JP5908837B2 - Method of operating laser apparatus for irradiating living hard tissue with laser, and method for producing acid-resistant living hard tissue - Google Patents

Description

The present invention relates to a method of operating a laser device for irradiating a laser to a biological hard tissue comprising an inorganic crystalline hydroxyapatite.
The present invention also relates to a method for producing an acid-resistant biological hard tissue by generating an acid-resistant participating substance in a biological hard tissue containing inorganic crystalline hydroxyapatite .

Laser has made it possible to irradiate even minute parts due to recent advances in optical fibers and other technologies. In vivo organs such as blood vessels irradiated with laser are instantly transcribed by the high energy of the laser, Since the cut end is blocked by heat coagulation, there is almost no bleeding, so-called bloodless surgery can be performed, and pathogens such as bacteria are also killed. Successful brain tumor surgery has been reported, and successful cases have been reported. In addition, surgery for laryngeal cancer, esophageal cancer, etc., which required long-term treatment, has a great merit that it can be discharged on the same day.
In dentistry, electric drills are conventionally used for the treatment of caries, etc., accompanied by intense pain and unpleasant high frequency sound and vibration, and people are hesitant to treat it, but laser treatment is In addition to such pain, noise, and vibration, it can be treated with little bleeding and has a bactericidal effect. Lasers, which are said to be “controlling the laser in the 21st century, control the medical treatment”, include the treatment of periodontal disease, cavity formation, caries (cutting) cutting, temporomandibular arthritis It has also been applied to various fields of dental clinical fields such as treatment and laser welding of prosthetics. In 2006, it was possible to apply insurance as an advanced medical technology.

  Mutans bacteria in a wide variety of bacteria living in the oral cavity adhere to the surface of the teeth, fermenting the “sucrose” in the eaten food to produce acid, and this acid gradually dissolves the teeth. Cavities occur. Fluorine was first discovered to show a caries prevention effect. This is a process of investigating dysplastic enamel called mottled teeth, where there are few caries in areas where mottled teeth are generated, and because the drinking water in those areas contains fluorine, It was found that there was a caries prevention effect. Attempts to prevent tooth decay by adding fluorine to tap water have been carried out all over the world, including the United States, Europe, Korea, and China. However, the optimum fluorine concentration is 1 ppm, and if it is higher (1.5 to 2 ppm), the frequency of becoming a group of teeth gradually increases, and further harmful effects occur due to the onset of osteosclerosis and osteosarcoma. Many reports have been issued. In 1965, with the promotion of WHO, fluoride was added to tap water in 40-60 countries at one time, but now it is reduced to 18 countries. In Japan, there is an opposition from civil society, and fluorine is not added to tap water. In addition, a fisher sealant that covers the fissures of the molars, which are sites of tooth decay, with resin or the like, and sugars such as xylitol and sorbitol in place of sucrose that induces caries are used for caries prevention.

The US (UCLA) Stern showed the possibility of dental caries prevention using a laser (see Non-Patent Document 1). In 1964, he discovered that a human extracted tooth was irradiated with a ruby laser, and that the irradiated site became difficult to dissolve even when immersed in an acidic solution. The application of acid resistance by laser has been confirmed by many researchers, and applied research for caries prevention has been carried out, but 1) laser irradiation for acid resistance given to laser-irradiated teeth The theory that physical (morphological) changes such as melting caused by teeth block the penetration of an acid solution by the 2) tooth crystal (inorganic crystals HAP: hydroxyapatite; Ca ₁₀ (PO ₄ ) ₆ (OH) by laser _It has been over 40 years since two contradicting theories that ₂ ) changed the chemical composition and become insoluble in acid have been submitted, but it remains unsolved, and the change in chemical composition is also inorganic. It is not explicitly specified how the crystalline HAP changes. In addition, when laser is applied to living body hard tissues such as teeth, how high the teeth will be and how the structure / composition of inorganic crystals HAP, which is the main component of teeth and bones, will change The basic theory is not established. Therefore, it seems that the dentist who performs laser treatment cannot give a detailed explanation that is convincing to the patient side, and the patient side is not in a sufficient consensus.
In addition, many of the existing hard tissue materials, including dental materials, medical materials, biomaterials, etc., are mixed with inorganic crystal HAP, but since inorganic crystal HAP is easily soluble in acidic solutions, It is desirable to develop materials that can cope with acid produced by bacteria living in the oral cavity and body fluid environments that change from basic to acidic due to inflammation of body diseases.

As a result of tackling this problem, the present inventors invented a method for identifying acid-resistant substances in living hard tissues and a method for investigating the heating status of living hard tissues by laser irradiation, and conducted evaluation and analysis using this method. It is Nd: YAG laser that can give acid resistance in a wide range, followed by CO ₂ laser, and Er: YAG laser that has been mainly used for cutting teeth and caries parts so far In addition, it was confirmed that a denatured region was present in a layer along the crater that draws a parabola and a wall portion of the crater, and the region exhibited acid resistance. Furthermore, these lasers are irradiated to a living hard tissue containing inorganic crystal HAP, and the living hard tissue is applied to the inside and / or surface of the living hard tissue as calcium acid pyrophosphate (PYR) and calcium metaphosphate. It was estimated that an acid-resistant biohard tissue can be produced by heating to a temperature of 1000 ° C. or higher where both (MET) are generated and 1500 ° C. or lower where melting does not occur (see Patent Document 1). .

JP 2007-332054 A

Stern R.M. H. : Laser beam on dental hard tissues. J. et al. D. Res. 43: 873, 1964

However, although the conventional lasers as described above are effective for imparting acid resistance to living hard tissues such as tooth strengthening treatment (prevention of dental caries) using these, the laser output is large, There was a problem that the amount of heat given to the tissue and surrounding tissues was large. In addition, there is a problem that the laser device is large and difficult to handle, and is expensive.
In addition, using these conventional lasers, a laser can be used to impart acid resistance to biological hard tissues including dental materials, medical materials, biomaterials, and the like including inorganic crystal HAP, and to produce acid resistant biological hard tissues. However, there was a problem that it was difficult to handle with high output and the production efficiency was low .

The present invention solves the above-mentioned problems of the prior art, and its purpose is to provide a low-power laser with a small amount of heat applied to the biological hard tissue and surrounding tissues, and to impart acid resistance to the biological hard tissue. It is an object of the present invention to provide a method for operating a laser device that is small, easy to handle, and inexpensive.
It is a further object of the present invention to provide a method for producing acid-resistant biohard tissue that is easy to handle and efficiently using a low-power laser and can impart acid resistance to the hard tissue .

In order to solve the above problems, the present invention provides a laser device for irradiating a living hard tissue containing inorganic crystalline hydroxyapatite with a laser, and an emitter that emits the laser, and one end connected to the emitter. In the operating method of the apparatus having a light guide means for guiding the laser at the other end, and an irradiator for irradiating the object with the laser connected to the other end of the light guide means, the wavelength of the laser is in 810 nm ± 20 nm, the output is equal to or less than 1.2 W, the power density of 0.8 W / cm ² or more 12.0 W / cm ² or less, and the energy density of 1.7 J / cm ² or more 50.0J / cm ² It is an operation method characterized by controlling irradiation of the laser from the irradiator so as to be as follows.
By adopting such an operating method, it is possible to reduce the amount of heat applied to the living hard tissue and its surrounding tissues, and to generate an acid-resistant substance in the living hard tissue.
The reason why the laser irradiation conditions are as described above is that when the output exceeds 1.2 W, the amount of heat given to the surrounding tissue on the laser irradiated surface is too large and the power density exceeds 12.0 W / cm ² , or When the energy density exceeds 50.0J / cm ^2, the amount of heat too large to be applied to the surface which is irradiated with the laser, or the power density is less than 0.8 W / cm ^2, or energy density of less than 1.7 J / cm ² This is because the acid-resistant substances are not sufficiently produced in the living hard tissue.

In the present invention, the power density and energy density refer to the power density and energy density on the irradiated surface of the laser.
In the present invention, “biological hard tissue” includes human and animal teeth and bones, dental materials, medical materials, biomaterials, and the like.

When the living hard tissue is a permanent tooth,
The wavelength of the laser is 810 nm ± 20 nm, the output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 6.54 J / cm ² or more 43 It is preferable to control the irradiation of the laser from the irradiator so as to be .56 J / cm ² or less.
When the hard tissue is a deciduous tooth,
The wavelength of the laser is 810 nm ± 20 nm, the output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.64 W / cm ² or less, and the energy density is 2.12 J / cm ² or more and 21. It is preferable to control the laser irradiation from the irradiator so as to be .28 J / cm ² or less.

Further, the present invention produces an acid-resistant biological hard tissue containing an inorganic crystalline hydroxyapatite in a biological hard tissue excluding the human body to produce an acid-resistant biological hard tissue, and has a wavelength of 810 nm ± 20 nm and an output of 1. 0W below, the power density is 1.09W / cm ² or more 10.89W / cm ² or less, and the laser energy density of 6.54J / cm ² or more 43.56J / cm ² or less biological hard tissue It is the manufacturing method of the acid-resistant biological hard tissue characterized by irradiating to.
By adopting such a method, it is possible to efficiently generate an acid-resistant participating substance in a living hard tissue using a low-power and easy-to-handle laser.

According to the operation method of the laser apparatus for irradiating a living body hard tissue containing inorganic crystalline hydroxyapatite of the present invention with a laser, a small and inexpensive laser apparatus is used, and the amount of heat given to the living body hard tissue and surrounding tissues is small. In addition, it is possible to provide a method for operating a laser device that can generate an acid-resistant substance in a living hard tissue.

  Moreover, according to the method for producing acid-resistant biological hard tissue of the present invention, it is possible to provide a method for efficiently generating an acid-resistant participating substance in the biological hard tissue by using a low-power and easy-to-handle laser.

It is a drawing substitute photograph which shows the SEM image of the surface of the permanent tooth irradiated with the laser by 3W (4 sec). It is a drawing substitute photograph which shows the SEM image of the surface of the permanent tooth irradiated with the laser by 1W (4 sec). It is a drawing substitute photograph which shows the SEM image of the surface of the permanent tooth irradiated with the laser at 0.3 W (4 sec). It is a drawing substitute photograph which shows the SEM image of the surface of the permanent tooth irradiated with laser by 0.1 W (6 sec). (A) And (b) is a drawing substitute photograph which shows the polarizing microscope image before immersion in the acidic solution of the permanent tooth of laser non-irradiation and 6 hours after immersion, respectively. (A), (b), and (c) are drawing-substituting photographs showing polarized microscope images before, 23 hours and 27 hours after immersion in an acidic solution of a permanent tooth laser-irradiated with 1 W (4 sec), respectively. It is. (A) And (b) is a drawing-substituting photograph showing polarization microscope images before and 10 hours after immersion in an acidic solution of a permanent tooth irradiated with laser at 0.3 W (4 sec), respectively. (A) And (b) is a drawing-substituting photograph showing polarization microscope images before and 7 hours after immersion in an acidic solution of permanent teeth laser-irradiated at 0.1 W (6 sec), respectively. It is a relationship diagram which shows the X-ray-diffraction pattern and qualitative-analysis result example of a permanent tooth without a laser irradiation. It is a relationship diagram which shows the X-ray-diffraction pattern of a permanent tooth irradiated with a laser at 3 W (4 sec), and the example of a qualitative analysis result. (A) And (b) is a relationship diagram which shows the X-ray-diffraction pattern and the example of a qualitative analysis result of the permanent tooth laser-irradiated by 1 W (4 sec) before and after immersion in an acidic solution, respectively. (A) And (b) is a relationship diagram which shows the example of the X-ray-diffraction pattern and qualitative analysis result of the permanent tooth laser-irradiated by 0.3 W (4 sec) before and after immersion in an acidic solution, respectively. (C) is the relationship diagram which shows the detailed example of a detailed qualitative analysis which expanded FIG.12 (b). (A) And (b) is a relationship diagram which respectively shows the X-ray-diffraction pattern and qualitative analysis result example of the permanent tooth laser-irradiated by 0.1 W (6 sec) before immersion in an acidic solution and after immersion. . It is a relationship diagram which shows the X-ray-diffraction pattern of the powder of the permanent tooth heated to 300 degreeC, and the example of a qualitative analysis result. (A) And (b) is the drawing substitute photograph which shows the polarizing microscope image after immersion for 5 hours, respectively before immersion to the acidic solution of the deciduous tooth laser-irradiated with 0.1 W (2 sec). (A) And (b) is a relationship diagram which shows the X-ray-diffraction pattern and qualitative analysis result example of the deciduous tooth laser-irradiated at 0.1 W (2 sec) before and after immersion in an acidic solution, respectively. . It is a block diagram of embodiment of the laser apparatus according to this invention.

First, the present inventors tried to elucidate the mechanism by which acid resistance is imparted to human permanent teeth by laser irradiation as follows.
Using SEM (scanning electron microscope), the surface of the tooth irradiated with laser was observed. Next, the laser irradiation sample is embedded in a polyester-based resin, and after the resin is solidified, it is longitudinally cut to a thickness of about 200 to 300 μm using a diamond cutter so that the laser irradiation portion is included. The longitudinal sample was polished with a grindstone under running water until the thickness became about 100 to 150 μm, and this was used as an analysis sample.
First, the sliced sample of the laser irradiated sample before being immersed in the acidic solution was observed using a polarizing microscope, and the analysis position was confirmed. Next, the substance was identified by qualitative analysis by a micro X-ray diffraction method. The sample was immersed in an acidic solution (2% lactic acid solution, pH 2.1), and the state of dissolution was observed with a polarizing microscope. Qualitative analysis was performed on the portion that remained without being dissolved with a micro X-ray diffractometer to identify the substance. The analysis results before and after being immersed in an acidic solution were compared, and substances involved in imparting acid resistance were identified.
Laser type and irradiation conditions: Semiconductor laser (OSL-3000, Nagata Electric Co., Ltd .: continuous wave, λ = 810 nm ± 20 nm, fiber diameter; 600 μm, fiber NA (aperture angle): 0.43 (angle 25. 2 °), distance from fiber tip to sample; 0.3 mm, irradiation conditions; 4 and 6 sec irradiation at 3 W, 2 W, 1 W, 0.5 W, 0.3 W, 0.2 W and 0.1 W). Table 1 shows the power density and energy density on the laser irradiated surface in the low output region.

SEM (scanning electron microscope); TM3000 (Hitachi), acceleration voltage 5-15 kV.
X-ray diffractometer and measurement conditions: micro X-ray diffractometer; PSPC / MDG (Rigaku Electric Co., Ltd.), collimator diameter: 100 μm, output: 50 kV, 200 mA. Angle measurement range: 5 to 80 °.
Immersion acidic solution: lactic acid solution (2% lactic acid solution, pH = 2.1), and the state of dissolution was observed with a polarizing microscope.
The laser irradiated teeth were observed with an SEM (scanning electron microscope). FIG. 1 shows a tooth surface (× 2000) irradiated with 3 W (4 sec). The center of the laser is recessed (that is, a part of the tissue is lost), the enamel is dissolved in the periphery, and the black round structure is equivalent to the enamel trabeculae from which the organic matter has been evaporated by the laser. I think that the. FIG. 2 shows a tooth surface (× 2000) irradiated with 1 W (4 sec). A laser-irradiated portion that has turned white into a circular shape different from the peripheral portion is observed, and a black circular structure corresponding to the enamel trabeculae is also observed. FIG. 3 shows a tooth surface (× 2000) irradiated with 0.3 W (4 sec). Compared with healthy teeth, the surface has a smooth structure, and the black circular structure seems to have changed enamel trabeculae. FIG. 4 shows a tooth surface (× 2000) irradiated with 0.1 W (6 sec). It can be seen that the tooth surface is smooth and the black structure corresponding to the enamel trabecula is even finer.
Observation with a polarizing microscope reveals that the laser-irradiated teeth exhibit a distinctly different interference color from normal teeth (see FIGS. 5-8). This is because the inorganic crystal HAP, which is the main component of the tooth, has a high-temperature phase such as α-TCP, β-TCP, PYR (calcium pyrophosphate: Ca ₂ P ₂ O ₇ ), MET (calcium metaphosphate: Ca It has been found that this is due to modification to a quasi-high temperature phase such as (PO ₃ ) ₂ ). FIG. 5A shows healthy teeth that are not irradiated with a laser, and a Hunter Schlegel shape, a parallel shape, and the like are observed. FIG. 7A shows a tooth irradiated with 0.3 W (4 sec), and a yellow denatured layer is observed in a region extending from the surface of the enamel irradiated with the laser to the intermediate portion. FIG. 8A shows a tooth irradiated with 0.1 W (6 sec), and a denatured layer having a yellowish brown color is observed in a region extending from the surface of the enamel irradiated with the laser to the middle portion.

(Theoretical swaying that provides acid resistance to laser-irradiated teeth)
It was discovered in 1964 by Stern in the United States (UCLA) that acid resistance was imparted to laser-irradiated teeth. The reasons for this are as follows: Two conflicting theories have been submitted: the theory that morphological changes block the penetration of acid solutions, and (2) the theory that laser crystals change the chemical composition and become insoluble in acids. Although it has passed through the above, it remains unsolved, and it has not been clarified in detail how the inorganic crystal HAP changes with respect to the chemical composition change. Many craters and cracks are generated on the tooth surface by irradiation with various conventional lasers (CO ₂ , Nd: YAG, Er: YAG, etc.) that have been performed so far, so that the penetration of the acidic solution can be blocked. It is clear that these cannot prevent the penetration of the solution, not the surface structure. Further, it has been found that the main component inorganic crystal HAP of teeth is denatured into α-TCP that is a high-temperature phase and β-TCP, PYR, MET, and the like that are quasi-high-temperature phases by the energy of the laser to be irradiated. Among these, α-TCP and β-TCP are known to be more soluble in acid than inorganic crystal HAP. Therefore, among the modified materials other than these, materials showing acid resistance are searched. Among them, PYR is noted. PYR is soluble in acid, but P ₂ O ₇ anion has affinity adsorptivity on the surface of inorganic crystal HAP crystal and blocks the dissolution of inorganic crystal HAP crystal. It is known to suppress. The other is MET. Since this MET has a long chain structure represented by {Ca (PO ₃ ) ₂ } _n and is hardly soluble in acids, acid resistance is imparted to the formation of this MET at the laser irradiation site. Is considered to be the main factor. In order to demonstrate this, as described below, the laser-irradiated teeth were immersed in an acidic solution (2% lactic acid solution, pH 2.1), and the progress thereof was observed with a polarizing microscope to identify substances that remained undissolved. A method was adopted in which a substance showing acid resistance was identified by comparing the substance identified before immersion with the remaining substance.

(Low power: Demonstration that acid resistance is imparted to teeth by irradiation of 1W or less)
In the standard sample not subjected to laser irradiation, the enamel completely dissolved and disappeared 6 hours after immersion (FIG. 5b). On the other hand, teeth irradiated with low power (1 W, 0.3 W, 0.1 W) used for pain relief, dentine hypersensitivity, and the like are shown in FIGS. 6 (a, b, c) and 7 b. And as shown to FIG. 8b, even if 7 hours passed, it remained without melt | dissolving and it was proved that these teeth were provided with acid resistance. As shown below, the degree of acid resistance was naturally higher even at low output as described below. 1 W (4 sec) irradiated sample; after 10 hours of immersion, the tooth neck begins to dissolve (Fig. 6a), and after 23 hours of immersion, the enamel deep layer is dissolved, but from the laser irradiated surface to the middle part The remaining region remains undissolved (FIG. 6b), and even after elapse of 27 hours after immersion, a part of the enamel irradiated with the laser remains undissolved (FIG. 6c). 0.3 W (4 sec) irradiated sample; after 10 hours of immersion, the enamel deep layer close to the dentin was lost, but the region from the laser-enameled enamel surface to the intermediate layer did not dissolve (FIG. 7b). 0.1 W (6 sec) irradiated sample; 7 hours after immersion, the region (FIG. 8a) that has been modified to yellowish brown by laser irradiation is observed to remain undissolved (FIG. 8b). Considering that the non-laser-irradiated teeth (enamel) are completely dissolved in 6 hours after immersion, acid resistance is imparted to the teeth even under the irradiation conditions of the lowest power (0.1 W) of this example. It is proved that it is done.

(Method for identifying acid-resistant substances)
The X-ray diffraction pattern of healthy non-irradiated teeth (enamel) is shown in FIG. A typical diffraction profile of an inorganic crystalline HAP that is the main component of a tooth is shown. When this tooth is irradiated with a laser having a high output (2 to 3 W or more), as shown in FIG. 10 (X-ray diffraction pattern when irradiated with 3 W (4 sec)), the inorganic crystal HAP as the main component is transformed into a high-temperature phase. Α-TCP, β-TCP, PYR, MET, etc. which are quasi-high temperature phases.
With low-power laser irradiation of 1 W, β-TCP, PYR, and MET, which are quasi-high-temperature phases, are quasi-high-temperature phases with irradiation of power lower than 1 W (for example, 0.5, 0.3, 0.1 W). Some PYR and MET were detected. In the researches of the present inventors so far, the fact that the high temperature phase α-TCP has been detected means that the tooth surface temperature has reached about 1200 ° C., and that the quasi-high temperature phase β-TCP has been detected. Is found to rise to around 700 ° C., and when PYR and MET are detected, it rises to around 300 ° C. (see Table 2 and FIG. 14). Human teeth (enamel and dentin) are powdered and divided into multiple lots, and these lots are used in the following multiple temperatures from room temperature to ultra-high temperature (1600-1700 ° C) using a high-temperature electric furnace. The structure / composition of the HAP crystal at each set temperature of 100, 300, 500, 700, 1000, 1200, 1280, 1400, 1600, 1620, 1650, and 1700 ° C. was measured by powder X-ray diffraction method. Table 2 summarizes the results of the qualitative analysis, but it has been found by subsequent experiments that MET is detected at around 300 ° C. FIG. 14 shows an example of an X-ray diffraction pattern and a qualitative analysis result obtained in this experiment at a set temperature of 300 ° C.

11 (a, b), FIG. 12 (a, b, c), and FIG. 13 (a, b), low output of 1 W (4 sec), 0.3 W (4 sec), and 0.1 W (6 sec), respectively. An X-ray diffraction pattern and qualitative analysis results before and after immersing irradiated teeth (enamel) in an acidic solution (2% lactic acid solution, pH 2.1) are shown. FIG. 11a shows the result before immersion in 1 W (4 sec), showing a diffraction profile of a typical inorganic crystal HAP, and quasi-high-temperature phases such as β-TCP, PYR, and MET are detected. FIG. 11 b shows the result after 1 W (4 sec) immersion, where the diffraction profile of a typical inorganic crystal HAP is broken and PYR and MET are detected predominantly. FIG. 12a shows the result before immersion of 0.3 W (4 sec), showing a diffraction profile of a typical inorganic crystal HAP, and a quasi-high temperature phase such as PYR or MET is detected. FIG. 12 b shows the result after immersion of 0.3 W (4 sec), typical three lattice planes (211) of inorganic crystal HAP; 2θ = 31.77 °, (112); 2θ = 32.19 °, (300); the diffraction profile from 2θ = 32.90 ° disappears, and instead PYR and MET are detected predominantly (see FIG. 12c for detailed qualitative analysis results). FIG. 12c is an enlarged view of FIG. 12b and shows a detailed qualitative analysis result. PYR (α−, β−) and MET (β−, γ−) are detected from the angle (2θ) of the diffraction line from a typical grating surface.
FIG. 13 a shows the result before immersion of 0.1 W (6 sec), showing the diffraction profile of a typical inorganic crystal HAP, and detecting a quasi-high temperature phase such as PYR or MET. FIG. 13 b shows the result after immersion of 0.1 W (6 sec). The diffraction profile of typical inorganic crystal HAP is broken, and PYR and MET are detected predominantly.

  Thus, in the enamel irradiated with 1 W (4 sec), β-TCP in a quasi-high temperature phase is detected (see FIG. 11a), but disappears after being immersed in an acidic solution (see FIG. 11b). This shows that it is soluble in acid like inorganic crystalline HAP. Under any of these low-power irradiation conditions, the X-ray diffraction pattern of typical inorganic crystal HAP is broken or disappeared (see FIG. 12b) after immersion, and PYR and MET are dominant instead. Has been detected. A detailed analysis example is shown in FIG. 12c: As an example, diffraction profiles from (031), (211), (131), (002), etc., which are typical lattice planes of α-PYR, are shown. The diffraction profiles from (008), (202), (200), (205) for β-PYR, (022), (202), (−112), (222), etc. for γ-MET are identified. Has been.

These experiments and analysis results demonstrate that it is these two substances, PYR and MET, that impart acid resistance to teeth by laser irradiation. Furthermore, as shown in these examples, acid resistance is imparted even under irradiation conditions (output of 1 W or less, that is, 0.5 W, 0.3 W, 0.1 W) as to whether or not warmth is felt even when applied to the skin. It is surprising that it has been found (of course, with the lowest power of this example, 0.1 W irradiation, the degree of acid resistance is weaker). It should be noted that these are irradiation conditions that are much lower than those normally applied to dentine hypersensitivity.
This is because the conventional medical laser (Er: YAG, CO ₂ , Nd: YAG, etc.) devices are aimed at cavity formation and caries part excision, etc., and the amount of heat given to the teeth due to irradiation at high power This means that it is possible to impart acid resistance to teeth (enhancing tooth quality and providing caries prevention effect) with a small amount of heat by laser irradiation under the above-mentioned irradiation conditions. To do. In addition, the treatment example using the conventional low-power laser (semiconductor laser etc.) device developed for the treatment of soft tissues such as stomatitis, dentine hypersensitivity, periodontitis, etc. has not been reported yet, This means that it is possible to impart acid resistance to the teeth (enhance the tooth quality and give a caries prevention effect) by laser irradiation.

The experiment and analysis results for human permanent teeth have been described above. Hereinafter, the experiment and analysis results for human milk teeth will be described.
Both permanent teeth and milk teeth are mainly composed of inorganic crystalline HAP, and there is no significant difference between the effects of laser irradiation (giving acid resistance) between permanent teeth and milk teeth. However, the size of the teeth is smaller in the deciduous teeth than in the permanent teeth, and the crystal size of the inorganic crystal HAP is slightly smaller in the deciduous teeth than in the permanent teeth. For this reason, in the experiment on the deciduous teeth, the laser irradiation time was set to 2 seconds, which is smaller than that of the permanent teeth.
The experimental procedure for the deciduous teeth was the same as that for the permanent teeth described above, except that the laser irradiation conditions were as shown in Table 3 below.

The observation results by SEM for the standard sample without laser irradiation and each sample irradiated with laser at each output shown in Table 3 were almost the same as those for permanent teeth.
Moreover, the observation result by the polarization microscope with respect to each of these samples showed the same tendency as the case of permanent teeth. Specifically, in the non-laser-irradiated standard sample, the time required for the enamel to completely dissolve after immersion in the acidic solution was 4 hours. On the other hand, in each of the samples irradiated with laser at each output in Table 3, the region modified by laser irradiation in the enamel remained undissolved even after 5 hours had passed after immersion. As an example, FIG. 15 shows polarization microscope images before and after immersion in a sample irradiated with laser at 0.1 W (2 sec). FIG. 15A is an image before immersion, and FIG. 15B is an image after 5 hours from immersion. In FIG. 15A, the yellowish brown region in the enamel is a region denatured by laser irradiation. It can be seen that this region remains without being dissolved in FIG.
Considering that laser non-irradiated teeth (enamel) are completely dissolved in 4 hours after immersion, acid resistance is imparted to the teeth even under irradiation conditions with the lowest power (0.1 W) in this experiment. It is proved that.
Moreover, the analysis result by the X ray diffraction method of the site | part which remained after immersion was the same as that of the case of a permanent tooth. As an example, FIG. 16 shows X-ray diffraction patterns and qualitative analysis results before and after immersion of teeth (enamel) irradiated with laser at 0.1 W (2 sec). FIG. 16A shows an X-ray diffraction pattern and qualitative analysis results before immersion, and FIG. 16B shows an X-ray diffraction pattern and qualitative analysis results after immersion, respectively.

As mentioned above, due to the theoretical fluctuation and demonstration of acid resistance imparted by laser irradiation, the tooth is imparted with acid resistance by low-power laser irradiation whether or not it feels warm even when applied to the skin (tooth It was proved that the quality was strengthened and the effect of preventing tooth decay was exhibited. Further, from Table 1 and Table 3 summarizes the irradiation conditions in this experiment, at the output of the laser is 1.2W or less, the power density of 0.8 W / cm ² or more 12.0 W / cm ² or less, and, By applying laser irradiation under an irradiation condition of an energy density of 1.7 J / cm ² or more and 50.0 J / cm ² or less, it is an acid-resistant substance in living hard tissues without causing thermal damage to teeth and surrounding tissues. It is considered that PYR and MET can be generated. On the other hand, if the output exceeds 1.2 W, the amount of heat applied to the teeth and surrounding tissues is too large, and if the power density exceeds 12.0 W / cm ² or the energy density exceeds 50.0 J / cm ² , the teeth heat is too large to be applied to either the power density is less than 0.8 W / cm ^2, or the energy density is less than 1.7 J / cm ^2, believed to acid resistance related substance to the teeth is not sufficiently generated .

More preferable ranges are an output of 1.0 W or less, a power density of 1.06 W / cm ² or more and 10.89 W / cm ² or less, and an energy density of 2.12 J / cm ² or more and 43.56 J / cm ^2. It is as follows.
Further, when the laser irradiation target is a human permanent tooth, the output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 6.54 J / cm ^2. It is preferable to set it as 43.56 J / cm < ² > or less. On the other hand, when the laser irradiation target is human milk teeth, the output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.64 W / cm ² or less, and the energy density is 2.12 J / it is preferable that the cm ² or more 21.28J / cm ² or less.

Hereinafter, an embodiment of the method of operating a laser apparatus according to the present invention in detail with reference to the accompanying drawings.
FIG. 17 is a configuration diagram of an embodiment of a laser apparatus according to the present invention.
In the figure, reference numeral 1 denotes a laser device, 23 is an emitter, 41 is a light guiding means (optical fiber), and 5 is an irradiator (handpiece). 3 is an operation panel, 21 is a CPU, 22 is a laser drive circuit, 24 is a motor drive circuit, and 52 is a condenser lens. In addition, 2 is a housing, 4 is a cable, and 51 is a tip of the irradiator 5.
A laser apparatus 1 for irradiating a living body hard tissue containing inorganic crystalline hydroxyapatite according to the present embodiment with a laser has an emitter 23 for emitting the laser, one end connected to the emitter 23, and a laser guided to the other end. The light guide means 41 that emits light, the irradiator 5 that is connected to the other end of the light guide means 41 and irradiates the living body hard tissue with the laser, and the irradiation control means that controls the irradiation of the laser from the irradiator 5.

Here, the irradiation control means includes the operation panel 3, the CPU 21, the laser drive circuit 22, the motor drive circuit 24, the condensing lens 52, and the condensing lens 52 forward and backward toward the tip 51 of the irradiator 5. A stepping motor (not shown) that is movable is preferably used.
The characteristics of the laser device 1 according to this embodiment, the irradiation control means, the output of the laser is 1.2W or less, the power density of 0.8 W / cm ² or more 12.0 W / cm ² or less, and the energy density Lies in controlling the laser irradiation from the irradiator 5 so that it becomes 1.7 J / cm ² or more and 50.0 J / cm ² or less.
Further, as a more preferable range, the output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 2.12 J / cm ² or more 43. 56 J / cm ² or less.

  As shown in FIG. 17, in the housing 2, a CPU 21 electrically connected to an operation panel 3 provided integrally or separately with the housing 2, and a laser drive circuit 22 electrically connected to the CPU 21 are provided. An emitter 23 electrically connected to the circuit 22 is provided. The emitter 23 is connected to one end of the light guide means 41 through known means (not shown) such as a collimator lens and a condenser lens so that the emitted laser is incident on one end of the light guide means 41 in the cable 4. . A condensing lens 52 for changing the focal position of the laser emitted from the other end of the light guide means 41 is movably provided inside the tip 51 of the irradiator 5 via the stepping motor. The stepping motor 53 is connected to a motor drive circuit 24 provided in the housing 2 and connected to the CPU 21 via an electric wire in the cable 4.

For example, when the dentist irradiates a patient's teeth with a laser to prevent dental caries, the operation panel 3 includes various buttons for inputting designated conditions for laser irradiation, a display for displaying input values, and the like. Has been placed. This specified condition preferably includes the laser output, the irradiation diameter (that is, the diameter of the irradiation region on the tooth surface) and the irradiation time. When entering a value of the laser output, determining selectable range of illumination diameter so that the power density is 0.8 W / cm ² or more 12.0 W / cm ² within the following ranges by CPU21 according to the value Then, when the value of the irradiation diameter is input within the determined range, the irradiation time can be selected so that the energy density is 1.7 J / cm ² or more and 50.0 J / cm ² or less according to the value. It is preferable that the range is determined by the CPU 21 and the irradiation time value is input within the determined range.

The inputted designated condition is transmitted to the CPU 21. The CPU 21 controls the emitter 23 via the laser driving circuit 22 and causes the emitter 23 to emit an output laser that complies with the specified specified condition. The laser emitted from the emitter 23 is emitted from the other end of the light guide 41 inside the tip 51 of the irradiator 5 through the light guide 41. At that time, it is preferable that the tip 51 of the irradiator 5 is in contact with the patient's teeth. In this state, the CPU 21 controls the stepping motor 53 via the motor drive circuit 24 so that the irradiation diameter of the laser emitted from the other end of the light guide means 41 becomes a value according to the input designated conditions. Thus, the position of the condenser lens 52 is adjusted to control the focal position of the laser.
In addition, when it is desired to generate acid-resistant substances in a wider range, every time the above operation is completed, the doctor may repeat the same operation by shifting the laser irradiation site.

According to the embodiment described above, it is possible to ensure that the laser irradiation is performed under the preferable irradiation conditions described above. Moreover, according to the laser irradiation conditions, the amount of heat applied to the teeth and the surrounding tissues is not too large, and PYR and MET, which are acid-resistant substances, can be generated in the enamel of the teeth. It is possible to provide a small and inexpensive method of operating a laser device that is suitable for use.

Next, a modified example of the embodiment of the laser apparatus according to the present invention will be described.
The laser device in this example has the same basic configuration as the laser device 1 shown in FIG.
In this example, when the living hard tissue to be irradiated with the laser is a permanent tooth, the laser output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and The laser beam from the irradiator 5 is controlled so that the energy density is 6.54 J / cm ² or more and 43.56 J / cm ² or less.
In addition to or instead of the above, when the living hard tissue to be irradiated with laser is a deciduous tooth, the laser output is 1.0 W or less and the power density is 1.06 W / cm ² or more and 10 .64W / cm ² or less, and, as the energy density is 2.12J / cm ² or more 21.28J / cm ² or less, it is preferable to control the irradiation of the laser from the irradiator 5.
Specifically, it is preferable that the laser device 1 further includes irradiation target input means (not shown) for the user to input whether the laser irradiation target is a human permanent tooth or a human milk tooth.
By setting it as such a structure, laser irradiation can be carried out on optimal conditions about each of a human permanent tooth and a human milk tooth, and acid resistance can be provided more effectively.

In the embodiment of the laser apparatus according to the present invention described above and the modification thereof, it has been described that the designated conditions for laser irradiation preferably include the laser output, the irradiation diameter, and the irradiation time. However, instead of the irradiation time, the irradiation position The speed of movement can also be used. In this case, as a configuration for moving the irradiation position, for example, a condensing lens 52 provided inside the tip 51 of the irradiator 5 is pivotally supported in the diameter direction and is swung around the axis at a desired angular velocity. It is preferable to provide a second stepping motor. Further, it is preferable to provide a second motor drive circuit for driving the motor, connect the CPU 21 to this circuit, and provide the operation panel 3 with a button for selecting the irradiation position moving speed.
Further, in the embodiment of the laser apparatus according to the present invention and the modification thereof, it has been described that all three of the laser output, the irradiation diameter, and the irradiation time are input. However, when one or two are input, the CPU 21 Can be configured to determine the remaining two or one specified condition to an appropriate value.
The designated condition may be at least one of laser output, focal position, waveform, irradiation time, and irradiation position instead of the above.
As the laser device, CO ₂ , Nd: YAG, Er: YAG, semiconductor laser, excimer laser, and other medical lasers including oscillation methods such as continuous wave and pulse wave can be used.

Next, an embodiment of a method for producing acid-resistant biohard tissue according to the present invention will be described.
Biological hard tissues that can be used in this production method include teeth and bones of animals including humans, dental materials including inorganic crystalline HAP, medical materials, biomaterials, and the like.
Dental materials include: Fischer sealant / dental adhesive filling material, pit and fissure sealing material, dental cement, composite, pulp capping agent, root canal filling material, artificial tooth, artificial tooth root, dental bone filling material, formation Examples include surgical materials, castable ceramics, crowns of apatite castable ceramics, and dentifrices.
Examples of medical materials include artificial bones, artificial joints, measures against body fluid environment of hip joints, bone cement, and the like.
Moreover, the laser apparatus which can be used for this manufacturing method is the laser apparatus 1 in the above-mentioned embodiment, or a desired commercially available laser apparatus (for example, semiconductor laser apparatus OSL-3000, Nagata Electric Industrial Co., Ltd.).

Using one of these laser devices, the output of the laser is 1.2W or less, the power density of 0.8 W / cm ² or more 12.0 W / cm ² or less, and the energy density of 1.7 J / cm ² The living hard tissue containing the inorganic crystal HAP is irradiated with a laser of 50.0 J / cm ² or less.
Further, as a more preferable range, the output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 2.12 J / cm ² or more 43. 56 J / cm ² or less.
Further, when the living hard tissue is a permanent tooth, the laser output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 6.54 J / cm. and a ^two or more 43.56J / cm ² or less. On the other hand, when the living hard tissue is a deciduous tooth, the laser output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.64 W / cm ² or less, and the energy density is 2.12 J. / Cm ² or more and 21.28 J / cm ² or less is preferable.
For example, using a semiconductor laser device OSL-3000, Nagata Electric Industry Co., Ltd., continuous wave, λ = 810 nm ± 20 nm, fiber diameter: 600 μm, fiber NA (aperture angle): 0.43 (angle 25.2 °) The distance from the fiber tip to the sample: 0.3 mm, laser output: 1 W, and irradiation time: 4 sec.
Even when a laser device such as Er: YAG, CO ₂ , Nd: YAG for the purpose of cavity formation or caries excision is used by irradiating a laser under the above-mentioned irradiation conditions, The amount of heat given to the surrounding tissue is not too large, and PYR and MET as acid-resistant substances can be generated in the biological hard tissue. In addition, by using a conventional semiconductor laser device developed for the treatment of soft tissues such as stomatitis, dentin hypersensitivity, periodontitis, etc., by irradiating the laser under the above-mentioned irradiation conditions, living hard tissue PYR and MET as acid-resistant substances can be produced therein.

  According to such an embodiment, human and animal teeth and bones, dental materials and medical materials including inorganic crystalline HAP, and PYR and MET as acid-resistant substances in biological hard tissues such as biomaterials have low output. It is possible to provide a method for efficiently generating an acid-resistant substance in a living hard tissue using a laser that is easy to handle.

Above, a method of operating a laser device in the embodiment described, and production how acid resistant organic hard tissue, based on the theory of acid resistance imparting obtained from irradiation experiments and previous experiments for hard tissue of a tooth, conventional Because it provides much safer acid resistance to teeth with a much lower output than that of the product, it can be immediately applied to the actual clinical field.

To date, the main roles of caries prevention methods are tooth brushing and sweetness restriction in Japan, and fluorine is the leading role in Europe and America. As mentioned above, fluorine is added to tap water in the United States and Europe, but some problems can be pointed out. For example, there is a report that the optimum concentration of fluorine to be added is 1 ppm, and if the concentration is higher than this (1.5 to 2.0 ppm or more), there is a greater risk of becoming group teeth, osteosarcoma, osteosclerosis, etc. about. Furthermore, it is difficult to control the fluorine concentration in the water source portion to which fluorine is added and the fluorine concentration of water flowing out from the faucet of each household water supply to 1 ppm. In addition, fluorine mouthwash, application of fluorine on the tooth surface, and sugars such as xylitol and sorbitol are used for caries prevention instead of sucrose which induces caries, but these effects are temporary. It cannot be sustained for a long time. However, these laser devices, their operating methods, acid-resistant biohard tissue manufacturing methods, and acid-resistant biohard tissue have the advantage that the tooth quality is permanently strengthened.
In addition, since a clear basic theory about the influence of laser irradiation on the teeth has been obtained, there is an advantage that the dentist can fully explain to the patient side and obtain patient consensus. In addition, since it can be treated with no pain, no vibration, and no noise without causing thermal damage to the teeth, children and the elderly can be treated with peace of mind without fear. Moreover, there is almost no bleeding during treatment. In addition, by irradiating the carious tooth-prone part (molar fissure part, adjacent part, tooth neck part) where the tip part of the toothbrush does not reach, it is preferable for caries fungi such as mutans bacteria that prefer to live in places with low oxygen. Sterilization can also be performed. Furthermore, it is smaller, lighter, and less expensive than conventional ones.
Conventional laser devices are quite large, heavy and expensive, so the penetration rate is only 25%. Compared to this, the low-power laser device has many advantages as described above, and can be applied immediately to the clinic, and is an epoch-making device that opens a new door to dental caries prevention dentistry. . In the future, it is expected that the use and spread rate will be increased particularly, and it is expected to contribute greatly to the health and welfare of the nation from children who suffer from tooth decay to the elderly.
A long time ago, there was a TV commercial saying that entertainers have teeth. Life is not only for entertainers, but for anyone. For wild animals, losing teeth immediately means death. If you lose your teeth due to tooth decay or periodontal disease, you will realize that teeth play an important role in maintaining and improving people's health. However, when it comes to treating dental caries, it is also true that the high frequency sound and vibration of an electric drill, and the pain that cannot be tolerated are jealous. A cure that is painless and free of vibrations and unpleasant high-frequency sounds was once a dream. However, it has been confirmed that the laser device according to the present invention, the operating method thereof, the method for producing acid-resistant biological hard tissue and the acid-resistant biological hard tissue are not dreams but are actual and actually exist in front of the eyes.

DESCRIPTION OF SYMBOLS 1 Laser apparatus 2 Housing 3 Operation panel 4 Cable 5 Irradiator 21 CPU
22 Laser drive circuit 23 Emitter 24 Motor drive circuit 41 Light guide means 51 Irradiator tip 52 Condensing lens

Claims (4)

A laser device for irradiating a living hard tissue containing inorganic crystalline hydroxyapatite with a laser, the emitter for emitting the laser, one end connected to the emitter, and a guide for guiding the laser to the other end In an operation method of an apparatus having light means and an illuminator connected to the other end of the light guide means and irradiating the object with the laser,
In a wavelength 810 nm ± 20 nm of the laser, the output is equal to or less than 1.2 W, the power density of 0.8 W / cm ² or more 12.0 W / cm ² or less, and the energy density of 1.7 J / cm ² to 50 An operating method, wherein the laser irradiation from the irradiator is controlled so as to be 0.0 J / cm ² or less. When the living hard tissue is a permanent tooth,
The wavelength of the laser is 810 nm ± 20 nm, the output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 6.54 J / cm ² or more 43 .56J / cm ² or less and so as, the operating method as claimed in claim 1, characterized in that for controlling the irradiation of the laser from the irradiator. When the living hard tissue is a deciduous tooth,
The wavelength of the laser is 810 nm ± 20 nm, the output is 1.0 W or less, the power density is 1.06 W / cm ² or more and 10.64 W / cm ² or less, and the energy density is 2.12 J / cm ² or more 21 .28J / cm ² or less and so as, the operating method as claimed in claim 1, characterized in that for controlling the irradiation of the laser from the irradiator. In producing an acid-resistant biohard tissue by generating an acid-resistant participating substance in a living hard tissue excluding the human body, including inorganic crystalline hydroxyapatite,
The wavelength is 810 nm ± 20 nm, the output is 1.0 W or less, the power density is 1.09 W / cm ² or more and 10.89 W / cm ² or less, and the energy density is 6.54 J / cm ² or more and 43.56 J / A method for producing an acid-resistant biological hard tissue, which comprises irradiating the biological hard tissue with a laser having a cm ² or less.