TECHNO BYTES Mini-implant anchorage for the orthodontic practitioner

Orthodontic anchorage is defined as resistance to undesired tooth movement. In the anteroposterior dimension, 3 anchorage situations are traditionally defined by the ratio of incisor retraction to molar protraction. While moderate anchorage entails reciprocal space closure, maximum anchorage means that most of the space is closed by retraction of the incisors, and minimum anchorage means that most of the space is closed by protraction of the buccal segments. Absolute anchorage, when the anchorage units remain completely stationary, is sometimes desirable but is usually unattainable with traditional orthodontic mechanics. The exception is the presence of ankylosed teeth in the anchorage unit. Under these special circumstances, forces applied to those teeth are completely transferred to the surrounding skeletal structures. This situation is sometimes called skeletal anchorage and, by the above definition, could also be called absolute anchorage. Understanding each patient’s anchorage requirements is of paramount importance and ensures high-quality care. Unexpected or unintended anchorage loss frequently results in a compromised finish. Traditionally, high-anchorage situations require excellent patient compliance with extraoral traction devices. This dependency on patient compliance greatly increases the risk for failure. Therefore, over the past 60 years, methods have been developed to create absolute skeletal anchorage