Apparatus for dental treatment provided with check valve in fluid passage

A dental treatment apparatus comprising:

• a pressurized fluid source for pressurizing and supplying fluid to perform dental treatment operation;
• fluid passage means for supplying said fluid pressurized to a dental treatment tool provided to the extreme end of a dental handpiece;
• suction means interposed between said pressurized fluid source and said handpiece and adapted to stop the flow of said pressurized fluid and to suck the fluid in a direction opposite to a supplying direction of said fluid when said dental treatment operation is terminated;
• and
• check valve means interposed in said fluid passage means between said suction means and said dental treatment tool, said check valve means including a resilient valving member and a through-slit formed in said valving member, said slit being extended apart under pressure to permit the fluid to pass therethrough when said pressurized fluid is conveyed through said check valve means during said dental treatment operation, said through-slit being closed by the resiliency of said valving member to inhibit the fluid lying between the check valve and the dental treatment tool from being sucked towards said suction means when said dental treatment operation is terminated.