joints should be within the therapeutic range

Anterior repositioning appears to be physiological as long as it is kept to a minimum and lies within the therapeutic range, as defined by the author. The posterior limit of this range is concentric and the anterior limit is Gelb's 4/7 position. There is no one treatment for all patients; therapy depends on each patient's signs and symptoms. However, all patients' joints should be within the therapeutic range. TMJ radiographs are used to monitor the changes in condylar position during treatment. Anterior repositioning usually produces a posterior open bite, and reconstruction, overlays, or orthodontic procedures are used to re-establish a functional occlusion.

http://www.tandfonline.com/doi/abs/10.1080/08869634.1988.11678220?journalCode=ycra20