Orthotics manufacturing is divided into two components, the
casting of the foot itself and the manufacture of the actual
custom made supports.
While several methods exist for making orthotics,
including some that are computer generated, the majority of
foot care professionals consider the plaster slipper cast
taken with the foot in a non weight bearing position, to be
the gold standard. However a poorly taken slipper cast is
not superior to a well taken cast of other means.
Advantages of slipper casting in non-weight
1. The non-weight bearing foot does not capture its structural
defects; for example if the arch flattens excessively (hyperpronation,
pes planus) then this occurs when the weight is on the foot.
This is why most of us believe that our arches are fine -
we look at them when there is very little weight on them,
for example when we are sitting.
2. Precise positioning of the foot; the pedorthist
can hold the joints including the ankle, subtalar (below the
ankle), midtarsal (bones in the middle portion) and the forefoot.
Positioning the forefoot up or down can increase or decrease
the height of the arch and the overall correction of the foot.
Most other casting methods cannot provide this degree of flexibility
of " intrinsic " cast correction.
The use of multiple lasers to create
an electronic 3-dimensional image is evolving and will likely
be capable of equaling the flexibility of slipper casting
in the coming years. Any casting method can be satisfactory
in skilled hands however, and alternative casting techniques
are often superior in specific conditions.