| Co-Investigator(Kenkyū-buntansha) |
MIAKE Yauo TOKYO DENTAL COLLEGE, DEPARTMENT OF DENTISTRY, ASSISTANT PROFESSOR, 歯学部, 助教授 (00157421)
MINAGUCHI Kiyoshi TOKYO DENTAL COLLEGE, DEPARTMENT OF DENTISTRY, PROFESSOR, 歯学部, 教授 (00133380)
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| Research Abstract |
It has longbeenknown (hat salivaplays arole in reminera!ization, but many of the studies previously conducted on the topic have been conceptual and have provided no objective proof from the standpoint of crystal morphology. This study involves experiments on completely impacted human enamel to elucidate the topic. llwasperformed inkeepingwith theregulafionof theEthicsCommitteeofTokyoDental College.Employingamodification of the windowmethod,we prepared several groups; an untreated(control) group,experimental groupAconsistingofuntreatedmaterials thathadbeen immersed inparotidfcaliva, untreated artificially demineralized material(control), and experimental group B consisting of artificially demineralized material that had been immersed in parotid saliva. In addition, fractured experimental materials were subjected to acid etching to determine acid resistance. These materials were observed by means of CMR, SEM, and HR-TEM.
CMR images showed acceleration of mineralization in experimental gro
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up A and a reniineralized layer in experimental group B, providing objective proof of the role that saliva plays in rjemineralization. Both the area of accelerated mineralization and the remineralized layer had acquired acid resistance.Because this connection must not be overlooked, the role of saliva-proteins is to be the one of our next research. Post-eruptive maturation of enamel crystals is observation made in connection withsaliva-induced remineralization clarifiedby this study. It is strongly suspected that acquisitionof acid resistance, together with this maturation, helps to reduce the likelihood of susceptibility to caries. The crystals on the surfaces ofuntreated materials were small and granular. Large and small crystalswith rounded angles wereobserved indemineralizedmaterials. Occasionallycentral perforations were seen. In contrast, minute granular or small granulated crystals were deposited on the outermost surface inmaterials fromexperimental group A. 3n addition tominute granular crystals, large numbers of needle crystals had deposited in materials from experimental group B,. Since enamel crystals grow from needle shape to hexagonal forms out of the c-axis,it seems probable that saliva contributes notonly to remineralization, butalso to crystal growth. We plan to make this our research theme. Less
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