1 If X is a topological (or metric) space and M is a metric space, then the set of all bounded continuous functions from X to M forms a metric space if we define the metric as above: d (f, g) = sup x in X d (f (x), g (x)) for any bounded continuous functions f and g.
Invisalign is orthodontic appliance, so since orthodontic treatment is allowed as an FSA expense, Invisalign is covered. Different companies have different rules concerning amounts set aside and the timing of how funds are used for orthodontics.
If your insurance covers orthodontics, then Invisalign is covered. The doctor doesnt tell the insurance company what method (Invisalign or Braces) is being used. Just call your insurance company and ask if they cover code D8090. Remember there may be dollar maximums on your plan for orthodontic work, so find out what they are, and what percentage the insurance company will cover.