Patent Description:
In the field of dentistry, a dental root canal treatment is sometimes conducted so as to remove the dental pulp, or control inflammation of the root apex. In a conventional root canal treatment, the treatment has been performed by cutting and enlarging a root canal with a reamer and a file and removing contaminating tissues and contaminants in the root canal, and then filling the root canal with a pharmaceutical.

However, the shape of a root canal is complicated, and the shape differs depending on the kind of the tooth and the individual. Therefore, in a root canal treatment, there is a part where enlargement of root canal with a reamer and a file is difficult, and an inflammatory factor remaining in the part where enlargement of the root canal is impossible would cause inflammation after the operation. Also, a bone defect can occur in the apical area, or a root apex lesion can occur, and treatments for these are also involved in a root canal treatment. Therefore, in a root canal treatment, it has been common that regeneration of the defected or lesioned bone is an index for determination of healing.

International Publication No. <CIT>discloses a treatment device that conducts a root canal treatment for reducing inflammatory factors, bacteria and the like in a root canal of tooth. In the treatment device, an electrode to be inserted into a root canal is included in a dental tool that communicates with a measuring device that measures the position of the root apex. Further, the dental tool is capable of communicating with a unit that applies an electric pulse. Therefore, the treatment device is capable of applying an electric pulse to the root canal via the electrode inserted into the root canal, and reducing inflammatory factors, bacteria and the like in a root canal by the applied electric pulse.

Furthermore, studies for promoting bone regeneration by utilizing a faint current have been made, and a DC current stimulation method (DC method), an AC current stimulation method (AC method), a capacity coupling type electrostimulation method (CCEF method) and the like are known (<NPL>).

However, in the root canal treatment, when a bone defect or a root apex lesion is generated in the apical area, healing is not determined until the defected or lesioned bone is regenerated, so that the time period until healing is determined is extended if a relatively long time is required for regeneration of the bone. Of course, in the root canal treatment, it is desired to shorten the time until achievement of healing because the patient feels an unpleasantness until healing is achieved.

The present disclosure was devised to solve the aforementioned problem, and it is an object of the present invention defined in the appended claims to provide a treatment device capable of shortening the time period until healing is determined even when a bone defect or a root apex lesion is generated in the apical area.

The treatment device according to the present invention is a treatment device that passes a high frequency current through a site to be treated. The treatment device includes a holder that holds an electrode to be located in a site to be treated, a power supply that passes a high frequency current through the electrode, and a controller that controls a frequency of the high frequency current to be passed through the electrode from the power supply. The controller controls the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> to <NUM>.

Hereinafter, the present disclosure will be described by referring to the drawings.

<FIG> is an external appearance view of a treatment device <FIG> is a block diagram showing a configuration of the treatment of <FIG>. <FIG> each are a schematic view for illustrating a method of regenerating bone in an apical area. In the apical area, it is sometimes the case that a bone defect or a root apex lesion is generated, and in a tooth <NUM> shown in <FIG>, a bone defect <NUM> is generated in alveolar bone <NUM> near a root apex <NUM>. In a root canal treatment, a significant time is required and the time period until healing is determined is elongated if one waits for natural regeneration of the bone of the part of bone defect <NUM>.

Here, in the treatment device <NUM> of <FIG>, as in tooth <NUM> shown in <FIG>, a root canal <NUM> is cut and enlarged with a cutting tool such as a reamer and a file, and a dental pulp <NUM> or an inflammatory factor in root canal <NUM> is removed, and then an electrode (file <NUM>) is inserted in root canal <NUM>, and a high frequency current is passed through the part of bone defect <NUM> which is a site to be treated.

The treatment device <NUM> is capable of promoting bone regeneration of the part by passing a high frequency current of a specific frequency through the part where bone defect <NUM> is generated (bone regeneration mode). In particular, in the present disclosure, it was newly found that bone regeneration in the part where bone defect <NUM> is generated is further promoted by controlling the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> to <NUM>. More preferably, it was newly found that bone regeneration is further promoted by controlling the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> ± <NUM>. By passage of a high frequency current having such a frequency, it is possible to promote bone regeneration not only in the part where bone defect <NUM> is generated, but also in the part where a root apex lesion is generated similarly. The high frequency current to be passed through the electrode in the bone regeneration mode is preferably a high frequency current of a sinusoidal wave. Of course, the high frequency current to be passed through the electrode in the bone regeneration mode is not necessarily limited to a high frequency current of a sinusoidal wave.

In treatment device <NUM>, besides passage of a high frequency current for promoting bone regeneration (bone regeneration mode), it is also possible to pass a high frequency current to cauterize and sterilize inflammatory factors, bacteria and the like remaining in root canal <NUM> by Joule heat after cutting and enlarging root canal <NUM> with a cutting tool (sterilization mode). Treatment device <NUM> need not achieve perfect sterilization, but only need to heat denature the dental pulp and granulation to necrose or deactivate them by passage of a high frequency current. The treatment of sterilizing inside root canal <NUM> by passage of a high frequency current is also called EMAT (Electro-Magnetic Apical Treatment), and is disclosed, for example, in a literature (for example, <NPL>). This disclosure reports that passage of a high frequency current through the affected part before and after treatment reduces inflammatory factors, bacteria and the like in the site to be treated and results in very excellent prognosis.

Specifically, as shown in <FIG>, treatment device <NUM> includes a unit <NUM> that passes a high frequency current through a file <NUM> which is a cutting tool (see <FIG>), and a file holder <NUM> for holding file <NUM>, and is capable of passing a high frequency current through file <NUM> attached to the tip end of file holder <NUM>. In this disclosure, file <NUM> is attached to the tip end of file holder <NUM>, and this file <NUM> serves as an electrode to be located in a site to be treated, however, file holder <NUM> and file <NUM> may be integrated.

File holder <NUM> is formed by an approximately bar-like casing, and is capable of holding a metallic part of file <NUM>. File holder <NUM> is capable of electrically connecting the file and unit <NUM> by holding the metallic part of file <NUM>. Unit <NUM> is provided with a display unit <NUM> and a setting operation unit <NUM>, and is connected with a foot switch <NUM> and a passive electrode <NUM>.

As shown in <FIG>, unit <NUM> is provided with a high-frequency signal generating circuit <NUM>, a detecting unit <NUM>, a control circuit <NUM>, a root canal length measuring circuit <NUM>, and a switch SW1 to a switch SW2 besides display unit <NUM> and setting operation unit <NUM>.

Setting operation unit <NUM> is a setting button provided to set the operation of treatment device <NUM>. In setting operation unit <NUM>, a current value, a frequency, an energization period of a high frequency current to be passed through file <NUM>, a display setting of display unit <NUM> and the like can be set. Here, the energization period is a time of one passage when energization with high frequency current by one operation is conducted by one-shot, and is a sum of times of plural passages when energization with high frequency current by one operation is divisionally conducted by the plural passages.

Foot switch <NUM> is an operational unit provided for operating passage of high frequency current, and a control signal is transmitted to high-frequency signal generating circuit <NUM> from control circuit <NUM> by being pressed down by a user. High-frequency signal generating circuit <NUM> passes a high frequency current set in setting operation unit <NUM> through file <NUM> according to the received control signal.

High-frequency signal generating circuit <NUM> passes a high frequency current having, for example, a frequency of <NUM> to <NUM> (second range) and a current value of <NUM> mA to <NUM> mA (a range required in a root canal treatment for reducing inflammatory factors, bacteria and the like in a root canal) between file <NUM> and passive electrode <NUM> in the sterilization mode. Also, high-frequency signal generating circuit <NUM> passes a high frequency current having, for example, a frequency of <NUM> to <NUM> (first range) and a current value of <NUM>µA to less than <NUM> mA (a range required in a root canal treatment for promoting bone regeneration in the site where a bone defect is generated in the root canal or in the root apex) between file <NUM> and passive electrode <NUM> in the bone regeneration mode. In high-frequency signal generating circuit <NUM>, the frequency of the high frequency current to be passed through file <NUM> in sterilization mode (second range) is different from the frequency of the high frequency current to be passed through file <NUM> in the bone regeneration mode (first range). Of course, the frequency and the current value of the high frequency current that can be generated in high-frequency signal generating circuit <NUM> are not limited to the frequency and the current value described above.

<FIG> is a chart showing a waveform of a high frequency current in the bone regeneration mode to be passed through the electrode of the treatment device of <FIG>. The chart shown in <FIG> is a conceptual diagram, and the illustrated waveform and wave number are different from the waveform and the wave number of an actual high frequency current. This also applies to the waveform of the high frequency current as follows. The user switches to the bone regeneration mode from the sterilization mode in setting operation unit <NUM>, and operates foot switch <NUM> in the part of bone defect <NUM> which is a site to be treated to cause high-frequency signal generating circuit <NUM> to pass a high frequency current through file <NUM>. The waveform shown in <FIG> is a waveform when high-frequency signal generating circuit <NUM> is driven in the bone regeneration mode, and is a waveform when a high frequency current of a sinusoidal wave having a frequency (for example, <NUM>) and a current value (for example, <NUM> mA) required for promoting bone regeneration is passed through a part of bone defect <NUM>.

The current value, the frequency, the energization period and the like of the high frequency current to be output from high-frequency signal generating circuit <NUM> can be set by operating setting operation unit <NUM>. Control circuit <NUM> controls high-frequency signal generating circuit <NUM> on the basis of the frequency and the current value detected by detecting unit <NUM> so that high-frequency signal generating circuit <NUM> can output the high frequency current having the frequency and the current value set in setting operation unit <NUM>. However, when control circuit <NUM> does not control high-frequency signal generating circuit <NUM> on the basis of the frequency and the current value by detecting unit <NUM>, treatment device <NUM> need not be provided with detecting unit <NUM>. For passage of a high frequency current, file <NUM> is inserted into root canal <NUM>, the tip end of file <NUM> is brought into contact with, for example, a part of bone defect <NUM>, and passive electrode <NUM> is brought into contact with a part of the patient body such as a gingiva <NUM> or a lip <NUM>. File holder <NUM> is a holding unit that holds file <NUM> which is an electrode to be located in a site to be treated, and high-frequency signal generating circuit <NUM> is a power supply unit that passes a high frequency current through the electrode.

Detecting unit <NUM> is a detector that detects a frequency and a current value of a high frequency current actually flowing in file <NUM> when a high frequency current is passed through file <NUM> from high-frequency signal generating circuit <NUM>. Control circuit <NUM> conducts control of a frequency and a current value of a high frequency current to be passed through file <NUM> for high-frequency signal generating circuit <NUM> on the basis of a frequency and a current value detected in detecting unit <NUM>. Control circuit <NUM> is provided with, as a hardware configuration, for example, a CPU (Central Processing Unit), a storage for storing programs, data and the like for executing the processing by the CPU, a RAM (Random Access Memory) functioning as work area of the CPU, a GPU (Graphics Processing Unit) mainly performing image processing, and an I/O interface for keeping the conformance of signals with peripheral equipment. The storage includes a storage unit such as nonvolatile memory provided inside control circuit <NUM>, and a storage unit connected via a network.

Root canal length measuring circuit <NUM> flows a signal for measuring root canal length between file <NUM> and passive electrode <NUM> to measure a position of the tip end of file <NUM>. Specifically, root canal length measuring circuit <NUM> applies two voltages having different frequencies between file <NUM> and passive electrode <NUM> to determine respective values of impedance, and identifies the position of the tip end of file <NUM> from root apex <NUM> according to a difference, a ratio or the like between these two values (actually values of voltage or current corresponding to the values of impedance). The measuring method of root canal length measurement is not limited to that described above, but various techniques including conventionally proposed measuring methods can be utilized. Also, in root canal length measurement, passive electrode <NUM> is brought into contact with a part of the patient body such as gingiva <NUM> or lip <NUM>.

Switch SW1 is provided to switch the electric connection between file <NUM>, and high-frequency signal generating circuit <NUM> or root canal length measuring circuit <NUM>. Also, switch SW2 is provided to switch the electric connection between passive electrode <NUM>, and high-frequency signal generating circuit <NUM> or root canal length measuring circuit <NUM>.

Switching between switch SW1 and switch SW2 is realized by control circuit <NUM> on the basis of input information from setting operation unit <NUM>. Specifically, control circuit <NUM> controls switch SW1 and switch SW2 such that file <NUM> and passive electrode <NUM> are connected with high-frequency signal generating circuit <NUM> when a high frequency current is passed through file <NUM>. Also, control circuit <NUM> controls switch SW1 and switch SW2 such that file <NUM> and passive electrode <NUM> are connected with root canal length measuring circuit <NUM> when a signal for root canal length measurement is flown between file <NUM> and passive electrode <NUM>. Here, switch SW1 and switch SW2 are controlled in accordance with the operation mode set in setting operation unit <NUM> to switch the connecting destinations of file <NUM> and passive electrode <NUM>. Switching between switch SW1 and switch SW2 may be linked with ON/OFF operation of foot switch <NUM>.

Here, high-frequency signal generating circuit <NUM> and root canal length measuring circuit <NUM> are electrically separated by switch SW1 and switch SW2. Therefore, while a high frequency current is output to file <NUM>, root canal length measuring circuit <NUM> is electrically disconnected from file <NUM> and passive electrode <NUM> by switch SW1 and switch SW2. Therefore, a high frequency current is not passed through root canal length measuring circuit <NUM>, and it is possible to prevent root canal length measuring circuit <NUM> from breaking by a high frequency current.

Also, it is possible to know where the tip end position of file <NUM> is located from the root apex by root canal length measuring circuit <NUM>. Therefore, the user is capable of switching from the root canal length measuring mode to the high-frequency energization mode by operating setting operation unit <NUM> after confirming that the tip end position of file <NUM> in the root canal has reached a position where the high frequency current is to be passed (for example, the part where bone defect <NUM> or a root apex lesion is generated) by root canal length measuring circuit <NUM>. Therefore, in treatment device <NUM>, it is possible to pass a high frequency current through file <NUM> while the tip end position of file <NUM> is kept at an appropriate position. Of course, treatment device <NUM> may be configured only to pass a high frequency current through file <NUM> without provision of root canal length measuring circuit <NUM>, and a high frequency current may be passed through file <NUM> while the tip end position of file <NUM> is confirmed with other root canal length measuring device.

Display unit <NUM> is configured, for example, by a liquid crystal display, and displays a current value being passed through file <NUM> by high-frequency signal generating circuit <NUM>, a position of the tip end of file <NUM> measured by root canal length measuring circuit <NUM>, and so on, and functions as an alarm unit that notifies necessary information of a user of treatment device <NUM>. Display unit <NUM> may notify, for example, of information that the frequency and the current value of the high frequency current being passed are out of the ranges of the frequency and the current value required for the root canal treatment when the frequency and the current value detected by the detecting unit <NUM> become out of the set ranges of frequency and current value. Display unit <NUM> may be configured by an organic EL display, electronic paper, a light-emitting diode or the like. The alarm unit may be a lamp or a speaker (not shown) besides display unit <NUM>, and may notify the user by lightening of the lamp, or may notify the user by outputting buzzer sound from the speaker.

Treatment device <NUM> controls the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> to <NUM> for promoting bone regeneration in the part where bone defect <NUM> or a root apex lesion is generated. More preferably, treatment device <NUM> controls the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> ± <NUM>. Promotion of bone regeneration caused by passing the high frequency current having such a frequency through the site to be treated is specifically described. <FIG> is a view for illustrating an experiment in which bone regeneration is conducted with the treatment device <NUM>. <FIG> is a view showing an experimental result of the experiment of regenerating bone conducted in <FIG>.

In the experiment shown in <FIG>, the experiment was conducted using a rat skull instead of a human tooth. In this experiment, the scalp of a rat m shown in <FIG> is incised to expose part of the skull P, and a bone defect 905a is prepared in the exposed skull P at one site on the left of rat m with a trephine bar of <NUM> in outside diameter. A high frequency current is passed through prepared bone defect 905a with treatment device <NUM>. Specifically, treatment device <NUM> passes a high frequency current through an electrode 11a from high-frequency signal generating circuit <NUM> in the condition that electrode 11a held by file holder <NUM> is located in an appropriately center part of bone defect 905a, and passive electrode <NUM> is stuck in the skin near the left ear of rat m. In this experiment, a needle instead of file <NUM> was used as electrode 11a.

A plurality of prepared rats m were subjected to the experiment while being divided into the following groups: rats m1 through which a high frequency current of <NUM> is passed; rats m2 through which a high frequency current of <NUM> is passed, rats m3 through which a high frequency current of <NUM> is passed, and rats m0 (control group) through which a high frequency current is not passed. For each rat m, passage of a high frequency current is conducted predetermined times at predetermined intervals. From the day on which electrode 11a was attached, the incised scalp was returned, and electrode 11a was stuck in the scalp of the approximately center part of bone defect 905a and a high frequency current was passed. The current value of the high frequency current to be passed was <NUM> mA.

The graph of <FIG> shows the result of the experiment shown in <FIG>. The vertical axis of the graph indicates hard tissue formation rate. Letting an area of prepared bone defect 905a be A, and a defective area after passage of a high frequency current predetermined times be DA, a hard tissue formation rate can be defined as (A-DA)/A. The hard tissue formation rate is an equivalent value of a bone regeneration rate. For measurement of defective area DA, a µCT device was used.

As in the graph of <FIG>, rats m1 (sample number n = <NUM>) through which a high frequency current of <NUM> was passed showed a hard tissue formation rate within a range of about <NUM>% to about <NUM>% with a median value of about <NUM>%. Rats m2 (sample number n = <NUM>) through which a high frequency current of <NUM> was passed showed a hard tissue formation rate within a range of about <NUM>% to about <NUM>% with a median value of about <NUM>%. Rats m3 (sample number n = <NUM>) through which a high frequency current of <NUM> was passed showed a hard tissue formation rate within a range of about <NUM>% to about <NUM>% with a median value of about <NUM>%. Rats m0 (control group) (sample number n = <NUM> through which a high frequency current was not passed showed a hard tissue formation rate within a range of about <NUM>% to about <NUM>% with a median value of about <NUM>%. A median value is indicated by a lateral bar in the graph of <FIG>.

As is apparent from the experimental result shown in <FIG>, by passing a high frequency current having a frequency ranging from <NUM> to <NUM> through the electrode, the hard tissue formation rate (= bone regeneration rate) is increased in comparison with the case where a high frequency current is not passed. It is found that the hard tissue formation rate is most increased especially by passing a high frequency current having a frequency of <NUM> through the electrode. In other words, the frequency most contributing to bone regeneration among the frequencies of high frequency current to be passed through the electrode is <NUM>.

Here, when the frequency varies from <NUM> to <NUM>, the hard tissue formation rate (median value) varies from about <NUM>% to about <NUM>%. Assuming that the relationship between the hard tissue formation rate and the frequency linearly changes, a variation of <NUM> in the frequency will result in a decrease of about <NUM>% in the hard tissue formation rate (median value). This indicates that the frequency can be controlled to the range of <NUM> ± <NUM> so as to ensure the hard tissue formation rate (median value) of greater than or equal to about <NUM>%.

In the treatment device <NUM>, since a high frequency current having a frequency within a range of <NUM> to <NUM> is used in the sterilization mode, it is preferred to control the frequency used in the bone regeneration mode to fall within a range of <NUM> to <NUM>.

As described above, the treatment device <NUM> includes file holder <NUM> that holds file <NUM> to be located in a site to be treated (for example, bone defect <NUM> or the like), high-frequency signal generating circuit <NUM> that passes a high frequency current through file <NUM>, and control circuit <NUM> that controls a frequency of a high frequency current to be passed through file <NUM> from high-frequency signal generating circuit <NUM>. Control circuit <NUM> controls the frequency of the high frequency current to be passed through file <NUM> to fall within a range of <NUM> to <NUM>. Preferably, the frequency of the high frequency current is controlled to fall within a range of <NUM> ± <NUM>.

In the treatment device <NUM> configured as described above, since the control circuit <NUM> controls the frequency of the high frequency current to be passed through the electrode to fall within a range of <NUM> to <NUM> (preferably, a range of <NUM> ± <NUM>), it is possible to promote bone regeneration and shorten the period until healing is determined even when a bone defect or a root apex lesion is generated in the apical area.

In the treatment device <NUM> described above a high frequency current passes through file <NUM> in the site to be treated while the user switches between the sterilization mode and the bone regeneration mode. It is, however, also possible that the treatment device operates first in the sterilization mode of sterilizing a root canal, and then automatically switches the mode and operates in the bone regeneration mode for promoting bone regeneration. Also in this case, the configuration of the treatment device <NUM> described above is employed, and the same constituent is denoted by the same reference numeral, and detailed description thereof is not repeated.

<FIG> is a chart showing a waveform of a high frequency current to be passed through an electrode of the treatment device <NUM> in this case. A user determines the position where a high frequency current is to be passed on the basis of root canal length measuring circuit <NUM>, and passes the high frequency current through file <NUM> from high-frequency signal generating circuit <NUM> by operating foot switch <NUM> at this energization position. The treatment device <NUM> operates first in the sterilization mode of sterilizing a root canal as a high-frequency energization mode.

In the operation in the sterilization mode, before actual passage of a high frequency current through file <NUM> from high-frequency signal generating circuit <NUM>, a high frequency current is preliminarily passed through file <NUM>. The energization in a preliminary period (PP) shown in <FIG> is preliminary energization, and actual energization is conducted in the following first period (TP1). In the energization of the first period, a high frequency current having a current value (for example, <NUM> mA to <NUM> mA) in the range of current value required for a root canal treatment for reducing inflammatory factors, bacteria and the like in a root canal is passed. In the energization of the preliminary period, by passing a current value that is smaller than the minimum current value (for example, <NUM> mA) of current values within the range of current value required for the root canal treatment as a preliminary current, pain or the like in the energization of the preliminary period can be mitigated. In the preliminary period and in the first period, a high frequency current having a frequency within a range of <NUM> to <NUM> (second range) is passed.

High-frequency signal generating circuit <NUM> includes a constant voltage circuit, and passes a high frequency current through file <NUM> by constant voltage control. Therefore, by applying, in the preliminary period, a high-frequency voltage that is lower than the high-frequency voltage to be applied in the first period, high-frequency signal generating circuit <NUM> can pass, in the preliminary period, a current value that is smaller than the current value to be passed in the first period. High-frequency signal generating circuit <NUM> may be configured by a constant current circuit, and may pass a high frequency current through file <NUM> by constant current control.

Control circuit <NUM> controls so that the current value of the high frequency current to be flown to file <NUM> from high-frequency signal generating circuit <NUM> in energization of the first period falls within a predetermined range, on the basis of the current value detected by detecting unit <NUM> when the preliminary current is flown to file <NUM>. In accordance with the difference or ratio between the assumed current value of preliminary current and the current value detected by detecting unit <NUM>, control circuit <NUM> changes the optimum voltage with which the current value of the high frequency current to be flown in file <NUM> falls within the predetermined range, and applies the voltage to high-frequency signal generating circuit <NUM>. That is, control circuit <NUM> optimizes the voltage to be applied to high-frequency signal generating circuit <NUM> so that the current value of the high frequency current to be flown in file <NUM> falls within the predetermined range. The current value of the high frequency current to be flown in file <NUM> is not limited to the current value required for a root canal treatment for reducing inflammatory factors, bacteria and the like in a root canal. In the above description, control circuit <NUM> compares the current value of the preliminary current and the current value detected by detecting unit <NUM> by difference, however, the comparison may be conducted by other comparing means such as ratio or the like.

High-frequency signal generating circuit <NUM> conducts energization of, for example, <NUM> seconds (<NUM>) as the preliminary period, followed by a rest period (TC) of, for example, <NUM> seconds (<NUM>), and conducts energization of, for example, <NUM> seconds (<NUM>) as the first period. High-frequency signal generating circuit <NUM> repeats the period of the first period and the rest period (total <NUM> second (<NUM>) N times (for example, <NUM> times) for one energization (for example, one operation of foot switch <NUM>). In treatment device <NUM>, as the user presses down foot switch <NUM> once, a high frequency current is passed through file <NUM> from high-frequency signal generating circuit <NUM> for about <NUM> second (including the rest period). The number of repetitions of control of the rest period and the first period can be set in advance in setting operation unit <NUM> by the user, and is set, for example, to <NUM>. Of course, the number of repetitions of control of the rest period and the first period may be set to a value other than <NUM>. Also, in setting operation unit <NUM>, an energization period (for example, <NUM> second) may be set rather than setting the number of repetitions of control of the rest period and the first period.

Next, treatment device <NUM> operates in the sterilization mode, and then operates in the bone regeneration mode. In the bone regeneration mode, a high frequency current having a frequency of <NUM> to <NUM> (first range) that is different from the frequency of the high frequency current passed in the sterilization mode (second range) is passed. Also, in the bone regeneration mode, a high frequency current having a smaller current value (for example, <NUM>µA to less than <NUM> mA) compared with the current value (for example, <NUM> mA to <NUM> mA) of the high frequency current passed in the sterilization mode is passed through file <NUM>. Energization of the second period (TP2) shown in <FIG> is energization in the bone regeneration mode. In <FIG>, while the length of the second period is described as being shorter than the length of the first period, the second period may be a length of about several seconds to about <NUM> seconds. Also, control circuit <NUM> may determine the voltage to be applied by high-frequency signal generating circuit <NUM> such that the current value of the high frequency current to be flown into file <NUM> from high-frequency signal generating circuit <NUM> in energization of the second period is a tiny current value on the basis of the current value detected by detecting unit <NUM> when the preliminary current is flown into file <NUM>.

Next, control of the high frequency mode to be passed through file <NUM> in treatment device <NUM> is described by using a flowchart. <FIG> is a flowchart for illustrating control of the treatment device. First, a user determines the position (site to be treated) where a high frequency current is to be passed on the basis of root canal length measuring circuit <NUM>, and operates treatment device <NUM> in the high frequency mode by operating foot switch <NUM> at this energization position. Control circuit <NUM> determines whether or not the energization period is the second period (step S10). When the energization period is not the second period (NO in step S10), control circuit <NUM> determines that the energization period is the first period and the operation mode is the sterilization mode, and notifies display unit <NUM> of information of executing the sterilization mode (step S11). Control circuit <NUM> displays the operation mode to be executed in step S11, and passes a high frequency current in the sterilization mode shown in <FIG> through file <NUM> (step S12).

Control circuit <NUM> determines whether or not the energization period is the first period (including the preliminary period and the rest period) (step S13). When the energization period is the first period (Yes in step S13), control circuit <NUM> returns the process to step S12, and passes a high frequency current in the sterilization mode through file <NUM>. Meanwhile, when the energization period is not the first period (NO in step S13), control circuit <NUM> determines that the energization period is the second period and the operation mode is the bone regeneration mode, and notifies display unit <NUM> of information of executing the bone regeneration mode (step S14). When the energization period is the second period (Yes in step S10), control circuit <NUM> advances the process to step S14.

Control circuit <NUM> displays the operation mode to be executed in step S14, and passes a high frequency current in the bone regeneration mode shown in <FIG> through file <NUM> (step S15). Here, the frequency and the current value to be passed in the bone regeneration mode are set values determined in advance, and can be set by a user with setting operation unit <NUM> or the like.

In order to promote bone regeneration, it is required that the frequency and the current value of the high frequency current to be passed through file <NUM> in the second period conform to the set values. Here, the set values are, for example, a value of frequency ranging from <NUM> to <NUM> (first range), and a value of current value ranging from <NUM>µA to less than <NUM> mA. Here, control circuit <NUM> determines whether or not the frequency and the current value detected by detecting unit <NUM> conform to the set values (step S16). When the frequency and the current value detected by detecting unit <NUM> do not conform to the set values (NO in step S16), control circuit <NUM> controls high-frequency signal generating circuit <NUM> to adjust the frequency and the current value of the high frequency current to be passed through file <NUM> to conform to the set values (step S17). Control circuit <NUM> adjusts the high frequency current to be passed in step S17, and then returns the process to step S16 to perform feedback control. Control circuit <NUM>, when feedback controlling the frequency and the current value of the high frequency current, may control display unit <NUM> to display that the frequency and the current become out of the above ranges when the frequency and the current value detected by detecting unit <NUM> vary to become out of the above ranges.

When the frequency and the current value detected by detecting unit <NUM> approximately conform to the set values (YES in step S16), control circuit <NUM> determines whether or not the second period has elapsed in the energization period (step S18). When the second period has not elapsed in the energization period (NO in step S18), control circuit <NUM> returns the process to step S15. On the other hand, when the second period has elapsed in the energization period (YES in S18), control circuit <NUM> ends the operation in the high frequency mode.

As described above, the treatment device <NUM> divides the one energization period in which control circuit <NUM> passes a high frequency current through file <NUM> into a plurality of periods, and the energization period includes the first period of passing a high frequency current having a frequency controlled to fall within the second range of <NUM> to <NUM> through file <NUM>, and the second period of passing a high frequency current having a frequency controlled to fall within the first range of <NUM> to <NUM> through file <NUM>. As a result, treatment device <NUM> can automatically switch the mode and operate in the bone regeneration mode of promoting bone regeneration after operating in the sterilization mode.

Claim 1:
A treatment device (<NUM>) that is configured to pass a high frequency current through a bone defect (<NUM>) generated in a root canal treatment, (<NUM>), the treatment device (<NUM>) comprising:
a holder (<NUM>) that holds an electrode (<NUM>) to be located at the bone defect (<NUM>);
a power supply unit (<NUM>) that is configured to pass a high frequency current through the electrode (<NUM>); and
a controller (<NUM>) that is configured to control a frequency of the high frequency current to be passed through the electrode (<NUM>) from the power supply unit (<NUM>),
the controller (<NUM>) controlling the frequency of the high frequency current to be passed through the electrode (<NUM>) to fall within a range of <NUM> to <NUM>; wherein
the high frequency current is configured to promote bone regeneration in the bone defect (<NUM>).