Teeth are richly supported by blood vessels and peripheral nerves. The aim of this study was to describe in detail the developmental time‐course and localization of blood vessels during early tooth formation and to compare that to innervation, as well as to address the putative role of vascular endothelial growth factor (VEGF), which is an essential regulator of vasculature development, in this process. The localization of blood vessels and neurites was compared using double immunofluorescence staining on sections at consecutive stages of the embryonic (E) and postnatal (PN) mandibular first molar tooth germ (E11‐PN7). Cellular mRNA expression domains of VEGF and its signaling receptor VEGFR2 were studied using sectional radioactive in situ hybridization. Expression of VEGF mRNA and the encoded protein were studied by RT‐PCR and western blot analysis, respectively, in the cap and early bell stage tooth germs, respectively. VEGFR2 was immunolocalized on tooth tissue sections. Smooth muscle cells were investigated by anti‐alpha smooth muscle actin (αSMA) antibodies. VEGF showed developmentally regulated epithelial and mesenchymal mRNA expression domains including the enamel knot signaling centers that correlated with the growth and navigation of the blood vessels expressing Vegfr2 and VEGFR2 to the dental papilla and enamel organ. Developing blood vessels were present in the jaw mesenchyme including the presumptive dental mesenchyme before the appearance of the epithelial dental placode and dental neurites. Similarly, formation of a blood vessel plexus around the bud stage tooth germ and ingrowth of vessels into dental papilla at E14 preceded ingrowth of neurites. Subsequently, pioneer blood vessels in the dental papilla started to receive smooth muscle coverage at the early embryonic bell stage. Establishment and patterning of the blood vessels and nerves during tooth formation are developmentally regulated, stepwise processes that likely involve differential patterning mechanisms. Development of tooth vascular supply is proposed to be regulated by local, tooth‐specific regulation by epithelial–mesenchymal tissue interactions and involving tooth target expressed VEGF signaling. Further investigations on tooth vascular development by local VEGF signaling, as well as how tooth innervation and development of blood vessels are integrated with advancing tooth organ formation by local signaling mechanisms, are warranted.
The expression of the Fgf11-13, -15, -17 and -20 in the epithelial signaling centers and/or epithelial-mesenchymal interfaces at key stages of the tooth formation suggest important functions in odontogenesis. Future analyses of the transgenic mice will help elucidate in vivo functions of the studied Fgfs during odontogenesis and whether any of the functions of the tooth expressed epithelial and mesenchymal Fgfs of different sub-families are redundant.
Background: Labial frenum is a fold of mucous membrane whose function is to attach lips and cheek to the alveolar mucosa, gingiva and underlying periosteum. The maxillary labial frenum has lot of variation in shape, size location. This study was aimed to assess the variation of maxillary labial frenum in the indigenous Chepang community of Nepal.Methods: A descriptive cross-sectional study was conducted among the Chepang community at Madi municipality in Chitwan, Nepal. The clinical examination was done by distending the upper lip upward for viewing. The obtained data was classified according to Mirko and Sewerin classification. Data was entered into Statistical Package for the Social Sciences version 16 and descriptive statistics was performed.Results: All the Chepang participants 102 (100 %) had mucosal type of maxillary frenum. Among the variations normal frenum was mostly present 74 (72.5%). This type was mostly present in male participants 44 (43.1%). Apart from this frenum with nodules and appendix was also observed.Conclusions: The mucosal type of frenal attachment was prevalent in Chepang Community and normal frenum was the most common type of frenal morphology. Keywords: Chepang community; maxillary labial frenum; mucosal
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