Visible lower teeth when opening mouth - can I change it? (photos)

I would recommend an evaluation by a dentist who does cosmetic cases and understands the facial cosmetics as well. This may be an alignment issue where the back teeth can be moved to open the front teeth more for better visibility.  It could be the teeth are smaller. It could also be the facial muscles and lips need to be lifted with a liquid facelift procedure or Botox. All of these factors should be looked at. 

Hi:It is difficult to tell you what to do without a photo.  However one can make their teeth longer to cover their bottom teeth in two ways:1.  Braces by extruding the teeth2.  Veneers and crowns.If you like the color and shape of your upper teeth Option number one is the best, if you would like to also improve the color dramatically and change the shape of your teeth option number 2 might be better.I suggest you consult an orthodontist and an expert cosmetic dentist with regards to both of the above options.Best of Luck!

Every Persons case is unique and needs individual attention as there are many factors involved.  I would suggest finding a dentist that you can talk to about your concerns and have them addressed.  In general, when bottom teeth show when talking there could be a misalignment of your teeth and/or bite.  Invisalign is a good way to move teeth in the proper position for optimum function as well as improving aesthetics.  Hope that helps!