Date post: | 21-Mar-2017 |
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DEFINE ERUPTION &DESCCRIBE ITS PHASES AMJAD AL_BLEAHID
Tooth Eruption Eruption is the axial or occlusal
movement of the developing teeth, in order to appear in the oral cavity & reach the occlusal plane
The onset of eruptive movement begins in the bell-stage
Axial movement begins with the onset of root formation & continues throughout the life span of the teeth
Eruption of tooth Axial or occlusal movement of teeth
(or teeth germs) From : Their developmental position
in the jaw To : Their functional position in the
oral cavity
Phases of Eruption Pre-
eruptive phase
Eruptive phase
Post-eruptive phase
Pre-Eruptive Phase STARTE : End of early bell ENDS : Beginning of root formation EVENTS : Jaw growth In length ,
width and height TYPES OF MOVEMENTS : 1-Bodily movement 2-Eccentric growth
Histological Changes During this phase, movements are achieved
in two ways :
1-bodily movement resorption occurs on the surface of the crypt wall in advance to the movement direction ,
while bone apposition by osteoblastic activity occurs on the crypt wall behind it.
2-Eccentric growth During root growth, there is only bone resorption on the surface of the crypt that faces the growing direction of the tooth germ
Eruptive Phase (Pre-Functional Eruptive Phase ) STARTS : at the time of root
formation ENDS : when the tooth has reached
the occlusal plane.
The Eruptive Stages 1- Intraosseous
stage
The eruptive movement occurs within the bony crypt
2- Supraosseous stage
The eruptive movement occurs within the connective tissue of the oral mucosa.
The movement is faster than before
Histological Changes Intraosseous stage Root Formation Periodontal Ligament Formation Alveolar Bone Formation Supraosseous stage Dentogingival Junction Formation Gubernacular Cord and Canal Formation
Post-eruptive Phase (Functional Eruptive Phase ) STARTS : when the teeth reach
occlusal plane & continues as long as they remain in the oral cavity
Histological Changes In this stage, the root, the periodontal
ligament & The alveolar bone continue their formation.
The teeth are subjected to 2 movements Occlusally & Mesially The erupting teeth is influenced by the
surrounding environmental factors that help in to determine the final position in the oral cavity (e.g. muscles forces & childhood habits) (Thumb suckling habits)
References Antonio Nanci: Ten cat`s Oral
Histology: Development, Structure, and Function, 8th ed. Elsevier Health Sciences, Mosby, 20`3
Bhasker, S.N.: Orban’s Oral Histology and Embryology, Edition By G.S. Kumar, Mosby 13th ed. 2011
Any question?