The proper jewelry for an initial labret piercing is a stainless steel bar with a flat disc on the inside of the lip and a bead on the outside. A properly-trained piercer will pierce your lip with a bar that is slightly too long, to allow the lip room to swell. If the bar is too short, there is a danger of the bead or disc embedding in the flesh. Your piercer should measure the thickness of your lip with calipers before cleaning and marking. The disc and bead unscrew from the bar so you can put a shorter bar in when the piercing is fully healed. If your labret becomes embedded, go immediately to a qualified piercer to have the jewelry removed.
An improperly placed labret piercing can rub against tooth enamel, eroding the surface of the teeth and causing microscopic craters that can lead to decay. A well-trained piercer will position the jewelry so it has the least possible contact with the surface of your teeth. A more serious potential problem is tooth drift, in which the jewelry erodes enamel between teeth to the extent that they move away from each other. A tooth that has moved out of position can only be repositioned with orthodontia, which can be quite expensive. Those with labret piercings must be especially careful to see their dentist regularly for check-ups.
If your jewelry touches your gums, it can slowly erode them, exposing the roots of your teeth. An exposed root is not covered in enamel and is even more prone to decay than the surface of the tooth. Root decay can lead to infection, which can spread to the jawbone if left unchecked. Gum recession is irreversible without expensive gum graft surgery, in which gum tissue is taken from another part of the mouth and transferred to the recessed area. At the first sign of gum erosion, remove the jewelry and go immediately to the dentist. You can lose your teeth if you don't take care of this problem as soon as it occurs.