Research On Dynamic Histological Development Of Rat Enamel Organ

Objective：The objective of the study was to observe development structure and histologicalstructure of the rat enamel organ, to master which development stages corresponding to theembryonic period, explore histological temporal characteristics of the development ofenamel organ and morphology observation and histologic changes into the enamel organdevelopment in different stages of explore into rats histological temporal characteristics ofthe development of enamel organ and explore into rats histological temporal characteristicsof the development of enamel organ and morphology observation and histologic changesinto the enamel organ development in different stages of the relationship between the resultof the morphology structure and histological change of the enamel organ in different stages.Method:Pregnant rats on13th,14th,16th,18th and20th days of gestation and new born rats2rd and3rd days old were anesthetized with intraperitoneal administration of overdosage ofchloral hydrate and disinfected in75%alcohol. After the exposure of organs withdissection scissors, fetuses were removed and beheaded and jaws were removed andexposed. Similary, the jaws of new born rats were exposed and tissues were fixed inparaformaldehyde, progressively dehydrated in alcohol, and embedded in paraffin. Tissuesections were obtained and stained with hematoxylin and eosin and observed under optical microscope.Results:In embryonic period of13days, tooth germ development turn into bud stage and thelocal epithelium increased thickness and inward depressed gradually; In embryonic period14days, the end of tooth plate proliferate and inward depressed obviously, that formed aepithelial bud like a bud; In the embryonic period of16days, the tooth germ developmentturn into cap stage, epithelial cells of the enamel organ divided into three layers, outerenamel epithelium, inner enamel epithelium, stellate reticulum; In embryonic period18days, tooth germ development enter into bell stage, epithelial cells of the enamel organdivided into four layers; In embryonic period of20days, tooth germ development enterinto late bell stage, basal lamina was gradually replaced by previous predentin; the neonatalrats born in2days, ameloblast turn in to early production; the neonatal rats born in2days,enamel matrix increased, and predentin transformed to dentin matrixConclusion:1. This experiment observed the morphological change of rat enamel organsystematically, we mastered histology timing characteristics and determined whichdevelopment stages corresponding to the embryonic period,2. The histological development of rat enamel organ was similar to that of humanenamel organ. We get a dynamic development model of rat enamel organ. It provides basisfor the pathogenesis of developmental anomalies of tooth.3. the development of rat enamel organ has experienced a series of dynamicdevelopment, which contains bud stage, cap stage, bell stage. In this process, enamel organ,dental papilla and dental follicle interact and give rise to the tissues of a normal tooth.