Clinicians continue to need anchorage that displays a high resistance to displacement. According to Newton's Third Law, there is a reaction for every action, control of which is difficult to achieve intraorally. Earlier, orthodontists used extraoral traction to reinforce intraoral anchorage. Nevertheless, patients seldom used headgears 24 hours a day - 7 days a week, hence this source of anchorage was often compromised.

The ideal intraoral anchorage would not displace, and would require a source devoid of periodontal membrane, which tends to respond to tension and pressure allowing movement through bone. Recently, prosthetic osseointegrated implants have been used as intraoral orthodontic anchorage, but their bulky size, cost and invasiveness have limited their orthodontic application.

We have used ordinary bone screws first to provide intraoral anchorage, but the screw heads failed to protect the gingiva from the impingement by the ligatures or attached elastomers. These became a source of constant gingival irritation and inflammation, which limited the usefulness of this type of implants. The design of the screw heads also made it difficult to connect coil springs and other elastomers to these ordinary bone screws. The development of small diameter titanium microimplants with specially designed heads that accept ligatures, coil springs and elastomers have helped to solve the main objections to previous implants and screws.

A typical surgical microscrew (left) and the newly designed Absoanchor£— microimplant with nickel titanium coil springs attached (right)


 Types of Microimplant

 Types of Instrumentation