The lingual arch is considered the “appliance of choice” to maintain arch length even when the space to be maintained is unilateral.  This simple retainer prevents both mesial and lingual tipping of the molars while maintaining the arch length.  Commonly, this appliance is designed with an arch wire soldered to two bands. 

However, with the Accu3D™ Metal Printed version, the entire frame is printed.  This makes it much more accurate than its traditional counterpart that needs to be soldered and “put together.”