The Effects Of Excessive Fluoride On Cultured Tooth Germ, Mineralization Of Dental Papilla Cells And Restoration Of Pulp

Though double effects of fluoride on tooth and bone have been accepted by most people, it is believed that proper fluoride is advantage was while excesve fluoride is disadvantageous, the mechanism of fluoride is not very clear. Now in crease of dental fluorosis resulting from caries prevention by fluoride intake have been increasingly paid more attention to. To understand the mechanism of dental fluorosis would provide theoretic evidence for proper fluoride supplement.The model of dental germ cultured in vitro is favourable for studying the effects of fluoride on tooth development. Some investigators have studied the mechanism of fluoride on tooth germ by the model last century. Affected by the poor experimental technique, the germ could only be alive for a limited time. It was found the enamelblast metabolize impressed by fluoride is reversible as time extended. This was not accordance with the finding in clinic. Abnormal mineralization of both enamel and dentin may occur by exposure to excessive fluoride during the stage of tooth germ formation. Some of the mechanisms about enamel fluorosis have been clarified. The knowledge about dentin fluorosis is limited and the mechanism is unclear.Abnormal mineralization of both enamel and dentin may occur by exposure to excessive fluoride during the stage of tooth germ formation. Whether the change is due to the odontoblast abnormal mineralization affected by fluoride was not clear. The pulp tissue could be repaired by. odontoblast forming reactive, reparative dentin as a response to external irritation, when tooth bourgeon topic fluoride could enhance theresistance to caries. It was approved by experiment in vitro that secondary caries could be inhibited and reminerlization could be promoted by fluoride. Now the dental restorative material contained fluoride was being used in clinic widely. Whether it affect reactive and reparative dentin has not been confirmed. To understand the mechanism of dentin fluorosis would provide theoretical evidence for proper fluoride supplement.Contents1. The Effects of Fluoride on the Development of mouse molars in vitro;2. The Effects of Fluoride on growing and proliferating activity, osteocalcin,type I collagen in cultured human dental papilla cells;3. The Effects of Fluoride on mineralization of cultured human dental papilla cells.Material, methods and results1. The Effects of Fluoride on the Development of mouse molars invitroOrgan cultured in vitro is a favourable model to studying the development. It kept the interaction of tissues and the intervention is easy to control. The objective of this experiment is to establish the model of the cultured tooth germ in vitro and examined the effect of fluoride on its development. The tooth germs from embryonic 18th d Babe mice's first maxillary molar were cultured in 96 hole ban in semi ~ solid BGJB medium with the condition 37 , CO2 5%. The explants were fixed in formaldehyde for 4 h after cultured for 0, 4, 8, 12days, HE staining was used to examine the germs. It was showed that the tooth germs developed well in vitro and both the inner enamel epithelia and odontoblastssecreted matrix while some of the enamel and dentin begin to mineralize. Because of the different environment between vitro and vivi, the germ grew slowly. The growing speed was 1/2 native. Anyway, the model was established and woule was used to the next studying on the effects of fluoride on the Development Of tooth germ.The explant cultured presence and absent 5.0 10-6g/L NaF. HE staining was used to examine the germs of 4th and 8th days while the 12 days germ was examined by the TEM. It was found the germ developed slowly at the presence of fluoride. The secretion of enamelblast and odontoblast was restrained. The arrangement of enamelblast was not so tightr as usual and some electric compact granule appeared in the cells. The project of the odontoblast expanded evidently. Not well~proportioned minerlization was found in enamel and dentin.2. The effects of fluoride...