Anchorage
Anchorage is resistance to unwanted tooth movement (Newton's third law reaction). Managing it prevents anchor teeth drifting into space meant for correction.
Intra-oral Anchorage Aids
- Nance holding arch — maxillary; acrylic button on the palate resists mesial molar movement.
- Lingual arch — mandibular; maintains molar position/arch length.
- Transpalatal arch (TPA) — connects maxillary molars for added anchorage.
Absolute & Extra-oral Anchorage
- TADs (mini-implants/temporary anchorage devices) — provide absolute skeletal anchorage, no patient compliance needed.
- Headgear — extra-oral anchorage/force to restrain maxillary growth or distalise molars.
Classification
Critical (maximum), moderate, and minimum anchorage based on how much of the available space is needed for the corrective movement.
Exam Tips ⭐
Nance = maxillary; lingual arch = mandibular; TADs = absolute anchorage; headgear = extra-oral.