An 18 year old female patient complains of prominent upper front teeth. Extra-oral examination reveals an acute nasolabial angle and lip strain. Intraoral examination shows a Class II incisor relation with 8 mm overjet and Class I molar relation. Maxillary first premolar extractions have been advised, of which almost all of the premolar space will be required for the retraction of the upper anteriors. According to Burstone’s classification for anchorage requirements, this patient can be categorized into which of the following groups?
High-Yield Explanation
It is convenient to classify an extraction arch by the differential space closure required between the anterior and the posterior teeth.
Group A arch is one in which posterior segments must remain in their original position and the full space is used for anterior retraction.
Group B arch requires that approximately one half of the space be used for retraction.
Group C arch requires that approximately all space be closed by protraction of the posterior teeth.