The purpose of this work was to describe the most commonly used retainers, to provide a more detailed review of the use and production of the essix retainer, and to give clear instructions to the patient about the maintenance of retainers. Essix is one of the most common and popular removable retainers. It is simple to use, economical and aesthetically very acceptable because of its transparency and firmness, but also because it is simpler and more affordable to produce, and it interfere less with speech compared to the acrylate plate retainers. Essix needs to be protected from damage caused by high temperatures and abrasive pastes. Consummation of food and drinks while wearing essix can cause teeth damage, because the remains of food and sweet drinks accumulate between the essix and the teeth. While handing essix to the patient it is important to emphasize the correct way of maintenance. The most effective way is to orally explain and then also to give written instructions to the patient. Keywords: essix, retainer; oral hygiene, orthodontic retention, thermoplastic material.