Worn Chipped or Cracked Teeth
Wear of teeth is often assumed to be "normal" with age. When the jaw is at rest the teeth are supposed to be slightly apart. This space is called "freeway space". The only time the teeth actually touch is during swallowing, that occurs about 2000 to 3000 times a day. When chewing foods, no matter how fast we chew, the teeth don't actually touch each other. The muscles know precisely when the teeth will touch. With the soft foods we consume in our modern diet, there is no real need for teeth to wear.
The only real reason for severe tooth wear is due to parafunction. Parafunction is putting teeth against teeth to clench or grind. The amount of force one develops in this grinding during sleep, especially during the Rapid Eye Movement (REM) part of the sleep cycle, is many times higher than the highest voluntary clench.
This parafunctional habit of clenching and grinding the teeth is due to a disharmony between the position where the teeth come together best for chewing (Habitual occlusion) and the position where the two jaws are related to each other when all the muscles of the jaws and posturing muscles of the head and neck are at their relaxed and unstrained position (Physiological Neuro Muscular occlusion). Grinding is the process of the muscles of the lower jaw grinding through the Habitual occlusion to hopefully reach the Neuro Muscular occlusion.
If the worn or chipped teeth are restored with crowns or other restorations without regard to this underlying cause, then the result will be the same to the new restorations as well, worn or chipped restorations! If the restorations are made with metal, as a solution to the wear problem, then the forces of the muscles will destroy the bone holding the teeth in the jaws over time. This leads also to receded gums, loose or lost teeth.