Diagnosis & Treatment of Mesially Rotated Upper 1st Molars

Often, a Class II molar relationship develops because the upper first molars are mesially rotated. Recent studies show that mesial molar rotation exists in over 80% of Class II malocclusions.¹ The importance of molar rotation in the development of Class II occlusion has been recognized for well over a century. In 1906 Angle wrote that the upper 1st molar is the key to development of good occlusion.² Strang, the author of the 1950 edition of the Textbook of Orthodontics, writes, “Rotation of teeth often appears in the maxillary arch…and the mesio-lingual cusp on the maxillary molar resists displacement so strongly that the crown often rotates bodily around this …root.”³ In the June 2003 issue of the Angle Orthodontist, authors Gunduz et al. described the etiology of upper molar rotation: