Abstract: An apparatus for treating a tooth includes a proximal chamber and a distal chamber disposed distal the proximal chamber and in fluid communication with the proximal chamber by way of a transition opening. The distal chamber includes an access opening disposed apart from and distal to the transition opening, the access opening to provide fluid communication between a treatment region of the tooth and the distal chamber. The apparatus includes a liquid supply port disposed to direct a liquid stream into the proximal chamber and over at least a portion of the transition opening. The apparatus includes an impingement member arranged within a path of the liquid stream, the impingement member having one or more surfaces positioned to redirect at least a portion of the liquid stream across at least a portion of the transition opening.