Ortho II (Finals) - 2 Orthomechanics Pt.1

__________ is the science that describes the

effect of force on a body. Tooth movement

occurs as a response to application of force. It

is important to have a sound knowledge of the

fundamental principles of biomechanics:

The fundamental principles of biomechanics:

• 1. to understand the design of the

  appliance

• 2. to know its mode of action

• 3. to understand the response of the tooth

  and other structures to force application

  of force

• 4. to select proper appliance appropriate

  for a given case.

• 5. to use the selected appliance in an

  efficient manner to bring about the

  desired changes.

Force is a vector:

Direction of force

The magnitude may be:

A free body in space has a point in its mass,

which behaves as if the whole mass is

concentrated at that single point.

When all points on a body move the same

amount in the same direction, such a

movement is called "translation" or "bodily

movement".

A tooth in the oral cavity is not a free body

because of its surrounding tissues which would

restrain its movement.

The Center of resistance of a single rooted tooth with normal alveolar bone level is situated at about one third the distance from the ___ to the ____ ____

Factors for location of tooth center of resistance:

• 1. Root length

• 2. Morphology bone

• 3. Number of roots

• 4. Level of alveolar bone

The center of resistance of maxilla is about _-

mm ____ to the orbitale.