Toothbrushes with a replaceable head having a threaded connection

An electric toothbrush, comprising:

• a housing defining a hollow interior having a motor and a first shaft disposed therein that is operatively connected to said motor, said housing having an engagement member extending along a longitudinal axis of said housing from an end thereof, said engagement member including a first thread helically extending about said engagement member;
• a brush head having a movable bristle carrier at a first end of said brush head and a deflectable second shaft operatively connected to said movable bristle carrier, said brush head having a receiving region at a second end of said brush head opposite said first end, said receiving region having an engagement surface with a second thread helically extending along said engagement surface, wherein said first thread and said second thread form a threaded connection that releasably couples said brush head to said handle when one of said handle or said brush head is rotated about said longitudinal axis;
• and
• wherein one of said handle and said brush head is rotated between about 180° and about 540° to form said threaded connection between said first thread and said second thread.

An electric toothbrush, comprising:

• a housing defining a hollow interior having a motor and a first shaft disposed therein that is operatively connected to said motor, said housing having an engagement member extending along a longitudinal axis of said housing from an end thereof, said engagement member including a first thread extending about said engagement member;
• and
• a brush head having a movable bristle carrier at a first end of said brush head and a second shaft operatively connected to said movable bristle carrier, said brush head having a receiving region at a second end of said brush head opposite said first end, said receiving region having an engagement surface with a second thread helically extending along said engagement surface,
• an arm attached to said second shaft, wherein a tab is disposed on said arm;
• and
• wherein said handle has an annular gap between an outer surface of said first shaft and an inner surface of handle for receiving said tab and at least a portion of said arm, and wherein said first thread and said second thread form a threaded connection that releasably couples said brush head to said handle when one of said handle or said brush head is rotated about said longitudinal axis, and wherein said annular gap extends about the entire perimeter of said first shaft.