It’s frequent and common in occurrence , to have been eating on something too hard , or not expected to be included with the food, and the freighting crack sound will appear , announcing broken filling, or broken tooth or a mix of both options.
Foreign objects in food, food that is too dry, frozen, or even bad baits of biting on hard objects are all common causes of broken teeth.
This situation can be as simple as a small chip of the restoration, and in such case it might not cause any pain, and sometimes the chipped filling gets swallowed , and I have seen a few people who would not notice the missing part, till it gets pick up on the next routine check up.
The broken filling can get more involving , and cause the inner side of the tooth to be exposed , which will cause the affected tooth to be sensitive to temperature changes . Such a case will require an immediate action of replacing that filling, or even getting a temporary filling arranged, till a further treatment can be done.
It can also be involving a bigger part of the tooth, and extending to the nerve part, which will cause severe pain almost instantly , sue to the sudden change after the mechanical fracture, in more complicated cases the tooth itself can be cracked, or the root can be fractured , which is a catastrophic event for the tooth itself.
The most common option to restore a broken filling is to have the filling replaced, when there is no much tooth structure to restore, a crown of chosen material might be the ideal option for a longer term restoration. In those cases when the nerve part of the tooth is affected , a root canal treatment might be required before having a crown over the tooth. Or the worse possible when the root of the tooth is broken , affecting the foundation of the tooth, in that case a tooth extraction might be the only treatment option.