The dental water jet was invented by Dr. Gerald Moyer, a dentist, and John Mattingly, an engineer, in Ft. Collins, Colorado, in the late 1950s. The dental water jet, also known as an oral irrigator, was introduced to the dental profession in Texas during the 1962 Dallas Dental Convention. Numerous studies measuring the irrigator's efficacy in different cohorts have been published in peer-reviewed journals. The results of those studies are discussed in this article. The bulk of research has been conducted on one product (Waterpik dental water jet, Water Pik, Inc, Fort Collins, CO). This article is designed to provide dental professionals with the evidence essential to making an informed decision on the oral health benefits and expected outcomes of the dental water jet.