What symptoms suggest bone loss?

Sometimes, none. Bone loss is assessed in post-menopausal women with a bone densiometry study. Estrogen tends to mitigate bone loss in pre-menopausal women. Many women with bone loss have no symptoms until a "spontaneous fracture" occurs with or without a fall.
Perio probing. Symptoms would be tooth mobility, bleeding gums, and may occur with or without pain. Halitosis is another symptom, and maybe loss of function if the bone loss is severe. Periodontal charting or probing, a process of measuring attachment level using the probes will clarify the extent of bone loss. Radiographic also helps diagnosis.
Usually none. Bone loss, which eventually leads to osteoporosis and osteopenia , does not cause symptoms. It does, however, increase the risk of fracture. A bone density test, or dxa, can determine if there is bone loss.