Osteoblasts and osteoclasts are two main cells participating in bone progressing. Osteoclasts is responsible for aged bone reabsorption and osteoblasts is responsible for new bone formation. The maintenance of helathy bones depend on the osteoblast and osteoclast activity.
If the osteoblast activity exceeds osteoclast activity, then would be harmulful effect on the bones, the bone mineral would be decline and the bones become weaker without osteoclast and osteoblast.
If the activity of osteoclasts(which demineralize bone) exceeded osteoblast activity(production of new bone), then the bone's mineral content(and thus its mass) would decline, making it weaker.
