Non-ring labrets can come with disk backs or fishtails. Posts that end with disk backs have a small flat circle of metal that screws to the jewelry, sometimes on the disk side inside the mouth, and sometimes a barbell end that caps the post on the outside. Fishtail-finished jewelry has a wire that lies along the inside of the lip perpendicular to the piercing, staying in place using much of the same principles as the Indian nostril screw does for nose piercings. This jewelry is inserted into the piercing from the front and twists into place to fit the front shape of the mouth. Which style works best for you can only be determined through your own experience. Each style has reports of rubbing the gums too much along with responses claiming comfort and ease of wear.If the gums are damaged from the labret, it is often a good idea to abandon the piercing rather than continue to try different jewelry styles. The dental tissue along the teeth is comprised of two layers. If the tougher outer layer is sufficiently damaged, it won't heal or grow back and can leave the underlying tissue open to inflamation and further damage. In some instances a small skin graft-like procedure, called a soft tissue alloplasty, may be necessary to repair the destroyed gum tissues.
To learn more about piercing, you might like Body Piercing: A Medical Dictionary, Bibliography, And Annotated Research Guide To Internet References by Icon Health Publications.
For body piercing aftercare, you might like Tattoo Goo Deluxe Tattoo & Piercing Care Kit or X-Pression & Blue Wave Piercing Aftercare Kit

