Participants were asked to give further details about how they liked wearing a headgear (external TDS [eTDS]) versus a dental retainer (intraoral TDS [iTDS]) version of the TDS, and whether they preferred a magnetic tongue barbell over a magnetic implant. Out of 11 participants, 10 preferred the concept of the iTDS, which was under development at the time of this study [21]. One participant stated that he did not know because he had had no experience with the iTDS. Six out of 10 participants who chose the iTDS preferred it to the eTDS because it was less visible