Is It Normal to Have Dry Lips and Have Lost Some Sense of Taste AFter Beginning Invisalign Treatment?

Invisalign trays are BPA free, and really shouldn't cause any type of allergic reaction.

If you got your attachments placed that day, it is possible that the altered taste and tongue sensation was due to a small amount of the tooth etchant contacting the tongue. Also if your mouth was held open for a period of time to place the attachments that would explain the dryness of your lips as well.

Your orthodontist would know better than the internet if there was something done during the procedure (like the items listed above) that could have potentially caused those symptoms.

It is probably a coincadence that you have finished your invisalign and now experiencing dry lips and altered taste.  This is the first report I have heard of this type.  There is no known physiologic connection between the events.  Dry lips and altered taste can be manifestations of other systemic conditions such as Scleroderma or Bechet's syndrome to name a couple.  Most likely your sensory alterations a just a temporary aberration, but you should get checked by an internal medicine specialist and or endocrinologist. Invisalign can't cause dry lips or altered taste.  An allergic reaction or chemical burn is possible, but I have never heard of it with invisalign before.