STEALTHAUTHENTIFICATION USING RANGE OF RADIO FREQUENCY TRANSPONDER IN THE ENDODONTIC SPACE

导读：近年来，自动识别程序（Auto-ID）在许多服务行业、商品和分销物流、金融、运输和医疗系统中得到了广泛的应用。自动识别的存在是为了提供有关过境人员、动物、货物和程序的信息。自动识别技术的最佳解决方案之一是使用硅芯片作为射频识别（RFID）技术。在日常生活中最常见的电子数据传输设备是智能卡，它是基于一个接触面（电话卡、银行卡），通过卡内的主机系统和芯片之间的数据通信来实现的。现在，设备和阅读器之间的非接触式数据传输的集成设计更加灵活。在理想的情况下，操作卡中的电子微芯片所需的电力也将通过非接触式技术从读取器传输。这种用于传输电力和数据的非接触式系统被称为RFID。方法：用10颗拔除的无龋人第三磨牙封装RFID应答器。使用中波频率（125 kHz Emfreccia ONMETALTM, Mitsubishi Materials， JAPAN）测试了15个圆柱形应答器（直径3 mm，长度13 mm）。准备牙髓腔，包括每颗牙齿的冠状腔和根管，以适应RFID的圆柱形核心，从牙齿的冠状侧。牙本质厚度的减小和牙腔体积的增大可能导致射频屏蔽功能的显著降低。保留3mm的牙本质厚度，以便在应答器和读取器之间作为射频屏障。使用三个丙烯酸圆柱体（ψ10×22 mm）作为对照，其中钻同轴孔（直径：3mm，深度：13mm）以适应应答器。读取器（EmfrecciaTM, Mitsubishi Materials）与封闭在牙本质内的应答器通信，位于牙轴的延长线上，因为这些标签具有沿圆柱形轴方向与读取器通信的尖锐方向性。牙被固定在一个塑料夹在车厢纵向轴方向。通过RS-232-C串行接口建立了IBM-PC兼容的数据传输实用程序，测量了最大通信范围。结果：未封装RFID应答器的平均通信距离为18.6±1.7mm (n=15)，而丙烯酸材料封装（对照组）和牙齿封装RFID应答器的平均通信距离分别为18.1±1.6 mm （n=45）和17.8±1.7mm （n=150）。与未包封者相比，其占比分别为97.3±1.6%和94.6±1.9%。在这些条件下未观察到统计学上的显著差异。在牙本质包封条件下，通信距离的实际减少幅度很小（5.4%）。讨论：携带身份信息的RFID标签贴在腕带上，已经用于快速识别住院病人。但持续佩戴腕带可能会给一些患者带来身体和精神上的压力。将RFID嵌入牙齿的方法可以使患者从腕带的压力中解脱出来。然而，应该详细阐述在使用嵌入式RFID时排除接受者心理压力的设计，例如将探测器放置在靠近人体嵌入位置的位置。口腔内嵌入的身份识别可以应用于与RFID读取器结合的移动电话。这种工程系统被称为“隐形识别”，它利用移动电话等通信设备。在大多数语音通信中，脸部与手机之间的距离相对较小。当手机配备RFID读写器时，可以在手机使用过程中通过检测RFID来建立身份。在口腔内很难检测到RFID应答器的存在。此外，似乎无法将语音通信与第三方使用牙齿上的RFID识别过程区分开来。不可见的方法是相对安全的，可以隐藏嵌入式RFID的存在，避免恶意目的。这有助于保护个人隐私。这个病人身体和精神上几乎没有什么约束。结论：牙体的绝缘作用小，足以穿透中频信号。少

INTRODUCTION: In recent years, automatic identification procedure (Auto-ID) has become very popular in many service industry, merchandise and distribution logistic, finance, transport and medical system. Auto-ID exists to provide information about people, animal, goods and procedure in transit. One of the technically optimal solutions of Auto-ID, using a silicon chip, has been provided as a technology of radio frequency identification (RFID). The most common form of electronic data-carrying-device in everyday life is a smart card based upon a contact field (phone card, bank card) on the data communication between host system and chip in housing of the card. Now an integrated design of contactless data transfer between the device and its reader is more flexible. In the ideal case, the power required to operate the electronic microchip in the card would also be transferred from the reader using contactless technology. This contactless system used for the transfer of power and data is cal … More led RFID. METHODS: Ten extracted human third molar teeth free from dental caries were used to encapsulate RFID transponders. Fifteen cylindrical transponders (o. d. 3 mm, length 13 mm) using a medium wave frequency (125 kHz Emfreccia ONMETALTM, Mitsubishi Materials, JAPAN) were tested. The endodontic cavity, including the coronal chamber and root canal of each tooth, was prepared to fit the cylindrical core of the RFID from the coronal side of the tooth. Volume expansion of cavity in the tooth and decrease of the dentin thickness might result in significant reduction of facility as a radio frequency shield. Dentin thickness of 3mm was preserved to allow functioning as a barrier for radio frequency between the transponder and the reader. Three acrylic cylinders (ψ10×22 mm) were used as controls in which co-axial holes (diameter: 3mm, depth: 13mm) were drilled to fit for the transponders. A reader (EmfrecciaTM, Mitsubishi Materials) that communicated with the transponder enclosed in dentin was located on the extension line of the tooth axis, because these tags had sharp directionality for communication with the reader along the cylindrical shaft direction. The tooth was held with a plastic clamp attached to a carriage in longitudinal axis direction. The maximum communication range was measured with establishment of the data transfer by a utility program for IBM-PC compatible via RS-232-C serial interface. RESULTS: The mean communication distance of unencapsulated RFID transponders was 18.6±1.7mm (n=15), while the mean ranges in RFID transponders encapsulated with acrylic materials (control) or teeth were 18.1±1.6 mm (n=45) and 17.8±1.7mm (n=150), respectively. The percentages of the range compared with the unencapsulated were 97.3±1.6% and 94.6±1.9%, respectively. No statistical significant difference under these conditions could be observed. The actual decrease of communication distance under dentin encapsulated conditions was very small (5.4%). DISCUSION: The RFID tag, holding ID information attached to the wristband, has already been carried out for a swift identification of inpatients. But continuous wearing of a wristband may induce physical and mental stress in some patients. The method embedding the RFID in the tooth might disengage the patients from the stress by the wristband. However, the contrivance to exclude psychological pressure on recipient in using the embedded RFID, such as placing the detector close to the embedded position in the human body, should be elaborated. Embedded ID into oral cavity could be apply to a mobile phone in combination with a RFID reader. This engineering system is called 'stealth identification' that utilizes communication equipment such as a mobile phone. In most of the voice communications, the distance between the face and the handset is relatively small. When the handset equips RFID reader, the identification can be established by detecting the RFID during the phone usage. It would be difficult to detect existence of the RFID transponder in the oral cavity. Furthermore, it seems almost impossible to distinguish voice communication from the identification process using the RFID in a tooth by the third party. The invisible method is relatively safe to hide the existence of imbedded RFID from malicious purpose. This contributes to the protection of individual privacy. The patient has little physical and mental restrain. CONCLUTION: The insulation effect of the tooth had small enough to allow for the penetration of the signal of the medium frequency band. Less