WAX PATTERN SURFACE-TREATING AGENT

Abstract

A wax pattern surface-treating agent includes a solvent, boron nitride, and at least one surfactant selected from a group consisting of an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and an amphoteric surfactant.

Claims

1. A wax pattern surface-treating agent comprising: a solvent; boron nitride; and at least one surfactant selected from a group consisting of an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and an amphoteric surfactant.

2. The wax pattern surface-treating agent according to claim 1, wherein a content ratio of the boron nitride is greater than or equal to 0.02% by mass and less than or equal to 20% by mass; and a content ratio of the at least one surfactant is greater than or equal to 0.01% by mass and less than or equal to 8% by mass.

3. The wax pattern surface-treating agent according to claim 1, wherein the solvent includes at least one substance selected from a group consisting of water, ethanol, methanol, propanol, butanol, pentanol, acetone, tetrahydrofuran, and methyl ethyl ketone.

Description

EXAMPLES

[0047] In the following, specific examples and comparative examples will be described. Note, however, that the present invention is not limited to the specific examples described below.

Example 1

[0048] (Preparation of Wax Pattern Surface-Treating Agent)

[0049] 98 parts by mass of methyl ethyl ketone as a solvent, 2 parts by mass of boron nitride powder (with average particle diameter of 4 m), and 0.2 parts by mass of sodium lauryl sulfate as an anionic surfactant were mixed together using a mixer to prepare a wax pattern surface-treating agent.

[0050] (Fabrication of Dental Prosthesis)

[0051] A dental impression of the teeth of a patient was taken using a silicone rubber impression material. Then, gypsum was poured into the dental impression to form a gypsum model.

[0052] Then, a wax pattern was formed on the gypsum model using dental wax (manufactured by GC Corporation, product name: Inlay Wax). Then, a sprue having a diameter of 2.5 mm was formed.

[0053] Then, the wax pattern and the sprue were attached to a crucible former. Then, the above-described wax pattern surface-treating agent was coated on the surface of the wax pattern and the surface of the sprue using a spray (wax pattern surface-treating agent coating step).

[0054] Then, a ring having a liner formed therein was arranged on the peripheral portion of the base of the crucible former to which the wax pattern and the sprue wire are attached so that the ring surrounds the wax pattern and the sprue.

[0055] Then, a slurry-like investment material (also referred to as a mold material) was poured into the interior of the ring, and the wax pattern and the sprue were invested in the investment material (investing step).

[0056] Note that a phosphate type investment material (manufactured by GC Europe, product name: Multi press vest) was used as the investment material.

[0057] After leaving the investment material to set, the crucible former was removed and the investment material including the wax pattern 11 was heated at 850 C. for 30 minutes in the air atmosphere to burn out the wax pattern to form a mold (burnout step).

[0058] After the burnout step, it was confirmed that the wax pattern and the sprue were removed.

[0059] Then, a lithium disilicate ceramic block was placed in the sprue of the mold, and press molding was performed by pressing the ceramic block with a piston while heating the mold and the ceramic block at 930 C. in the air atmosphere. By performing the press molding process, the sprue portion and void portion in the mold was filled with ceramic material.

[0060] After cooling, the ceramic molded body was taken out of the mold and the sprue portion was cut to obtain a dental prosthesis.

[0061] A total of ten dental prostheses including the above dental prosthesis were produced in a similar manner, and the dental prostheses were subjected to sandblasting with glass beads at a pressure of 0.4 MPa to remove deposits on their surface. Then, visual evaluation was performed to determine whether the surfaces included reaction layers. The reaction layer is an intermediate layer between the investment material and the ceramic material and constitutes roughness as described in the present embodiment. In the visual evaluation, a dental prosthesis having a reaction layer with a diameter greater than or equal to 1 mm was evaluated as a rejected product, and a dental prosthesis having a reaction layer with a diameter less than 1 mm was evaluated as an accepted product that was able to control roughening.

[0062] In the present example, all of the ten dental prostheses produced were deemed accepted products.

Example 2 to Example 8

[0063] In Examples 2 to 8, dental prostheses were produced and evaluated in the same manner as in Example 1, except that the wax pattern surface-treating agent were prepared to have different compositions as indicated in Table 1 below. The evaluation results are also indicated in Table 1.

[0064] Note that in Example 3 where water was used as the solvent of the wax pattern surface-treating agent, after coating the surface of the wax pattern and the surface of the sprue with the wax pattern surface-treating agent by spraying, the wax pattern surface-treating agent was dried with a drier set to 45 C. before performing the investing step.

[0065] In Examples 3, 4 and 6, boron nitride powder having an average particle diameter of 6 m or 12 m was used as indicated in Table 1.

[0066] Also, the polyoxyethylene alkyl ether used as the surfactant as indicated in Table 1 preferably has an alkyl group with a number of carbons greater than or equal to 12 and less than or equal to 14 and a branched structure derived from a secondary alcohol used as a raw material for synthesis.

Comparative Examples 1 to 3

[0067] In Comparative Example 1 and Comparative Example 2, dental prostheses were prepared and evaluated in the same manner as in Example 1, except that the wax pattern surface-treating agent was prepared to have different compositions as indicated in Table 1. In Comparative Example 1, boron nitride was not added, and in Comparative Example 2, no surfactant was added. The evaluation results are also indicated in Table 1.

[0068] In Comparative Example 3, a dental prosthesis was prepared and evaluated in the same manner as in Example 1, except that the wax pattern surface-treating agent coating step was not performed. The evaluation results are indicated in Table 1.

TABLE-US-00001 TABLE 1 EX- EX- EX- EX- EX- EX- EX- EX- COMPAR- COMPAR- COMPAR- AM- AM- AM- AM- AM- AM- AM- AM- ATIVE ATIVE ATIVE PLE PLE PLE PLE PLE PLE PLE PLE EXAMPLE EXAMPLE EXAMPLE 1 2 3 4 5 6 7 8 1 2 3 WAX SOLVENT METHYL 98 98 98 98 98 N/A PATTERN ETHYL SURFACE- KETONE TREATING ETHANOL 98 AGENT WATER 98 COMPO- 2- 98 98 98 NENTS PROPANOL (PARTS BORON AVERAGE 2 2 15 10 4 2 BY MASS) NITRIDE PARTICLE DIAMETER 4 m AVERAGE 2 0.02 PARTICLE DIAMETER 6 m AVERAGE 2 PARTICLE DIAMETER 12 m SURFACT- SODIUM 0.2 0.2 0.2 8 ANT LAURYL SULFATE POLYOXY- 0.2 0.2 0.2 2 0.2 ETHYLENE ALKYL ETHER EVAL- NUMBER ACCEPTED/ 10/10 10/10 10/10 10/10 8/10 8/10 10/10 10/10 0/10 4/10 0/10 UATION NUMBER EVALUATED RESULT

[0069] It can be appreciated from comparison of the evaluations results of Examples 1 to 4, Example 7, and Example 8 as indicated in Table 1 that various solvents and surfactants can be used. Also, it can be appreciated that the average particle diameter of boron nitride is not particularly limited.

[0070] Note, however, that in Example 3 where water was used as the solvent, the wax pattern surface-treating agent had to be dried after being coated on the surface of the wax pattern and the surface of the sprue as described above. This suggests that it is more preferable to use a volatile component as the solvent.

[0071] Also, when preparing the wax pattern surface-treating agent, a substantial amount of foam was formed in Examples 1, 2, and 7 such that the foam had to be removed before performing the wax pattern surface-treating agent coating step. In contrast, in Examples 3, 4 and 8, almost no foam was observed such that the wax pattern surface-treating agent coating step could be performed immediately after preparing the wax pattern surface-treating agent.

[0072] In Example 5, 8 out of 10 dental prostheses were deemed accepted products thereby confirming that roughening could be sufficiently controlled. However, because boron nitride powder was added at a relatively large amount of 15 parts by mass, in the wax pattern surface-treating agent coating step, when the wax pattern surface-treating agent was coated by spraying in the same manner as in Example 1, clogging occurred at the nozzle. As such, the wax pattern surface-treating agent was coated using a brush in Example 5. As a result, it took a longer time to perform the wax pattern surface-treating agent coating step as compared with Example 1.

[0073] In Example 6, 8 out of 10 dental prostheses were deemed accepted products thereby confirming that roughening could be sufficiently controlled. However, because boron nitride powder was added at a relatively small amount of 0.02 parts by mass, there were cases in which a part of the wax pattern surface could not be coated with a sufficient amount of boron nitride thereby resulting in two of the dental prostheses being deemed rejected products.

[0074] In Comparative Example 1 and Comparative Example 2, boron nitride powder or a surfactant was not added to the wax pattern surface-treating agent. As a result, in Comparative Example 1 where boron nitride powder was not added, roughening was observed in all the dental prostheses produced.

[0075] In Comparative Example 2 where a surfactant was not added, only 4 out of 10 dental prostheses were deemed accepted products. It can be presumed that because no surfactant was added, boron nitride could not be sufficiently dispersed in the wax pattern surface-treating agent and boron nitride could not be evenly coated on the surface of the wax pattern.

[0076] In Comparative Example 3, because the wax pattern surface-treating agent coating step was not performed, roughening was observed on the surfaces of all the dental prostheses produced.

[0077] Although a wax pattern surface-treating agent according to the present invention has been described above with respect to illustrative embodiments and examples, the present invention is not limited to the above embodiments and examples. That is, various modifications and changes may be made within the scope of the present invention as described in the claims.

[0078] The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2016-060528 filed on Mar. 24, 2016, the entire contents of which are herein incorporated by reference.