Development of mandibular cartilages in the rat

The mammalian mandible develops around Meckel's cartilage and other secondary cartilages, including the dentary. There have already been many studies of the development of the rat mandible that have employed histological serial sections. However, no previous investigators have captured the three-dimensional features of the developmental process.In this study, the technique of double staining with alizarin red S and alcian blue was employed directly on whole body specimens to investigate the three-dimensional development of the rat mandible.We found that the molar socket obstructs the developing mandible, causing it to emerge medial to Meckel's cartilage. Our results also indicate that the secondary mandibular cartilages may contribute to supplementary growth in response to local factors.