Ortho Lec 1st quiz Flashcards
what are the 2 kinds of tooth movement?
- Physiologic tooth migration
- Orthodontic tooth movement
This is the movement of the tooth as part of normal processes in growth and development.
Physiologic tooth migration
Naturally occurring tooth movements take place during and after ___
Tooth eruption
why?
-There is no application of any orthodontic forces and yet the tooth is moving due to the presence of physiologic force.
FACT : The physiologic force is said to be equivalent to the capillary pulse pressure that is 20-26 g/cm2 of root surface.
Examples of physiologic tooth movement are mesial drifting, eruption, and changes in tooth position during mastication.
Orthodontic tooth movement, on the other hand, is brought about by _____ which varies according to the type of movement desired.
orthodontic force
how orthodontic tooth movement occurs? there should always be an___
- Pressure (PRESSURE SIDE)
- Area of tension (TENSION SIDE)
Where the tooth is moving to ___
Pressure side
Behind the movement is ____
Tension side
Osteoclasts are present in ___
Pressure side
Osteoblasts are present in ____
Tension side
Bone resorption occurs in ___
Pressure side
Bone deposition occurs in
Tension side
_____ is a phenomenon observed in many crystalline materials in which a deformation of the crystal structure produces a flow of electric current as electrons are displaced from one part of the crystal lattice to another
Piezoelectricity
Bone mineral and collagen are ___
piezoelectric
means?????
they can be moved by electric signals.
Piezoelectric signals have two unusual characteristics: and these are
- a quick decay rate, and
- the production of an equivalent signal, opposite in direction, when the force is released.
The periodontal ligament (PDL) is composed of a _______ that surrounds the tooth root and connects it to the inner wall of the alveolar bone.
complex vascular and highly cellular connective tissue
It is a soft connective tissue that surrounds the root of a tooth occupying the space between the root of a tooth and the walls of the alveolar bone and that of gingiva.
complex vascular and highly cellular connective tissue
The functions of the periodontal ligament: in terms of supportive
Protective cushion
The functions of the periodontal ligament: in terms of formative
storehouse of cells
The functions of the periodontal ligament: in terms of Nutritive
source of nutrients
The functions of the periodontal ligament: in terms of Sensory
sensory plexus
Dentoalveolar unit, is consists of these and greatly affected by the orthodontic force applied
- Cementum
- PDL
- Alveolar bone proper
Light forces : Compressed PDL
Pressure side
Light forces : Fluid expressed from PDL space
Pressure side
Light forces : Decreased blood flow
Pressure side
Light forces : Bone deformation allows release of prostaglandins that stimulates osteoclastic and osteoblastic activity
Pressure side
Light forces :
It takes about 48 hours before the first osteoclast appear which may arrive in 2 waves:
- From local cellular population
- From distant areas via blood flow
Pressure side
Light forces:
Frontal resorption occurs on the immediate site of pressure
Tooth movement begins
Pressure side
Light forces : Stretched PDL
Tension side
Light forces : PDL space becomes enlarged
Tension side
Light forces : Increased vascularity leads to mobilization of osteoblast and fibroblast in those area
Tension side
Light forces : Appearance of osteoblasts from progenitor cells in the PDL
Tension side
Light forces : Remodeling activity occurs
Tension side
Heavy Forces : Blood vessels totally occluded
Pressure side
Heavy forces : Blood supply to the PDL is cut off
Pressure side
Heavy forces : PDL mangled/distorted
Pressure side
Heavy forces : Formation of a hyalinized area (avascular)
Pressure side
Heavy forces : Undermining resorption occurs wherein attack is from the underside of the lamina dura
Pressure side
Heavy forces : Osteoclasts are activated
pressure side
Heavy forces : Tooth moves within 7-14 days (delayed)
pressure side
Heavy forces : Increase in blood flow
Tension side
Heavy forces : PDL fibers are torn
Tension side
Heavy forces : Bone deposition by osteoblasts
Tension side
