Vacuum-formed (Essix) retainer
Another common type is the vacuum formed retainer (VFR). This is a polypropylene or polyvinylchloride (PVC) material, typically .020″ or .030″ thick. Essix is a brand name many dental offices are familiar with. This clear or transparent retainer fits over the entire arch of teeth or only from canine to canine (clip on retainer) and is produced from a mold. It is similar in appearance to Invisalign trays, though the latter are not considered “retainers”. VFRs, if worn 24 hours per day, do not allow the upper and lower teeth to touch because plastic covers the chewing surfaces of the teeth. Some orthodontists feel that it is important for the top and bottom chewing surfaces to meet to allow for “favorable settling” to occur. VFRs are less expensive, less conspicuous, and easier to wear than Hawley retainers. However, for patients with disorders such as Bruxism, VFRs are prone to rapid breakage and deterioration, especially if the material is PVC, a short chain molecule. This breaks down swiftly as compared to polypropylene, a long chain molecule.
Most removable retainers are supplied with a retainer case for protection. During the first few days of retainer use, many people experience extra saliva in their mouth. This is natural and is due to the presence of a new object inside the mouth and consequent stimulation of the salivary glands. It may be difficult to speak for a while after getting a retainer, but this speech difficulty should go away over time as one gets used to wearing it.
