Dear JACUSTOMER-oc4wehs2,Teeth crumble for the same reasons any structure crumbles: the forces to which they are exposed exceed their strength. Following that line of reasoning, a tooth might disintegrate if it is structurally weakened, or if the forces to which it is exposed are excessive (or, a combination of those two factors).In the structural weakening category, tooth decay is a major contributing factor. Granted, there may not currently be any decay in your teeth, but deep or extensive fillings due to previous tooth decay can significantly lower the tooth's fracture threshold, to the point where normal functional chewing forces can initiate cracks that spread through the tooth.In addition to deep decay or extensive fillings, some teeth suffer from congenital weakness-- either inherited deficiencies in the tooth dentin or enamel, or weaknesses acquired during tooth formation; these will also make teeth more vulnerable to disintegration.
On the other side of the coin, there are those factors where potentially damaging forces may be applied to the teeth--- perhaps from a single traumatic incident (a fall, an accident, finding an unexpected stone in an olive or fruit, for example), or due to habitual and chronic tooth clenching and grinding (bruxism). These events can progressively wear the teeth and introduce fractures which can eventually cause breakage.
Your dentist can assess your teeth and determine which of these factors are present in your mouth.In the case of extensively or deeply filled teeth, the use of appropriate restorations are often all that is needed. For example, replacement of large fillings with crowns can not only repair current damage, but strengthen the teeth against further disintegration.
Hope this helps...