RESUMEN
OBJECTIVE: To study role of dental follicle in tooth root development. METHODS: 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. RESULTS: 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. CONCLUSION: Dental follicle play an important role in tooth root development. It probably can lead tooth root to develop in normal direction.
Asunto(s)
Saco Dental , Germen Dentario , Animales , Cavidad Pulpar , Órgano del Esmalte , Ratones , Ratones Desnudos , Diente Molar , Odontogénesis , Diente , Raíz del DienteRESUMEN
PURPOSE: To observed the changes of the developed mouse's dental germs after transplanting into nude mouse and find some theoretical foundation for establishing an innovative experimental model. METHODS: Eight tooth germs from four 5th day postnatal Balb/c mice were transplanted to the back muscles of the adult nude mice. At seventh and fourteenth day after grafting, the germs were collected, fixed, demineralized, dehydrated, and embedded in wax. Serial sections of 5 microm thick were made following the routine methods, stained with haematoxylin-eosin dying solution, and observed under a light microscope. The mandibular first molars were taken out from the 12th and 19th day postnatal mouse. Serial sections of 5 microm thick were made following the routine methods, then compared with the germs after graft. RESULTS: All implantations were located in the superficial muscles with abundant capillary vessels. The dental germs could further developed after grafting under the microscope, but slower than dental germs self-development. The layer of dentin was thin, plenty of dentin with disorganized dentin tubule formed after grafting. Although the location of Hertwig's epithelial root sheath hardly moved, the roots developed further. The floor of pulp chamber could form and the pulp chambers were shrinking. The degree of calcification in the area of root increased very clearly. The inflammatory reaction was found at 7th day while hardly noted at 14th day after grafting. CONCLUSIONS: It suggests that late development of mouse tooth germs could further develop after heterotopic transplantation within the superficial muscles of the nude mouse. This model is useful for study of tooth root development in short time.
Asunto(s)
Odontogénesis , Germen Dentario/anatomía & histología , Germen Dentario/trasplante , Raíz del Diente/crecimiento & desarrollo , Animales , Animales Recién Nacidos , Dentina , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Diente Molar , Técnicas de Cultivo de Órganos , Músculos Superficiales de la Espalda , Diente , Germen Dentario/crecimiento & desarrolloRESUMEN
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Asunto(s)
Proceso Alveolar/citología , Proteínas de la Matriz Extracelular/análisis , Encía/química , Osteoblastos/química , Ligamento Periodontal/química , Proteoglicanos/análisis , Proceso Alveolar/crecimiento & desarrollo , Animales , Biglicano , Decorina , Fibromodulina , Encía/crecimiento & desarrollo , Inmunohistoquímica , Ratones , Ratones Endogámicos BALB C , Ligamento Periodontal/crecimiento & desarrollo , Germen Dentario/químicaRESUMEN
PURPOSE: To study the distribution of dentin matrix protein 1, osteopontin and bone sialoprotein during cementum formation and cementoblasts differentiation in mouse. METHODS: Thirty six BALB/c postnatal mice were divided into four groups according to the developing stages, nine in each was subdivided into three parts randomly to examine the location of DMP1, OPN and BSP, a tooth developing study model was built and examined using histological methods correspondingly. PV two steps immunohistochemical assay was used to localize the distribution of the three regulatory factors timely and spatially. Repeated measures ANOVA and statistical analysis software of CMIAS were used to analyze the intensity of the dyed images. RESULTS: There was a series expression of the three regulatory proteins. DMP1 was expressed in the dental follicle cells in day 5 of postnatal stages and negatively expressed when the cell began to differentiate; meanwhile, since day 10 and on OPN was positively located in cementoblasts until the root developed completely; but BSP was expressed in the same cell in day 15 to 20, and then decreased to be negative. There were significant differences statistically among the three factors in each stage observed in the study except OPN between day 15 and 25. CONCLUSIONS: There are different locations timely and spatially among the three proteins, it hints that they play important different roles during the differentiation of cementoblasts and formation of cementum.