An adaptation system (500), comprises a mouthpiece (10), configured to be positioned in a mouth of a person, and an external sensor device (20). The external sensor device (20) is configured to be positioned at the person, wherein the external sensor device (20) comprises at least one sensor (22) configured to sense at least one measurable quantity when the mouthpiece (10) is positioned in the person's mouth and the external sensor device (20) is positioned at the person. Further, the adaptation system (500) comprises an analysis device (30) configured to determine a compliance of the adaptation system and/or to determine an orientation of an upper jaw (100) and a lower jaw (200) to each other derived from the at least one sensed measurable quantity.
