is resorbed the force is directed towards
the root of the primary tooth.

8.  Osteoclasts are large multinucleated cells with a
vacuolated cytoplasm and have a striated border (brush
border)
 Acid phosphatase is the active enzyme released by the
Osteoclasts.
 The brush border is adjacent to the resorbing front of
the hard tissue.
 Osteoclasts appear in the cup shaped depressions called
Howship’s lacunae towards the hard tissue being
resorbed.

9. Osteoclasts residing in Howship’s lacunae

10. 3. Increased force
 Increased muscular growth results in more force on the
already weakened tooth and eventually the tooth falls.

11. Events in shedding of teeth
 The process of resorption involves the initial breakdown
of small areas of hard tissue and then ingestion and
complete dissolution of the breakdown products.
 When the hard tissue is attacked by enzymes, the
collagen meshwork is disrupted and the crystals are
released.
 The crystals are then taken up by the osteoclasts in
their vacuoles and digested.

12.  The disrupted collagen fibres are then destroyed by
fibroblasts.
 Resorption like eruption is not a continuous process,
periods of activity alternate with periods of rest.