| Background and objectiveIn recent years, based on the theory of tooth development and stem cell, toothtissue engineering and tooth regeneration become a hot point in oral regenerativemedicine. However, the suitable culture model of a three-dimensional tooth germ stillremains elusive. In this study, we aim to compare two environments, the subrenalcapsule and oral submucosa, for producing well-formed teeth from mouse toothgerms.MethodsFifty ICR mice(thirty were female, twenty were male, about thirty gram for eachmouse)were devided into two groups in random:1. Experimental group: GroupA-transplanted ED14.5tooth germs into renal subcapsular, each mouse can betransplanted twelve tooth germs and totally were three mice and thirty-six tooth germs.Group B-transplanted ED14.5tooth germs into oral submucosa layer, each mouse canbe transplanted two tooth germs and totally were eighteen mice and thirty-six toothgerms.2. Normal control group: Group C-took a embryonic day14.5pregnant mouse,didn’t do any processing, in order to make its natural parturition. At intervals of3,4,8weeks after transplantation, the host mice were sacrificed, kidneys and oral mucousmembranes were dissected to obtain the teeth. And then the transplanted explantswere evaluated with histological structures, hardness and elastic modulus test, andchemical compositions.Results1. Morphology observation of the graft: the morphology of the crown was quiteas contemporaneous molar in group A, in which it had obvious cusps. As to the groupB, the crown was smaller, and the shape of the cusps were not significant, in allstudies to date, it was flat at the bored of crown and root, and there was no signs ofroots’development.2. HE staining showed the normal tooth structure in both three groups, therewere HERS which didn’t develop well in group A and group B;3~4weeks aftertransplantation, the dentin and enamel in group A were more thicker than group B inwhich the ameloblasts and odontoblasts were differentiated not very well;8weeks after transplantation, the degradation of ameloblasts and odontoblasts happened, someof the pulp tissues became organized like a network structure.3. Statistics of the tooth formation: in the same group, the probability of toothformation would decline following the increase of observation time; in the sameobservation point in time, the probability of tooth formation in group A was higherthan group B.4. Hardness and elastic modulus test results: in the test of enamel hardness, onlythe hardness of four weeks in group B was lower than group C(P＜0.05), and thedifference between other groups was not significant(P＞0.05). in the test of enamelmodulus, the elastic modulus of enamel in three weeks of group A was slightly lowerthan group C, but the difference was not significant(P＞0.05), the elastic modulus ofenamel in four weeks of group A and group B was significantly lower than group Cand three weeks of group B(P＜0.01). the hardness and elastic modulus of dentin inthree groups was not significant(P＞0.05).5. Raman spectroscopy results: three groups were grow in harmony in general,they all had the largest peak in the point of961cm-1, but the three weeks of group Bhad a obvious peak in the point of2947cm-1.Conclusion1. For the development of ED14.5tooth germs, we can obtain almost the wholetooth in subrenal capsule transplantation after three or four weeks.2. The buccal submucosa environment still has a certain influence on tooth germdevelopment, although there is some difference about the tooth development betweenthis environment and subrenal capsule environment. |
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