Interceptive ortho 1 Flashcards
What is the eruption of descidious teeth
A B D C E
Whe would extraction be indicated for natal/neo-natal teeth
If
-mobile and presents a risk of inhalation
-is causing difficulty with breatfeeding
Whar are the 3 phases of tooth eruption
Pre eruptive
Eruptive
Post eruptive
What does the pre-eruptive phase start and end
starts when the crown starts to form and ends when crown formation complete / root formation about to start.
When does eruptive phase start and end and what are the 2 stages its split into
starts as soon as the root starts to form and ends when the teeth reach the occlusal plane
Split into intra-osseous stage and extra-osseous stage
When does the post-eruptive phase start
tooth movement / eruption
continues as the root forms and throughout life in
extremely small increments
What happens in the pre-eruptive phase
The developing crowns move
constantly within the jaws
Small mesial and distal tooth
movements occur
The developing crowns reposition themselves in response to increasing length , width and height
of the jaws
Movement of tooth crowns is
contained within the bony crypts
What happens in the eruptive phase
Relative position of deciduous and permanent teeth alter due to eruption of the deciduous teeth and increase in height of the surrounding alveolar bone
Movements in the eruptive phase occur in response to what
- Positional changes of neighbouring crowns
*Growth of the mandible and maxilla
*Resorption of the deciduous tooth roots
What happens in the Intra-osseous stage of the eruptive phase
- Root formation – starts with proliferation of the epithelial root sheath and continues with the production of dentine and pulp
- Movement of the developing tooth – in an occlusal or incisal direction (slow - several months)
- The reduced enamel epithelium fuses with the oral epithelium forming the junctional epithelium which then starts to thin out
What happens in the extra-osseous stage of the eruptive phase
- Penetration of the tooth’s crown tip through the epithelial layers (fast 1-2 weeks )
- The crown continues to move through the mucosa in an occlusal direction until it contacts the opposing tooth (slow -several months)
- Environmental factors such as muscle forces from cheeks, lips and tongue help determine final tooth position
What is the eruption pathway
Within the Dental follicle degeneration occurs.
Blood vessels decrease in number, nerve fibres
break up into pieces. The resulting area becomes known as the eruption pathway
What is the Gubernacular cord
In the periphery of the eruption pathway other fibres are formed from the dental follicle
this guides the teeth to
erupt in the oral cavity
What happens in the post-eruptive phase and why does it occur
Movement after tooth has already reached the
occlusal plane
-Occurs in response to increases in height of the growing alveolar bone and jaws
-In response to attrition and abrasion (teeth erupt slightly to compensate for wear on occlusal surfaces, proximal surface tooth wear leads to mesial drift)
-In response to loss of opposing teeth = over-eruption
What causes tooth eruption
Multifactorial
- Root formation
- Remodelling of the alveolar bone
- Development of the periodontal ligament
