The Evaluetion of The Hypersensitivity Depression Effect Using The Hypersensitive Dentine Simulator

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12470402
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Conservative dentistry
• Research Institution: Tohoku University
• Principal Investigator: ISHIHATA Hiroshi Tohoku University, Dental Hospital, Assistant Professor, 歯学部・附属病院, 助手 (40261523)
• Co-Investigator(Kenkyū-buntansha): SHOJI Kanako Tohoku University, Dental Hospital, Asisstant Professor, 歯学部・附属病院, 助手 (90302158) ; IIYAMA Masao Tohoku University, Graduate School of Dentistry , Assistant Professor, 大学院・歯学研究科, 助手 (00193152) ; SHOJI Shigeru Tohoku University, Dental Hospital, Lecturer, 歯学部・附属病院, 講師 (10142986)
• Project Period (FY): 2000 – 2001
• Keywords: HYPERSENSITIVE / SIMULATOR / LUMINESCENCE / PHOTODIODE / LUMINOL / DENTINE

Research Abstract

Dentine perception is evoked by the transfer of internal fluid in the dentine microtubule according to the hydrodynamics theory, therefore, the technique which measures the deterrence of the transfer of dentinal tubule internal fluid seems to be useful in order to objectively evaluate the hypersensitive dentine control material. Ten extracted human third molar teeth were used in this study. The dentine slices at the crown part of 1 and 1.5mm thickness were prepared in tooth axis vertical surface. These slices were fixed in the 10% neutral formalin solution. The dentine microtubule were opened to wash in the experiment by 3O% hydrogen peroxide water. From both slice sides where the dentine microtubule in the tooth crown and tooth pulp side opened, these dentine slices were held with the O-ring by the transparent acrylic tube. 1% sodium hydroxide solution in the acrylic tube in the tooth pulp side with the 0.02% luminol was filled. 1% potassium ferricyanide solution including the 0.3% hy drogen peroxide water which similarly removed the fine particle in the acrylic tube in the tooth crown side by the Millipore Corp. filter of ostia size of 0.2 μm was satisfied. The photodiode (s6204 : Hamamatsu Photonics Co.)which contained preamplifier and thermoelectric cooling device by having approximately 30mm distances in the neighborhood of the sample was installed. The equipment with sample was installed in the black box which almost perfectly cuts off the outside light. The light emission of luminol chemiluminescence evoked by the active oxygen of hydrogen peroxide water is generated by the mixture of the reagents filled in the acrylic tube of both sides through dentine microtubules. The luminous phenomenon was detected in the photodiode. The optical output from the photodiode was recorded through the AD converter in personal computer after observing by the oscilloscope. In the condition that the reagent just contacted both dentine slice sides, there was a slight light emission of the transience. The light emission was observed time-dependent, when 10〜500mmHg air pressure was applied for the acrylic tube that the potassium ferricyanide and hydrogen peroxide solution was filled. These light emission quantity had the correlation which was positive with the pressure in the same sample, though there is the fluctuation in proportion to individual sample, and the light emission quantity changed. At the light emission quantity in using slice samples of the 1.0mm thickness which was excellent in the permeability in the dentine, the light emission quantity tended to generally increase in comparison with 1.5mm samples. In the condition without opening of dentine microtubule by 30% hydrogen peroxide water, the dentine sample could not demonstrate the light emission even in any loading of reagent. It is a system that dentine hypersentive simulator using the chemiluminescence visualizes the transfer of the internal fluid in dentine microtubule and that it can be supersensitized, and that it can be observed. It is possible to show the degree of the opening of the dentine microtubule in fluctuation situation of the light emission quantity. This system seems to be very much the usefulness as the tool which can straightforwardly evaluate the effect of the control material for dentine hypersensitive disease.