Patent Description:
There is a demand for detecting abnormalities related to bacteria attached to various objects. Here, a dental implant treatment is a treatment method for joining an artificial tooth to which the functions and form of a tooth are imparted on a fixture that is an artificial tooth root embedded in the jawbone.

The artificial tooth may be directly coupled to the fixture (one-piece type) or may be fixed to an abutment (abutment portion) fixed to the fixture (two-piece type).

Since dental implants are stored in the oral cavity and used for a long period of time, it is known that bacteria attached between the dental implant and the gums are activated and/or proliferate depending on an environment in the oral cavity, thereby causing peri-implant mucositis.

As a dental implant for preventing such a disease caused by bacteria, Patent Literature <NUM> describes "a dental implant (<NUM>) or an element thereof comprising a transmucosal portion (<NUM>), wherein at least a part of the transmucosal portion (<NUM>) includes a biocide (<NUM>) and/or a pH adjuster".

Patent Literature <NUM>: <CIT> Further relevant prior art documents are <CIT>, <CIT>, <CIT> and <CIT>.

In order to prevent inflammation caused by bacteria occurring around the dental implant, a method in which a dentist diagnoses a state of a tissue around the implant (for example, examination of a probing depth, observation of bleeding at the time of probing, confirmation of presence or absence of drainage, and the like) is often adopted in a periodic examination by the dentist.

However, according to the above method, although it is possible to detect a state in which inflammation has already occurred, there is a problem that it is not possible to detect a situation before inflammation occurs, specifically, a situation in which the activity of bacteria improves or bacteria starts to proliferate. Note that the problems of abnormalities related to bacteria may occur not only in dental implants but also in various objects.

Therefore, an object of the present invention is to provide an apparatus capable of easily obtaining information for determining presence or absence of an abnormality related to bacteria attached to an object. In addition, another object of the present invention is to provide a data collection method.

As a result of intensive studies to achieve the above objects, the present inventor have found that the above objects can be achieved by the following configurations.

According to the present invention, it is possible to provide an apparatus capable of easily obtaining information for evaluating the activity of bacteria around a dental implant. In addition, the present invention can also provide a data collection method.

A detection apparatus <NUM> according to a first embodiment of the present invention will be described with reference to the drawings.

The detection apparatus <NUM> detects an abnormality related to bacteria attached to a dental implant (exemplifying an object). The abnormality related to bacteria is, for example, activation of bacteria or proliferation of bacteria or the like.

<FIG> is a block diagram of the detection apparatus <NUM>, <FIG> is a hardware configuration diagram of the detection apparatus <NUM>, and <FIG> is a schematic diagram of the detection apparatus <NUM>.

The detection apparatus <NUM> illustrated in <FIG> includes an electrode formation unit <NUM>, a detection unit <NUM>, a measurement unit <NUM>, an adjustment unit <NUM>, a comparison unit <NUM>, an abnormality detection unit <NUM>, an electron source emission unit <NUM>, a control unit <NUM>, and an input/output device including a display device 19a and an input device 19b.

Among those units and devices, the control unit <NUM> includes a central processing unit 18a and a storage device 18b, and the comparison unit <NUM> and the abnormality detection unit <NUM> correspond to a program stored in the storage device 18b and to the central processing unit 18a. In addition, the adjustment unit <NUM> and the measurement unit <NUM> are controlled by the control unit <NUM>, and the detection unit <NUM>, the electron source emission unit <NUM>, which is constituted integrally with the detection unit <NUM>, and the electrode formation unit <NUM> are controlled by the control unit <NUM> via the adjustment unit <NUM> and the measurement unit <NUM>.

As illustrated in <FIG>, in the detection apparatus <NUM>, the electrode formation unit <NUM> and a dental implant Imp are brought into contact with each other to form one electrode (working electrode WE). That is, the electrode formation unit <NUM> forms the working electrode WE by coming into contact with the dental implant Imp. In the present specification, the "dental implant" means a one-piece type fixture and abutment and a two-piece type fixture and abutment and usually includes a conductive material such as titanium or a titanium alloy.

The dental implant Imp is usually arranged in the oral cavity, and the periphery thereof is wetted with an electrolytic solution such as saliva.

The detection unit <NUM> constitutes an electrode (counter electrode CE) paired with the working electrode WE, and the working electrode WE and the counter electrode CE are arranged apart from each other via the electrolytic solution.

The electrode formation unit <NUM> and the detection unit <NUM> are electrically connected via the measurement unit <NUM>, and the measurement unit <NUM> can measure a current flowing between the working electrode WE and the counter electrode CE.

The present inventor has conducted intensive studies to electrochemically detect the activity of bacteria in the oral cavity. As a result, it has been found that bacteria transfer electrons to an extracellular solid (electron conductor), thereby obtaining energy in a state in which the bacteria can exert pathogenicity. Note that becoming a state in which pathogenicity can be exhibited means, for example, becoming a state in which a biofilm is formed as a result of activation or proliferation of bacteria (that is, occurrence of an abnormality related to bacteria) and a state in which the biofilm is acidified. Note that the biofilm is a membrane formed by attachment of bacteria to a surface.

Specifically, regarding Streptococcus mutans bacteria cultured under acidic conditions (pH <NUM>) and Streptococcus mutans bacteria cultured under neutral conditions, the present inventor observed sections stained specifically for oxidation-reduction reaction with a transmission electron microscope and found that the surface of a cell wall and an inner cell membrane are specifically stained in a case where the Streptococcus mutans bacteria are cultured under acidic conditions.

In addition, it has also been confirmed that Capnocytophaga ochracea bacteria, which are also known as causative bacteria of periodontal diseases, specifically express electron transfer enzymes in an anaerobic environment.

The above illustrates that biofilm formation, metabolism in the biofilm, and acidification of the biofilm and occurrence of a current (electron transfer to the extracellular solid) have a close relationship each other.

The present inventor conducted an experiment to examine electron transfer in the intraoral bacteria that are Streptococcus mutans (S. mutans) under acidic conditions. <FIG> is a graph illustrating experimental results (temporal changes in a current) regarding electron transfer in the intraoral bacteria. Note that the current was measured by an anaerobic reactor device including three electrodes (reference electrode, working electrode, and indium tin oxide (ITO) electrode). The current was measured in the presence of the intraoral bacteria in the presence of <NUM> glucose (electron source). Note that intraoral bacteria cultured in an acidic unbuffered solution (pH <NUM> ± <NUM>) were used. Specifically, each electrode was arranged in a culture solution of the intraoral bacteria in which <NUM> glucose was present, and a current flowing between the working electrode and the ITO electrode when an electric potential was applied was measured.

As can be grasped from <FIG>, it has been found that a detected current increases with time. That is, it can be said that electron transfer in the intraoral bacteria become active with the lapse of time. A state in which electron transfer become active is considered to be a state in which a biofilm is formed on the surface of the electrode and the intraoral bacteria are activated and proliferating. Note that, it is considered that a current value correlates with the number of the intraoral bacteria. Utilizing the above findings, the detection apparatus <NUM> of the present invention employs a configuration in which an abnormality related to bacteria is detected according to a change in a current flowing between electrodes.

Note that in <FIG>, the temporal changes in the current are detected over several hours, but a time length for detecting temporal changes in the current is any length. For example, in the detection apparatus <NUM> of the present invention, a temporal change in the current may be detected for a very short time length (for example, for several seconds).

As understood from the above description, in a case where there is an abnormality related to bacteria around the dental implant (for example, in a case where the bacteria are activated and/or proliferating), it is presumed that the bacteria obtain energy by transferring surplus electrons to the dental implant that is an extracellular solid.

In the detection apparatus <NUM>, the dental implant Imp is formed as one electrode and is connected to the counter electrode CE (detection unit <NUM>) via the measurement unit <NUM>. Therefore, the detection of the current value in the detection apparatus <NUM> means a state in which electron transfer from the bacteria to the dental implant Imp has occurred, that is, a state in which the bacteria can exert pathogenicity (for example, a state in which a biofilm is formed and a state in which the biofilm is acidified). Eventually, it is a state in which an abnormality related to the bacteria attached to the dental implant Imp has occurred. As understood from the above description, it can also be said that the current flowing between the electrode pair reflects an activity situation of the bacteria present around the working electrode WE and the counter electrode CE (for example, a situation of activation of the bacteria or a situation of proliferation of the bacteria).

By scanning over the dental implant Imp with the detection unit <NUM> and observing a change in the current value during the scan, it is possible to specify a place where the above-described abnormality has occurred (abnormality occurrence position).

Conventionally, it is general that as for inflammation caused by bacteria occurring between a dental implant and the gums, it is confirmed visually that inflammation had occurred and then the inflammation is addressed. In contrast, by using the detection apparatus <NUM>, the abnormality occurrence position can be easily and quickly specified, and the abnormality can also be detected at a stage before visible inflammation occurs.

In addition, the detection apparatus <NUM> includes the adjustment unit <NUM>. The adjustment unit <NUM> applies an electric potential between the working electrode WE formed by the electrode formation unit <NUM> and the counter electrode CE that is the detection unit <NUM>. Since the detection apparatus <NUM> includes the adjustment unit <NUM>, even in a case where the number of cells of the bacteria is small, a more excellent response speed can be obtained by applying an electric potential between both electrodes. The form of the adjustment unit <NUM> is not particularly limited, but typically, a potentio/galvanostat (P/G stat, illustrated a symbol "PGST" in <FIG>) including the measurement unit <NUM> and the adjustment unit <NUM> can be used.

Note that the detection apparatus <NUM> includes the adjustment unit <NUM>, but the detection apparatus <NUM> according to the first embodiment of the present invention may not include the adjustment unit <NUM>. In a state in which the bacteria exhibit pathogenicity, it is presumed that the bacteria transfer electrons to the dental implant Imp that is an extracellular solid (electrical conductor) to obtain energy. That is, in a case where the bacteria exhibit pathogenicity, it is possible to detect a current without applying an electric potential if a connection to the counter electrode CE and the dental implant Imp is made to form a circuit.

In <FIG>, the dental implant Imp is embedded in a jawbone <NUM>, and an artificial tooth <NUM> is fixed to a tip portion. A part of the dental implant Imp is exposed from gums <NUM>. The electrode formation unit <NUM> is brought in contact with the dental implant Imp at an exposed portion Pos1, and the electrode formation unit <NUM> and the dental implant Imp constitute the working electrode WE.

Meanwhile, the detection unit <NUM> includes an electrode <NUM> and the electron source emission unit <NUM>. The electron source emission unit <NUM> includes a nozzle 17a for emitting an electron source (typically, an aqueous solution containing an electron source), an electron source storage unit 17c communicating with the nozzle 17a via a pipe, and a pump 17b arranged in the pipe, and the electron source emission unit <NUM> is configured so that a predetermined amount of the electron source is emitted by operating the pump 17b controlled by the control unit <NUM>.

The electrode <NUM> is arranged so as to come in contact with an electrolytic solution <NUM> (typically saliva) present around the dental implant Imp and is arranged with the working electrode WE via the electrolytic solution <NUM> to function as the counter electrode CE. Each of the electrodes is electrically connected by the potentio/galvano (P/G) stat PGST, and a current flowing between both electrodes can be measured.

The electron source emitted from the electron source emission unit <NUM> is selected from glucose or lactic acid or solutions thereof. The electron source emission unit <NUM> may emit the electron source itself and may emit a solution containing the electron source. Typically, an aqueous solution containing the electron source can be used, and examples thereof include physiological saline containing the electron source and the like.

<FIG> is a schematic diagram illustrating a method of detecting the occurrence of the abnormality by the detection apparatus <NUM> and specifying the abnormality occurrence position. In <FIG>, a fine biofilm <NUM> is formed on the dental implant Imp, and the bacteria are activated.

<FIG> schematically illustrates a response detected by the measurement unit <NUM> with a horizontal axis representing observation time and a vertical axis representing a current. A broken line illustrates a response in a case where there is no abnormality (in a case where there is no electron transfer), and a solid line illustrates a response in a case where there is an abnormality (in a case where there is electron transfer).

The biofilm <NUM> is formed on the dental implant Imp, and electron transfer from the bacteria to the dental implant Imp occurs. According to the detection apparatus <NUM>, the occurrence of the abnormality can be detected by detecting a current caused by the electron transfer.

In addition, since the detection apparatus <NUM> includes the detection unit <NUM> formed by integrating the electrode <NUM> and the electron source emission unit <NUM> (nozzle 17a), it is possible to specify the abnormality occurrence position by scanning over the dental implant Imp with the detection unit <NUM>.

A scan is performed from a position illustrated by (A) to a position illustrated by (B) in <FIG> with the detection unit <NUM>. At this time, a response measured at the position of (A) is defined as (a), and a response measured at the position of (B) is defined as (b).

First, at the position of (A), an electron source <NUM> emitted from the nozzle 17a is more likely to reach the bacteria in the biofilm <NUM>, at the position of (A), and thus, as illustrated in (a), the detected current increases after emission inj of the electron source <NUM>.

Meanwhile, at the position of (B), the electron source <NUM> emitted from the nozzle 17a is less likely to reach the biofilm <NUM> due to the bacteria in the biofilm and thus the current increases more gradually or does not increase.

That is, by examining a response while scanning with the detection unit <NUM>, it can be specified that the electron source is consumed and the current value increases, that is, the activity of the bacteria increases in a portion where a larger current is obtained as compared with the surroundings.

Since the detection apparatus <NUM> includes the electron source emission unit <NUM>, the detection apparatus <NUM> can detect a smaller amount of the bacteria and has a wider dynamic range and/or has a faster response speed.

In the detection apparatus <NUM> of <FIG>, the electron source emission unit <NUM> includes the nozzle 17a for emitting the electron source (typically, an aqueous solution containing an electron source), the electron source storage unit 17c communicating with the nozzle 17a via a pipe, and the pump 17b arranged in the pipe, and the electron source emission unit <NUM> is configured so that a predetermined amount of the electron source is emitted by operating the pump 17b controlled by the control unit <NUM>.

Note that in the detection apparatus <NUM>, the detection unit <NUM> and the electron source emission unit <NUM> are integrally formed, and the electron source emitted from the electron source emission unit <NUM> can be more efficiently arranged between the detection unit <NUM> and the dental implant Imp.

Note that the detection apparatus <NUM> according to the first embodiment of the present invention is not limited to the above, and the detection unit <NUM> and the electron source emission unit <NUM> may be arranged separately.

In addition, in the detection apparatus <NUM>, an amount of the electron source emitted by the electron source emission unit <NUM> and a timing when the electron source is emitted by the electron source emission unit <NUM> are controlled by the control unit <NUM>, but the detection apparatus <NUM> according to the first embodiment of the present invention is not limited to the above, and the operation and stop of the pump 17b may be controlled by an operator.

The measurement unit <NUM> measures the current between the working electrode WE and the counter electrode CE. When the current is measured, a measurement ID is generated by the measurement unit <NUM>, and data on time from the start of the measurement and a current value obtained at corresponding observation time is generated and stored for each measurement ID in an area secured in the storage device 18b.

The data generated by the measurement unit <NUM> is passed to the comparison unit <NUM>. The comparison unit <NUM> compares the data generated by the measurement unit <NUM> with a predetermined reference (hereinafter referred to as a "reference threshold"). For example, the comparison unit <NUM> extracts data on the current value at a predetermined observation time and compares the extracted data with the reference threshold. Specifically, the comparison unit <NUM> compares whether the extracted data exceeds the reference threshold.

A result of the comparison is passed to the abnormality detection unit <NUM>. The abnormality detection unit <NUM> detects an abnormality related to the bacteria attached to the dental implant Imp on the basis of the result of the comparison by the comparison unit <NUM>. Specifically, in a case where the comparison unit <NUM> determines that the extracted data exceeds the reference threshold, the abnormality detection unit <NUM> determines that there is an abnormality related to the bacteria attached to the dental implant Imp. Then, the abnormality detection unit <NUM> prompts the display device 19a to display the measurement result, and the process ends.

Meanwhile, in a case where the comparison unit <NUM> determines that the extracted data is less than the reference threshold, the abnormality detection unit <NUM> determines that there is no abnormality related to the bacteria attached to the dental implant Imp.

As understood from the above description, the comparison unit <NUM> and the abnormality detection unit <NUM> function as a "determination unit" for determining the presence or absence of an abnormality related to the bacteria attached to the dental implant Imp according to the current measured by the measurement unit <NUM>. Note that it is not essential for the abnormality detection unit <NUM> to prompt the display device 19a to display the measurement result.

Note that in <FIG>, the display device 19a and the input device 19b, and the P/G stat PGST including the measurement unit <NUM> and the adjustment unit <NUM> are constituted separately but may be constituted integrally.

In addition, although the detection apparatus <NUM> includes the display device 19a and the input device 19b, the detection apparatus <NUM> according to the first embodiment of the present invention may not include the display device 19a and the input device 19b. In that case, a tablet terminal or the like that can wirelessly communicate with the detection apparatus <NUM> can also be used as a display device and an input device.

In addition, in a case where as a result of the comparison by the comparison unit <NUM>, the extracted data does not satisfy a reference, the abnormality detection unit <NUM> prompts the display device 19a to display attention calling information. The attention calling information typically means that the activity of the bacteria improves or the bacteria may be proliferating on an implant surface, more specifically, on a measurement target site (position of the detection unit <NUM>). By performing this operation while scanning over the dental implant Imp with the detection unit <NUM>, it is possible to specify the abnormality occurrence position on the dental implant Imp.

Since in the detection apparatus <NUM>, the dental implant Imp serves as one electrode, and the detection unit <NUM> serves as the other electrode, it is possible to easily obtain information for evaluating the activity of the bacteria in a narrow range around the detection unit <NUM>. Even for the same tooth, it is possible to easily obtain information for evaluating the activity of the bacteria in a narrow range by dividing the tooth into sites on a buccal side (lip side), a palate side (tongue side), and the like.

Note that the detection apparatus <NUM> may further include a reference electrode. In a case where the detection apparatus <NUM> includes the reference electrode, an electrode potential can be measured. In a case where the detection apparatus <NUM> includes the reference electrode, the detection apparatus <NUM> may be arranged independently from the electrode formation unit <NUM> and the detection unit <NUM> or may be arranged integrally with the electrode formation unit <NUM> and/or the detection unit <NUM>. In particular, it is preferable that the detection unit <NUM> and the reference electrode are constituted integrally from the viewpoint of easier handling.

A data collection method of the present invention is a data collection method according to claim <NUM>. <FIG> is a flowchart of the data collection method.

First, an electrical conductor is brought into contact with a dental implant in contact with an electrolytic solution to form an electrode (S1). The electrical conductor is not particularly limited, and examples thereof include carbon, gold, platinum, silver, molybdenum, cobalt, nickel, palladium, ruthenium, and the like, and the electrical conductor may be indium tin oxide or the like. In addition, a shape and the like are not particularly limited, but the shape is preferably a probe shape or a wire shape from the viewpoint of easier contact with the dental implant.

Next, an electrode different from the electrode is brought into contact with the electrolytic solution (S2). Here, the electrolytic solution is typically preferably saliva around the dental implant or the like and may be a mixture of an aqueous solution containing an electron source (for example, physiological saline containing glucose) and saliva.

A material of the electrode is not particularly limited, and the materials exemplified above as the electrical conductor can be used. In addition, a shape and the like are not particularly limited, but the shape is preferably a probe shape or a wire shape the viewpoint of easier contact with the dental implant.

An electrode pair is formed as described above, and then a current flowing between the electrode pair is measured (S3). The current reflects the activity of pathogenic microorganisms around the dental implant. Thus, data collected using the above data collection method (current measured at S3) can be used to evaluate the activity of pathogenic microorganisms around the dental implant.

A second embodiment of the present invention will be described. Note that elements having actions or functions similar to those of the first embodiment in embodiments exemplified below will be appropriately omitted from detailed description by using reference signs used in the description of the first embodiment.

<FIG> is a schematic diagram illustrating a usage aspect of a detection apparatus <NUM> according to the second embodiment. In <FIG>, only an electrode formation unit <NUM> and a detection unit <NUM> in the detection apparatus <NUM> are illustrated for convenience. In the first embodiment, an abnormality related to the bacteria attached to the dental implant is detected, but in the second embodiment, an abnormality related to bacteria attached to an endoscope <NUM> (exemplifying an object) is detected.

Note that a configuration of the detection apparatus <NUM> is similar to that of the first embodiment.

The endoscope <NUM> is a medical device for observing the inside of the human body (for example, the gastrointestinal tract and the large intestine). Specifically, the endoscope <NUM> includes an insertion unit <NUM> and an operation unit <NUM>. The insertion unit <NUM> is a portion to be inserted into the human body. An imaging element C capable of imaging the inside of the human body is mounted at a distal end of the insertion unit <NUM>. The operation unit <NUM> is an operator operated by an operator (typically, a doctor).

In the second embodiment, an abnormality related to the bacteria attached to the insertion unit <NUM> of the endoscope <NUM> is detected. The electrode formation unit <NUM> is in contact with the insertion unit <NUM>, and the electrode formation unit <NUM> and the insertion unit <NUM> constitutes a working electrode WE. In addition, the detection unit <NUM> constitutes an electrode (counter electrode CE) paired with the working electrode WE. Then, as in the first embodiment, the working electrode WE and the counter electrode CE are arranged apart from each other via an electrolytic solution. Note that in the second embodiment, for example, physiological saline is used as the electrolytic solution.

In the detection apparatus <NUM> of the second embodiment, a scan over the insertion unit <NUM> is performed with the detection unit <NUM>, and a change in a current value during the scan is observed as in the first embodiment. As in the first embodiment, in a state in which the bacteria exhibit pathogenicity, the bacteria transfer electrons to the insertion unit <NUM> that is an extracellular solid (electrical conductor). Therefore, a current is detected by a measurement unit <NUM>.

As in the first embodiment, the measurement unit <NUM> measures a current between the working electrode WE and the counter electrode CE. As in the first embodiment, the comparison unit <NUM> compares data on the current value measured by the measurement unit <NUM> with a reference threshold. Then, as in the first embodiment, an abnormality detection unit <NUM> detects an abnormality related to bacteria attached to the insertion unit <NUM> on the basis of a result of the comparison by the comparison unit <NUM>.

Also in the second embodiment, effects similar to the effects of the first embodiment are achieved. In addition, since the endoscope <NUM> is inserted into the human body, an abnormality particularly related to bacteria becomes a problem. For example, when the endoscope <NUM> is inserted into the human body in a state in which the bacteria attached to the insertion unit <NUM> are activated or proliferate, an infection or the like may occur. According to the detection apparatus <NUM> of the second embodiment, it is possible to easily and quickly detect the abnormality related to bacteria attached to the endoscope <NUM>.

Note that in <FIG>, a configuration for detecting an abnormality related to bacteria attached to the surface of the insertion unit <NUM> has been exemplified, but a portion for detecting an abnormality related to bacteria in the endoscope <NUM> is not limited to the above example. For example, an abnormality related to bacteria in the operation unit <NUM> may be detected.

In addition, an object to be detected for an abnormality related to bacteria is not limited to the dental implant and the endoscope. Various articles capable of functioning as electrodes are exemplified as the object. For example, various medical instruments such as surgical instruments (for example, scalpels and forceps) and cannulas are exemplified as the object. Note that in a case where a tubular article such as a cannula is used as the object, it is also possible to detect an abnormality related to bacteria attached to the inside of a tube by inserting the detection unit <NUM> into the tube. In addition, various devices used in food factories, factories manufacturing precision devices, and the like may be used as the object. As understood from the above description, various objects in which occurrence of bacteria is a problem are targets for detecting an abnormality related to bacteria in the detection apparatus of the present application.

Bacteria attached to various objects cause various problems in terms of hygiene and health. For example, conventionally, it is general that, as for inflammation caused by bacteria occurring between a dental implant and the gums, it is confirmed visually that inflammation had occurred and then the inflammation is addressed. In contrast, by using the detection apparatus according to the present invention, it is possible to perform measurement easily and quickly, and it is possible to detect before the occurrence of visible inflammation, more specifically, to detect, on the basis of a current, a situation in which the activity of bacteria increases.

Claim 1:
A detection apparatus (<NUM>) comprising:
an electrode formation unit (<NUM>) that is configured to be brought into contact with an object to form an electrode;
a detection unit (<NUM>) that constitutes an electrode pair with the electrode, wherein the detection unit (<NUM>) further includes an electron source emission unit (<NUM>) capable of emitting an electron source (<NUM>),
- wherein said electron source is selected from glucose or lactic acid, or solutions thereof, and
- wherein the electron source emission unit (<NUM>) includes a nozzle (17a) for emitting said electron source, an electron source storage unit (17c) communicating with the nozzle (17a) via a pipe, and a pump (17b) arranged in the pipe, and the electron source emission unit (<NUM>) is configured so that a predetermined amount of the electron source is emitted by operating the pump (17b) controlled by a control unit (<NUM>);
a measurement unit (<NUM>) that is configured to measure a current flowing between the electrode and the detection unit (<NUM>); and
a determination unit that is configured to determine presence or absence of an abnormality related to bacteria attached to the object according to the current measured by the measurement unit (<NUM>).