A lavage unit including: a handpiece; an irrigation tube that extends from a source of irrigating fluid to the handpiece; a tip assembly that extends forward from the handpiece, the tip assembly including an irrigation tube that is connected to the handpiece irrigation tube through which the irrigating fluid is discharged; a pump that is selectively actuatable for forcing irrigating fluid through the tip assembly irrigation tube; and a control assembly for regulating the actuation of the pump, the control assembly including a trigger (561 820) that is moveably mounted to the handpiece and that is manually actuated for controlling the actuation of the pump; wherein the control assembly and the trigger (561 820) are collectively configured so that the trigger has: a first position in which the control assembly holds the pump in an off state; and a second position in which the control assembly causes the pump to go into the on state wherein said trigger transitions from the first position to the on second position when a manual force is applied to the trigger and, upon the removal of the manual force, returns to the first position; characterized in that: the control assembly and the trigger (561, 820) are further collectively configured so that the trigger also has a third position in which the said control assembly actuates the pump, wherein once said trigger is moved to the third position, the trigger remains in the third position until a disengaging force is applied to the trigger to move the trigger to at least one of the first position or the second position. a handpiece; an irrigation tube that extends from a source of irrigating fluid to the handpiece; a tip assembly that extends forward from the handpiece, the tip assembly including an irrigation tube that is connected to the handpiece irrigation tube through which the irrigating fluid is discharged; a pump that is selectively actuatable for forcing irrigating fluid through the tip assembly irrigation tube; and a control assembly for regulating the actuation of the pump, the control assembly including a trigger (561 820) that is moveably mounted to the handpiece and that is manually actuated for controlling the actuation of the pump; wherein the control assembly and the trigger (561 820) are collectively configured so that the trigger has: a first position in which the control assembly holds the pump in an off state; and a second position in which the control assembly causes the pump to go into the on state wherein said trigger transitions from the first position to the on second position when a manual force is applied to the trigger and, upon the removal of the manual force, returns to the first position; characterized in that: the control assembly and the trigger (561, 820) are further collectively configured so that the trigger also has a third position in which the said control assembly actuates the pump, wherein once said trigger is moved to the third position, the trigger remains in the third position until a disengaging force is applied to the trigger to move the trigger to at least one of the first position or the second position. the control assembly and the trigger (561, 820) are further collectively configured so that the trigger also has a third position in which the said control assembly actuates the pump, wherein once said trigger is moved to the third position, the trigger remains in the third position until a disengaging force is applied to the trigger to move the trigger to at least one of the first position or the second position.