For 3 years I use dirty white spot mirror to floss with inhale/exhale toward mirror. Can it cause gum recession or less effective invisalign treatment?

No. The mirror will neither cause gingival recession or affect Invisalign treatment.
NO. Gum recession caused by gum disease, improper oral hygiene, and/or expanding teeth off of their bone support. It is not caused by the reflective surface you look into or breathe on. If you have both gum recession and a malocclusion, it is best to be evaluated by a specialist Periodontist and a specialist Orthodontist who will consult with each other to provide you with the best care possible.
Mirror not problem. Gum recession is not caused while using a dirty spotted mirror. Gingival recession can be caused by overly aggressive brushing or not brushing and flossing at all.

Related Questions

For 8months I use a dirty mirror which has white spots to floss while on invisalign. Can this cause invisalign treatment less effective, gum recession?

No. A dirty mirror on the wall will not affect your invisalign treatment or cause your gums to recede. Read more...
Definitely, no. It all depends on your doctor expertise and the right expectations about the results you will get. The dirty mirror does not affect your invisalign treatment outcome. Good luck. Read more...
No association. Recession caused by gum disease (infection), overly aggressive brushing, and/or expanding teeth off of "basal bone support." Clear aligners work by expanding tooth alignment to provide the room for alignment. Please discuss your recession with your General Dentist and your Orthodontic Specialist...referral to a Periodontist may be prudent. Read more...