Choosing the right material for a custom foot orthotic depends on a few key factors, including the patient’s condition, activity level, footwear, and personal comfort preferences.The basic structure of a custom foot orthotic device is referred to as the “frame”or alternatively “shell”. Frames can vary by rigidity, thickness, depth, width and material. The effectiveness of your orthotic therapy will be enhanced by pairing the proper frame material with the objective of treatment. A general guideline is to use a softer material for a rigid foot, and a more rigid material for a flexible foot. Of course, there are many exceptions to this guideline, and you should consider every case as unique unto itself.