JP2009011470A - Dental diagnostic apparatus, endodontic instrument using it and dental examination table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dental diagnostic apparatus capable of accurately obtaining information relating to the inside of a tooth, especially a root canal, without being affected by a liquid chemical or the like. <P>SOLUTION: This invention relates to the dental diagnostic apparatus provided with: a measurement electrode 3; an oral cavity electrode 5; a measurement signal impressing means; a measurement means; and an arithmetic processing means, wherein the information relating to the root canal of a tooth is obtained from an electric characteristic value. The measurement electrode 3 is inserted to the root canal of the tooth 1 which is a measurement object, and the oral cavity electrode 5 is electrically brought into contact with an oral cavity mucosa 4. Also, the measurement signal impressing means impresses measurement signals between the measurement electrode 3 and the oral cavity electrode 5, and the measurement means measures an electric response between the measurement electrode 3 and the oral cavity electrode 5 for the plurality of measurement signals of different frequencies. Further, the arithmetic processing means computes the electric characteristic value of the prescribed part of an equivalent circuit for which a conduction route between the measurement electrode 3 and the oral cavity electrode 5 is modeled on the basis of the electric response. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dental diagnostic instrument, an endodontic treatment apparatus using the dental diagnostic instrument, and a dental examination table, and in particular, a dental diagnostic instrument for obtaining information on the inside of a tooth and a tooth using the dental diagnostic instrument The present invention relates to an internal therapy device and a dental examination table.

  An electrical apex detector (electric root canal length) is used as a dental diagnostic device for detecting the position of the apex, which is one of the information about the internal components of the tooth, particularly the root canal (determining the root canal length). Measuring instrument) (hereinafter, the term “electrical” is omitted). In a conventional apex detector, for example, apex detection is performed according to a schematic diagram as shown in FIG. In the apex detector that performs apex detection with the configuration illustrated in FIG. 9, the measurement electrode 103 is inserted into the root canal 102 of the tooth 101, and the distal end 104 of the measurement electrode 103 and the oral cavity in electrical contact with the oral mucosa. The impedance value with the electrode 105 is measured to detect that the tip 104 of the measurement electrode 103 has reached the root apex 106. In this method, when the measurement electrode 103 reaches the apex, the impedance of the root canal (impedance within the tooth) is not measured, but the root apex 106 and the oral electrode 105 that is in electrical contact with the oral mucosa. The impedance value between them is measured.

  In the apex detector that performs apex detection with the configuration illustrated in FIG. 9, the value of the current flowing through the detection resistor 108 is measured based on the measurement signal supplied from the signal applying unit 107 to obtain the impedance value. In addition to the above-described method and the method of measuring the impedance value itself, the impedance value in this field is measured using the voltage across the detection resistor 108 shown in FIG. 9 and the resistance value obtained at a certain current or voltage as a measurement index. A method of calculating the impedance value of the part to be measured may be used. Hereinafter, these methods are collectively referred to as “determining the impedance value”.

  The conventional apex detector states that "the impedance value of the tip of the measurement electrode inserted into the oral mucosa and the root canal is the age, tooth type when the tip of the measurement electrode reaches the periodontal ligament via the apical hole. It is based on the measurement principle that “there is no difference due to, and takes a substantially constant value (6.5 kΩ)”. 10, the periodontal membrane 109 is a film covering the entire root of the tooth 101, and the tip 104 of the measurement electrode 103 is connected to the root of the root from the apical hole 110. The position in contact with the film 109 is the apex.

  In the apex detector that performs apex detection with the configuration illustrated in FIG. 9, when the measurement current corresponding to the impedance value in the detection resistor 108 reaches a value corresponding to the impedance value of 6.5 kΩ, the tip of the measurement electrode 103 is detected. It is determined that 104 reaches the periodontal ligament 109 via the apical hole 110. Some conventional apex detectors measure the apex position using the ratio or difference of impedance values. Details are described in Patent Document 1 and Patent Document 2. Furthermore, Patent Document 3 discloses an apex detector that shows apex detection by using an impedance value and a ratio or difference of impedance values in combination and selectively or simultaneously displaying them. As mentioned above, although the description about the apex detector was described, there existed, for example, a diagnostic device for detecting the pulp with an impedance value of 15 kΩ as a reference value as a diagnostic device for electrically performing endodontic diagnosis. Diagnostic equipment is also included in the technical field to which the present invention belongs.

Japanese Patent No. 2873722 Japanese Examined Patent Publication No. 62-2817 Japanese Patent No. 3113109

  The conventional apex detector states that "the impedance value of the tip of the measurement electrode inserted into the oral mucosa and the root canal is the age, tooth type when the tip of the measurement electrode reaches the periodontal ligament via the apical hole. It is based on the measurement principle that “there is no difference due to, and takes a substantially constant value (6.5 kΩ)”. However, this measurement principle is established when the root canal is dry, and if there is a conductive chemical or blood in the root canal, the impedance value between the periodontal ligament and the oral mucosa is It fluctuates greatly. For this reason, it has been difficult for the conventional apex detector to detect the apex position of a tooth in which a conductive chemical or blood is present in the root canal. In addition, since the inside of the root canal is usually in a wet state, it has been necessary to forcibly dry the inside of the root canal in order to detect the apex position with a conventional apex detector.

  The case of measuring the apex position using a conventional apex detector will be described in detail with respect to each part in the tooth, particularly a tooth in which the root canal is wet. First, FIG. 11 shows a schematic diagram of an apex detection mode of a conventional apex detector showing an equivalent circuit of a portion from the oral mucosa 111 through the periodontal membrane 109 to the root canal 102. In FIG. 11, the conductive chemical solution 112 exists in the root canal 102, and the conductive chemical solution 112 overflows from the apical hole 110, and the impedance value between the periodontal membrane 109 and the oral mucosa 111 is greatly increased. descend.

  As shown in FIG. 11, when the equivalent circuit between the periodontal ligament 109 and the oral mucosa 111 is regarded as a parallel circuit of a resistor R and a capacitor C, the value of the resistor R is the value when the root canal is wet, There is a tendency to decrease to 1 / k times and increase the value of capacity C to m times that during drying. However, k and m are both coefficients of 1 or more determined by the wet state of the root canal. In addition, in all teeth, the values of the resistance R and the capacitance C are not necessarily fluctuated, but it may be assumed that the above-mentioned tendency is generally observed. In the conventional apex detector that performs apex detection with the configuration shown in FIG. 11, the impedance value between the tip 104 of the measurement electrode 103 and the oral mucosa 111 is greatly reduced due to the influence of the conductive chemical solution 112. Therefore, a detection error occurs. In particular, since the impedance between the tip 104 of the measurement electrode 103 and the apical hole 110 is greatly reduced, an erroneous detection result that the tip of the measurement electrode 103 has reached the apex is present even though the tip of the measurement electrode 103 is in front of the apex. Get. In addition, the wet state in the root canal is not limited to the conductive chemical solution 112, and a decrease in the impedance value between the periodontal membrane 109 and the oral mucosa 111 is also observed in blood or saliva.

  In addition, in the equivalent circuit shown in FIG. 11, an intracanal impedance Zr exists between the tip of the measurement electrode 103 and the periodontal membrane 109 present in the apical hole 110. In FIG. 11, this is shown as a series resistance Zr for convenience. In this case, the impedance value between the distal end of the measurement electrode 103 and the oral mucosa 111 to be measured is the impedance value between the distal end of the measurement electrode 103 and the periodontal membrane 109 at the apical hole 110 and the apical hole. This is a composite value of the impedance value between the periodontal membrane 109 and the oral mucosa 111 at the site 110. Therefore, when the impedance value between the distal end 104 of the measurement electrode 103 and the oral mucosa 111 becomes 6.5 kΩ or less due to the influence of the drug solution 112 as described above, the position where the combined value becomes 6.5 kΩ is the root. The apex position is erroneously displayed.

  Specifically, for example, under the influence of the conductive chemical solution 112, the impedance value between the periodontal membrane 109 and the oral mucosa 111 is 4 kΩ, and the tip of the measurement electrode 103 at a position 3 mm from the apex And an impedance value between the periodontal ligament 109 existing at the site of the apical hole 110 is 2.5 kΩ. In this case, since the sum (synthetic value) of both impedance values is 6.5 kΩ, the conventional apex detector erroneously displays the position where the measurement electrode 103 is 3 mm away from the apex as the apex position. .

  Therefore, as shown in Patent Document 1 or 2, a method has been developed that eliminates measurement errors caused by the conductive chemical solution 112 and the like by performing apex detection using the ratio and difference of impedance values. However, it is an object of the present invention to provide a dental diagnostic instrument that can accurately obtain information on the inside of a tooth without being affected by a chemical solution or the like by a completely different method. The above description is mainly based on apical detectors. However, the present application is not limited to apical detection, and various applications related to the inside of the tooth, such as detection of presence or absence of caries and caries in the tooth. The purpose is to obtain useful information.

  The solution means according to claim 1 of the present invention is to use a dental diagnostic instrument comprising a measurement electrode, an oral electrode, a measurement signal applying means, a measurement means, and an arithmetic processing means, and having electrical characteristics. It is to adopt a method of obtaining information about the inside of the tooth from the value. In this dental diagnostic device, the measurement electrode is inserted into the pulp cavity (the medullary chamber and root canal) inside the tooth to be measured, and the oral electrode is brought into electrical contact with the oral mucosa. The measurement signal applying means applies a measurement signal between the measurement electrode and the oral electrode, and the measurement means responds to a plurality of measurement signals having different frequencies with an electrical response between the measurement electrode and the oral electrode. Measure. Further, the arithmetic processing means calculates an electrical characteristic value of a predetermined portion of the equivalent circuit that models the conductive path between the measurement electrode and the oral electrode based on the electrical response. For example, when the measurement electrode is inserted into the root canal as in claim 2 of the present invention, the dental diagnostic device is a diagnostic device for obtaining information about the root canal.

  The solution according to claim 3 of the present invention employs a dental diagnostic device in which the measurement signal applying means applies a measurement signal having at least the same number of different frequencies as the number of components of the equivalent circuit. It is.

  The solving means according to claim 4 of the present invention has a table in which the arithmetic processing means obtains in advance an electrical characteristic value of a predetermined portion of the equivalent circuit corresponding to the electrical response, and the measuring means uses the table from the table. The dental diagnostic device is characterized in that an electrical characteristic value of a predetermined portion of an equivalent circuit corresponding to the measured electrical response is obtained.

  In the solution means which concerns on Claim 5 of this invention, the equivalent circuit is comprised by the endodontic circuit part corresponding to the inside of a tooth | gear, and the other external tooth circuit part. The term “inside of the tooth” as used herein refers to the inside of the tooth, such as the medullary canal and root canal, and the term “other” refers to the path from the outside of the apical hole to the oral mucosa via the alveolar bone and gums. .

  In the solution means which concerns on Claim 6 of this invention, it is a circuit which made the external circuit part of the equivalent circuit the parallel circuit of the resistance element and the capacitive element, and connected the resistance element of the endodontic circuit part in series to the parallel circuit. It is characterized by that.

  The solution means according to claim 7 of the present invention is characterized in that the equivalent circuit is a circuit in which the capacitive element of the extradental circuit section and the resistance element of the endodontic circuit section are connected in series. The circuit configuration adopted as the solution means according to claims 5 to 7 does not claim that the actual endodontic circuit and extradental circuit are the above-described configurations themselves, but each solution. As an example, the configuration of an equivalent circuit that can be employed is given.

  The solution according to claim 8 of the present invention is to use a value based on at least one of the elements constituting the endodontic circuit section as an electrical characteristic value for dental diagnosis. The feature is to adopt a dental diagnostic device.

  The solution according to claim 9 of the present invention is based on a value based on at least one of the elements constituting the endodontic circuit part and on at least one of the elements constituting the extradental circuit part. The use of a dental diagnostic device characterized in that a value calculated with the value is used as an electrical characteristic value for dental diagnosis.

  The solving means according to claim 10 of the present invention is preset based on an experiment whether the arithmetic processing means actually adopts the first electrical characteristic value or the second electrical characteristic value. The information regarding the inside of a tooth | gear is obtained by switching on the basis of a threshold value. Here, the first electrical characteristic value is a value based on at least one component among the components constituting the endodontic circuit section in the equivalent circuit. The second electrical characteristic value is a calculated value of a value based on at least one component of the endodontic circuit unit and a value based on at least one component of the extradental circuit unit. A specific description of this configuration will be described in detail in the section of Embodiment 3 <Modification>.

  The solving means according to claim 11 of the present invention is characterized in that the information related to the inside of the tooth is at least one of position information of the tip of the measurement electrode, presence / absence of a crypt, and presence / absence of caries inside the tooth Adopting a dental diagnostic device.

  According to a twelfth aspect of the present invention, there is provided a solution means for detecting the position of the tip of the measuring electrode obtained from a value based on an electrical response and information on the inside of a tooth obtained from an electrical characteristic value calculated by an arithmetic processing means. Is switched according to a predetermined reference corresponding to the position in the root canal of the measurement electrode, and a dental diagnostic device characterized in that the apex position is detected is adopted. The “value based on the electrical response” referred to here may be the value of the electrical response itself, or a value obtained by calculating a plurality of electrical response values (for example, a difference or ratio of impedance values). Value). A specific description of this configuration will be described in detail in the section of Embodiment 3 <Modification>.

  In the solution means which concerns on Claim 13 of this invention, the display part which displays the information regarding the inside of a tooth | gear is further provided, It is characterized by the above-mentioned. In this display unit, the solution means according to claim 10 described above can be used together to switch between the information based on the first electrical characteristic value and the information based on the second electrical characteristic value.

  In the solution means which concerns on Claim 14 of this invention, a display part displays the information regarding the inside of a tooth | gear visually.

  In the solution means which concerns on Claim 15 of this invention, a display part displays the information regarding the inside of a tooth | gear auditoryly, It is characterized by the above-mentioned. The display unit according to any one of claims 13 to 15, which extracts and displays information related to the inside of a tooth in particular, is a conventional root canal length measuring instrument, for example, an impedance between a measurement electrode tip and an oral electrode. The information to be displayed is different from the display unit employed in the root canal length measuring device that obtains the value, that is, the information including both the information inside and outside the tooth.

  The solution means which concerns on Claim 16 of this invention is employ | adopting a measurement electrode, a buccal electrode, a measurement signal application means, a measurement means, and a signal processing means for a dental diagnostic device. In this dental diagnostic device, the measurement electrode is inserted into the tooth (root canal or the like) to be measured, and the oral electrode is brought into electrical contact with the oral mucosa. The measurement signal applying means applies a measurement signal between the measurement electrode and the oral electrode, and the measurement means measures an electrical response between the measurement electrode and the oral electrode for a plurality of measurement signals having different frequencies. To do. Further, the signal processing means determines the electrical characteristics between the measurement electrode and the oral electrode, and combines the electrical characteristics of the endodontic section from the measuring electrode to the apex and the remaining sections other than the endodontic section. Is obtained based on the electrical response, the measurement result obtained by removing the influence of at least a part of the electrical characteristic of the remaining section from the combined characteristic is acquired, and information corresponding to the measurement result is output. Also in this dental diagnostic device, together with the measurement result, other obtainable input values (as described above in the explanation of claim 8, electrical characteristic values of values based on at least one component of the equivalent circuit, The value obtained as described above for claim 9 and a value such as an electrical characteristic value of the calculated value) are used in combination, and appropriately switched according to a predetermined reference corresponding to the position in the root canal of the measurement electrode, You can also get information about the inside. This configuration will also be described in detail in the section of Embodiment 3 <Modification>.

  According to a seventeenth aspect of the present invention, the endodontic treatment apparatus is provided with a diagnostic function similar to that of any one of the dental diagnostic instruments employed in the respective solving means. is there.

  A solution means according to claim 18 of the present invention is to provide at least one of a dental diagnostic device or an endodontic treatment device employed in each of the above solution means on a dental examination table.

  The dental diagnostic device according to claim 1 of the present invention separates electrical characteristic values of predetermined portions of an equivalent circuit modeling the conductive path between the measurement electrode and the oral electrode based on the electrical response. Thus, information on the inside of the tooth is obtained, so that information on the inside of the tooth can be obtained accurately without being affected by exudate, blood, chemicals, etc. existing inside the tooth. Furthermore, according to the dental diagnostic device of the second aspect, information on the root canal of the tooth can be obtained. For example, when the tip of the measurement electrode reaches the periodontal ligament existing in the apical hole, the impedance value between the tip of the measurement electrode and the periodontal ligament of the apical hole is almost zero regardless of the environment in the root canal. Can be assumed. Therefore, when performing root canal length measurement using the dental diagnostic instrument described in the present invention, when the impedance value between the measurement electrode tip and the periodontal ligament becomes a value near zero, the apex position It is possible to accurately obtain information (root canal length) inside a tooth without being affected by a chemical solution or the like. In conventional electrical root canal length measurement, the impedance value from the measurement electrode tip to the oral electrode has been measured. On the other hand, the idea of obtaining only the impedance value between the tip of the measurement electrode and the periodontal ligament of the apex as in the present invention is completely new.

  In the dental diagnostic device according to claim 3 of the present invention, since the signal applying means applies a measurement signal having at least the same number of different frequencies as the number of components of the equivalent circuit, the value of the component of the equivalent circuit is calculated. Can be requested.

  The dental diagnostic device according to claim 4 of the present invention obtains the electrical characteristic value of a predetermined portion of the equivalent circuit corresponding to the electrical response measured by the measuring means from a preset table, so that a complicated calculation is performed. Information about the root canal can be obtained quickly without performing processing.

  In the dental diagnostic device according to claim 5 of the present invention, the equivalent circuit has an endodontic circuit portion corresponding to the inside of the tooth (between the tip of the measurement electrode inserted into the root canal and the periodontal ligament), Since it is configured by an extra-tooth circuit other than that (between the periodontal ligament and the oral mucosa), only information relating to the inside of the tooth (for example, the root canal) can be obtained separately by processing such as computation. The term “inside of the tooth” as used herein refers to the inside of the tooth such as the medulla and the root canal, and “other” refers to the route from the outside of the apical hole to the oral mucosa via the alveolar bone and gingiva. Point to. Again, based on the electrical response, the electrical characteristic value of a predetermined part of the equivalent circuit that models the conduction path between the measurement electrode and the oral electrode is separately calculated to obtain information on the inside of the tooth. Therefore, it is possible to accurately obtain information on the inside of the tooth without being affected by exudate, blood, chemicals, etc. existing inside the tooth. Furthermore, according to the dental diagnostic device of the second aspect, information on the root canal of the tooth can be obtained. For example, when the tip of the measurement electrode reaches the periodontal ligament existing in the apical hole, the impedance value between the tip of the measurement electrode and the periodontal ligament of the apical hole is almost zero regardless of the environment in the root canal. Can be assumed. Therefore, when performing root canal length measurement using the dental diagnostic instrument described in the present invention, when the impedance value between the measurement electrode tip and the periodontal ligament becomes a value near zero, the apex position It is possible to accurately obtain information (root canal length) inside a tooth without being affected by a chemical solution or the like.

  According to a sixth aspect of the present invention, in the dental diagnostic device, the equivalent circuit is a circuit in which the external circuit part is a parallel circuit of a resistance element and a capacitive element, and the resistance element of the endodontic circuit part is connected in series to the parallel circuit. Therefore, if each resistance element and capacitance element are obtained individually, information on the inside of the tooth (for example, root canal) can be obtained accurately.

  The dental diagnostic device according to claim 7 of the present invention is a circuit in which the equivalent circuit is simplified and the capacitance element of the extradental circuit part and the resistance element of the endodontic circuit part are connected in series. Processing can be simplified.

  The dental diagnostic device according to claim 8 of the present invention uses a value based on at least one component of the endodontic circuit section as an electrical characteristic value for dental diagnosis. Further, the dental diagnostic device according to claim 9 is configured to calculate a calculated value of a value based on at least one component of the endodontic circuit unit and a value based on at least one component of the extradental circuit unit. It is used as an electrical characteristic value for diagnosis. In this case, since the electrical characteristic value can be obtained in various modes, the range of information to be obtained is widened, and information on the necessary inside of the tooth (for example, root canal) can be obtained with higher accuracy.

  The dental diagnostic device according to claims 10 to 12 of the present invention switches the electrical characteristic value or information on the root canal based on a predetermined standard, for example, based on a threshold value set in advance based on an experiment. Since highly accurate or user-friendly information can be obtained depending on the position of the measurement electrode, a better diagnosis can be performed. Specifically, for example, in a device configured such that the display value decreases as it approaches the apex, the smaller of the two types of electrical property values at the position of a certain measurement electrode as a condition for switching between the two types of electrical property values. A mode in which one of the values is selected can be considered.

  According to a thirteenth aspect of the present invention, a dental diagnostic device includes a display unit that displays information related to the inside of a tooth. If the display part displays the information regarding the inside of a tooth visually or auditorily like the dental diagnostic device of Claim 14 or 15, the information regarding the inside of a tooth will be easy for a dentist etc. Can be confirmed. In addition, this display unit extracts and displays information related to the inside of the tooth in particular, and is a conventional root canal length measuring instrument, for example, an impedance value between the tip of the measurement electrode and the oral electrode, that is, the inside of the tooth. The information to be displayed is different from the display unit employed in the root canal length measuring instrument that obtains information including both information outside the tooth.

  The dental diagnostic device according to claim 16 of the present invention has electrical characteristics of the endodontic segment from the measurement electrode to the apex and the remaining segment other than the endodontic segment based on the electrical response. From the included values (hereinafter referred to as “composite characteristics”), obtain a measurement result from which the influence of at least a part of the electrical characteristics of the section other than the endodontic area is removed, and output information according to the measurement result Therefore, information on the inside of the tooth can be obtained accurately.

  Since the root canal treatment device according to claim 17 of the present invention has the diagnostic function of the dental diagnostic device according to the present invention, the treatment can proceed while diagnosing the root canal, and the treatment can be efficiently performed. Yes. That is, a diagnosis similar to the diagnosis using the above-described dental diagnostic device can be performed before or during treatment of each part of the tooth, particularly the root canal.

  In the dental examination table (dental examination unit) according to claim 18 of the present invention, the examination table for holding the patient, various examination instruments for treating the patient, means for operating the examination instrument, gargle use In addition to a normal medical table (dental medical unit) such as a spit-on and a display device, the dental diagnostic device described in the present invention is also provided, so that the patient can be moved for diagnosis of the inside of the tooth, particularly the root canal. This saves the trouble of carrying the device and carrying the device and makes it possible to perform more efficient medical care.

(Embodiment 1)
<Overview>
The dental diagnostic device according to the present embodiment is a device for obtaining information related to the inside of a tooth, particularly the root canal, but in the following, the root apex is detected in particular (measures the root canal length). The detector will be described. However, the dental diagnosis device according to the present invention is not limited to the apex detector that detects the apex position, and for example, the dental pulp and the caries in the teeth can be diagnosed. Further, in the apex detector according to the present embodiment, as an example of the present invention, a conductive path between the measurement electrode and the oral mucosa is modeled and the equivalent of the resistance Rs, the resistance Rp, and the capacitance Cp shown in FIG. As a circuit, electrical characteristic values based on the components of the equivalent circuit are obtained by calculation, and the apex position is detected.

<Configuration and specific examples>
FIG. 2 shows a schematic diagram when using the apex detector according to the present embodiment. In the apex detector used in the embodiment shown in FIG. 2, the measurement electrode 3 is inserted into the root canal 2 of the tooth 1, and the oral electrode 5 is in electrical contact with the tip of the measurement electrode 3 and the oral mucosa 4. Is measured to detect that the tip of the measuring electrode 3 has reached the apex 6. FIG. 2 is a diagram showing a mode of detecting the apex position with the root canal 2 as a diagnosis target. As will be described later, the present invention relates to a medullary chamber (not shown) above the root canal. Based on the premise, it is also possible to make the diagnosis subject to diagnosis. In the present specification, when “intradental” or “inside of a tooth” is described, these include the root canal and the medullary canal. The impedance measurement in this embodiment is performed by applying a measurement signal from the signal applying unit 7 and measuring the current flowing through the detection resistor 8 shown in FIG. In addition to the above-described method and the method of measuring the impedance value itself, the impedance measurement in this field is measured using the voltage across the detection resistor 8 shown in FIG. 1, the resistance value obtained at a certain current and voltage, etc. as a measurement index. The method of calculating the impedance value of the portion may be as described in the background art section. Further, as shown in FIG. 2, there is a periodontal ligament 10 between the tooth 1 and the gingiva 9. The periodontal ligament is a film that covers the root part widely. In the following description, the term “periodontal ligament” means “the periodontal ligament 10 present in the vicinity of the apical hole 6”.

  Next, an equivalent circuit between the measurement electrode 3 and the oral electrode 5 will be described. First, the equivalent circuit shown in FIG. 1 includes three elements: a resistor Rs, a resistor Rp, and a capacitor Cp. In the equivalent circuit, the resistance Rs is the impedance between the measurement electrode 3 and the periodontal ligament 10 (endodontic circuit part), and the parallel circuit of the resistance Rp and the capacitance Cp is between the periodontal ligament 10 and the oral mucosa 4 ( It corresponds to the impedance of the extra-dental circuit part). That is, in the equivalent circuit shown in FIG. 1, the endodontic section (intradental circuit portion) from the measurement electrode 3 to the apex 6 is the resistance Rs, and the remaining section other than the endodontic section (extradental circuit portion) is the resistance Rp and the capacitance. It is regarded as a characteristic including an electric characteristic constituted by a parallel circuit of Cp, that is, a synthetic characteristic referred to in this specification. Since the equivalent circuit shown in FIG. 1 is an equivalent circuit of a living body, it is not strictly equivalent and does not claim that the equivalent circuit shown in FIG. 1 is an electrical equivalent circuit of a tooth. The equivalent circuit shown in FIG. 1 is an equivalent circuit employed in the present application, and is given as an example that can approximate the electrical characteristics of the teeth to the extent that there is no practical problem.

  The resistance Rs, which is the impedance between the measurement electrode 3 and the periodontal ligament 10, corresponds to the distance between the measurement electrode 3 and the periodontal ligament 10, so that the value of the resistance Rs increases as the measurement electrode 3 approaches the apex 6. Get smaller. Note that when the measurement electrode 3 approaches the position of the apex 6, the distance between the tip of the measurement electrode 3 and the periodontal ligament 10 becomes a value substantially close to zero, as is apparent from the structure of the tooth 1. Therefore, in the apex detector according to the present embodiment, wetting is basically performed in the root canal by using the value of the resistance Rs when the distance between the measurement electrode 3 and the periodontal ligament 10 is substantially zero. The apex position can be detected without being affected by the state. In other words, it is possible to detect the apex position by extracting only the electrical characteristics corresponding to the equivalent circuit Rs corresponding to the endodontic section from the combined characteristics including the endodontic section and the extradental section. It is.

  Of course, as described in paragraph 0044, since the equivalent circuit shown in FIG. 1 is an equivalent circuit of a living body, it is not strictly equivalent, and the equivalent circuit shown in FIG. 1 claims to be an electrical equivalent circuit of a tooth. Not. The equivalent circuit shown in FIG. 1 is given as an example that can approximate the electrical characteristics of the teeth to the extent that there is no practical problem. Therefore, even when the distance between the measurement electrode 3 and the periodontal ligament 10 is almost zero, the value of the resistance Rs may not become zero. Further, the value of the resistance Rs is independent of the impedance between the periodontal ligament 10 and the oral mucosa 4 and thus is not affected by the impedance fluctuation between the periodontal ligament 10 and the oral mucosa 4. In the apex detector according to the present embodiment, the electrical apex position (value of resistance Rs) of the portion when the distance between the measurement electrode 3 and the periodontal ligament 10 is almost zero is obtained to determine the apex position. Can be detected.

  Next, the value of the resistance Rs obtained by the apex detector according to the present embodiment is specifically shown. FIG. 3 shows a change in the value of resistance Rs measured using five extracted teeth. In the graph shown in FIG. 3, the horizontal axis represents the distance from the tip of the measurement electrode 3 to the apex 6 (unit: mm), and the vertical axis represents the value of the resistance Rs (unit: kΩ or anonymous). In the graph shown in FIG. 3, the value of the resistance Rs decreases as the measurement electrode 3 approaches the root apex 6. Therefore, according to the graph shown in FIG. 3, if the apex detection value that is a predetermined threshold is set to 1.0 (the unit is an anonymous number), the apex detector according to the present embodiment can accurately detect the apex. The position can be detected.

  In the apex detector according to the present embodiment, it is not necessary to accurately obtain the resistance value of the resistor Rs, and a value (resistance Rs) corresponding to the resistance value of the resistor Rs, which is information necessary for detecting the apex position. It is only necessary to obtain the value of () and to detect how the value has changed to the apex position. In the graph shown in FIG. 3, since the measurement data is based on the extracted tooth, the periodontal ligament 10 does not exist, so the distance to the actual apex 6 is taken as the horizontal axis.

<Detailed operation example>
FIG. 4 is a block diagram showing in more detail the configuration of the apex detector according to the present embodiment. The apex detector shown in FIG. 4 includes an oscillator 20 that outputs a measurement signal having a frequency f, an oscillator 21 that outputs a measurement signal having a frequency 5f (5 times f), and a measurement signal having a frequency 25f (25 times f). Is provided with an oscillator capable of generating measurement signals of three different frequencies. In the present embodiment, since there are three components of the equivalent circuit shown in FIG. 1, measurement results at at least three different frequencies are required to solve simultaneous equations representing the impedance of the equivalent circuit described later. Become. In the present embodiment, as the plurality of frequencies to be used, the fundamental frequency f is 1 time, 5 times, or 25 times (that is, the fundamental frequency and its harmonics), but the present invention is not limited to this and is fundamental. The frequency f may be 1 time, 10 times, 100 times, or the like.

  The apex detector shown in FIG. 4 includes an analog multiplexer 23, a buffer 24, and a timing controller 25. Further, the apex detector shown in FIG. 4 includes a waveform shaping circuit 26, an A / D converter 27, an arithmetic circuit 28, a display unit 29, and a detection resistor 8. The timing controller 25 controls the operation timing of each circuit. Based on the control, the analog multiplexer 23 switches the outputs of the oscillators 20, 21, 22 every 10 msec, for example. Then, the output from the analog multiplexer 23 is applied to the measurement electrode 3 via the buffer 24.

In the apex detector according to the present embodiment, a change in measurement current is detected as a change in impedance value between the measurement electrode 3 and the oral mucosa 4. That is, a change in impedance value between the measurement electrode 3 and the oral mucosa 4 at each frequency of the measurement signal is detected as a measurement current in the detection resistor 8. The measured current is rectified by the waveform shaping circuit 26 to adjust the waveform, and then converted into digital data by the A / D converter 27.

  Further, the arithmetic circuit 28 sequentially latches the digital data from the A / D converter 27 and determines the resistance from the impedance value between the measurement electrode 3 and the oral mucosa 4 measured at each frequency f, 5f, 25f. A value corresponding to the resistance value of Rs, a value corresponding to the resistance value of the resistor Rp, and a value corresponding to the capacitance value of the capacitor Cp are obtained by calculation. In the measurement of the impedance value, it is desirable to measure each of the frequencies f, 5f, and 25f at the position in the root canal where the measurement electrode 3 is substantially the same, but the position of the measurement electrode 5 is not necessarily exactly the same. In both cases, the detection accuracy of the apex position is hardly affected.

  In the present embodiment, the value corresponding to the resistance value of the resistor Rs (the value of the resistor Rs) is used as the electrical characteristic value of the predetermined portion of the equivalent circuit, and the apex position is detected using the electrical characteristic value. . Note that the predetermined portion of the equivalent circuit is not the entire equivalent circuit but only a portion. Specifically, using a comparator (or a program that realizes a comparison function in software) provided in the arithmetic circuit 28, the root apex detection value stored in advance and the electrical characteristic value are compared to determine the root. The apex position is detected and displayed on the display unit 29. The display unit 29 also changes the electrical characteristic value up to the apex position from the blinking of one display LED, the color change of the display LED, the swing of the pointer of the analog meter, and the plurality of display LEDs. Or a combination of a tooth schematic diagram and a bar graph. The display on the display unit 29 is not limited to the visual sense, and may be an audible warning display using a buzzer or a speaker. When such an auditory display is performed, for example, as the measurement electrode approaches the apex, the interval between intermittent sounds is increased or the volume is increased to determine that the measurement electrode is approaching the apex. It can be configured to notify the person. Of course, position information corresponding to the distance to the apex may be displayed.

  Next, the operation of the arithmetic circuit 28 according to the present embodiment will be described in detail. First, in the arithmetic circuit 28, an equivalent circuit that models a conductive path between the measurement electrode 3 and the oral mucosa 4 is set in advance. In the present embodiment, this equivalent circuit is the equivalent circuit shown in FIG. 1, but the present invention is not limited to adopting this equivalent circuit, and a simplified equivalent circuit described later can also be used. . The selection of the equivalent circuit should be performed as appropriate in consideration of cost, simplicity of configuration and calculation, endodontic (root canal) diagnosis accuracy, etc. in actually designing the apparatus. The main point of the present invention is The object is to obtain information on the tooth structure, particularly the root canal, by obtaining the electrical characteristic values of the parts that constitute the components of the equivalent circuit. In the equivalent circuit shown in FIG. 1, the impedance can be represented by an equation of Rs + Rp // Cp, and the symbol “//” in the equation represents a combined resistance in parallel connection.

  The resistance value of the resistor Rs is Rsv, the resistance value of the resistor Rp is Rpv, and the capacitance value of the capacitor Cp is Cpv. When the frequency of the measurement signal is f, 5f, and 25f, the impedance values of the capacitor Cp are set to 1 / (2πfCpv), 1 / (10πfCpv), and 1 / (50πfCpv). In the present embodiment, the impedance value is approximated as 1 / (jωCpv) = 1 / (ωCp) for simplification (angular frequency ω = 2π × frequency).

  Then, using these values, the impedance value at the frequency f can be expressed as Equation 1.

  Similarly, the impedance value at a frequency of 5 f can be expressed as Equation 2.

  Similarly, the impedance value at a frequency of 25 f can be expressed as Equation 3.

  In the arithmetic circuit 28, the impedance values between the measurement electrode 3 and the oral mucosa 4 measured at the frequencies f, 5f, and 25f are sequentially input with respect to the above equation, and the simultaneous equations of Equations 1 to 3 are obtained. If solved, the resistance value Rsv, the resistance value Rpv, and the capacitance value Cpv can be obtained. That is, the arithmetic circuit 28 can determine the values of the equivalent circuit components (resistance Rs, resistance Rp, capacitance Cp) at the position where the tip of the measurement electrode 3 exists.

  As a simpler method, the values of the components Rs, Rp, Cp obtained by combining the impedance values between the measurement electrode 3 and the oral mucosa 4 measured at the frequency f, the frequency 5f, and the frequency 25f can be calculated in advance. Alternatively, a method may be used in which the value of the component (for example, the resistance Rs) is derived from the impedance value obtained from the tooth 1 to be measured from the table.

  Note that the table may be provided in the arithmetic circuit 28 or in an external storage unit. Further, in order to reduce the amount of data stored in the table, a format in which data is discretely stored and an interpolation process is used may be used. Furthermore, instead of using the data stored in the table as the values of the constituent elements Rs, Rp, and Cp, display values representing the apex position may be stored.

  As described above, in the present embodiment, the electrical characteristic value of a predetermined portion of the equivalent circuit that models the conductive path between the tip of the measurement electrode 3 and the oral mucosa 4 (oral electrode 5) is obtained by calculation or the like. Therefore, the apex position can be detected with high accuracy without being affected by a chemical solution or the like. In this embodiment, the apex position is detected as information about the root canal. However, the dental diagnostic device according to the present invention is not limited to this, and obtains an electrical characteristic value of a predetermined portion of the equivalent circuit. Thus, it is possible to obtain information on necessary root canals and information on tooth structures other than root canals, such as the presence of medulla and caries. For example, when detecting exposed pulp and caries, pay attention to the endodontic resistance value, etc., which is part of the equivalent circuit components, and set the threshold value corresponding to exposed pulp and caries to detect exposed pulp and caries. can do.

(Embodiment 2)
<Overview>
The dental diagnostic instrument according to the present embodiment is an apex detector having substantially the same configuration as that of the first embodiment, but models a conductive path between the measurement electrode 3 and the oral mucosa 4 (oral electrode 5). The equivalent circuit is different. The equivalent circuit according to the present embodiment is regarded as the equivalent circuit shown in FIG. The equivalent circuit shown in FIG. 5 has a configuration in which the parallel circuit portion composed of the resistor Rp and the capacitor Cp in FIG. 1 is replaced with a capacitor Cs.

  Also in the present embodiment, the impedance value is measured by measuring a current or the like using the detection resistor 8 provided in the detection circuit. The equivalent circuit shown in FIG. 5 is an example, and the equivalent circuit used in the dental diagnostic device according to the present invention is not limited to the equivalent circuit shown in FIG. 1 or FIG. is there. In the equivalent circuit shown in FIG. 5, the resistance Rs corresponds to the impedance between the measurement electrode 3 and the periodontal membrane 10, and the capacitance Cs corresponds to the impedance between the periodontal membrane 10 and the oral mucosa 4. That is, in the equivalent circuit shown in FIG. 5, the endodontic circuit portion corresponding to the root canal 2 is constituted by the resistor Rs and the extradental circuit portion is constituted by the capacitor Cs.

  Furthermore, the calculation for obtaining the components of the equivalent circuit in the present embodiment is a total of two components of the equivalent circuit in FIG. 5, that is, one resistor and one capacitor. One measurement signal is sufficient. That is, the measurement signal having the frequency 25f used in the first embodiment is not necessary in this embodiment. Therefore, the apex detector according to the present embodiment can simplify the measurement circuit and easily calculate the components. The dental diagnostic device according to the present embodiment has the same configuration as the block diagram shown in FIG. 4 except that the oscillator 22 having the frequency 25f is not provided.

<Detailed operation example>
The operation of the arithmetic circuit 28 according to the present embodiment is also basically the same as that of the first embodiment, and the impedance between the measurement electrode 3 and the oral mucosa 4 corresponding to the measurement signals of the frequency f and the frequency 5f. Measure the value. Then, as in the case of using the equivalent circuit of FIG. 5, a simultaneous equation consisting of Equation 4 and Equation 5 representing the impedance value using the resistance value Rsv of the resistor Rs and the capacitance value Csv of the capacitor Cs is established and measured. The simultaneous equations are solved using the impedance values thus obtained, and the values of the components (resistance Rs, capacitance Cs) of the equivalent circuit at each measurement position are obtained.

  Also in the present embodiment, the value of the resistance Rs is obtained for detecting the apex position, and the change in the value up to the apex detection value that is a predetermined threshold is displayed on the display unit 29. Also in this embodiment, it is not always necessary to obtain the resistance value of the resistor Rs, and a value corresponding to the resistance value may be obtained.

  As a simpler method, the constituent elements Rs and Cs obtained by combining the impedance values between the measurement electrode 3 and the oral mucosa 4 measured at the frequency f and the frequency 5f are calculated in advance, A value of a component (for example, resistance Rs) may be derived from the table from each impedance value obtained from the tooth 1 to be measured. Note that the table may be provided in the arithmetic circuit 28 or in an external storage unit. Further, in order to reduce the amount of data stored in the table, a format in which data is discretely stored and an interpolation process is used may be used. Furthermore, instead of using the data stored in the table as the values of the constituent elements Rs and Cs, a value representing the apex position may be stored.

  Next, a specific example of the value of the resistance Rs obtained by the apex detector according to the present embodiment is also basically the same as the graph of FIG. 3 shown in the first embodiment. Therefore, detailed description is omitted in this embodiment.

(Embodiment 3)
<Overview>
In the first and second embodiments, the apex position is detected using the value of the resistance Rs that is a component of the equivalent circuit as it is. On the other hand, in the apex detector according to the present embodiment, the apex position is detected using an operation value obtained by combining the components of the equivalent circuit.

<Specific example>
For example, the apex position can be detected using the product value of the resistance Rs and the capacitance Cs obtained in the second embodiment. Thus, the detection principle of the apex position when using the calculated value (product value) of the resistance Rs and the capacitance Cs is based on the principle that the value of the resistance Rs is proportional to the distance between the measurement electrode 3 and the apex 6. Instead, based on the principle that the closer the measurement electrode 3 is to the apex 6, the stronger the impedance value between the measurement electrode 3 and the oral mucosa 4 is affected by the capacitive component existing outside the root canal. Yes. The apex detector according to the present embodiment also has the configuration of the block diagram shown in FIG. 4 although there is a difference in the number of oscillators due to the difference in the number of components of the equivalent circuit. Therefore, the calculation of the resistance Rs and the capacitance Cs is processed by the calculation circuit 28.

  Next, a product value of the resistance Rs and the capacitance Cs obtained by the apex detector according to the present embodiment is specifically shown. FIG. 6 shows a change in the product value of the resistance Rs and the capacitance Cs measured using the extracted five teeth. In the graph shown in FIG. 6, the horizontal axis represents the distance from the measurement electrode 3 to the apex 6 (unit is mm), and the vertical axis is the product value of the resistance Rs and the capacitance Cs (unit is kΩ × nF, or anonymous). Represents. In the graph shown in FIG. 6, the product value of the resistance Rs and the capacitance Cs in the vicinity of the apex 6 is approximately 0.0002 to 0.0003 at the apex, and the apex can be detected using the product value. it is obvious. In addition, a substantially constant value of 0.0035 is shown at a position of −0.5 mm from the apex, and it is recognized that the position near the apex can also be detected. Therefore, in the apex detector according to the present embodiment, the apex detection value that is a predetermined threshold value is set, and the apex detection value is compared with the product value of the resistor Rs and the capacitance Cs. It is possible to detect the apex position well. Of course, it is possible to display the apex position even if the display meter is driven corresponding to the product value of the obtained resistance Rs and capacitance Cs. In FIG. 6, a very small value is selected as the product value, but it goes without saying that it can be converted into a more manageable value in an actual circuit.

  As a simpler method, the product value of the resistance Rs and the capacitance Cs corresponding to the impedance value is calculated in advance and stored in a table in the arithmetic circuit 28, and the resistance value is obtained from the impedance value obtained from the tooth 1 to be measured. The product value of Rs and capacity Cs may be derived from the table. In addition, a display value displayed as a root canal length measurement result is also stored in a table created based on the product value of the resistance Rs and the capacitance Cs, and the display value is directly derived from the obtained impedance value from the table. May be. Note that the table may be provided in the arithmetic circuit 28 or in an external storage unit. Further, in order to reduce the amount of data stored in the table, a format in which data is discretely stored and an interpolation process is used may be used.

<Modification>
As a modification of the apex detector according to the present embodiment, a configuration in which the value of the resistance Rs and the product value of the resistance Rs and the capacitance Cs are switched and used for detection of the apex position can be considered. As shown in FIG. 3, the change in the value of the resistance Rs with respect to the distance from the measurement electrode 3 to the apex 6 is substantially constant, but the product value of the resistance Rs and the capacitance Cs has a large change in the vicinity of the apex 6. Therefore, in this modification, the product value of the resistance Rs and the capacitance Cs is used in the vicinity of the apex 6, and the value of the resistance Rs is used up to the vicinity of the apex 6, and the detection result is displayed on the apex detector. It is possible to switch the display so that Thereby, in this modification, the display corresponding to the position of the measurement electrode can be realized and the position of the root apex 6 can be detected more accurately even until the tip of the measurement electrode reaches the vicinity of the apex. A root canal length measuring instrument with the characteristics of the method is feasible.

  In other words, if the value used for apex detection changes abruptly in the vicinity of the apex, the characteristic that apex detection can be performed accurately is used. For example, if the apex detection characteristic is such that the product value changes by 90% within a range of −1 mm from the apex, the detection error is theoretically −1 mm or less. However, since the display up to -1 mm hardly changes, it is very difficult to sensuously grasp the tip position of the measurement electrode. Therefore, the display gradually changes depending on the value of the resistance Rs up to −1 mm, and the position of the apex is accurately determined from the position of −1 mm from the apex to the apex using the product value of the resistance Rs and the capacitance Cs. The display which can detect is performed.

  In addition, as a condition for switching both values, for example, if the device has a configuration in which the display value decreases as it approaches the apex, the smaller value of the two values at the position of a certain measurement electrode 3 is set. It is possible to choose. In other words, if the conditions are used, the product value of the resistance Rs and the capacitance Cs that rapidly decrease is adopted in the vicinity of the apex 6, and the value of the resistance Rs that changes gently is adopted at other positions. Become. However, it is necessary to adjust the scale of the vertical axis so that both values can be directly compared. Further, as the predetermined reference to be switched, the product value itself of the resistance Rs and the capacitance Cs may be used, or any value indicating the position of the measurement electrode 3 such as the value of the resistance Rs itself can be used. It is. The value used for detection of the apex position is not limited to the above value, and the ratio of impedance values between the measurement electrode 3 and the oral mucosa 4 used in the conventional apex detector may be used. . Further, in order to smoothly shift the meter display value at the time of switching, it is also possible to use the product value of the resistor Rs and the capacitor Cs and the sum value after weighting each of the values of the resistor Rs. If each weighting value is gradually changed according to a predetermined reference and finally the weighting value to the value of the resistor Rs is set to 0, a smooth transition is possible.

  For example, in the detection of the apex position, a configuration may be used in which the product value of the resistance Rs and the capacitance Cs and the ratio of the impedance value between the measurement electrode 3 and the oral mucosa 4 are switched under a predetermined condition. The ratio of the impedance value between the measurement electrode 3 and the oral mucosa 4 is an indication value indicating the position information of the tip of the measurement electrode 3 used in the apex detector. It is a value based on an impedance value which is an electrical response between the two.

  When the product value of the resistance Rs and the capacitance Cs is used, the value changes even when the measurement electrode 3 is away from the apex 6. However, when the ratio of impedance values between the measurement electrode 3 and the oral mucosa 4 is used, the value does not change so much when the measurement electrode 3 is away from the apex 6 when the root canal 2 is dry. It changes rapidly in the vicinity of the apex. Therefore, by using the product value of the resistance Rs and the capacitance Cs when the measurement electrode 3 is away from the apex 6, and using the ratio of the impedance values between the measurement electrode 3 and the oral mucosa 4 near the apex 6. In addition, it is possible to perform practical apex position detection that is easy to see and has high accuracy. Needless to say, in this modified example, it is also possible to use a table obtained and stored in advance.

(Embodiment 4)
Conventional apex detectors that have been used in the past have, for example, a configuration in which 6.5 kΩ is an impedance value corresponding to the apex position, while 15 kΩ is an impedance value corresponding to the exposed point. This is based on the well-known principle that in root canal length measurement, if root canal impedance is 15 kΩ or more, it indicates that there is no exposure. Also in the embodiment of the present invention, by using the same method as described above, it is possible to detect the exposed spine and to provide a dental diagnostic device. In the present embodiment in which the present invention is used for detection of the exposed bone, the exposed bone is detected not by the root canal impedance but by the value of the capacitance component of the equivalent circuit. Also in this case, the equivalent circuit to be employed and the method of calculating the values used for the detection of the exposure can be appropriately determined by design as in the above embodiment.

(Embodiment 5)
<Root canal treatment device>
The dental diagnostic device shown in the first to fourth embodiments can be incorporated in an endodontic treatment device such as a root canal enlargement micromotor or a scaler. A schematic view of the endodontic treatment apparatus is shown in FIG. The endodontic treatment apparatus shown in FIG. 7 includes a handpiece H and a stationary controller body C. The handpiece H includes a head 41 to which a cutting tool 40 is attached, a handpiece body 42, and a shank 43. And is connected to the controller main body C through the tube 44. Further, the handpiece main body 42 incorporates a micromotor as a motor for driving the cutting tool 40.

  The controller main body C includes the apex detector shown in the first to third embodiments or the exposed spine detector shown in the fourth embodiment, an operation unit 45, a display unit 46, and the like. . In addition, the measurement electrode 3 and the oral electrode 5 can be connected to the controller main body C. In the endodontic treatment apparatus shown in FIG. 7, the apex position and the exposed pulp are detected using the measurement electrode 3 and the oral electrode 5. In the endodontic treatment apparatus shown in FIG. 7, the measurement electrode 3 is provided independently of the handpiece H. However, the present invention is not limited to this, and the measurement signal for detecting apex in the handpiece H is not limited thereto. The measuring electrode 3 and the cutting tool 40 may be configured in the same manner by providing a conductive path for transmitting the current. Moreover, it is good also as a structure which can attach or detach only an apex detector or a spinal cord detector, and conversely, the structure of the controller main body C is provided in the handpiece H or attached detachably so that the handpiece H alone Can be a cordless endodontic treatment device with apical detection function. At this time, the apex detector or the demyelination detector is completed as one device and may be incorporated in the endodontic treatment apparatus, or the detection function of the apex detector or the demyelination detector is exhibited. Each component required for this purpose may be divided and mounted in the endodontic treatment apparatus.

  Furthermore, according to the endodontic treatment apparatus, since the detection of the apex and the pulp and the endodontic treatment can be performed in parallel, the endodontic apparatus is based on the detection result of the apex and the detection of the pulp. The driving is controlled, for example, by gradually reducing the driving force as the tip of the cutting tool 40 approaches the apex, or by reversing or stopping the rotation of the cutting tool 40 when reaching the apex. It is possible to improve the safety of the apparatus and the usability of the apparatus.

  As described above, the example in which the dental diagnostic device is incorporated in the endodontic treatment device has been described, but the endodontic treatment device according to the present embodiment includes a dental diagnosis device and an endodontic treatment device configured separately. It includes those that are used as a set of endodontic treatment devices by being electrically or mechanically connected. In this case, the lead wire is connected so as to transmit the measurement signal output from the dental diagnostic device to the cutting tool of the endodontic treatment device, and the cutting tool of the endodontic treatment device is used as a measurement electrode, or the endodontic treatment device together with the connection. Can be switched to a display for dental diagnosis, and the driving force of the endodontic treatment apparatus can be controlled based on the diagnosis result of the dental diagnostic device as described above.

<Dental clinic>
Further, the dental diagnostic device (apical detector) shown in the first to third embodiments, the dental diagnostic device (blade pulp detector) shown in the fourth embodiment, or the endodontic treatment described above. The device can be incorporated into a dental table (dental unit). A dental examination table 50 shown in FIG. 8 includes a diagnosis table 51 for holding a patient in a sitting position or a supine position, a display unit 52 for performing display necessary for diagnosis, and an operation unit for receiving operation inputs for diagnosis. 53, a module unit 54 incorporating a dental diagnostic device or an endodontic device, a spitton unit 55 for a patient to gargle, and a moving table 56 on which equipment and module unit 54 necessary for medical care are placed. It has.

  The apex detector shown in the first to third embodiments, the exposed pulp detector shown in the fourth embodiment, or the endodontic treatment device described above is used as a dental unit (for dental practice) as the module unit 54. The information of the module unit 54 is displayed on the display unit 52. The present invention is not limited to the dental examination table (dental practice unit) 50 shown in FIG. 8, and the dental diagnostic instrument shown in the first to fourth embodiments or the endodontic treatment described above in some form. The apparatus may be used as a set of dental examination tables (dental examination units) by being incorporated in or connected to the dental examination table. Further, the above-described dental examination table (dental examination unit) may also be configured to control the driving of the dental examination table (dental examination unit) based on the apex detection result and the detection result.

It is a figure which shows the equivalent circuit of the apex detector which concerns on Embodiment 1 of this invention. It is a use mode schematic of the apex detector which concerns on Embodiment 1 of this invention. It is a figure which shows the change of the value of resistance Rs which the apex detector which concerns on Embodiment 1 of this invention detects. It is a block diagram of the apex detector according to the first embodiment of the present invention. It is a figure which shows the equivalent circuit of the apex detector which concerns on Embodiment 2 of this invention. It is a figure which shows the change of the product value of resistance Rs and the capacity | capacitance Cs which the apex detector which concerns on Embodiment 3 of this invention detects. It is the schematic of the root canal treatment apparatus which concerns on Embodiment 4 of this invention. It is the schematic of the dental examination table which concerns on Embodiment 4 of this invention. It is a figure for demonstrating the usage aspect of the apex detector used as the premise of this invention. It is a figure for demonstrating the structure of the tooth apex vicinity vicinity used as the premise of this invention. It is a use mode schematic of the apex detector used as the premise of the present invention.

Explanation of symbols

  1 tooth, 2 root canal, 3 measurement electrode, 4 oral mucosa, 5 oral electrode, 6 apex, 7 signal application unit, 8 detection resistance, 9 gingiva, 10 periodontal ligament, 20, 21, 22 oscillator, 23 analog multiplexer , 24 buffers, 25 timing controller, 26 waveform shaping circuit, 27 A-D converter, 28 arithmetic circuit, 29 display unit, 101 teeth, 102 root canal, 103 measurement electrode, 104 tip of measurement electrode, 105 oral electrode, 106 Root apex, 107 Signal application unit, 108 Detection resistance, 109 Periodontal ligament, 110 Root apex, 111 Oral mucosa, 112 Drug solution.

Claims (18)

A measurement electrode inserted into the tooth to be measured;
An oral electrode in electrical contact with the oral mucosa;
Measurement signal applying means for applying a measurement signal between the measurement electrode and the oral electrode;
Measuring means for measuring an electrical response between the measurement electrode and the oral electrode with respect to a plurality of measurement signals having different frequencies;
Computation processing means for computing an electrical characteristic value of a predetermined portion of an equivalent circuit that models a conductive path between the measurement electrode and the oral electrode based on the electrical response,
A dental diagnostic device characterized in that information on the inside of the tooth is obtained from the electrical characteristic value. The dental diagnostic device according to claim 1,
The dental diagnostic instrument characterized in that the inside of the tooth to be measured into which the measurement electrode is inserted is a root canal of the tooth. The dental diagnostic device according to claim 1 or 2,
The dental diagnosis device, wherein the measurement signal applying means applies the measurement signal having at least the same number of different frequencies as the number of components of the equivalent circuit. The dental diagnostic instrument according to any one of claims 1 to 3,
The arithmetic processing means has a table in which the electrical characteristic value of a predetermined portion of the equivalent circuit corresponding to the electrical response is obtained in advance.
An electrical characteristic value of a predetermined portion of the equivalent circuit corresponding to the electrical response measured by the measuring means is obtained from the table. The dental diagnostic device according to any one of claims 1 to 4,
The said equivalent circuit is comprised by the endodontic circuit part corresponding to the inside of the said tooth | gear, and the other external tooth circuit part, The dental diagnostic device characterized by the above-mentioned. The dental diagnostic instrument according to claim 5,
In the equivalent circuit, the external circuit portion is a parallel circuit of a resistive element and a capacitive element,
A dental diagnostic device, wherein the parallel circuit is a circuit in which resistance elements of the endodontic circuit portion are connected in series. The dental diagnostic instrument according to claim 5,
The equivalent circuit is a circuit in which a capacitive element of the extradental circuit portion and a resistance element of the endodontic circuit portion are connected in series. The dental diagnostic instrument according to any one of claims 5 to 7,
The dental diagnostic device according to claim 1, wherein the electrical characteristic value is a value based on at least one component of the endodontic circuit section. The dental diagnostic instrument according to any one of claims 5 to 7,
The electrical characteristic value is a calculated value of a value based on at least one component of the endodontic circuit portion and a value based on at least one component of the front external circuit portion. Diagnostic device. The dental diagnostic instrument according to any one of claims 5 to 7,
The arithmetic processing means switches between the electrical characteristic value according to claim 8 and the electrical characteristic value according to claim 9 according to a predetermined reference to obtain information on the inside of the tooth. A dental diagnostic device. The dental diagnostic device according to any one of claims 1 to 10,
The information on the inside of the tooth is at least one of position information of the tip of the measurement electrode, presence / absence of a medulla and presence / absence of caries inside the tooth. The dental diagnostic instrument according to claim 11,
The position information of the tip of the measurement electrode obtained from the value based on the electrical response, and the information on the inside of the tooth obtained from the electrical characteristic value calculated by the calculation processing means on a predetermined basis A dental diagnostic device characterized by switching to detect the apex position. The dental diagnostic device according to any one of claims 1 to 12,
The dental diagnostic device further comprising a display unit for displaying information on the inside of the tooth. The dental diagnostic instrument according to claim 13,
The said diagnostic part visually displays the information regarding the inside of the said tooth | gear, The dental diagnostic device characterized by the above-mentioned. The dental diagnostic instrument according to claim 13 or 14,
The display unit is configured to audibly display information related to the inside of the tooth. A measuring electrode to be inserted into the root canal of the tooth to be measured;
An oral electrode in electrical contact with the oral mucosa;
Measurement signal applying means for applying a measurement signal between the measurement electrode and the oral electrode;
Measuring means for measuring an electrical response between the measurement electrode and the oral electrode with respect to a plurality of measurement signals having different frequencies;
The electrical characteristic between the measurement electrode and the oral electrode was regarded as a composite characteristic of the respective electrical characteristics of the endodontic segment from the measurement electrode to the apex and the remaining segment other than the endodontic segment. A signal processing means for obtaining a measurement result obtained by removing at least part of the influence of the electrical characteristic of the remaining section from the combined characteristic based on the electrical response and outputting information corresponding to the measurement result; A dental diagnostic device comprising:   An endodontic treatment apparatus comprising the dental diagnostic device according to any one of claims 1 to 16.   A dental examination table comprising at least one of the dental diagnostic device according to any one of claims 1 to 16 and the endodontic treatment device according to claim 17.

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