This article is from the Piercing FAQ, by Anne Greenblatt with numerous contributions by others.
The risks of oral piercings include chipped and cracked teeth and
damage to other oral tissues, including irritation or loss of gum
tissue and, in extreme cases, bone loss beneath the gums. These risks
can be reduced, but not altogether eliminated, by appropriate
placement and jewelry selection. The risk of swallowing or inhaling
jewelry is reduced by wearing high-quality jewelry and frequently
checking that it is secure. Swallowed jewelry usually passes within
three days but can be potentially very dangerous.
 
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