The disease that causes bones to become weak is called "Osteoporosis".
Osteoporosis
Osteoporosis is a disease in which bones become fragile and more likely to break.
Osteoporosis
Their bones naturally losing (some) strength.
Over time your bones will become fragile.
Condition caused by calcium deficiency; bones become porous, weak, and fragile.
Osteoporosis is the most common one, but there are others.
periodontal disease?
No, bones are actually very strong. If they were fragile you wouldn't be able to run or jump or carry heavy things.
weak bones that bones that are very fragile means that they are very weak or easily breakable.
Osteoporosis
Paget's Disease causes bone cells to break down more rapidly than they can be rebuilt. It causes pain, and makes bones more susceptible to breaking.