Toothbrush with a toothpaste container and a dosing trigger

A toothbrush comprising:

• an elongated structure formed at a lower end with a hollow handle having an interior cavity;
• a sliding piston in said interior cavity subdividing said interior cavity into an intermediate chamber above said piston and containing a supply of a toothpaste, and a lower chamber communicating with an exterior through a minute orifice;
• a variable-volume upper chamber formed at an upper end of said hollow handle;
• a spring-loaded first valve blocking flow of toothpaste from said upper chamber back into said intermediate chamber, but permitting flow of toothpaste from said intermediate chamber into said upper chamber upon a reduction in pressure in said upper chamber;
• a trigger at the upper end of said hollow handle, manually displaceable generally axially thereon, and decreasing a volume of said upper chamber to displace toothpaste therefrom, said trigger having an elastic repositioning device in the form of a spring urging said trigger into a position corresponding to a maximum volume of said upper chamber;
• a tubular extension axially retractible in said housing and axially extensible therefrom, said extension having:
• a passage extending along a length thereof and communicating with said upper chamber in an extended position of said extension to receive toothpaste therefrom upon actuation of said trigger, said passage not receiving toothpaste from said upper chamber in a retracted position of said extension,
• a brush head at an end of said extension having a head orifice communicating between said passage and said brush for delivering toothpaste to bristles thereof, and
• a spring-loaded second valve at said head orifice to allow toothpaste to pass through said head orifice only when pressure in said passage is in excess of ambient pressure;
• and
• seals around said extension and at a location of communication between said upper chamber and said passage.