The Clockwise Wedge and The Counter Clockwise Wedge
These two new Wedge instruments are used to enhance the rotational movement of specific teeth, one of the least predictable movements with aligners. The Wedges produce an indent in either the mesial or distal side on the facial (near the line angle of the tooth) with the intent of functioning similar to a typical “rotational wedge” used with braces. This can be combined by using the same Wedge instrument on the lingual side of the aligner, but on the (mesial or distal) line angle on the opposite side of the tooth. In this manner, the two opposing Wedge indents can create the force for a rotational couple.
In other words, by producing an indent on the mesial or distal side of the facial plastic and a corresponding, but opposite, depression on the lingual side of the tooth, a rotational force couple is produced. It is important to keep in mind that aligners do flex to accommodate Clear Collection indents. For organizational purposes, The Counter Clockwise Wedge is used to affect a mesial rotation of the Mandibular Right and Maxillary Left teeth. This instrument is also used to affect a distal rotation of Mandibular Left and Maxillary Right. In contrast, The Clockwise Wedge is used to affect a distal rotation of Mandibular Right and Maxillary Left teeth. It is also used to affect a mesial rotation of Mandibular Left and Maxillary Right.
As an alternative, the Wedge instruments can also produce a “reservoir” depression in an aligner (from the inside out) in a location where a bonded attachment is desired. This reservoir is filled with composite, applied to the tooth, and cured. A scan or impression can then be taken to create aligners that employ the new attachment(s).
Dr. Bowman adds, “Rotational movements, especially of laterals and canines, have been recognized as having poor predictability. This may warrant the application of customized rotational wedges, hence the need for these new Wedge instruments.”