Bringing Upper Front Teeth Down with Braces & Elastics?

My upper teeth show very little when I smile, and my lower teeth are mostly visible. How many mm can upper teeth potentially be brought down with traditional braces? Is it possible to get gums to follow, or would that only elongate teeth and make them look longer? If you wear elastics in a triangle hooked on one bracket on upper and two on lower jaw, does that bring the upper teeth more down or the lower more up? I would like my upper teeth brought down without bringing my lower teeth up. Thanks