A chipped tooth and a cracked tooth, though similar, are different.
A crack in the tooth usually starts near the gum line and spreads toward the chewing surface. Though the tooth remains intact, a fracture line may become visible across the tooth. In some cases, the fracture is only visible using a microscope, and a dental professional has to find it.
In other cases, the crack may extend through the entire tooth from the chewing surface to the root (the part of the tooth inside the bone socket).
A chipped tooth is a tooth that has broken. A small or large piece may have been knocked off through a fall, sports injury, or other trauma to the mouth, including biting something hard.
Chipped teeth are the most common dental injury.