Microimplant screws for Anchorage in Orthodontics:Dawn of a New Era-Part II

Advantages of Microimplants
Use of these devices leads to:

24 X 7 Force delivery
simplified mechanics,
improved results,
drastic reduction (upto 40%) in treatment timing,
reduction in number of extractions
Minimal dependence on patient co operation

Disadvantages of Microimplants

High Cost of the devices
Failure of about 10% fixures
Problem in site selection in patients with poor Bone quality
Patient acceptance may be an issue in some cultures

Common Indications for placement of Temporary Anchorage devices/mini implants
Every case is not suited for microimplants. Minimal anchorage cases now can be treated non extraction with MI, many other average extraction cases we found that treatment objectives are achieved and extraction space is still remaining. Hence the cases where you need molars to come forward to occupy some of the ext space, are better done without MI or done with caution.

Mini implants are used most beneficially where three dimensional stable anchorage is needed, some of these situations are:
Where you can not afford any movement of reactive units (maximum anchorage case)
Patient with several missing teeth making it difficult to engage posterior units
For difficult tooth movements, eg intrusion of anterior and posterior segments and ditalisation
Where asymmetrical tooth movement is needed
To treat borderline cases with non extraction method
Doing extreme ortho when patient is not willing to undergo orthognathic surgery

Common SITES OF PLACEMENT-see pic below
MAXILLA:

Infrazygomatic crest area.
Tuberosity area.
Between 1st and 2nd molars buccally.
Between 1st molar and 2nd premolar buccally.
Between canine and premolar buccally.
Between incisors facially.
Mid palatal Area.

MANDIBLE:

Retromolar Area.
Between 1st and 2nd molars buccally.
Between 1st molar and 2nd premolar buccally.
Between canine and premolar buccally.

Read the other sections on Microimplants:
Next section: Types, Site selection and Placment methods