A root canal sealer and its application

Abstract

The present invention discloses a root canal sealer and its application; wherein, the root canal sealer includes: tricalcium silicate-based mineral trioxide aggregate, nano-zinc oxide quantum dots and an aqueous solution. In this application, by mixing MTA and ZnO QDs to form a root canal sealer, its setting time, fluidity, radiopacity and clinical apical filling operation have no obvious difference compared with MTA alone, and it can reduce the dissolution rate of the composite material and shows good antibacterial effect against Enterococcus faecalis.

Description

Technical Field

[0001] The present invention belongs to the field of dentistry, and particularly relates to a root canal sealer and its application. Background Art

[0002] A root canal sealer is a product used for dental restoration; it can fill the gaps between gutta-percha points and between the gutta-percha points and the root canal wall, playing a role in stabilizing the irregular root canal structure.

[0003] Mineral trioxide aggregate (MTA) is a medical material used in departments such as stomatology. The MTA powder contains fine hydrophilic particles and requires the participation of water during the polymerization and curing reaction. When the powder is mixed with sterile water, the MTA powder will hydrate into a gelatinous colloid, forming a firm structure. MTA has good tissue compatibility, marginal sealing performance, and also has a certain ability to induce tissue regeneration. Clinically, it is mainly used for direct pulp capping, apical retrograde filling, apical barrier for incompletely developed apical foramina, repair of perforations in the root canal side wall and pulp chamber floor, etc.

[0004] Since the curing of MTA is not affected by pulp exudates, it has a strong alkalinity similar to calcium hydroxide, can induce dentin formation, and can be used as a pulp capping agent. As a retrograde filling material, MTA has low toxicity to periapical tissues and good biocompatibility. Compared with other materials, MTA has superior performance, and its marginal sealing performance is better than that of other retrograde filling materials. MTA also has a certain antibacterial effect, good biocompatibility, causes less inflammatory reaction, can promote the growth and reproduction of tissue cells, promote the formation of dental hard tissues, and the formation of cementum at the apical resection section. It has great potential in the application as a root canal sealer.

[0005] Although MTA has many advantages, its inhibitory effect on Enterococcus faecalis and Streptococcus mutans is poor. For example, the results of the agar diffusion test using MTA materials by Morita et al. showed that the antibacterial effect of MTA materials on Enterococcus faecalis is very poor (Antibacterial activities and mineral induction abilities of proprietary MTA cements).

[0006] Therefore, how to improve the antibacterial performance of MTA against Enterococcus faecalis when used as a root canal sealer is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a preparation method of a canine root canal sealer containing zinc oxide quantum dots.

[0008] The technical solution of the present invention to solve the above technical problems is as follows: A root canal sealer, comprising: tricalcium silicate-based mineral trioxide aggregate, nano-zinc oxide quantum dots, and an aqueous solution.

[0009] The beneficial effects of the preparation method of the canine root canal sealer containing zinc oxide quantum dots disclosed in the present application are as follows: In the present application, by mixing MTA and ZnO QDs to form a root canal sealer, there are no significant differences in its setting time, flowability, radiopacity, and clinical apical filling operation compared with MTA alone, and it can reduce the dissolution rate of the composite material and show good antibacterial effects against Enterococcus faecalis.

[0010] In an alternative embodiment, the concentration of the nano-zinc oxide quantum dots in the aqueous solution does not exceed 2 mg / mL.

[0011] In an alternative embodiment, the concentration of the nano-zinc oxide quantum dots in the aqueous solution is 0.25 - 2 mg / mL.

[0012] In an alternative embodiment, the concentration of the nano-zinc oxide in the aqueous solution is 0.25 - 0.5 mg / mL.

[0013] In an alternative embodiment, the concentration of the tricalcium silicate-based mineral trioxide aggregate in the aqueous solution is 1.5 g / mL.

[0014] The present application also provides a preparation method of a dental filling, including the above root canal sealer, and further comprising the following steps:

[0015] Mix the tricalcium silicate-based mineral trioxide aggregate, the nano-zinc oxide quantum dots, and the aqueous solution to obtain a mixture;

[0016] Cure the mixture, and a dental filling is obtained after curing.

[0017] The present application also provides a dental filling prepared by the above method.

[0018] The present application also provides a medical device, which includes the above root canal sealer; and

[0019] A first container, which contains the powder phase;

[0020] A second container, which contains the aqueous solution.

[0021] The present application also provides an application of the above root canal sealer in dental treatment.

[0022] The present application also provides an application of the above root canal sealer in canine dental treatment. Detailed implementation manners

[0023] The principles and features of the present application will be described below in conjunction with embodiments. The examples given are only for explaining the present application and are not intended to limit the scope of the present application.

[0024] The following discloses various different embodiments or examples for implementing the described subject technical solutions. To simplify the disclosure, specific examples of one or more arrangements in which each feature exists are described below, but the examples given are not intended to limit this specification. In the specification, when the first feature is connected to the second feature described subsequently, it may include an embodiment of direct connection, or may also include an embodiment of forming additional features. Further, it also includes an embodiment in which one or more other intervening features are used to indirectly connect or combine the first feature and the second feature, so that the first feature and the second feature may not be directly connected.

[0025] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0026] It can be understood that the following nouns / abbreviations that appear in the present application are all proprietary nouns in the art, and those skilled in the art can know the meaning of the noun without any difficulty:

[0027] MTA: Mineral trioxide aggregate;

[0028] ZnO QDs: Zinc oxide quantum dots.

[0029] The present application provides a root canal sealer, which is composed of MTA, zinc oxide quantum dots and a water solution. To facilitate the explanation of the effects of the present application, the present application provides several relatively specific embodiments to illustrate the present application.

[0030] In the following embodiments, MTA is purchased from Wuhan Guanya Medical Devices Co., Ltd.

[0031] ZnO QDs can be purchased as commercially available ZnO QDs, or can be prepared by the following method:

[0032] Take 2.93 g of KOH powder and dissolve it in 30 mL of absolute ethanol for later use. Place anhydrous zinc acetate (Zn(COOH)2) and absolute ethanol in a clean beaker, stir in a magnetic stirrer at 78 °C for 30 min, then add the prepared KOH solution and stir until the solution becomes clear; add 1 mL of 3-aminopropyltriethoxysilane (APTES) solution and stir for 1 h, then dry at 80 °C to form a powder.

[0033] Control example:

[0034] Prepare a root canal sealer, which consists of a powder phase of MTA and a liquid phase of water. Before use, place MTA and water separately. When using, mix MTA and water for use.

[0035] Example 1:

[0036] Prepare a root canal sealer by mixing MTA and water solution at a powder-liquid ratio of 1.5 g:1 mL, and at the same time add different amounts of ZnO QDs so that the concentration of ZnO QDs in the preparation is 0.25 mg / mL respectively.

[0037] Example 2

[0038] Prepare a root canal sealer by mixing MTA and water solution at a powder-liquid ratio of 1.5 g:1 mL, and at the same time add different amounts of ZnO QDs so that the concentration of ZnO QDs in the preparation is 0.5 mg / mL respectively.

[0039] Example 3

[0040] Prepare a root canal sealer by mixing MTA and water solution at a powder-liquid ratio of 1.5 g:1 mL, and at the same time add different amounts of ZnO QDs so that the concentration of ZnO QDs in the preparation is 1.0 mg / mL respectively.

[0041] Example 4

[0042] Prepare a root canal sealer by mixing MTA and water solution at a powder-liquid ratio of 1.5 g:1 mL, and at the same time add different amounts of ZnO QDs so that the concentration of ZnO QDs in the preparation is 2.0 mg / mL respectively.

[0043] Example 5

[0044] Test the setting times of the above control example and Examples 1 to 4. The specific test method is as follows:

[0045] Add the prepared root canal sealer into a circular mold (inner cavity diameter d = 10 mm, h = 2 mm), and then place the mold in a thermo-hygrostat at a temperature of 37 °C and a humidity of 95%. Gently press the surface of the sealer material with a Vicat apparatus, start timing from the end of mixing, and the curing time is when no indentation appears anymore. Each material is measured 3 times and the average value is taken. The specific test results are shown in Table 1:

[0046] Table 1

[0047]

[0048] As can be seen from Table 1, there are no obvious changes in the curing times of Example 1, Example 2, and Example 4 compared with the comparative example. Only the average curing time of Example 4 with a ZnO QDs concentration of 1.0 mg / mL added increases by 0.31% compared with the blank group. It shows that adding ZnO QDs with a concentration of 0.25 - 2.0 mg / mL has no significant effect on the curing time of the root canal sealer.

[0049] Example 6:

[0050] Test the fluidity of the above comparative example, Example 1 to Example 4. The specific test method is as follows:

[0051] Use a disposable 1 mL syringe to place 0.05 mL ± 0.005 mL of the prepared root canal sealer at the center of a glass plate (20 g); after 180 s, place a second glass plate on top of the sealer, and place a calibrated weight of 100 g on the second glass plate. Remove the weight after 10 min, and then use a digital caliper to measure the longest diameter and the shortest diameter of the obtained sealer; when the diameter difference is observed to be less than 1 mm, record the average value of the two diameters, and the diameter of each sample should not be less than 20 mm. Each sealer is measured 3 times and the average value is taken. The specific test results are shown in Table 2:

[0052] Table 2

[0053]

[0054] As can be seen from Table 2, as the concentration of added ZnO QDs increases, the fluidity of MTA gradually decreases. The average fluidity of MTA with 0.5 mg / mL ZnO QDs added decreases by about 1.5%, the average fluidity of MTA with 1.0 mg / mL ZnO QDs added decreases by about 5.0%, and the fluidity of MTA with 2.0 mg / mL ZnO QDs added decreases by about 7.7%. It shows that adding ZnO QDs will slightly reduce the fluidity of the root canal sealer disclosed in this application and will reduce the sealing effect after filling to a certain extent.

[0055] Example 7

[0056] The solubility of the above comparative examples and Examples 1 to 4 was tested. The specific test method is as follows:

[0057] After the prepared root canal sealer was added to a circular mold and cured, the root canal sealer was taken out of the mold. Each root canal sealer round block sample was weighed 3 times and the average value was taken, accurate to 0.001 g. The sample was placed in a petri dish containing 50 mL of distilled water, and the petri dish was weighed before use; the petri dish was placed in a constant temperature and humidity chamber at 37 °C and 95% humidity for 24 h, then the sample was rinsed with 2 - 3 mL of distilled water, and then the sample was taken out. The petri dish was dried in an oven at 110 °C; it was cooled to room temperature in a drying container and weighed again. Finally, the percentage of the difference in weight of the petri dish before and after use to the original sample mass was calculated, that is, the dissolution rate of the sample, accurate to 0.1%. Each sealer was measured 3 times and the average value was taken. The specific results are shown in Table 3:

[0058] Table 3

[0059]

[0060] It can be seen from Table 3 that the solubility of Examples 1 to 4 is lower than that of the comparative example. The addition of ZnO QDs on the surface will reduce the solubility of MTA to a certain extent. Among them, the solubility of the MTA material added with 1 mg / mL ZnO QDs is only 20.03% of that of the comparative example, and the solubility of the MTA material added with 2 mg / mL ZnO QDs is 59.57% of that of the comparative example. However, as the concentration of ZnO QDs increases, the solubility of the root canal sealer also gradually increases, indicating that the higher the concentration of ZnO QDs added, the lower the solubility of the root canal sealer.

[0061] The solubility of the root canal sealer has an adverse effect on practical applications because when the sealer decomposes in the surrounding tissue, it will cause inflammation and cytotoxic reactions. According to international standards (ISO 6876 and ANSI / ADA Specification No. 57), the solubility of the root canal sealer when stored in water should not exceed 3% mass fraction. According to the test of this application, the dissolution rate of the MTA material alone reaches 7%. After adding ZnO QDs, the dissolution rate of the mixed preparation decreases and increases with the increase of the ZnO QDs concentration. When the ZnO QDs concentration is 0.25 and 0.5 mg / mL, the dissolution rate of the mixed preparation can meet the international standard, which plays a certain role in optimizing the dissolution rate of MTA.

[0062] Example 8

[0063] The radiopacity of the above comparative examples and Examples 1 to 4 was tested. The specific test method is as follows:

[0064] Place the prepared round blocks of root canal sealer and the wedge-shaped stepped aluminum plates (99.99% pure aluminum, thickness 1 - 12 mm, adjacent step spacing 1 mm) on a digital imaging plate, and use a dental X-ray machine to take parallel projection X-ray films (projection parameters: 70 kV, 8 mA, projection distance 30 cm, exposure time 0.12 s). Obtain digital periapical films through a digital imaging plate scanner, output the images in JPG format on the display screen, stipulate that the images are not adjusted for brightness and contrast, measure the gray levels of the specimens and aluminum wedges of different thicknesses on each X-ray film. First, calculate the relationship curve between the gray level and the thickness of the aluminum wedge, and then obtain the thickness of the aluminum wedge corresponding to the gray level of each specimen as the X-ray radiopacity value of the specimen. Take the average of the radiopacity values of 3 samples of each sealer as the X-ray radiopacity value of the sealer. The result should not be lower than the equivalent radiopacity of a 3-mm-thick aluminum plate. The final test results are shown in Table 4 as follows:

[0065] Table 4

[0066]

[0067] As can be seen from the above table, compared with the comparative example, from Example 1 to Example 4, as the concentration of added ZnO QDs increases, the average radiopacity value of the mixed preparation increases. There is no significant difference in the average radiopacity value between the MTA mixed preparation with ZnO QDs added at a concentration within 2 mg / mL and the radiopacity value of the MTA material without added ZnO QDs.

[0068] Table 4 shows that the radiation resistance of all Examples 1 to 4 is higher than 3 mm Al, meeting the recommendations of ISO 6876:2012. Adding ZnO QDs will increase the X-radiopacity value of the mixed material, but adding ZnO QDs at a concentration within 2 mg / mL will not significantly affect the radiopacity value of MTA.

[0069] Example 9:

[0070] Test the antibacterial properties of the above comparative example and Examples 1 to 4. The specific test method is as follows:

[0071] Prepare BHI agar plates evenly inoculated with Enterococcus faecalis. Immediately punch holes in the center of the plates, add the prepared root canal sealer into the holes, and place them in a 37°C constant temperature incubator for 24 h; after preparing the sealer, put it into a standard mold to make slices. After 24 h, take out the sealer slices, attach them to the plates and mark them, and then put them into a 37°C incubator. Compare the antimicrobial effects of the mixed materials according to the diameter of the antibacterial circle. Repeat the experiment 3 times and take the average value. The specific results are shown in Table 5 as follows:

[0072] Table 5

[0073]

[0074] As can be seen from Table 5, compared with the comparative example, the diameters of the inhibition zones of Examples 1 to 4 with ZnO QDs added have all increased to varying degrees. Among them, the diameters of the inhibition zones of Examples 2, 3, and 4 compared with that of the comparative example have increased by 4.7%, 13%, and 6.2% respectively. Among them, the average diameter of the inhibition zone of the root canal sealer with a ZnO QDs concentration of 1.0 mg / mL is the largest, indicating the strongest antibacterial effect. From the above results, it can be proved that adding ZnO QDs can enhance the antibacterial effect of MTA material against Enterococcus faecalis, and the enhancement effect is the strongest when the added concentration is 1.0 mg / mL.

[0075] Example 10

[0076] The root canal filling operations of the above comparative example, Examples 1 to 4 were evaluated, and the specific evaluation methods are as follows:

[0077] Five adult male beagle dogs were used, and the conditions of the beagle dogs are shown in Table 6:

[0078] Table 6

[0079]

[0080] Five operators randomly selected a beagle dog, anesthetized the animal by intravenous injection of Zoletil (10 mg / kg), and randomly selected 3 molars in the oral cavity of the dog. The dental pulp was removed using a file. After removing the dental pulp, the exposed root canal was thoroughly cleaned with normal saline. After the root canal was completely dried, Example 1 was used for filling. The curing time of the material and the filling effect after complete solidification during the operation were scored according to the scoring rules in Tables 7 and 8, and the scoring results were analyzed.

[0081] Table 7

[0082]

[0083] Table 8

[0084]

[0085] The evaluation results of the final curing time are shown in Table 9, and the evaluation results of the filling operation effect are shown in Table 10.

[0086] Table 9

[0087]

[0088] Table 10

[0089]

[0090] Since adding ZnO QDs within 2 mg / mL has no significant effect on the setting time, fluidity, and radiopacity of the hybrid material, we selected Example 1 with the lowest ZnO QDs concentration for the evaluation of root apex filling operation. In the evaluation of root apex filling operation, the performance of Example 1 was stable and the bonding was generally good.

[0091] As can be seen from Table 9, the average score of the three operators was 0, and the average score of the two operators was 0.3. There was no significant difference in the scoring results of the five individuals. As can be seen from Table 10, the average score of one operator was 0.3, and there was a phenomenon of a little air bubble inside the filling of one molar. The average scores of the other four operators were all 0 points. It shows that the root canal sealer mixed with ZnOQDs and MTA can solidify at 110 minutes during the root apex filling operation of dogs, and the bonding condition is good. There is no loosening phenomenon after curing, and the performance is stable.

[0092] Summary:

[0093] Mixing ZnO QDs with a concentration of 0.25 - 2 mg / mL has no significant effect on the setting time, fluidity, and radiopacity of the MTA root canal sealer. Adding ZnO QDs can reduce the dissolution rate of the root canal sealer and improve the antibacterial performance of the root canal sealer. The antibacterial property of the mixed preparation is the strongest when adding 1 mg / mL ZnO QDs. The MTA mixed preparation added with 0.25 mg / mL concentration of ZnO QDs shows stable performance, solidification rate, and bonding degree during the root apex filling operation of experimental dogs.

[0094] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A root canal sealer, characterized in that, Comprising: Trioxide mineral polymer, nano-zinc oxide quantum dots and aqueous solution, wherein the concentration of the nano-zinc oxide quantum dots in the aqueous solution is 0.25 - 0.5 mg / mL, and the concentration of the trioxide mineral polymer in the aqueous solution is 1.5 g / mL.

2. A method for preparing a dental filling, characterized in that, Comprising the root canal sealer according to claim 1, and further comprising the following steps: Mix the trioxide mineral polymer, the nano-zinc oxide quantum dots and the aqueous solution to obtain a mixture; Cure the mixture, and a dental filling is obtained after curing.

3. A dental filling prepared by the preparation method according to claim 2.

4. A medical device, characterized in that, Comprising the root canal sealer according to claim 1; and A first container, which contains a powder phase; A second container, which contains the aqueous solution.

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