Patent Application
20200009021
The present invention relates to a dental composition and a method of preparing the same, and more particularly to a dental hydraulic composition including hydraulic cement and a non-aqueous liquid and a method of preparing the same.
Damage to tooth enamel begins due to acids generated through the decomposition of sugar components by bacteria living in the oral cavity to thus cause tooth decay, which is referred to as dental caries. When dental caries are confined to the enamel, little pain is experienced, but when the caries progress to the dentin or pulp, severe pain may result. In this case, root-canal treatment for eliminating the pulp in the root canal has to be performed. When root-canal treatment is performed, it is necessary to fill the empty space in the root canal to suppress the occurrence of secondary infection, Gutta-percha and a sealer being the most widely used materials for filling the empty space in the root canal.
Gutta-percha, which is a very safe material for use in living bodies, has been used for a long time, but is a solid material and thus has to be loaded using heat and pressure, making it difficult to completely fill the convoluted root canal therewith. Hence, various ointment-type sealers have also been used to offset the disadvantages of Gutta-percha. Examples of sealers used to date include resin, zinc oxide, calcium hydroxide, silicone and the like, but have defects of low biosafety or poor adhesion to a tooth structure or Gutta-percha.
Mineral trioxide aggregate (MTA) was first introduced in 1992 by Mahmoud Torabinejad, a professor at the University of Roma Linda in the USA, and has come to be widely used as a dental composition because it is composed of tooth-like components. MTA is composed of Portland cement and bismuth oxide, which is a radiopaque agent. Portland cement comprises dicalcium silicate, tricalcium silicate, tricalcium aluminate, and tricalcium aluminoferrite, and has the property of curing upon contact with water. Calcium silicate is formed into calcium silicate hydrate gel upon contact with water, and furthermore, calcium hydroxide may be formed as a byproduct thereof, thus exhibiting a high pH. Due to the high pH thereof, antibacterial effects are manifested in the oral cavity.
MTA is advantageous because of antibacterial effects and tooth-like components, as described above. Upon application thereof to the tooth, however, the powder, which is used by being mixed with water, begins to react at the time of mixing with water, and thus has the disadvantages of a short working time of less than 5 min and a long curing time of about 4 hr. Furthermore, MTA is problematic in that it appears grayish due to the ferrite component and thus the tooth may be colored, and also in that there is a need to use an additional carrier when applied to a narrow root canal.
Therefore, it is necessary to develop a dental hydraulic composition that is easy to use and has a long working time, a short curing time, and improved biocompatibility.
Accordingly, the present invention is intended to provide a dental composition and a method of preparing the same.
In addition, the present invention is intended to provide a dental hydraulic composition, which is easy to use and is improved from the aspects of aesthetic appearance, curability and biocompatibility, and a method of preparing the same.
An aspect of the present invention provides a dental composition, comprising:
cement; and
a non-aqueous liquid,
in which the cement includes:
a first domain including alite;
a second domain including belite; and
a matrix located between one or more selected from the group consisting of the first domain and the second domain and configured to include silicon (Si)-atom-doped tricalcium aluminate (3CaO.Al2O3).
Also, the silicon-atom-doped tricalcium aluminate may be configured such that a portion of aluminum atoms of tricalcium aluminate (3CaO.Al2O3) is substituted with a silicon atom.
Also, the silicon (Si)-doped tricalcium aluminate (3CaO.Al2O3) may be configured such that silicon (Si) is doped in an amount of 0.5 to 15 wt %.
Also, the dental composition may further comprise at least one of a radiopaque agent, a calcium phosphate compound, and a curing modifier.
Also, the dental composition may include 100 parts by weight of the cement; 10 to 100 parts by weight of the non-aqueous liquid; and at least one of 20 to 200 parts by weight of the radiopaque agent, 1 to 30 parts by weight of the calcium phosphate compound and 0.1 to 20 parts by weight of the curing modifier.
Also, the cement may be configured such that a weight ratio (D:M) of a weight sum (D, D1+D2) of the first domain (D1) and the second domain (D2) to a weight of the matrix (M) is 99:1 to 70:30.
Also, the cement may be a hydraulic material prepared by reacting a mixture comprising calcium oxide, silicon dioxide, and aluminum oxide through heat treatment.
Also, the non-aqueous liquid may include at least one selected from among ethanol, propanol, vegetable fat and oil, animal fat and oil, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin, and preferably includes polypropylene glycol, because polypropylene glycol has high biocompatibility compared to polyethylene glycol. When polypropylene glycol is included as the non-aqueous liquid, another non-aqueous liquid other than polypropylene glycol may be further included.
Also, the calcium phosphate compound may include at least one selected from among calcium phosphate, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, apatite, octacalcium phosphate, biphasic calcium phosphate, amorphous calcium phosphate, casein phosphopeptide-amorphous calcium phosphate, and bioactive glass.
Also, the calcium phosphate compound may be bioactive glass.
Also, the bioactive glass may be represented by Chemical Formula 1 below.
(SiO2)x(Na2O)y(CaO)z(P2O5)w [Chemical Formula 1]
In Chemical Formula 1, x, y, z, and w are numbers of moles, 30≤x≤70, 0≤y≤40, 10≤z≤50, and 1≤w≤10.
Also, the radiopaque agent may include at least one selected from among zinc oxide, barium sulfate, zirconium oxide, bismuth oxide, barium oxide, iodoform, tantalum oxide, and calcium tungstate.
Also, the curing modifier may include at least one selected from among calcium sulfate dihydrate, calcium sulfate hemihydrate, calcium chloride, and calcium formate.
Also, the dental composition may further comprise a viscosity modifier.
Also, the amount of the viscosity modifier may be 0.1 to 20 parts by weight.
Also, the viscosity modifier may include at least one selected from among cellulose, a cellulose derivative, xanthan gum, polyvinyl alcohol, polyacrylic acid, and polyvinylpyrrolidone.
Also, the dental composition may be in a paste form.
Another aspect of the present invention provides a dental material obtained through hydraulic treatment of the above dental composition.
Still another aspect of the present invention provides a method of preparing a dental composition, comprising manufacturing cement and preparing a composition including the cement and a non-aqueous liquid.
Here, the cement may include a first domain including alite, a second domain including belite, and a matrix located between one or more selected from the group consisting of the first domain and the second domain and configured to include silicon (Si)-atom-doped tricalcium aluminate (3CaO. Al2O3).
Also, the composition may further comprise at least one of a radiopaque agent and a calcium-phosphate-based compound.
Also, the manufacturing the cement may be performed by reacting a mixture comprising calcium oxide, silicon dioxide, and aluminum oxide through heat treatment.
According to the present invention, a dental hydraulic composition and a method of preparing the same can be provided.
Also, according to the present invention, a dental hydraulic composition, which is provided in the form of a single ointment-type composition and is thus easy to use and is improved from the aspects of aesthetic appearance, curability and biocompatibility, and a method of preparing the same can be provided.
Hereinafter, embodiments of the present invention are described in detail with reference to the appended drawings so as to be easily performed by a person having ordinary skill in the art to which the present invention belongs.
However, the following description does not limit the present invention to specific embodiments, and moreover, descriptions of known techniques, even if they are pertinent to the present invention, are considered unnecessary and may be omitted insofar as they would make the characteristics of the invention unclear.
The terms herein are used to explain specific embodiments and are not intended to limit the present invention. Unless otherwise stated, the singular expression includes a plural expression. In this application, the terms “include” or “have” are used to designate the presence of features, numbers, steps, operations, elements, or combinations thereof described in the specification, and should be understood as not excluding the presence or additional possibility of one or more different features, numbers, steps, operations, elements, or combinations thereof.
According to the present invention, a dental hydraulic composition is described below.
An aspect of the present invention pertains to a dental composition, comprising cement and a non-aqueous liquid, in which the cement includes a first domain including alite, a second domain including belite, and a matrix located between one or more selected from the group consisting of the first domain and the second domain and configured to include silicon (Si)-atom-doped tricalcium aluminate (3CaO.Al2O3).
The silicon (Si)-doped tricalcium aluminate (3CaO.Al2O3) may be configured such that silicon (Si) is doped is an amount of 0.5 to 15 wt %, preferably 1 to 10 wt %, and more preferably 2 to 5 wt %.
The firing temperature of the cement having the domain and matrix structure falls in the range of 1200° C. to 1550° C., preferably 1300° C. to 1500° C., and more preferably 1400° C. to 1500° C. If the firing temperature thereof is lower than 1200° C., belite is mainly formed, rather than alite, undesirably lowering the strength of the cement. On the other hand, if the firing temperature thereof is higher than 1550° C., alite may be formed, but alite, among the components of the cement, may decompose during firing, undesirably lowering the strength of the cement.
The heating rate required to reach the firing temperature of the cement having the domain and matrix structure is 1° C./min to 20° C./min, and preferably 2° C./min to 10° C./min. If the heating rate required to reach the firing temperature thereof is less than 1° C./min, the time becomes excessively prolonged, undesirably lowering productivity. On the other hand, if the heating rate required to reach the firing temperature thereof exceeds 20° C./min, the reaction time between the mixed materials is not sufficient and some materials are left behind and thus the cement strength is lowered, which is undesirable.
The firing time in the temperature range for forming the cement having the domain and matrix structure falls in the range of 0.5 hr to 24 hr, and preferably 1 hr to 12 hr. If the firing time is less than 0.5 hr, the reaction time between the mixed materials is not sufficient and some materials are left behind and thus the cement strength is lowered, which is undesirable. On the other hand, if the firing time exceeds 24 hr, excessive energy consumption is required, thus negating economic benefits, which is undesirable.
The non-aqueous liquid may include at least one selected from among ethanol, propanol, vegetable fat and oil, animal fat and oil, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin.
The non-aqueous liquid is preferably contained in an amount of 10 to 100 parts by weight based on 100 parts by weight of the cement.
The calcium phosphate may include at least one selected from among calcium phosphate, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, apatite, octacalcium phosphate, biphasic calcium phosphate, amorphous calcium phosphate, casein phosphopeptide-amorphous calcium phosphate, and bioactive glass.
The calcium phosphate compound may be bioactive glass.
The bioactive glass may be represented by Chemical Formula 1 below.
(SiO2)x(Na2O)y(CaO)z(P2O5)w [Chemical Formula 1]
In Chemical Formula 1, x, y, z, and w are numbers of moles, 30x≤70, 0≤y≤40, 10≤z≤50, and 1≤w≤10.
Calcium hydroxide, generated as a byproduct during hydraulic treatment of the cement, is dissolved in saliva in the oral cavity to thus increase the pH and exhibit an antibacterial effect. Also, it reacts with calcium phosphate to give hydroxyapatite, which is a component of the teeth.
The calcium phosphate is preferably used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the cement.
Also, the dental composition may include a radiopaque agent in order to confirm the results of treatment.
The radiopaque agent may include at least one selected from among zinc oxide, barium sulfate, zirconium oxide, bismuth oxide, barium oxide, iodoform, tantalum oxide, and calcium tungstate.
The radiopaque agent is preferably used in an amount of 20 to 200 parts by weight based on 100 parts by weight of the cement.
Also, the dental composition may further include a viscosity modifier.
The viscosity modifier may include at least one selected from among cellulose, a cellulose derivative, xanthan gum, polyvinyl alcohol, polyacrylic acid, and polyvinylpyrrolidone.
The viscosity modifier is preferably used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the cement.
Also, the dental composition may further include a curing modifier.
The curing modifier may include at least one selected from among calcium sulfate dihydrate, calcium sulfate hemihydrate, calcium chloride, and calcium formate.
The curing modifier is preferably used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the cement.
Another aspect of the present invention pertains to a dental material obtained through hydraulic treatment of the dental composition of the present invention.
Still another aspect of the present invention pertains to a method of preparing a dental composition, comprising manufacturing cement and preparing a composition comprising the cement and a non-aqueous liquid.
Here, the cement may include a first domain including alite, a second domain including belite, and a matrix located between one or more selected from the group consisting of the first domain and the second domain and configured to include silicon (Si)-atom-doped tricalcium aluminate (3CaO.Al2O3).
Also, the composition may further include at least one of a radiopaque agent and a calcium-phosphate-based compound.
Also, the cement may be manufactured by subjecting a mixture comprising calcium oxide, silicon dioxide, and aluminum oxide to reaction through heat treatment and firing.
A better understanding of the present invention will be given through the following preferred examples, which are merely set forth to illustrate the present invention but are not to be construed as limiting the scope of the present invention.
141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide, which had been dried at 105° C. for 24 hr or more, were weighed, placed in a V-shaped mixer containing ceramic balls having sizes of 10 mm, 5 mm and 1 mm at a predetermined ratio in the same volume as the material mixture in order to realize uniform mixing of materials having different particle sizes and specific gravities and pulverization thereof to a certain size, and then mixed at 50 rpm for 4 hr.
After mixing, the ceramic balls were removed, and the resulting mixture was formed into a hollow cylinder in order to achieve a totally uniform reaction, placed in a platinum crucible, fired in a firing furnace at 1,500° C. for 1 hr 30 min, immediately taken out of the firing furnace, and rapidly cooled to 25° C. for 10 min using a cooling fan in an ambient atmosphere.
The rapidly cooled cement was primarily pulverized to a size of 1 mm or less under dry conditions, and ⅕ of the volume of a ceramic bottle was filled with the primarily pulverized cement, and ceramic balls having sizes of 10 mm, 5 mm and 1 mm at a predetermined ratio were placed in ⅕ of the volume of the bottle, followed by pulverization for 24 hr. Here, the ceramic bottle and the ceramic balls were used after drying at 105° C. for 24 hr or more. The pulverized materials were sieved to an average particle size of 10 μm or less, yielding a cement powder.
The phase of the powder thus obtained was analyzed using a D/max 2200V/PC, available from Rigaku, Japan. Here, the analysis conditions were 2theta=20−60°, scan speed=5°/min, target=CuKα1, and acceleration voltage of 40 kV and 20 mA.
The cement of Preparation Example 2 was manufactured in the same manner as in Preparation Example 1, with the exception that 137 parts by weight of calcium oxide, 45 parts by weight of silicon dioxide and 18 parts by weight of aluminum oxide were used, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide as in Preparation Example 1.
The phase analysis of the cement of Preparation Example 2 was performed in the same manner as the phase analysis of the cement of Preparation Example 1.
The cement of Preparation Example 3 was manufactured in the same manner as in Preparation Example 1, with the exception that 141 parts by weight of calcium oxide, 45 parts by weight of silicon dioxide and 14 parts by weight of aluminum oxide were used, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide as in Preparation Example 1.
The phase analysis of the powder of Preparation Example 3 was performed in the same manner as the phase analysis of the powder of Preparation Example 1.
137 parts by weight of calcium oxide, 45 parts by weight of silicon dioxide, and 14 parts by weight of aluminum oxide, which had been dried at 105° C. for 24 hr or more, were weighed, placed in a V-shaped mixer containing ceramic balls having sizes of 10 mm, 5 mm and 1 mm at a predetermined ratio in the same volume of the material mixture in order to realize uniform mixing of materials having different particle sizes and specific gravities and pulverization thereof to a certain size, and then mixed at 50 rpm for 4 hr. After completion of mixing, the ceramic balls were removed, and the resulting mixture was formed into a hollow cylinder in order to achieve a totally uniform reaction, placed in a platinum crucible, fired in a firing furnace at 1,500° C. for 1 hr 30 min, immediately taken out of the firing furnace, and rapidly cooled to 25° C. for 10 min using a cooling fan in an ambient atmosphere. The rapidly cooled cement was pulverized under the same pulverization conditions as in Preparation Example 1, and the cement powder of Preparation Example 4 was further mixed with 1.3 parts by weight of silicon dioxide and 4.5 parts by weight of aluminum oxide. The mixed powder was analyzed in the same manner as in Example 1.
The cement of Comparative Preparation Example 1 was manufactured in the same manner as in Preparation Example 1, with the exception that 141 parts by weight of calcium oxide and 50.4 parts by weight of silicon dioxide were used, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide as in Preparation Example 1.
The phase analysis of the cement of Comparative Preparation Example 1 was performed in the same manner as the phase analysis of the cement of Preparation Example 1.
The cement of Comparative Preparation Example 2 was manufactured in the same manner as in Preparation Example 1, with the exception that 151 parts by weight of calcium oxide and 60 parts by weight of silicon dioxide were used and firing at 1,600° C. and then air cooling were performed, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide, firing at 1,500° C. and then rapid cooling as in Preparation Example 1.
The phase analysis of the cement of Comparative Preparation Example 2 was performed in the same manner as the phase analysis of the cement of Preparation Example 1.
The cement of Comparative Preparation Example 3 was manufactured in the same manner as in Preparation Example 1, with the exception that 118.8 parts by weight of calcium oxide, 49 parts by weight of silicon dioxide, 10.75 parts by weight of boehmite (aluminum oxide) and 4.61 parts by weight of ferrite oxide (iron oxide) were used and firing at 1,550° C. and then air cooling were performed, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide, firing at 1,500° C. and then rapid cooling as in Preparation Example 1.
The phase analysis of the cement of Comparative Preparation Example 3 was performed in the same manner as the phase analysis of the cement of Preparation Example 1.
The cement of Comparative Preparation Example 4 was manufactured in the same manner as in Preparation Example 1, with the exception that 137 parts by weight of calcium oxide, 45 parts by weight of silicon dioxide and 18 parts by weight of aluminum oxide were used and air cooling was performed, in lieu of using 141.5 parts by weight of calcium oxide, 51.7 parts by weight of silicon dioxide, 2.1 parts by weight of aluminum oxide, 0.7 parts by weight of iron oxide, and 0.6 parts by weight of magnesium oxide and rapid cooling to 25° C. for 10 min using a cooling fan in an ambient atmosphere as in Preparation Example 1.
The phase analysis of the cement of Comparative Preparation Example 4 was performed in the same manner as the phase analysis of the cement of Preparation Example 1.
Table 1 below shows the components and amounts of the cement, the firing temperature and the cooling process in Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 4.
52 parts by weight of the cement manufactured in Preparation Example 2, 20 parts by weight of polypropylene glycol, 25 parts by weight of zirconium oxide and 3 parts by weight of calcium sulfate dihydrate were mixed at 100 rpm for 4 hr using a mixer and allowed to stand for 30 min in a vacuum (−0.095±0.005 MPa) in order to defoam the hydraulic composition and increase the packing density.
Thereafter, a vessel was filled with the hydraulic composition, thereby yielding a dental hydraulic composition.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that the cement manufactured in Preparation Example 3 was used in lieu of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that 50 parts by weight of the cement manufactured in Preparation Example 2 and 2 parts by weight of bioactive glass ((SiO2)9(Na2O)5(CaO)5(P2O5)1) were used, in lieu of 52 parts by weight of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 3, with the exception that 60 parts by weight of the cement manufactured in Preparation Example 2 and 10 parts by weight of polypropylene glycol were used, in lieu of 50 parts by weight of the cement manufactured in Preparation Example 2 and 20 parts by weight of polypropylene glycol.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that 62 parts by weight of the cement manufactured in Preparation
Example 2 and 10 parts by weight of polypropylene glycol were used, in lieu of 52 parts by weight of the cement manufactured in Preparation Example 2 and 20 parts by weight of polypropylene glycol.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that 52 parts by weight of the cement manufactured in Preparation
Example 4 was used, in lieu of 52 parts by weight of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 4, with the exception that 60 parts by weight of the cement manufactured in Preparation Example 2 and 2 parts by weight of tricalcium phosphate were used, in lieu of 60 parts by weight of the cement manufactured in Preparation Example 2 and 2 parts by weight of bioactive glass ((SiO2)9(Na2O)5(CaO)5(P2O5)1).
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that the ordinary Portland cement manufactured in Preparation Example was used, in lieu of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that the cement manufactured in Comparative Preparation Example 2 was used, in lieu of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that the cement manufactured in Comparative Preparation Example 3 was used, in lieu of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 2, with the exception that 52 parts by weight of the cement manufactured in Comparative Preparation Example 4 was used, in lieu of the cement manufactured in Preparation Example 2.
A dental hydraulic composition was prepared in the same manner as in Example 1, with the exception that the cement manufactured in Comparative Preparation Example 1 was used, in lieu of the cement manufactured in Preparation Example 2.
Table 2 below shows the components and amounts of the dental hydraulic compositions of Examples 1 to 7 and Comparative Examples 1 to 5.
Table 3 below shows the results of evaluation of flowability and compressive strength of the dental compositions of Examples 1 to 7 and Comparative Examples 1 to 5.
For the evaluation of flowability of the dental composition, two glass plates having a size of 40 mm (width)×40 mm (length), a thickness of about 5 mm and a weight of about 20 g were prepared. 0.05±0.005 ml of the dental composition was placed on the center of one of the glass plates and covered with the other glass plate, to which a weight of 120±2 g was then applied for 10 min. After 10 min, the spread size of the dental composition was measured and measurement values in which the difference between maximum and minimum values was less than 1 mm were recorded, determined three times and averaged.
The compressive strength of the dental composition was determined in a manner in which a gypsum mold having a cavity with a diameter of 4 mm and a height of 6 mm was stored in a constant-temperature and constant-humidity chamber at a temperature of 37±1° C. and a humidity of 95%, the cavity thereof was filled with the sample in the constant-temperature and constant-humidity chamber, and the sample was separated from the mold after 1 day, 7 days, 14 days, and 28 days, followed by testing under a force of 100 N at a speed of 1 mm/min using a UTM (Universal Testing Machine), measurement five times and averaging.
As is apparent from the results of evaluation of flowability, the flowability varied depending on the amount of cement in the dental composition, and in Examples 1, 2 and 3, the amount of cement in the dental composition was smaller than that in Examples 4, 5 and 7, and thus high flowability was exhibited. As such, the dental composition having high flowability may be used as a sealer, and the dental composition having low flowability may be used for repair.
Based on the results of measurement of compressive strength, the dental composition of Example 4 exhibited the highest compressive strength, and the dental compositions of Examples 5 and 7 showed high compressive strength compared to the examples prepared under other conditions.
With reference to
With reference to
As described above, based on the results of EDS, Si and Al were observed to be distributed in the matrix, and the matrix was observed to be a silicon-doped tricalcium aluminate matrix configured such that aluminum of tricalcium aluminate was substituted with silicon.
In contrast, with reference to
Preparation Example 2 and Comparative Preparation Example 3.
Even after the mixture of Preparation Example 2 was fired at 1500° C., the initial shape thereof was maintained. However, after firing of the mixture of Comparative Preparation Example 3 at 1550° C., the initial shape thereof disappeared and the decomposed powder shape was observed.
Thus, the shape of the mixture after firing varied depending on the temperature at which the mixture was fired.
The internal shape of the cement manufactured in Preparation Example 2 was different from that of the cement manufactured in Comparative Preparation Example 4.
This means that the internal structure varied depending on the cooling conditions even when the same material was used.
With reference to
With reference to
With reference to
With reference to
With reference to
With reference to
With reference to
In accordance with ISO 6876:2012, evaluation was performed through the following method. Specifically, a gypsum mold having a cavity with a diameter of 10 mm and a height of 1 mm was stored in a constant-temperature and constant-humidity chamber at a temperature of 37±1° C. and a humidity of 95%, and the cavity thereof was filled with the sample in the constant-temperature and constant-humidity chamber. During curing, a Gilmore needle having a weight of 100±5 g and a tip diameter of 2±0.1 mm was placed on the surface of the sample for 15 sec, which was repeated until no mark caused thereby was observed with the naked eye. The time at which no mark was observed was determined to be the curing time, and was measured three times and averaged. The results are shown in Table 5 below.
As is apparent from Table 5, the curing time of the dental hydraulic compositions of Examples 1 to 5 and 7 was faster than the curing time of the dental hydraulic compositions of Comparative Examples 1 to 5.
The reason why the curing time of the dental hydraulic composition of Comparative Example 2 was long was that the amount of belite having low curing reactivity was relatively high compared to Comparative Example 5 and thus affected the curing time.
The reason why the curing time of the dental hydraulic composition of Comparative Example 3 was long was that the materials decomposed during the firing process impeded the curing reaction and thus affected the curing time.
The reason why the curing time of the dental hydraulic composition of Comparative Example 4 was long was that the amount of belite that was produced in the cement under air cooling conditions was large compared to the cement manufactured under rapid cooling conditions, and thus the curing reaction rate was decreased compared to the cement composition used in Example 1, thus affecting the curing time.
With reference to
In accordance with ISO 23317:2014, evaluation was performed through the following method.
700 ml of distilled water and magnetic bars were placed in a 1 L plastic beaker and the beaker was covered with transparent glass or a wrap. A water bath was placed on a magnetic stirrer and the beaker was placed therein. During stirring, heat was applied until the temperature of the water bath was 36.5±1.5° C. 8.035 g of NaCl, 0.355 g of NaHCO3, 0.225 g of KCl, 0.231 g of K2HPO43H2O, 0.311 g of MgCl26H2O, 39 ml of 1 mol/L HCl, 0.292 g of CaCl2, and 0.072 g of Na2SO4 were dissolved with stirring one by one. As such, if the amount of the solution was less than 0.9 L, distilled water was added to make 0.9 L. When the temperature of the solution was measured and thus reached 36.5±1.5° C., tris was added little by little and changes in pH were observed. When the pH of the solution was 7.45±0.01, the addition of tris was stopped and an HCl solution was added. The HCl solution was added until the pH was 7.42±0.01. When the pH was less than 7.42±0.01, the remaining tris was dissolved little by little. The pH was adjusted to the range of 7.42 to 7.45, and tris was completely dissolved and then HCl was added little by little such that the pH of the solution was 7.42±0.01. The prepared solution was placed in a 1 L volumetric flask, distilled water was added to the 1 L marking line of the flask, and the flask was placed in a water bath so that the solution temperature was decreased to less than 20° C. When the temperature became less than 20° C., distilled water was added to the 1 L marking line of the flask.
A mold having a diameter of 10±2 mm and a height of 2±1 mm was filled with the sample of each of Examples 1 and 3 to give a test specimen, the surface area (Sa) of which was then calculated. The volume of SBF (Vs) necessary for the test was calculated using Equation 1 below.
Vs=100 mm×Sa [Equation 1]
The calculated volume of SBF was placed in a plastic vessel with a lid. Heat was applied until the temperature of the SBF was 36.5° C., and the test specimen was placed therein. Here, the test specimen has to be completely immersed in SBF. The SBF containing the test specimen therein was stored at 36.5° C., and the test specimen was periodically taken out and washed with water. The washed test specimen was dried in a desiccator at room temperature. The surface of the dried test specimen was observed through SEM and XRD.
With reference to the SEM images of
Specifically, with reference to the XRD data (after 4 weeks) of
With reference to
A syringe for use in root-canal treatment was filled with the dental composition of Example 3 of the present invention so as to prevent foaming and was equipped with a dispensing tip so that the root canal was filled therewith.
With reference to
If the interface between the dentin and the dental composition or between the GP and the dental composition is not sealed with the composition, a microleak may develop and secondary caries attributable to tooth bacteria may occur.
With reference to
According to the present invention, a dental composition is a single ointment-type composition comprising cement, a non-aqueous liquid, a radiopaque agent and calcium phosphate, and is thus easy to use and can be improved from the aspects of aesthetic appearance, curability and biocompatibility.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0028689 | Mar 2017 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2018/002598 | 3/5/2018 | WO | 00 |
