A method for assessment of orthodontic treatment for a patient include: calculating a first feature value according to a facial profile of the patient calculating a second feature value according to a facial midline of the patient and a mesial surface of one of anterior teeth in an orthodontic quadrant calculating a space value according to a difference between an arch length of a dental arch portion of the orthodontic quadrant, and a sum of mesiodistal diameters of crowns of teeth encompassed by the dental arch portion and calculating an assessment value indicating a proposed displacement for a molar in the orthodontic quadrant according to the space value and the first and second feature values.
