DENTAL GLASS AND DENTAL COMPOSITION

Abstract

A dental glass includes, in terms of oxide:phosphorus (P.sub.2O.sub.5) by greater than or equal to 40% by mass and less than or equal to 70% by mass; potassium (K.sub.2O) by greater than or equal to 20% by mass and less than or equal to 40% by mass; and calcium (CaO) by greater than or equal to 1% by mass and less than or equal to 20% by mass, wherein the dental glass does not substantially contain silicon and aluminum.

Claims

1. A dental glass comprising, in terms of oxide: phosphorus (P.sub.2O.sub.5) by greater than or equal to 40% by mass and less than or equal to 70% by mass; potassium (K.sub.2O) by greater than or equal to 20% by mass and less than or equal to 40% by mass; and calcium (CaO) by greater than or equal to 1% by mass and less than or equal to 20% by mass, wherein the dental glass does not substantially contain silicon and aluminum.

2. A dental composition comprising the dental glass according to claim 1.

Description

EXAMPLES

[0066] Although specific Examples and Comparative Examples will be described in the following, the present invention is not limited to the examples.

[0067] First, the evaluation methods of the dental glasses produced in the following Examples and Comparative Examples will be described.

(Vitrification)

[0068] In each of the following Examples and Comparative Examples, a material composition was prepared by mixing materials for a dental glass, the prepared material composition was heated and melted, and thereafter rapidly cooled to an ambient temperature to prepare the dental glass. Then, the state of each prepared dental glass was visually confirmed and evaluated as GOOD when vitrification was confirmed, and POOR when it was not vitrified. Note that when it was not vitrified, it means that a dental glass could not be prepared, and thus the subsequent evaluation was not carried out.

(Solubility in Water)

[0069] The prepared dental glass was pulverized to prepare a pulverized glass having an average particle diameter of 10 m. Subsequently, the pulverized glass is dispersed in distilled water to have a concentration of 1% by mass (mass of charged dental glass), and the mixture is stirred at an ambient temperature for 1 hour. Next, undissolved glass powder was recovered with filter paper, and dried. Thereafter, the mass of the undissolved dental glass after being dried (undissolved dental glass mass) was measured, and the solubility of the dental glass in water was calculated by the following formula (1).

(solubility of dental glass in water (mass %))=[(input dental glass mass)(undissolved dental glass mass)]/(input dental glass mass)100Formula (1)

(pH after being Dissolved in Water)

[0070] The prepared dental glass was pulverized to prepare a pulverized glass having an average particle diameter of 10 m. Next, a pH, after the pulverized glass was dispersed in distilled water so as to have a concentration of 1% by mass and stirred at an ambient temperature for 1 hour, was measured as the pH after being dissolved in water.

Example 1

[0071] Phosphoric acid, calcium phosphate, and sodium carbonate as materials were weighed and mixed so as to have the composition indicated in Table 1. Then, the obtained mixture was placed in a platinum crucible, heated at 1100 C. in an air atmosphere and melted, then poured out on a stainless steel plate and rapidly cooled by being pressed by an iron to produce a dental glass.

[0072] Note that in Table 1, with respect to P, Na, K, Ca, Sr, B, Si, Al, La, Zn and Ag, the ratios in terms of oxides are indicated.

Example 2 to Example 8

[0073] Except that materials were weighed and mixed such that the dental glasses had the compositions indicated in Table 1 for respective Examples, the dental glasses were prepared and evaluated similarly to Example 1.

[0074] The results are indicated in Table 1.

Comparative Example 1 to Comparative Example 9

[0075] Except that materials were weighed and mixed such that the dental glasses had the compositions indicated in Table 1 for respective Comparative Examples, the dental glasses were prepared and evaluated similarly to Example 1.

[0076] The results are indicated in Table 1.

TABLE-US-00001 TABLE 1 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple 1 2 3 4 5 6 7 8 COM- P.sub.2O.sub.5 68.3 57.7 59.6 53.9 44.2 49.8 52.4 59.8 POSI- Na.sub.2O 28.1 25.1 33.4 23.8 21.0 39.0 TION K.sub.2O 32.1 33.0 OF CaO 3.6 5.3 1.0 4.3 6.4 2.2 3.4 1.2 DENTAL SrO 10.3 8.4 8.6 4.6 GLASS B.sub.2O.sub.3 1.6 1.3 3.6 (MASS %) SiO.sub.2 Al.sub.2O.sub.3 La.sub.2O.sub.3 4.5 17.0 17.5 ZnO 1.5 3.9 AgO 6.5 F 2.1 Fe S EVALUATION VITRIFI- GOOD GOOD GOOD GOOD GOOD GOOD GOOD GOOD RESULTS CATION SOLUBILITY 78.0% 28.0% 88.0% 56.0% 21.0% 89.0% 15.0% 100.0% IN WATER pH AFTER 7.3 7.5 8.7 7.0 8.4 6.8 8.4 9.6 BEING DISSOLVED IN WATER Com- Com- Com- Com- Com- Com- Com- Com- Com- parative parative parative parative parative parative parative parative parative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple 1 2 3 4 5 6 7 8 9 COM- P.sub.2O.sub.5 73.7 68.7 35.4 42.6 47.5 67.0 53.1 6.6 50.1 POSI- Na.sub.2O 21.8 33.8 16.2 8.4 30.6 TION K.sub.2O 56.4 15.5 32.3 OF CaO 2.9 31.3 6.2 1.0 10.1 7.2 2.5 15.8 DENTAL SrO 26.9 GLASS B.sub.2O.sub.3 4.8 19.3 (MASS %) SiO.sub.2 47.0 Al.sub.2O.sub.3 11.4 La.sub.2O.sub.3 9.6 ZnO 1.6 4.8 6.2 AgO 5.2 F 24.6 1.9 Fe S EVALUATION VITRIFI- GOOD GOOD POOR POOR GOOD GOOD GOOD GOOD GOOD RESULTS CATION SOLUBILITY 32.0% 8.0% 2.6% 7.1% 1.3% 2.4% 2.6% IN WATER pH AFTER 3.1 3.9 7.2 3.0 2.5 11.8 7.5 BEING DISSOLVED IN WATER

[0077] According to the results indicated in Table 1, it was confirmed that in each of Example 1 to Example 8, the solubility in water was high and greater than or equal to 10%. Accordingly, the dental glasses could be confirmed as being excellent in a property of releasing ions such as calcium ions and phosphate ions contained in the dental glasses for the respective Examples. Also, the pH after being dissolved in water was in a range of greater than or equal to 5 and less than or equal to 11, and the dental glasses could be confirmed as being applicable into a mouth.

[0078] In contrast, Comparative Example 2 and Comparative Examples 5 to 9 had the solubility in water less than 10%, and could be confirmed as not having a sufficient solubility in water. Therefore, the dental glasses could be confirmed as being inferior in a property of releasing ions such as calcium ions and phosphate ions.

[0079] Also, in Comparative Example 1, although the solubility in water was 32% and high, the pH after being dissolved in water was 3.1 and very low, Comparative Example 1 could be confirmed as not being applicable into a mouth.

[0080] In Comparative Examples 3 and 4, vitrification could not be confirmed. That is, dental glass could not be obtained.

[0081] Although dental glasses and dental compositions have been described above with reference to the embodiment, the examples, etc., the present invention is not limited to the embodiments, the examples, etc. described above. Various modifications and changes can be made within the scope of the present invention recited in the claims.