When an Orthodontist talks about the need for Mesialization, they mean that teeth need to be pulled forward, toward the midline. For example, they might decide that you need molar mesialization, where your molars are pulled forward in the arch. Molar mesialization is often used as part of the treatment for patients who have had extractions or are missing teeth. Because of the anatomy of your jaws, it is easier to mesialize the upper jaw (maxillary arch) than the lower jaw (mandibular arch). One appliances commonly used for molar mesialization is the Mesial Jet, as pictured above.