(B) Primary osteoclasts were isolated from the crushed long bones of the same mice and plated on glass coverslips or on dentin slices to quantify numbers and activity, respectively. Osteoclasts were identified as cells with three or more nuclei that stained positive for TRAP activity (upper) and excavated pits in dentin slices, as demonstrated by SEM (lower, bar = 20 μm). No statistical differences were observed either in the number of TRAP-positive cells or in their resorptive activity.