butterfly arch: a device for precise controlling of the upper molars in three planes of space.

intra-oral appliances such as transpalatal arch and nance appliance fail to resist against forces that tend to loosen the anchorage. the infirmity arises due to the long lever arm and the mesial force that is perpendicular to the long axis of the appliance. the butterfly arch is presented here as an intra-oral appliance that withstands the mesially directed forces with a mechanism that puts strain on a stiff wire along its long axis. the unique shape of the butterfly arch is advantageous in maximum anchorage cases, cases in which arch width preservation is critical and cases with a vertical growth pattern. with the aid of the butterfly arch, clinical concerns such as patient cooperation, wearing extra-oral appliances, complicated mechanics in extraction cases and control of the arch length, arch width and vertical dimension would be greatly diminished.