Which cell is primarily responsible for bone resorption?

Osteoclasts are the primary bone-resorbing cells — large, multinucleated cells derived from monocyte/macrophage lineage. They use H+ pumps and lysosomal enzymes (cathepsins) to dissolve bone. Osteoblasts BUILD bone. Odontoblasts form dentin. Odontoclasts resorb root structure (primary teeth). Osteoclast = bone breakdown.