Root canal filling material manufacturing method, root canal filling material

Abstract

To provide a root canal filling material capable of obtaining a stable paste form. [Solution] A method for producing a root canal filling material includes a first kneading step in which calcium hydroxide, a thickener, and water are kneaded while being heated, a step in which the kneaded composition is heated and allowed to stand, and a second kneading step in which the composition that has been allowed to stand is kneaded.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to root canal filling materials, and in particular to paste root canal filling materials. [Background technology]

[0002] In the field of dentistry, root canal filling materials are used after root canal treatment for infected root canals or pulpectomy. Calcium hydroxide is used as the active ingredient in root canal filling materials because it has antiseptic, analgesic, and healing-promoting properties.

[0003] When calcium hydroxide is used as the active ingredient in root canal filling materials, it is sometimes mixed with purified water or other liquids before use and applied to the affected area, but it is also available in a pre-formed paste form packed in a syringe. This makes it convenient for practitioners to fill the affected area as the paste is extracted from the syringe.

[0004] For example, Patent Document 1 discloses that calcium hydroxide is used in a root canal filling material and that it is provided in a paste form. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-84338 Summary of the Invention [Problem to be solved by the invention]

[0006] Calcium hydroxide is difficult to prepare into a stable paste, and requires long-term kneading before it can become a paste. Even when it does become a paste, the consistency and flow stability are poor.

[0007] The present disclosure aims to provide a method for producing a root canal filling material that can be in a stable paste form, and also to provide such a root canal filling material. [Means for solving the problem]

[0008] The present application discloses a method for producing a root canal filling material, the method including a first kneading step of kneading calcium hydroxide, a thickener, and water while heating them, a step of heating the kneaded composition and leaving it to stand, and a second kneading step of kneading the composition that has been left to stand. Here, "heating" means adding heat to maintain a certain temperature state.

[0009] The heating in the first kneading step is in the range of 40°C or higher and 90°C or lower, and the kneading time is 10 minutes or longer. The heating in the leaving step is in the range of 40°C or higher and 90°C or lower, and the leaving time can be 10 hours or longer.

[0010] The thickening agent may include hypromellose acetate succinate.

[0011] The present disclosure also discloses a root canal filling material containing calcium hydroxide and a thickener, the thickener including hypromellose acetate succinate. [Effects of the Invention]

[0012] According to the present disclosure, a paste-like root canal filling material can be stably obtained. DETAILED DESCRIPTION OF THE INVENTION

[0013] The above-described functions and advantages of the present disclosure will become apparent from the following embodiments, although the present disclosure is not limited to these embodiments.

[0014] 1.Root canal filling material In one embodiment, the root canal filling material is a composition containing calcium hydroxide, a contrast agent, a thickener, and water.

[0015] 1.1.Calcium hydroxide Calcium hydroxide functions as the main active ingredient in the therapeutic effects of root canal filling materials, namely, it exerts disinfecting, analgesic, healing promoting effects, etc. The content of calcium hydroxide in the root canal filling material composition is preferably 2% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total amount of the composition. This allows the above-mentioned effects of calcium hydroxide to be obtained. Furthermore, the content of calcium hydroxide is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on the total amount of the composition. This range ensures the fluidity of the composition in combination with other components that make up the composition, making it easy to extrude from a syringe container.

[0016] 1.2.Contrast agents The root canal filling material of this embodiment may contain a contrast agent in order to ensure ease of X-ray imaging. Examples of contrast agents include barium sulfate, zirconium oxide, bismuth subnitrate, bismuth trioxide, bismuth carbonate, zinc oxide, etc. Among these, barium sulfate is preferred. The content of the contrast agent in the root canal filling material composition is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total amount of the composition. This allows the contrast agent to exhibit its X-ray imaging function. Furthermore, the content of the contrast agent is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total amount of the composition. This makes it easier to adjust the consistency of the root canal filling material.

[0017] 1.3.Thickeners The root canal filling material of this form contains a thickener, which allows the consistency of the root canal filling material to be adjusted. Examples of thickeners in this embodiment include hydroxypropyl cellulose, polyhydric alcohols (dihydric alcohols such as propylene glycol, polypropylene glycol, and polyethylene glycol, and trihydric alcohols such as glycerin), and hypromellose acetate succinate. These materials may be used alone or in combination. Among these, from the viewpoint of water solubility and ease of adjusting consistency, it is preferable to include at least one of hydroxypropyl methylcellulose, polypropylene glycol, and hypromellose acetate succinate, and more preferably hypromellose acetate succinate.

[0018] The content of the thickener in the root canal filling material composition is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total amount of the composition. The content of the thickener is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the composition. These ranges ensure the fluidity of the composition in combination with other components constituting the composition, and make it easier to adjust the consistency.

[0019] 1.4.Water The water is not limited, but purified water can be preferably used. The content of water in the root canal filling material composition is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total amount of the composition. The content of water is preferably 60% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less, based on the total amount of the composition. These ranges ensure the fluidity of the composition in combination with other components constituting the composition, and make it easier to adjust the consistency.

[0020] 2. Manufacturing method The root canal filling material of this embodiment can be manufactured, for example, as follows. A manufacturing method according to one embodiment includes the steps of first kneading S11, heating and leaving S12, cooling S13, second kneading S14, and filtering S15. Each step will be described below.

[0021] 2.1. First kneading In the first kneading step S11, the various materials constituting the root canal filling material are mixed together and kneaded. Specifically, the thickener is added to the water while kneading, followed by the addition of calcium hydroxide and contrast medium. The kneading continues while scraping off unevenly distributed material, if necessary. Furthermore, in the first kneading S11, it is preferable to heat the mixture while kneading. Specifically, the temperature is preferably in the range of 40°C or higher and 90°C or lower, and more preferably 50°C or higher and 80°C or lower. The kneading time may be a certain period of time, preferably 10 minutes or more, more preferably 15 minutes or more, and even more preferably 20 minutes or more, while the kneading time is preferably 40 minutes or less, more preferably 30 minutes or less.

[0022] 2.2.Heating and standing In the heating and standing step S12, the composition obtained in the first kneading step is heated to a predetermined temperature and left standing for a certain period of time. This step can be carried out in a constant temperature room or the like. Specifically, the heating temperature should be at least higher than the ambient temperature (so-called air temperature), but is preferably in the range of 40°C or higher and 90°C or lower, and more preferably 50°C or higher and 80°C or lower. On the other hand, the standing time is preferably 10 hours or more, more preferably 15 hours or more, and even more preferably 20 hours or more, and is preferably 30 hours or less.

[0023] 2.3. Cooling In the step of cooling S13, the composition obtained in the heating and standing step S12 is cooled by natural cooling to room temperature.

[0024] 2.4. Second mixing In the second kneading step S14, the composition obtained in the cooling step S13 is kneaded again. This kneading is performed so as not to raise the temperature. To achieve this, for example, a cycle of kneading for several minutes and then cooling is repeated, and / or a liquid thickener (propylene glycol) is added. Such second kneading is carried out for a period of 10 minutes or more and 30 minutes or less.

[0025] 2.5.Filtration In the filtering step S15, foreign matter and lumps are removed (filtered) from the composition obtained as described above to obtain a root canal filling material.

[0026] 3. Effects etc. The root canal filling material obtained as described above has little variation in consistency, which can improve production efficiency. Conventional methods often fail to produce a paste or an appropriate consistency, which is insufficient from the perspective of stable product production. In contrast, the present disclosure solves these problems and makes it possible to efficiently produce root canal filling materials of stable quality. Furthermore, according to the root canal filling material of the present disclosure, it is possible to suppress changes in consistency over time during storage of the root canal filling material, which is advantageous in terms of quality stability over time.

[0027] In the manufacturing method of the present disclosure, the composition is heated in the first kneading and / or heating and standing step as described above, which causes calcium hydroxide to precipitate (calcium hydroxide has the property of becoming less soluble as the temperature increases), and since this precipitated calcium hydroxide is fine and has a fairly uniform particle size, the composition can be subsequently kneaded for a short time in the second kneading step as described above, thereby obtaining a highly stable composition. Conventionally, kneading has been required for a long period of time, and quality control associated with kneading has been difficult and has led to a lack of stability, but this problem can be solved by the present disclosure.

[0028] 4. Test Example 4.1. Test Example 1 In Test Example 1, the effect of heating in the first kneading step in the above production method was investigated. In Test Example 1, the ingredients were 36.0% by mass of calcium hydroxide, 24.0% by mass of barium sulfate, 1.0% by mass of hypromellose acetate succinate, 18.0% by mass of propylene glycol, and 21.0% by mass of purified water.

[0029] In Test Example 1-1, the heating temperature in the first kneading was set to 50° C., and four different kneading times (10 minutes, 20 minutes, 30 minutes, and 40 minutes) were performed. The heating and standing time was 20 hours at the heating temperature. In Test Example 1-2, the heating temperature in the first kneading was set to 60° C., and four different kneading times (10 minutes, 20 minutes, 30 minutes, and 40 minutes) were performed. The heating and standing time was 20 hours at the heating temperature. In Test Example 1-3, the heating temperature in the first kneading was set to 80° C., and four different kneading times (10 minutes, 20 minutes, 30 minutes, and 40 minutes) were performed. The heating and standing time was 20 hours at the heating temperature. In Test Examples 1-4, heating was not performed in the first mixing step, and heating and standing were not performed. Four different mixing times (75 minutes, 90 minutes, 105 minutes, and 120 minutes) were performed. The reason for the long mixing times in Test Examples 1-4 is that the root canal filling material composition did not become paste-like with the mixing times in Test Example 1 (10 minutes, 20 minutes, 30 minutes, and 40 minutes), so the mixing times were extended to ensure a mixing time sufficient to obtain a paste-like composition.

[0030] In Test Example 1, the consistency of the obtained root canal filling material was examined. The consistency was measured as follows. 0.5 mL of the resulting root canal filling material was placed between 20 g glass plates, and a 100 g load was placed on top of it for 10 minutes. The size of the largest part of the spread root canal filling material was measured and used as the consistency. The results are shown in Table 1.

[0031] [Table 1]

[0032] As can be seen from the results, a stable consistency could be obtained by ensuring a mixing time of at least 10 minutes in Test Examples 1-1, 1-2, and 1-3. In contrast, in Test Example 1-4, the consistency varied greatly depending on the mixing time. It is also clear that in Test Example 1-4, a long period of kneading is required to obtain a paste state.

[0033] 4.2. Test Example 2 In Test Example 2, the effect of the heating and standing time in the above manufacturing method was investigated. The composition of the materials was the same as in Test Example 1. In Test Examples 2-1 and 2-2, the heating temperature in the first kneading was 60°C and the kneading time was 20 minutes. The heating and standing time was performed at the same heating temperature for three times (13 hours, 20 hours, and 30 hours). Test Examples 2-1 and 2-2 differ only in raw material lot, and the material composition and test conditions are the same. The consistency was also measured in Test Example 2. The measurement method was the same as in Test Example 1. The results are shown in Table 2.

[0034] [Table 2]

[0035] As can be seen from the results, a root canal filling material with a stable consistency can be obtained by leaving it at rest for at least 13 hours, and stability is further improved by leaving it for 20 hours or more.

[0036] 4.3. Test Example 3 In Test Example 3, a root canal filling material was prepared and the change in consistency over time was examined. The composition of the material was the same as in Test Example 1. In Test Example 3-1, a root canal filling material was prepared by the manufacturing method according to the embodiment described above. Specifically, the heating temperature in the first kneading step was set to 60°C, and the kneading time was set to 20 minutes. The heating and standing time was set to the heating temperature for 20 hours. In Test Example 3-2, a root canal filling material was obtained by kneading for 25 minutes without heating.

[0037] In Test Example 3, to obtain changes over time, the root canal filling material was stored at 40°C and 75% humidity, and the consistency was measured at 1 month, 3 months, and 6 months. The consistency measurements were the same as in the Test Example. The results are shown in Table 3.

[0038] [Table 3]

[0039] As can be seen from Table 3, deterioration over time can be suppressed by heating.

[0040] 4.4. Test Example 4 In Test Example 4, the type of thickener was changed and the consistency was measured. Everything except the type and amount of thickener was the same as Test Example 1. The amount of thickener was adjusted by changing the amount of water. In addition, the root canal filling material was prepared in Test Example 1-2 (heated to 60°C) with a mixing time of 20 minutes. The consistency was measured in the same way as Test Example 1. The results are shown in Table 4.

[0041] [Table 4]

[0042] The consistency is preferably in the range of 20 mm to 28 mm, and hypromellose acetate succinate was able to stably achieve this consistency. Sodium alginate was able to achieve a consistency similar to that of hypromellose acetate succinate, but the paste was not smooth and had a crumbly texture that was difficult to extrude from a syringe.

Claims

1. 1. A method for producing a root canal filling material, comprising: a first kneading step of kneading calcium hydroxide, a thickener, and water while heating; a step of heating the kneaded composition and leaving it to stand; A second kneading step of kneading the composition after the standing. A method for manufacturing root canal filling material.

2. The heating in the first kneading is in the range of 40°C or more and 90°C or less, and the kneading time is 10 minutes or more, The heating in the leaving step is in the range of 40°C or higher and 90°C or lower, and the leaving time is 10 hours or longer. A method for producing the root canal filling material according to claim 1.

3. The method for producing a root canal filling material according to claim 1 or 2, wherein the thickener comprises hypromellose acetate succinate.

4. Contains calcium hydroxide and a thickener, The thickener comprises hypromellose acetate succinate, Root canal filling material.

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