A dental instrument is disclosed, which comprises a guide tube (100) having a channel (84) permitting propagation of a pressurized liquid along at least a portion of a length of the guide tube (100), the guide tube (100) having a proximal end and a distal end, wherein the distal end, during treatment, is disposed in, near, or on a portion of the tooth under treatment. An impingement member (110) has an impingement surface (114). The pressurized liquid, during operation of the instrument, can propagate along the channel (84) and impinge upon the impingement member (110) to slow, disrupt or deflect at least a portion of the pressurized liquid.
