ZIRCONIA-BASED IMPLANT COMPOSITION

Abstract

Proposed is a zirconia-based implant composition capable of preventing discoloration under gamma irradiation. The zirconia-based implant composition is characterized by including zirconium dioxide (Zro.sub.2), yttrium oxide (Y.sub.2O.sub.3) added to the above zirconium dioxide, an oxide of pentavalent ions added for reducing the concentration of oxygen vacancies caused by the above yttrium oxide (Y.sub.2O.sub.3), a colorant oxide added for reducing discoloration, and an oxide of tetravalent ions added for improving sinterability.

Claims

1. A zirconia-based implant composition comprising: zirconium dioxide (Zro.sub.2); yttrium oxide (Y.sub.2O.sub.3); an oxide of pentavalent ions; and at least one colorant oxide of erbium oxide (Er.sub.2O.sub.3), europium oxide (Eu.sub.2O.sub.3), and iron oxide (Fe.sub.2O.sub.3).

2. The implant composition of claim 1, wherein the oxide of the pentavalent ions is niobium pentoxide (Nb.sub.2O.sub.5).

3. The implant composition of claim 1, further comprising an oxide of tetravalent ions.

4. The implant composition of claim 3, wherein the oxide of the tetravalent ions comprises at least one of silicon dioxide (SiO.sub.2), titanium dioxide (TiO.sub.2), and cerium oxide (CeO.sub.2).

5. The implant composition of claim 1, further comprising an oxide of tetravalent ions, wherein the oxide of the pentavalent ions is niobium pentoxide (Nb.sub.2O.sub.5), the oxide of the tetravalent ions comprises silicon dioxide (SiO.sub.2), titanium dioxide (TiO.sub.2), and cerium oxide (CeO.sub.2), zirconium dioxide (ZrO.sub.2) has a content in a range of 79.0 to 93.6 mol %, yttrium oxide (Y.sub.2O.sub.3) has a content in a range of 3.0 to 6.0 mol %, the oxide of the pentavalent ions has a content in a range of 3.0 to 10.0 mol %, the colorant oxide has a content in a range of 0.2 to 2.0 mol %, silicon dioxide (SiO.sub.2) has a content in a range of 0.01 to 1.0 mol %, titanium dioxide (TiO.sub.2) has a content in a range of 0.01 to 1.0 mol %, and cerium oxide (CeO.sub.2) has a content in a range of 0.2 to 2.0 mol %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is an exemplary diagram showing changes in color of a zirconia-based implant sample, according to one embodiment of the present disclosure, before/after gamma irradiation;

[0018] FIG. 2 is a diagram showing changes in contact angle and surface free energy of a zirconia-based implant sample, according to one embodiment of the present disclosure, before/after gamma irradiation and during thermal treatment; and

[0019] FIG. 3 is a graph showing changes in surface free energy f a zirconia-based implant sample, according to one embodiment of the present disclosure, as a function of thermal treatment temperature after gamma irradiation.

DETAILED DESCRIPTION

[0020] The present disclosure will be described in detail below with reference to the accompanying drawings illustrated as examples of specific embodiments under which the present disclosure may be implemented to make clear of the objectives, technical solutions, and advantages of the present disclosure. These embodiments are described in sufficient detail so that those skilled in the art can readily practice the present disclosure.

[0021] Furthermore, throughout the detailed description and claims of the present disclosure, the terms, such as include and comprise, and variations thereof are not intended to exclude other technical features, additions, components, or steps. Other objectives, advantages, and features of the present disclosure will be revealed to those skilled in the art, partially from this specification and partially from the implementation of the present disclosure. The following examples and drawings are provided as examples and are not intended to limit the present disclosure. Moreover, the present disclosure encompasses all possible combinations of embodiments indicated herein. It should be understood that various embodiments of the present disclosure are different but are not necessarily mutually exclusive. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims, when appropriately interpreted, along with the full range of equivalents to what the claims claim.

[0022] FIG. 1 illustrates changes in color of a zirconia-based implant sample, according to one embodiment of the present disclosure, before/after gamma irradiation, FIG. 2 shows changes in contact angle and surface free energy of a zirconia-based implant sample, according to one embodiment of the present disclosure, before/after gamma irradiation and during thermal treatment, and FIG. 3 is a graph showing changes in surface free energy of a zirconia-based implant sample, according to one embodiment of the present disclosure, as a function of thermal treatment temperature after gamma irradiation.

[0023] Typically, compositional changes in zirconia are problematic in terms of deterioration in mechanical properties or increased vulnerability to low-temperature degradation. In one embodiment of the present disclosure, additives that address discoloration issues in zirconia-based implants sterilized by gamma irradiation will be presented to describe examples regarding discoloration prevention and changes in mechanical properties.

[0024] First of all, these additives may reduce the concentration of oxygen vacancies caused by Y ions with an oxidation state of 3 that are fundamentally added to zirconia, the implant material, by adding oxides of pentavalent ions. To this, colorant oxides for reducing discoloration to black may be added, as shown in FIG. 1, to minimize discoloration caused by gamma irradiation. Furthermore, in this process, the surface tension may be increased during an additional thermal treatment process to improve osseointegration properties during implant placement, thereby increasing the implant success rate.

[0025] For the detailed description thereof, a zirconia-based implant composition, according to one embodiment of the present disclosure, includes zirconium dioxide (Zro.sub.2), yttrium oxide (Y.sub.2O.sub.3), an oxide of pentavalent ions added for reducing the concentration of oxygen vacancies caused by the above yttrium oxide (Y.sub.2O.sub.3), a colorant oxide added for reducing discoloration, and an oxide of tetravalent ions added for improving sinterability.

[0026] The oxide of the pentavalent ions may be niobium pentoxide (Nb.sub.2O.sub.5), and the colorant oxide may be any one of erbium oxide (Er.sub.2O.sub.3), europium oxide (Eu.sub.2O.sub.3), and iron oxide (Fe.sub.2O.sub.3).

[0027] The oxide of the tetravalent ions includes silicon dioxide (SiO.sub.2), titanium dioxide (TiO.sub.2), and cerium oxide (CeO.sub.2). Silicon dioxide (SiO.sub.2) and titanium dioxide (TiO.sub.2) are additives that help improve sinterability, while cerium oxide (CeO.sub.2) serves as a colorant oxide.

[0028] The composition, types of oxides, and content ranges thereof for the zirconia-based implant composition, according to one embodiment of the present disclosure, are as follows.

[0029] Zirconium dioxide (ZrO.sub.2) has a content in the range of 79.0 to 93.6 mol %, yttrium oxide (Y.sub.2O.sub.3), which is an oxide of trivalent ions and serves as a zirconia stabilizer, has a content in the range of 3.0 to 6.0 mol %, niobium pentoxide (Nb.sub.2O.sub.5), which is the oxide of the pentavalent ions, has a content in the range of 3.0 to 10.0 mol %, any one of erbium oxide (Er.sub.2O.sub.3), europium oxide (Eu.sub.2O.sub.3), and iron oxide (Fe.sub.2O.sub.3), serving as the colorant oxide for realizing the color of the gingiva, has a content in the range of 0.2 to 2.0 mol %, silicon dioxide (SiO.sub.2) and titanium dioxide (TiO.sub.2), which are the oxides of the tetravalent ions, each independently have a content in the range of 0.01 to 1.0 mol %, and cerium oxide (CeO.sub.2) has a content in the range of 0.2 to 2.0 mol %.

Example

[0030] Hereinafter, a zirconia-based implant sample, according to one example of the present disclosure (when referred to as a sample of the present disclosure), and a control sample (3Y-TZP, Tosoh cop) will be compared in terms of composition. The composition of the zirconia-based implant sample, according to one example of the present disclosure, and the composition of the control sample are as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Sample of present disclosure ZrO.sub.2 Y.sub.2O.sub.3 Nb.sub.2O.sub.5 SiO.sub.2 TiO.sub.2 CeO.sub.2 Er.sub.2O.sub.3 Molar 91.19 4.41 3.28 0.18 0.27 0.46 0.21 concentration Control sample ZrO.sub.2 Y.sub.2O.sub.3 HfO.sub.2 Al.sub.2O.sub.3 SiO.sub.2 Fe.sub.2O.sub.3 Na.sub.2O Molar 93.64 3 3.1 0.13 0.04 0.01 0.08 concentration

[0031] First of all, the changes in the colors of the sample of the present disclosure and the control sample before and after gamma irradiation are as shown in FIG. 1. As shown in Table 1, the zirconia-based implant sample, according to one example of the present disclosure, reduces the concentration of oxygen vacancies caused by yttrium oxide (Y.sub.2O.sub.3), which is the oxide of the trivalent ions fundamentally added to zirconia, by adding niobium pentoxide (Nb.sub.2O.sub.5), which is the oxide of the pentavalent ions. In addition, compared to the case of the control sample (3Y-TZP) in FIG. 1, the effect of minimizing the discoloration of the sample of the present disclosure to black caused by gamma irradiation can be obtained by adding the colorant oxide.

[0032] Referring to FIG. 2, in which the water contact angle and surface free energy of the sample of the present disclosure irradiation and during are measured before and after gamma thermal treatment, the contact angle between .sub.SL and .sub.LG appears to decrease before gamma irradiation (before sterilization) and after gamma irradiation, while the surface free energy relatively appears to increase.

[0033] In addition, when performing an additional thermal treatment process on the sample irradiated with gamma rays, the surface free energy appears to increase, indicating that during the additional thermal treatment process, the surface tension is increased, and osseointegration properties can thus be improved during implant placement.

[0034] Referring to FIG. 3, which is a graph showing changes in the surface free energy as a function of thermal treatment temperature after gamma irradiation, the surface free energy appears to dramatically increase in a range where the temperature of a room is 150 C. or higher.

[0035] According to the example described above, the present disclosure can cause compositional changes in the zirconia-based implant material to reduce the concentration of oxygen vacancies responsible for discoloration while adding the colorant oxides for reducing discoloration to black, thereby minimizing discoloration caused by gamma irradiation. Furthermore, in this process, the surface tension can be increased through the additional thermal treatment process to improve osseointegration properties during implant placement, thereby obtaining the effect of increasing the implant success rate.

[0036] For reference, a manufacturing process of the implant having the composition ratios as listed in Table 1 is to be further described.

[0037] First, zirconium dioxide (Zro.sub.2), yttrium oxide (Y.sub.2O.sub.3), and niobium pentoxide (Nb.sub.2O.sub.5), serving as the raw materials, are prepared, mixed, and subjected to solution treatment, followed by adding silicon dioxide (SiO.sub.2) and titanium dioxide (TiO.sub.2), serving as sintering agents, and cerium oxide (CeO.sub.2) and erbium oxide (Er.sub.2O.sub.3), serving as colorant oxides. Then, an injection molding process is performed to shape an implant.

[0038] Subsequently, degreasing and sintering processes are performed to remove organic matter and impart sintering properties, and hot isostatic pressing (HIP) and thermal treatment processes are then performed for densification and color restoration. Next, gamma irradiation is performed for sterilization, and an additional thermal treatment process is performed for color restoration.

[0039] Although the present disclosure has been described hereinabove with reference to the embodiment shown in the drawing, this is merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom. For example, even though dental implants were illustrated in the embodiment of the present disclosure, the embodiment of the present disclosure can be equally applied to surgical implants. Thus, the true technical protection scope of the present disclosure should be defined by the technical ideas of the appended claims.