This tag implies that the bands and artists are Serbian or originated in Serbia. Music represented by this tag is often highly commercial. Other, possibly better, Serbian tags are, for example Novi Val or nova srpska scena.
Relapse means that the teeth can take up to one year or more to stabilize after treatment. If you had gaps between your teeth before treatment, the retention period will be longer. Usually, retainers are worn for as long a time as you have had your braces.
After the braces come off however, there is no such control. The forces of occlusion, wear, and the tongue come back into play. Even if the teeth are held in place with a bonded retainer after appliance removal, the position of the teeth will still change with time. Retainers are the key to preventing tooth movement.