Biomechanics
Newton’s third law of motion states that for every action there is an equal and opposite reaction. This concept in physics affects every aspect of Phoenix orthodontic biomechanics. Since the sums of the forces and the moments must equal zero in a state of equilibrium, unwanted side effects occur with almost any Phoenix orthodontic movement. For example, if a canine is retracted with Invisalign, the posterior teeth will be protracted with the same amount of force.
In order to reduce these unwanted movements, anchorage requirements must be considered for each case. There are three classifications of anchorage for cases requiring extraction.
Phoenix orthodontists have limited options to produce this anchorage. Even the father of modern Phoenix orthodontics, Edward Angle, discussed this problem, “According to the well-known law of physics, action and reaction are equal and opposite, hence it must follow that the resistance of anchorage must be greater than that offered by the tooth to be moved, otherwise there will be displacement of the anchorage and failure in the movement of the teeth to the extent, or, possibly, in the direction desired. The sources at our disposal for securing anchorage or resistance are, first, the teeth themselves, and second, sources external to the teeth and anchorages may be classified as simple, stationary, reciprocal, intermaxillary and occipital”. Today, Phoenix orthodontists incorporate Invisalign to utilize the bone as an anchor, creating a new term, absolute anchorage.
Litchfield Park Office
5220 N. Dysart Rd #150
Litchfield Park, AZ 85340
TEL: 623.536.4939
FAX: 623.536.4877
Phoenix Office
7550 N. 19th Ave #101
Phoenix, AZ 85021
TEL: 602.864.0004
FAX: 602.864.0070
