Figure 3. In situ hybridization for MMP 8 (a-d) and MMP 13 (e-h) during root formation and eruption of maxillary first molars. (a,e) Week 2. (b,c,f,g) Week 4. (d,h) Week 6. The insert in (f) is an image with a higher magnification of the enclosed region. Arrowheads in (c), (e) and (f) indicate hybridization signals. B, alveolar bone; P, periodontal ligaments; C, cementum; D, dentin. Bars = 10 µm (a,e); 20 µm (b,d,f,h); 5 µm (c,g).