Osteoclasts were isolated from the crushed long bones of juvenile Sam68+/+ and Sam68−/− mice and used for quantitative studies as described [64]. Briefly, cells were plated on glass coverslips or on dentin slices in 24-well cluster plates for assessment of cell number and pit number, respectively. Cover slips were immersed in 4% paraformaldehyde and stained for TRAP activity after 2 h. Dentin slices were left for 28 h before removing the cells with 1 M ammonium hydroxide and air drying before coating with sputter Au-Pd and examination with scanning electron microscopy (McGill Electron Microscopy Centre). Light microscope images were captured using a Leica DMR microscope equipped with a Retiga 1300 camera. Quantitative analyses were performed using Adobe Photoshop and the data presented as the mean ± SD of two or three independent experiments. Statistical comparisons were made using the Student's t test.