ABSTRACT
<p><b>OBJECTIVE</b>To study role of dental follicle in tooth root development.</p><p><b>METHODS</b>Sixteen mandibular first molar dental germs from eight five-day postnatal Balb/c mice were divided into two groups randomly. Dental follicle of germs in one group was undetached and that of another group was removed. Subsequently, each of the germs was separately transplanted to back-muscles of adult nude mice. At seventh and fourteenth day after transplanting, the germs were collected, fixed, demineralized, dehydrated, and embedded in wax in sequence. Serial sections of 5 microm thick were made following the routine methods, stained with haematoxylin-eosin dying solution, and observed under a light microscope.</p><p><b>RESULTS</b>All implantations were located in the back-muscles with abundant capillary vasculature. Under microscope, although all tooth germs could further develop after grafting, tooth germs without dental follicle developed slowly with small size and low calcification compared to those with dental follicle. Although position of Hertwig's epithelial root sheath of all germs seemed no changing, roots of the group with dental follicle could further develop and the roots develop toward the apical direction; this tendency couldn't be seen in the germs of another group. Inflammatory cells could be seen in and out of the pulp cavity of the two groups at 7th day after grafting, while no obvious inflammatory cell was observed at 14th day after grafting.</p><p><b>CONCLUSION</b>Dental follicle play an important role in tooth root development. It probably can lead tooth root to develop in normal direction.</p>
Subject(s)
Animals , Mice , Dental Pulp Cavity , Dental Sac , Enamel Organ , Mice, Nude , Molar , Odontogenesis , Tooth , Tooth Germ , Tooth RootABSTRACT
<p><b>OBJECTIVE</b>To study the distribution and expression of fibromodulin, decorin and biglycan in developing normal periodontal tissues, so as to understand its role in periodontal tissue formation.</p><p><b>METHODS</b>Thirty six BALB/c mice in different developing stages were killed and their bilateral mandibular first molars with surrounding alveolar bones and gingival tissues were taken out, Power Vision two steps immunohistochemical method with anti-fibromodulin, anti-decorin and anti-biglycan was used to detect the tissue distribution and cellular localization of fibromodulin and related proteoglycans, decorin and biglycan.</p><p><b>RESULTS</b>Fibromodulin was strongly expressed in the subcutaneous gingival connective tissue, periodontal ligament, mainly in gingival and periodontal fibroblasts as well as their matrices. Strong expression was also noted in the area close to the interfaces of periodontal ligament-alveolar bone and periodontal ligament-cementum. Decorin was strongly expressed in the area of gingival connective tissue, periodontal ligament and the surface of alveolar bone, while biglycan was stained evidently in gingival connective tissue throughout the period of investigation, but negative in the surface of alveolar bone and osteoblasts.</p><p><b>CONCLUSIONS</b>Fibromodulin may interact with decorin and biglycan to regulate the network formation of gingival connective tissues and periodontal collagen fibers, and may be involved in mineralization of the alveolar bone and cementum.</p>