If you would like more retention to your Bioliner, use the Retention Dimple Plier to place a 1 mm dimple in the tray gingival to the contacts. Start by placing dimples in your tray bilaterally mesial of the 1st molars.  If additional retention is needed, place dimples in the  tray between the 1st and 2nd molars and 1st and 2nd bicuspids. Maximum retention can be achieved by placing lingual dimples on the same teeth.