本研究發展出以電阻抗法作為齲齒檢測機制，且能隨牙齒表面形貌改變形狀的流體探針。基於琺瑯質有著極高的阻抗值，當琺瑯質被齲蝕產生孔洞，阻抗值很小的唾液將代替琺瑯質填充至孔洞，利用此點可判斷出何處有齲齒的危機。流體探針之尖端液體可在親水性牙齒表面自發地延展，並且滲入齲齒孔隙中，與牙齒有著緊密的接觸，減小了接觸電阻的產生。探針尖端使用聚甲基丙烯酸甲酯為主要材料，以雷射雕刻製作出寬度約100um的液體流道。液體流道鍍有一層銀金屬，可同時作為引導電流的通道；表面覆有一層高分子薄膜，讓液體能從探針尖端流出，並藉以保護流道。管狀氣流則圍繞著流體探針，有著阻絕牙齒表面水膜的功能，讓電流能夠通過牙齒內部；同時藉由調整氣流壓力的大小，進而控制探針液體的延展面積。流體探針已成功判斷出健康與齲齒位置的不同，牙齒健康處的阻抗值約大於齲齒處阻抗值的30倍以上，是相當靈敏且可靠的齲齒檢測工具。流體探針同時能夠檢測隱藏在牙縫的齲齒，此項是其他齲齒檢測方式所難以達到的功能。期望未來此檢測系統能發展成熟，應用至一般家庭生活，成為齲齒診斷上的利器。

This thesis presents a miniature fluidic probe that is capable of self-adapting its shape to teeth and detecting caries at its early stage by sensing the variation in electrical-impedance. The fluidic probe, whose liquid tip spontaneously spreads on hydrophilic tooth surfaces and into underneath caries, is employed to create intimate electrical contact for impedance sensing. A tubular air sleeve shaped by the probe casing is applied around the contact point to insulate it from surrounding saliva, and to regulate the spreading of the liquid tip. In the prototype demonstration, 23 un-restored, extracted premolar teeth were investigated and the results indicated >30 times impedance variations between sound and carious teeth, by which caries could be identified in a sensitive and reliable manner. Furthermore, the fluidic probe has been successfully applied to detect approximal caries, which hides between adjacent teeth and is hardly detected by any existing techniques. As such, the proposed self-adaptive fluidic probe could readily serve as a diagnostic tool, which is critical to caries prevention and home-care applications.

[1]Thomas Klinke, et al, “Caries Detection at Discoloured Occlusal Sites: A Comparison of Four Methods within Two Age Groups,” Int Poster J Dent Oral Med 2006, Vol 8 No 01, Poster 309.
[2]B. J. Orban著, 彭清迥, 鄭莉珮 譯, Orban’s Oral Histology and Embryology, 合記圖書出版社, 1987
[3]http://www.tpsmedical.co.uk/
[4]R. R. Alfano, S. S. Yao, “Human Teeth with and without Dental Caries Studied by Visible Luminescent Spectroscopy,” Journal of Dental Research 60 (2): 120-122 1981.
[5]H. Bjeckhagen, F. Sundstrom, et al, “Early Detection of Enamel Caries by the Luminescence Excited by Visible Laser Light,” Swedish Dental Journal 6 (1): 1-7 1982.
[6]E.D.J. Dejong , F. Sundstrom, et al, “A New Method for in vivo Quantification of Changes in Initial Enamel Caries with Laser Fluorescence” Caries Research 29 (1): 2-7, 1995.
[7]M .Ando, A.F. Hall, et al, “Relative Ability of Laser Fluorescence Techniques to Quantitate Early Mineral Loss in vitro,” Caries Research 31 (2): 125-131, 1997.
[8]A.G.F. Zandona, et al, “Laser Fluorescence Detection of Demineralization in Artificial Occlusal Fissures,” Caries Research 32 (1): 31-40, 1998.
[9]M.D. Lagerweij, et al, “The Validity and Repeatability of Three Light-Induced Fluorescence Systems: An in vitro Study,” Caries Research 33 (3): 220-226, 1999.
[10]Angel Sanchez-Figueras, “Laser Fluorescence Detection of Occlusal Caries,” Clinical Utilization of the Kavo Diagnodent.
[11]F. Sundstrom, K. Fredriksson, et al, “Laser-Induced Fluorescence from Sound and Carious Tooth Substance - Spectroscopic Studies,” Swedish Dental Journal 9 (2): 71-80 1985.
[12]J. Vaarkamp, et al, “Quantitative Diagnosis of Small Approximal Caries Lesions Utilizing Wavelength-Dependent Fiber-Optic Transillumination,” Journal of Dental Research 76 (4): 875-882 ,1997.
[13]S. Keem, M. Elbaum, “Wavelet Representations for Monitoring Changes in Teeth Imaged with Digital Imaging Fiber-Optic Transillumination,” IEEE Transactions on Medical Imaging 16 (5): 653-663, 1997.
[14]M. Culjat, et al, “Imaging of Human Tooth Enamel Using Ultrasound,” IEEE Transactions on Medical Imaging 22 (4): 526-529, 2003.
[15]P. Pincus, “A New Method of Examination of Molar Teeth Grooves for the Presence of Dental Caries,” Journal of Physiology, 1951.
[16]H. Nomura, et al, “Some Observations on Electric Conductivity of the Tooth,” Bull Tokyo Dent Coll 12:15-23.
[17]M.-C.D.N.J.M. Huysmans, et al, “Impedance Spectroscopy of Teeth with and without Approximal Caries Lesions - An in vitro Study,” Journal of Dental Research 75 (11): 1871-1878, 1996.
[18]C. Longbottom, M.-C.D.N.J.M. Huysmans, et al, “Detection of Dental Decay and Its Extent Using Ac Impedance Spectroscopy,” Nature Medicine 2 (2): 235-237, 1996.
[19]M.-C.D.N.J.M. Huysmans, et al, “Electrical Conductance and Electrode Area on Sound Smooth Enamel in Extracted Teeth,” Caries Research 29 (2): 88-93, 1995.
[20]W. Adamson, “Physical Chemistry of Surfaces,” 6th ed, 1997.
[21]M.-C.D.N.J.M. Huysmans, et al, “Temperature Dependence of the Electrical Resistance of Sound and Carious Teeth.” Journal of Dental Research 79 (7): 1464-1468, 2000.
[22]M.-C.D.N.J.M. Huysmans, et al, “Electrical Conductance and Electrode Area on Sound Smooth Enamel in Extracted Teeth,” Caries Research 29:88-93.