Anchorage Flashcards
List the types of anchorage
Headgear Palatal arches Lingual arches Intra-oral elastics TAD's
Define anchorage
The resistance to unwanted tooth moved. Think of Newton's third law Example Class II Div 1 Aim-reduce overjet Unwanted tooth movement - molars moving forward
What are the sources of anchorage?
Intra-maxillary Inter-maxillary Simple Compound Stationary Reciprocal
What is simple anchorage?
Active movement of one tooth pulled against several anchor teeth
What is compound anchorage?
The resistance provided by more than one tooth with greater support is used to move teeth with less support.
What is stationary anchorage?
This type of anchorage is the strongest (TADs) With stationary anchorage, it is difficult to prevent movement of the anchor teeth all together.
What is reciprocal anchorage?
This type of anchorage is when two teeth or two groups of teeth move in equal and opposite directions. (URA with screw, RME, Crossbite elastics on both sides, TPA)
What does anchorage depend on?
- The number of teeth that need to be used
- The distance teeth need to be moved
- Aims of treatment
- Type of tooth movement planned
- Root surface area of teeth used for anchorage
- Skeletal pattern - PATIENTS WITH INCREASED VERTICAL PROPORTIONS AND BACKWARD GROWTH ROTATION HAVE THE RISK OF EXPERIENCING MORE ANCHORAGE LOSS, DUE TO DIFFERENT MUSCULAR STRENGTH
- Occlusal interlock - good intercuspation at the end of treatment can prevent anchorage loss
How can increasing anchorage be achieved?
Increasing the anchor unit by adding more teeth to it can help to prevent unwanted movement of active teeth
More teeth being included in the anchor unit results in more force
What type of movements result in more or less anchorage movement?
Tipping -less chance of anchorage loss
Bodily - more chance of anchorage loss
How do intra-oral elastics help with anchorage?
Intermaxillary elastics such as class II and class III use the opposing arch to reinforce anchorage
How can a TPA assist with anchorage?
Stops the upper first and second molars from moving mesially as soon as the mesio-buccal root of the upper first permanent molars hits cortical bone.
Maintains intermolar width
What is anchorage loss?
Anchorage loss is where undesirable tooth movement happens and this can be seen in all three planes of space
AP -front to back
Vertical - up and down
Transverse - side to side
What can cause anchorage loss?
Forces that are too heavy Maxillary arch more susceptible Occlusal interfernces Vertical growth pattern Poor patient compliance
Give an example of anchorage loss
Posterior teeth move forwards instead of incisor teeth moving backwards when reducing an overjet
