Cherry loop: a new loop to move the mandibular molar mesially

Abstract: The aim of this study was to test the clinical efficacy of a new loop named ‘cherry loop’ in correcting the Class II relationship by the mesial movement of the first lower molars in the Tweed–Merrifield technique. We compared the amount of molar mesial movement in two groups of patients treated with upper first bicuspid and lower second bicuspid extractions. The study was conducted using two X-rays, one before treatment and one after the molars had moved. Mandibular molars and incisors were traced and their positions analyzed along a Cartesian coordinate system. Movements were related to stable structures: lower borders of the mandible and the symphysis. The cherry loop performance was compared to that of the shoehorn loop. Cherry loop averaged 5.25 mm of average mesial movement, whereas the shoehorn loop yielded only 3.28 mm. The vertical control of molars was better with the new loop; we had only 1.24 mm of extrusion compared to 3.24 mm with the usual loop. The anteroposterior stability of the incisors was better too; we had 1.54 mm of distal movement of the crowns compared to 2.24 mm with the shoehorn loop. A serendipitous finding was that the occlusal plane could be controlled by the cherry loop. It can be oriented to best fit the growth pattern. In turn, in the growing patient, a favorable skeletal response can be expected.