The lower posterior segments frequently erupt with lingual inclination of the crowns and the upper posterior segments erupt with buccal inclination of the crowns.  This will result in over-erupted “hanging” palatal cusps and occlusal interferences during lateral movements.  One of the requirements of the American Board is to level the Curve of Wilson to eliminate these interferences.  The Avex appliance is designed with progressive buccal crown torque (uprighting torque) in the lower posterior segment and progressive buccal root torque in the upper posterior segment to allow for leveling the Curve …

The relationship between the lower lateral incisors and the lower canines is a difficult relationship to correct. This is because in many cases the lower incisors are flared forward and the lower canines are inclined lingually due to the presence of overbite. A significant amount of over-correction from the Andrews’ norms in both the torque and in-out dimension is helpful in properly aligning teeth in these areas.
The Andrews’ norms for lower incisor torque is -1o. Placing -6o of torque in the lower incisors helps to upright these teeth. This brings …

Finishing consists of managing a number of dental and skeletal factors in the sagittal, vertical and traverse dimensions. Two critical factors that become very important at the end of treatment are bracket placement and the features built in to the pre-adjusted appliance. Pre-adjusted brackets are designed based on values measured at the center of the clinical crown (Andrews). While there are some modifications to this location, in most cases this is the ideal position. After initial placement and leveling, bracket position is greatly enhanced by …

In the upper and lower posterior segments, the goal in orthodontic treatment is to level the marginal ridges, align the central fossae, and level the curve of Wilson. One of the most difficult areas to achieve this key three dimensional relationship is in the lower second bicuspid-lower first molar area.
The average occlusal – gingival height of the lower second bicuspid is 7 mm, and that of the first molar is 5 mm. The center of the clinical crown, where bracket slots are normally placed, is then 3.5 mm below the …