Self-ligating braces have brackets with a built-in locking mechanism so that elastic or wire ties don’t need to be used to hold the wire. Normal braces (non self-ligating braces) need elastic or wire ligature ties to hold the archwire into the bracket.
Self-ligating braces have no significant advantage except for an aesthetic benefit in the case of tooth-coloured braces. Because self-ligating braces don't need clear elastic ligature ties to hold the archwire in place, there is no unsightly discolouration from tea, coffee, red wine and curry stains.
The most effective tooth-coloured, self-ligating braces are ones with Nickel titanium clips. Those with porcelain sliding mechanisms look slightly better initially but soon pick up stains and are also not as effective at controlling the tooth positions.