Abstract: Apparatus and methods for root canal treatments are provided. In some embodiments, an aiming element may be used to position a high-velocity liquid jet near a desired location in the tooth. Embodiments of the aiming element may include an interrupter that deflects or impedes the liquid jet when it is not desirable for the jet to propagate from the aiming element. Embodiments of the aiming element may include an elongated member that permits passage of the liquid jet through a channel. The elongated member may include one or more openings, for example, on sides and/or ends of the member. Some root canal cleaning techniques include one or more applications of the liquid jet followed by application of a disinfectant such as, for example, an aqueous solution of sodium hypochlorite.