Toothbrush

Toothbrushes were a device for cleaning teeth.

The Doctor told Richard Dunbar that he was leaving immediately for Antarctica, telling him he might as well and that he had his toothbrush. (DW: The Seeds of Doom)

The Minyans invented the toothbrush after they rose up against the Time Lords. (DW: Underworld)

The Doctor lent Martha Jones his toothbrush when she complained as to lacking one. (DW: The Shakespeare Code)

When ReThinx changed history with the Continuity Cap, Sonic screwdrivers became Sonic toothbrushes. (DWAM: The Continuity Cap)

The Doctor accidently picked up an electric toothbrush instead of his Sonic screwdriver when he rushed to help Craig Owens. (DW: The Lodger)

A future incarnation of the Doctor wore a toothbrush in his breast pocket. (DWM: Party Animals)