JP2019131457A - Radiopaque glass and use thereof - Google Patents

Abstract

To provide a lead-free radiopaque glass with relatively low refractivity and improved radiopacity.SOLUTION: The invention relates to a radiopaque glass having a refractive index nof 1.480 to 1.561, where the glass is free of SrO and PbO apart from inevitable impurities. The glass is based on a SiO, AlOand BOsystem. The radiopacity can be adjusted using CSO in particular in combination with BaO and/or SnOoptionally in conjunction with fluorine. The glass may be used in particular as a dental glass or optical glass.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lead-free radiopaque glass and its use.

In the dental field, the use of dental plastic compounds for the restoration of teeth is increasing. This dental plastic compound is usually composed of a matrix made of an organic resin and various inorganic fillers. The inorganic filler is mainly composed of glass, (glass) ceramic, quartz or other crystalline material (eg YbF ₃ ), sol-gel material and / or aerosil powder, and is added as a filler to the plastic compound.

  By using dental plastic compounds, the harmful side effects of amalgam that may occur are avoided and an improved aesthetic impression is achieved. Depending on the choice of dental plastic compound, this dental plastic compound can be used for various dental restoration procedures, such as dental fillings or inlays, onlays, etc., and also on crowns and bridges Can also be used.

  The filler itself minimizes shrinkage caused by polymerization of the resin matrix during curing and at the same time increases wear resistance. For example, if there is a strong adhesion between the tooth wall and the filling, too much polymerization shrinkage can cause destruction of the tooth wall. If the adhesion is not sufficient for this, if the polymerization shrinkage is too great, a peripheral gap may form between the tooth wall and the filling, which may promote secondary caries.

In addition, the fillers have specific physical and chemical requirements:
The filler must be processed into as fine a powder as possible. The finer the powder, the more uniform the appearance of the filling. At the same time, the abrasiveness of the filling is improved, thereby reducing the area under attack and thus improving the wear resistance, thereby extending the durability of the filling. It is further desirable that the powder does not agglomerate in order to be able to process the powder well.

  Furthermore, it is preferred that the filler is coated with a functionalized silane. This is because it achieves the formulaliformability of dental compounds and improves the mechanical properties. In so doing, the surface of the filler particles is usually covered with at least partially functionalized silane.

  It is desirable that dental glass as a filler is as well matched as possible to the resin matrix with regard to its transparency and possibly refractive index. In addition, the entire dental plastic compound, and hence the filler, is aesthetically adapted to the natural tooth material, so that the difference between the dental plastic compound and the surrounding healthy tooth material is as much as possible. Can be reduced. With respect to this aesthetic standard, the role of reducing the particle size of the powdered filler as much as possible also plays a role.

  The good chemical durability of the filler, in particular of water, can further contribute to prolonging the life of the tooth restoration procedure.

For the treatment of the patient, it is further unconditionally necessary that the dental restoration procedure be visible on an X-ray image. Since the resin matrix is generally invisible in X-ray images, care must be taken that the filler exhibits the necessary X-ray absorption. A filler that sufficiently absorbs X-rays is called X-ray opacity. In general, filler components, such as certain components of glass, or additives are responsible for radiopacity. Such an additive is also called a radiopaque material. In addition to conventional X-ray opaque material of the dental glass filler is YbF _3, which can be added in the form of milled crystalline.

  The radiopacity of dental glass or dental material is described relative to the X-ray absorption of aluminum as Aluminum Gleichwertdicke (ALGWD) according to DIN ISO 4049. Relative ALGWD is based on a sample thickness of 2 mm. A relative ALGWD of 200% means that a 2 mm thick glass plate with a plane parallel surface produces the same X-ray attenuation as a 4 mm thick aluminum plate. Similarly, a relative ALGWD of 500% means that a 2 mm thick glass plate with a plane parallel surface produces X-ray attenuation equivalent to a 10 mm thick aluminum plate. In the following, the radiopacity of glass is described by relative ALGWD (expressed in%) data.

  Dental plastic compounds are often thixotropic when uncured because they are usually filled from the cartridge into the cavity and shaped there when applied. That is, when pressure is applied, the viscosity decreases, and when there is no pressure action, shape stability is obtained.

  In filling materials, a distinction is made between inert materials and reactive dental materials. Dental cement belongs to reactive dental materials. In the case of dental cements, such as glass ionomer cements, the dental material is cured by the chemical reaction between the filler and the organic acid, so the reactivity of the filler depends on the curing characteristics of the dental material and thus its processability. Affects. This is often a condensation process, which may be preceded by surface hardening with radicals, for example under the action of UV light. In this case, the glass may be used as a filler that initiates or participates in a chemical reaction or may be used as an inert additive that does not participate in the reaction. This chemical reaction is then caused by other fillers contained in the glass ionomer cement as well.

  In addition to pure inert fillers and pure reactive fillers, there are a variety of intermediates that cannot be described in detail herein. Examples of this intermediate include “compomer” and “resin reinforced glass ionomer cement” (RMGIC).

  In contrast, composites (also referred to as filled composites) contain more fully chemically highly inert fillers. This is because the curing behavior is initially determined by the components of the resin matrix itself and therefore the chemical reaction of the filler and / or additive is often an obstacle.

  Glass is often used as a filler for dental plastic compounds because it can be a type of raw material that exhibits a variety of properties based on its various compositions. Other applications as dental raw materials are possible, which may be in pure form or as a component of a material mixture, for example inlays, onlays, crowning materials and bridges, for artificial teeth Application to materials or other materials for prosthetic, conservative and / or prophylactic treatment is also possible. Such glasses in applications as dental raw materials are generally referred to as dental glasses.

  In addition to the above properties of dental glass, it is also desirable not to contain toxic lead oxide (PbO).

  Thus, dental glass is a particularly high value glass. Such glasses can be used in optical applications as well, especially where the application of glass radiopacity is beneficial. X-ray opacity means that the glass absorbs electromagnetic radiation in the X-ray spectral region, so that the corresponding glass is simultaneously a filter for X-rays. X-rays can damage sensitive electronic components. In the case of electronic image sensors, the transmission of X-ray quanta may destroy, for example, corresponding areas of the sensor or cause unwanted sensor signals that can be perceived as, for example, image damage and / or noise pixels. It is therefore necessary or at least preferred for certain applications to protect electronic components from X-rays by filtering out the X-rays by filtering with a corresponding glass from the spectrum of incident radiation.

Although many dental glasses and other optical glasses having similar optical layers or exhibiting comparable chemical compositions have been described in the prior art, these glasses are critical in manufacturing and / or application. Demonstrate disadvantages. In particular, many of these glasses contain relatively large amounts of fluoride and / or Li ₂ O, which vaporize very easily during the melting or melting process, thereby allowing precise control of the glass composition. It becomes difficult.

Barium-free chemically inert dental glasses for use as fillers in composites are the subject of DE 198 49 388 A1 (DE 198 49 388 A1). The glass proposed in this document necessarily contains ZnO and F proportions in the low refractive glass. The latter can cause a reaction with the resin matrix, which can also affect its polymerization behavior. Furthermore, since the SiO ₂ ratio is limited to 20-45% by mass, the described glass can be sufficiently included in the radiopaque material and F. In particular, when the content of ZnO and ZrO ₂ is low, it is recommended to add SrO to 27% by mass.

  International Publication No. 2005/060921 (WO2005 / 060921 A1) describes glass fillers that are particularly suitable for dental composites. This glass filler contains 9 to 20 mol% of an alkali oxide. The purpose of this document is to provide glass particles having a lower alkali ion concentration in the periphery of the particles than in the center of the particles. This means that the described glass exhibits intentional chemical instability. This is because otherwise this concentration behavior is not achieved. This presupposes that this necessary low chemical durability is achieved by making the proportion of alkali metal in the starting glass as described above.

EP 0 855 606 (EP 0885606 B1) describes alkali silicate glasses which are used as fillers for dental materials. By setting the Al ₂ O ₃ ratio to at least 5% by mass, the viscosity increases in the high SiO ₂ content glass, thereby producing a very high melting temperature. As an essential component, sodium oxide and potassium oxide are contained. Further, this glass does not contain a component that imparts radiopacity.

German Offenlegungsschrift 44 43 173 (DE 4443173 A1) comprises barium-free high-zirconium-containing glasses which exhibit a ZrO ₂ content of more than 12% by weight and contain other oxides. This type of filler is particularly too reactive for modern dental compounds, for example acrylate-based, which can lead to uncontrollable curing too fast. Zirconium oxide in this amount tends to cause devitrification. This results in phase separation with possibly nucleation and subsequent crystallization. Furthermore, the production of such glass is carried out unless the alkali content is increased in order to ensure that the melting temperature is not too high (if the melting temperature is too high it can overload the melting apparatus). I can't. Such a high alkali content, of course, adversely affects the chemical durability of the glass.

  German Offenlegungsschrift DE 195 45 517 (DE 199 45 517 A1) likewise describes high-zirconium-containing glasses which exhibit the same problems as the above-mentioned glasses when applied in the dental field.

DE 102 2005 51387 (DE 10 2005 051 387 B3) describes La ₂ O as dental glass in order to achieve radiopacity and a refractive value of 1.50 to 1.549. Magnesium-aluminosilicate glasses exhibiting a high content of ₃ and / or Y ₂ O ₃ and WO ₃ and ZrO ₂ are described. In this case, the glass is barium oxide free, strontium oxide free and alkali metal oxide free. Because of the high magnesium oxide content, such glasses tend to phase separate. Furthermore, since it contains WO ₃ and ZrO ₂ , there is a drawback that it is remarkably easy to crystallize. Furthermore, by containing these, the melting temperature is increased. La ₂ O ₃ is expensive as a raw material and is therefore desirable to avoid.

German Offenlegungsschrift 10 2009008951 (DE 10 2009 008 951 A1) discloses radiopaque, barium-free glass and its use as dental glass, which glass Naturally it contains zirconium oxide. ZrO ₂ and Cs ₂ O and / or La ₂ O ₃ are used together to achieve a narrow range of refractive values of 1.518 to 1.533. In order to be able to melt such glass, a higher K ₂ O ratio is further required. The problem with such glasses is again the crystallization tendency with relatively high melting temperatures and the raw material costs due to the use of La ₂ O ₃ . Glasses with low refractive values are not described in this prior art.

German Patent No. 102011084501 (DE 10 2011 084 501 B3) discloses a barium-free radiopaque glass having a refractive value of 1.50 to 1.58. This glass is based on a combination of SrO and La ₂ O ₃ and ZrO ₂ as radiopaque material. Furthermore, Cs ₂ O can be added to increase the radiopacity. The disadvantage of this glass is that it has a high melting temperature and shows a tendency to crystallize. As mentioned above, La ₂ O ₃ is very expensive.

JP 2004-002062 A (JP 2004-002062 A) discloses a glass substrate for flat display. In addition to SrO, the disclosed glass mainly contains BaO and a high proportion of Al ₂ O ₃ and MgO as a whole. The components Al ₂ O ₃ , SrO, BaO and MgO are required as network modifying components to ensure the meltability of the glass. These glasses are also not considered for application as dental glass. This is because it is far from showing the necessary radiopacity. Apart from this, the inclusion of Al ₂ O ₃ increases the viscosity in the high SiO ₂ -containing glass, thereby requiring a high melting temperature for production. The high content of MgO is disadvantageous in dental use glasses with a low refractive value and at the same time a high radiopacity. MgO is other alkaline earth oxides CaO, without increasing the X-ray opacity to the same extent as SrO and BaO, mainly an increase in refraction value n _d is significant, therefore low refraction value and a high X-ray opaque The balance aimed at between sex can be difficult.

The glasses mentioned in the prior art are common in that they are poorly water resistant or too reactive and / or not radiopaque or contain components harmful to the environment and / or health. ing. Many known dental glasses further contain SrO, which significantly increases the melting temperature. In addition to these economic disadvantages, high SrO percentages cause crystallization processes that are difficult to control during many glass manufacturing processes. In addition, known radiopaque materials used alone or in known combinations (usually in combination with La ₂ O ₃ ) allow any achievable radiopacity to be achieved without significantly increasing the refractive index. It has been found that it cannot be improved sufficiently. Glass having a refractive index higher than 1.65 (for example, described in International Publication No. 2007/034258 (WO 2007/034258 A1)) is actually used as a filler for dental glass, dental plastic compounds, etc. Currently not enough to do. Furthermore, lanthanum oxide is expensive, which has the disadvantage of reducing the economics of glass made using lanthanum oxide.

German Patent Application Publication No. 198449388 International Publication No. 2005/060921 European Patent No. 0886066 German Patent Application Publication No. 1945517 German Patent Application Publication No. 1945517 German patent invention No. 1020050513387 German Patent Application Publication No. 102009008951 German patent invention 102011084501 specification JP 2004-002062 A International Publication No. 2007/034258 German patent invention No. 4100604 German patent invention No. 10222964 US Pat. No. 5,641,347 European Patent Application No. 1547572

  It is an object of the present invention to provide a glass that is lead-free, radiopaque, relatively low in refraction, and improved in radiopacity. In particular, the object of the present invention is to show an accurately defined refraction value in a given range of refraction values and to improve the radiopacity with respect to this refraction value, also for improved productivity. It is also providing the glass system which can manufacture the glass which shows this more easily. This glass should preferably also be suitable for use in the medical field, in particular in the dentistry field as dental glass and as optical glass. In this case, the plastic matrix can be efficiently manufactured and nevertheless is of high value and biocompatibility, suitable for protection of passive and active teeth, and processability, surrounding plastic matrix It should exhibit outstanding properties in terms of setting behavior and long-term stability and strength. In order to meet the demands in modern dental treatment and dental technology, the glasses according to the invention must furthermore exhibit at least good water resistance.

The glass according to the present invention, such as Fe ₂ O ₃ , CoO, NiO, CuO, etc., in its basic matrix, except for inevitable impurities or contaminants and / or residual components that are difficult to avoid in industrial production. Should be free of any coloring components, thereby enabling an optimal starting chromaticity coordinate that can be matched to the tone of the teeth and / or to match the transmission spectrum of electromagnetic radiation for optical applications. to enable. Furthermore, the second glass phase and / or the colorable particles that cause scattering and likewise change the color impression should be free. One or more other glass phases can reduce the durability of the glass.

  This problem is solved by the glass according to the independent claims. Preferred embodiments and applications are evident from the dependent claims.

In particular, by mass% of oxide base, the following:
SiO ₂ 35~75
B ₂ O ₃ 2-16
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~14
BaO 0-24
Cs ₂ O 1~30
SnO ₂ 0~15
F 0-8
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and X-ray opaque glasses exhibiting a refractive index _{n d} of 1.480 to 1.561 are provided.

Cs ₂ O is always contained in the glass according to the present invention as a radiopaque material. In an advantageous embodiment, this is used in combination with at least one other radiopaque material because of the good radiopacity of the glass. In a particularly advantageous embodiment, in addition to Cs ₂ O, at least BaO or SnO ₂ is also included as radiopaque material, optionally also La ₂ O ₃ . Further advantageous SnO ₂ -containing radiopaque glasses have SnO _{2 in addition} to Cs ₂ O and BaO and optionally also La ₂ O ₃ . Other advantageous embodiments comprise a combination of Cs ₂ O and La ₂ O ₃ as radiopaque components, wherein the advantageous aspects of this embodiment may be free of BaO.

  Many advantageous embodiments of the radiopaque glass described above may contain fluorine (fluorine-containing embodiment). The component fluorine may be included to better adjust the refractive index depending on the radiopaque material used. When fluorine is contained, its content is advantageously 0.3% by weight or more, preferably 0.5% by weight or more. An advantageous upper limit may be 6% by weight, advantageously 5.5% by weight, preferably 2.5% by weight. Another advantageous aspect is that the fluorine content is clearly reduced in the range from 0% by weight to less than 0.3% by weight, that is, such an aspect is fluorine poor (fluorine poor aspect). On the contrary, it may be fluorine-free (fluorine-free embodiment).

An advantageous fluorine-containing embodiment of the present invention is the oxide-based weight percent, which is:
SiO ₂ 35~75
B ₂ O ₃ 4-15, especially 5-15
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~10
BaO 0.6-24
Cs ₂ O 1~30
SnO ₂ 0-15, especially 1-15
F ≧ 0.3, especially ≧ 0.5
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and an X-ray opaque glasses exhibiting a refractive index _{n d} of from 1.480 to 1.561.

Within the scope of the present invention, when aspects of the fluorine-containing, advantageously lower aspect, namely it is possible to advantageously lower aspects and SnO ₂ advantageous subaspect of free of SnO ₂ containing. An advantageous sub-embodiment containing SnO ₂ comprises SnO ₂ preferably greater than 0 to 15% by weight, preferably 0.3 to 15% by weight or 0.5 to 15% by weight and also preferably 1 to 15% by weight. Include by content.

A similarly advantageous content of SnO ₂ is more than 4% by mass to 15% by mass. Alternatively, the fluorine-containing X-ray opaque glasses, advantageously may be SnO ₂ free (SnO ₂ free subaspect).

An advantageous fluorine-reduced embodiment of the present invention (fluorine-poor or fluorine-free embodiment) is the oxide-based weight percent and is:
SiO ₂ 35~75
B ₂ O ₃ 4-15, especially 5-15
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~10
BaO 0-24, especially 0.6-24
Cs ₂ O 1~30
SnO ₂ 0~15
F 0 or more and less than 0.3, but BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and an X-ray opaque glasses exhibiting a refractive index _{n d} of from 1.480 to 1.561.

Within the scope of the invention, even in the case of embodiments with reduced fluorine, advantageous sub-embodiments may be distinguished, i.e. advantageous sub-embodiments containing SnO ₂ and advantageous sub-embodiments containing no SnO _2. A distinction may be made. An advantageous sub-embodiment containing SnO ₂ comprises SnO ₂ preferably greater than 0 to 15% by weight, preferably 0.3 to 15% by weight or 0.5 to 15% by weight and also preferably 1 to 15% by weight. Include by content. A similarly advantageous content of SnO ₂ is more than 4% by mass to 15% by mass. Alternatively, the fluorine-poor and / or fluorine-free radiopaque glass may advantageously be SnO ₂ free (sub-embodiment free of SnO ₂ ).

The glass according to the present invention exhibits a refractive index n _d (also referred to as a refractive value) of 1.480 to 1.561. Thereby, the glass according to the invention is very well adapted to the provided dental plastics and / or acrylate-based resins in this refractive index range, so that the glasses according to the invention are dental plastics. It specifically meets the aesthetic demands for natural appearance, which are imposed on compounds, especially dental glass-plastic composites.

The glasses according to the present invention achieve the required properties of lead-containing dental glasses with respect to X-ray absorption without the use of lead or other health-sensitive substances. The glass according to the invention is lead-free. In this case, the concept of “free” means, for example, that it may be based on air pollution and / or impurities of the raw material used, and does not contain this substance, except for unavoidable contamination. Even in the case of contamination of the glass by undesirable substances, especially in the case of dental glass, generally 300 ppm for Fe ₂ O ₃ , preferably at most 100 ppm, 30 ppm for PbO, 20 ppm for As ₂ O ₃ 20 ppm for Sb ₂ O ₃ and 100 ppm for other impurities should not be exceeded. SrO always coexists closely with BaO in the raw material. Depending on the purity of the BaO raw material, up to 0.7% by weight of SrO may be contained in the glass according to the invention. This limit value is included by the expression “excluding inevitable impurities ... not included”. Particularly preferably, of course, the glass according to the invention does not contain any of the aforementioned undesirable substances. Preferably, SrO is not actively added as a component to the glass according to the invention.

  X-ray absorption and thereby radiopacity is preferably achieved by a combination of radiopaque materials.

In an advantageous embodiment of the invention, the radiopacity is determined by the combination of Cs ₂ O, BaO and / or SnO ₂ , ie by the presence of at least two of these components, preferably the presence of these three components. Is achieved. Try to achieve radiopacity, usually by increasing the content of superabsorbent components as high as possible, or by combining with La ₂ O ₃ with previous dental glasses In contrast, in this aspect of the invention, radiopacity is achieved by a suitable combination of at least two components BaO, SnO ₂ and / or Cs ₂ O effective for radiopacity. Is done. In this way, particularly stringent requirements regarding the optical properties of the glass and very good water resistance and / or chemical durability can be achieved. Preferably, the total content of BaO, SnO ₂ and Cs ₂ O is at least 8% by mass, more preferably at least 10% by mass, particularly preferably at least 12% by mass. If these components are too small, the X-ray absorption is too low. The higher the sum of these radiopaque materials in the glass, the higher the radiopacity. A preferred upper limit for the sum of BaO, SnO ₂ and Cs ₂ O may be 51% by weight, advantageously 49% by weight, preferably 47% by weight, likewise preferably 45% by weight, more preferably 43% by weight.

  In particular, in the case of an advantageous embodiment containing fluorine, the radiopaque glass further comprises a defined amount of fluorine, which depends on the respective amount of radiopaque material. Used to intentionally adjust the refractive index of the glass. As a result, the X-ray opacity can surely be increased by using a relatively large amount of X-ray opaque material in the glass, but at the same time, the effect of increasing the refractive index of the obtained glass is negated. . By adding fluorine, the increase in refractive index can be kept within the limit value, or even suppressed.

Surprisingly, the combination of the components BaO, Cs ₂ O and / or SnO ₂ acting as radiopaque material, optionally with F, is high in a relatively wide refractive index range of 1.480 to 1.561. It has been found that it is particularly suitable for producing glasses that exhibit radiopacity. Thus, within the scope of the present invention, the sum of BaO, Cs ₂ O, SnO ₂ and F is at least 8% by weight or at least 9% by weight, preferably at least 10% by weight, based on the weight of the oxide. Is intended. Preferably, this sum is at least 11% or at least 12%, in many advantageous embodiments preferably 13% or at least 14%, in other advantageous embodiments at least 15% by weight. % Or at least 16% by weight or at least 17% by weight. The preferred upper limit for the sum of BaO, Cs ₂ O, SnO ₂ and F is 56% by weight, advantageously 54% by weight, preferably 52% by weight, more preferably 50% by weight, more preferably 48% by weight. Good. In many advantageous embodiments, 42% or 36% or 35% by weight may be a suitable upper limit for this total. Glasses with lower refractive values tend to achieve lower radiopacity than glasses with higher refractive values and correspondingly tend to achieve lower values of equivalent aluminum thickness. It is generally known. This is due to the fact that a relatively small amount of radiopaque material can be used for low refractive glass. If the proportion of radiopaque material is increased, the refractive index will be shifted to a higher value. The advantageous combination of BaO, Cs ₂ O and / or SnO ₂ and in particular F increases the radiopacity of the glass and the corresponding aluminum equivalent thickness over the entire refractive index range according to the invention. It is possible to shift. This means that at the same refraction value, a much higher value of X-ray visibility than can be achieved can be achieved. Furthermore, it is possible to intentionally adjust the refraction value in the radiopaque glass.

Particularly advantageous embodiments of the radiopaque glass with fluorine and an advantageous combination of three radiopaque materials are the following:
SiO ₂ 38~70
B ₂ O ₃ 6-15
Al ₂ O ₃ 1-7
K ₂ O 0~7
BaO 0.8-20
Cs ₂ O 1~28
SnO ₂ 1-15, preferably more than 4 and 15 or less F 0.75-2.5
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10.

  Overall, the present invention allows the refractive index of the glass to be deliberately adjusted to the respective requirements by changing the proportions of the components in the described system, with the glass being given It is achieved to provide a glass system that exhibits improved radiopacity at a refractive index of. This facilitates the production of various refractive glasses exhibiting high radiopacity.

The glass components for all glasses according to the invention and advantageous embodiments are described below:
Basically, the glass according to the invention contains SiO ₂ as a glass-forming component in a proportion of 35 to 75% by weight. This upper limit is 75% by mass in the present invention. A higher content of SiO ₂ can result in undesirably high melting temperatures and may fail to achieve the required radiopacity. As an upper limit for SiO ₂ , in the case of an advantageous embodiment, 73% by weight, preferably 70% by weight, particularly preferably 68.5% by weight or 65% by weight, may be selected. Many advantageous embodiments have a SiO ₂ upper limit of 64% by weight, preferably 61% or 59% or 56% or 53% by weight. In the present invention, the lower limit is 35% by mass. Lower contents may adversely affect chemical durability and tendency to devitrification. The SiO ₂ lower limit may be 36% by weight, advantageously 37% by weight, preferably 38% by weight, more preferably 39% by weight in the case of a preferred glass composition. Many embodiments, the SiO _2, preferably at least 40 wt%, preferably have at least 42% by weight or at least 45 wt% or at least 47 wt%, or at least 50% by weight. A preferred embodiment of the glass according to the invention is intended for a content of 38 to 70% by weight, particularly preferably 39 to 70% by weight, of SiO ₂ .

B ₂ O ₃ is intended to have a content of 2 to 16% by weight, advantageously 4 to 15% by weight, preferably 5 to 15% by weight, in the glass according to the invention. Preferably, this may be included in the range of 6-15% or 7-15% by weight. Many advantageous embodiments have a range of 3 to 14% by weight for this component. B ₂ O ₃ has a positive effect on glass formation and melting behavior. In addition, it is used as a flux. Besides the action of lowering the melting temperature, the use of B ₂ O ₃ simultaneously causes an improvement in the crystallization stability of the glass according to the invention. Therefore, in the present invention, the lower limit is 2% by mass. In the case of many glasses, a preferred lower limit for boron oxide may be selected as 3% by weight or 4% by weight, preferably 5% by weight, advantageously 6% by weight, preferably 7% by weight. The upper limit for boron oxide is 16% by weight, preferably 15% by weight in the present invention. Higher proportions are not recommended in this system due to the threat of chemical durability. Preferably up to 14.5% by weight, advantageously up to 14% by weight, of boron oxide may be included. If the B ₂ O ₃ content is too high, segregation may occur in the glass, which in itself creates undesirable refractive value non-uniformity and, on the other hand, also adversely affects chemical durability. Effect.

In the glass according to the present invention, Al ₂ O ₃ is necessarily contained in the range of 0.8 to 7.5% by mass. Preferably, this may be included in the range of 0.8-6% or 1-7% by weight. Al ₂ O ₃ improves the chemical durability of the glass. Therefore, in the case of the present invention, this is at least 0.8% by weight in the glass. Preferably, aluminum oxide may be used at least 1% by weight, preferably at least 1.2% by weight. However, it is not preferred to exceed an Al ₂ O ₃ content of about 7.5% by weight, in order not to increase the viscosity of the glass, especially in the hot working range, so that it becomes difficult to melt the glass. Furthermore, if the amount of aluminum oxide is too large, the tendency to devitrification and the resistance of the glass to acid deteriorate. Preferably, the upper limit of Al ₂ O ₃ is 7% by mass, particularly preferably 6.5% by mass or 6% by mass.

Alkali oxides consisting of the group Li ₂ O, Na ₂ O, K ₂ O may be necessary to allow the glass to be roughly melted. K ₂ O is used for adjusting the melting temperature and at the same time strengthens the glass network structure. Thus, in the case of the present invention, this is present in the glass composition in a proportion of 0 to 14% by weight, advantageously 0 to 12% by weight, preferably 0 to 10% by weight. For K ₂ O for many advantageous embodiments, a range of 0 to 7% by weight, in particular 0 to 5% by weight, may be preferred. It is not preferred to exceed the upper limit according to the invention of 14% by weight for K ₂ O. This is because the alkali oxide content decreases the chemical durability. Preferably, as upper limit, 12% or 11% by weight, preferably 10% by weight, advantageously 7% by weight, advantageously 6% by weight, may be selected. A particularly advantageous embodiment has up to 5% by weight, particularly preferably up to 4% by weight, of K ₂ O. The preferred lower limit of K ₂ O may be 0.5%, 1%, 1.5% or 2% by weight for many embodiments. Embodiments without K ₂ O are possible within the scope of the present invention.

Sodium ions and lithium ions may dissolve more easily from the glass matrix due to their small size, thereby reducing chemical durability, especially water resistance. In the case of an advantageous embodiment of the invention, the radiopaque glass is free of Na ₂ O and / or Li ₂ O, except for inevitable impurities.

  Impurities may be introduced into the glass due to contamination of the raw materials used for glass manufacture and / or due to contamination and / or corrosion of the melting equipment used. Such impurities generally do not exceed a proportion of 0.2% by weight, in particular 0.1% by weight. This also includes, of course, that each component is completely free. In other words, “component free” means that the glass is substantially free of these components, that is, these components are present in the glass as unavoidable impurities, but in the glass composition as individual components. Means not added.

  The content rate of barium oxide is 0-24 mass%, Preferably it is 0.6-24 mass%. A range of 0.8 to 20% by weight is preferred, and in the case of many embodiments, a range of 1 to 18.5% by weight is particularly preferred. If the amount of BaO is too high, chemical durability is deteriorated. Therefore, it is not preferable to exceed the upper limit of 24% by mass. As an upper limit, in the case of many embodiments, preferably 22% by weight or 21% by weight, particularly preferably 20% by weight, preferably 18.5% by weight or 18% by weight may also be selected. Other advantageous upper limits may be 17%, 15%, 14%, 12% or 10% by weight. In an advantageous embodiment, it is preferred that at least 0.6% by weight of BaO is included in the glass in order to achieve X-ray absorption with other substances. Preferably, BaO may be contained in the glass at least 0.8% by weight, preferably at least 1% by weight, particularly preferably at least 1.1% by weight. Some advantageous embodiments may have a lower limit of 2%, 4% or 6% by weight of BaO. However, within the scope of the invention, BaO-free radiopaque glasses are also possible and will be described next.

An advantageous embodiment of the radiopaque glass may be free of BaO. In the case of such glasses, the radiopacity may be based solely on Cs ₂ O. In order to achieve higher absorption of X-rays, La ₂ O ₃ and / or SnO ₂ may be advantageously used as additional X-ray opaque material in addition to Cs ₂ O contained in the glass. . An advantageous embodiment included according to the invention of a radiopaque glass exhibiting a refractive index n _{d of} 1.480 to 1.561, which is free of PbO and BaO, except for inevitable impurities, is an oxide-based mass. % And below:
SiO ₂ 35-75, especially 38-70
B ₂ O ₃ 2 to 16, especially 5 to 15, preferably 6 to 15
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0 to 14, especially 0-10, preferably 0-7
Cs ₂ O 1-30, especially 6-28, preferably 7-24
SnO ₂ 0-15, especially 0-6, preferably 0-3
F 0-8, especially 0-6, preferably 0-3
La ₂ O ₃ 0-19, especially 0-16
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
It is.

In the case of the BaO-free embodiment, as the X-ray opaque material, the component Cs ₂ O or a combination of Cs ₂ O and La ₂ O ₃ and / or SnO ₂ has a desired X-ray opaqueness in a desired refractive index range. Can be enough to get. For glasses in the medical field, in particular in the dental field, the BaO-free embodiment is an advantageous alternative to the known BaO-containing and / or SrO-containing radiopaque glasses. The BaO-free embodiment also advantageously has a low fluorine content, in particular less than 2% by weight, preferably less than 1% by weight, advantageously less than 0.5% by weight or less than 0.3% by weight. Have. An advantageous BaO-free embodiment may be fluorine-free.

In the case of the present invention, Cs ₂ O is similarly used for adjusting X-ray visibility, but at the same time contributes to improvement of meltability. In the case of the present invention, 1 to 30% by weight, preferably 1 to 28% by weight, particularly preferably 1.5 to 26% by weight, quite particularly preferably 2 to 25% by weight of Cs ₂ O is contained in the glass composition. It is. The alkali metal Cs is more immobile in the glass matrix than the alkali metals Li, Na, K and Rb. This therefore does not dissolve very significantly and therefore does not worsen the chemical durability much more than the alkali metals mentioned. An excessively small amount of Cs ₂ O causes a deterioration in X-ray visibility and an increase in melting temperature, so the lower limit according to the present invention is 1% by mass. In the case of a preferred glass composition, this lower limit may be 1.5% by weight, particularly preferably 2% by weight, preferably 2.5% by weight, particularly preferably 3% by weight. Many advantageous embodiments may contain at least 5% or at least 6% or at least 7% by weight of Cs ₂ O. In other advantageous embodiments, the lower limit for Cs ₂ O may be 9% by weight or 10% by weight. In the case of the present invention, it is preferable to include the following Cs ₂ O 30% by weight. This is because otherwise chemical durability deteriorates. Preferred glass compositions comprise up to 28% by weight Cs ₂ O, advantageously up to 26% by weight Cs ₂ O, preferably up to 25% by weight or up to 24% by weight Cs ₂ O. Many advantageous embodiments may contain up to 22%, preferably up to 20% or up to 19% by weight of Cs ₂ O.

SnO ₂ may preferably be used to adjust x-ray visibility as well. This contributes to high radiopacity, in which case the refraction value does not increase much more significantly than with other radiopaque materials. This component is contained in the glass composition in a proportion of 0 to 15% by mass. Many embodiments of the glass according to the present invention are SnO ₂ free.

In the case of SnO ₂ -containing embodiments, this is advantageously 0.5-15% by weight, preferably 1-15% by weight, preferably 3-15% by weight, preferably 4-15% by weight, more preferably 4% by weight. More than 15% by mass to 15% by mass, particularly preferably 4 to 12% by mass, and most preferably 4 to 10% by mass is contained in the glass composition. Since too little SnO ₂ can cause poor X-ray visibility, this component is at least 0.1 wt.% Or 0.3 wt.% In the preferred embodiment containing SnO ₂ , It is preferably contained at least 0.5% by mass or at least 1% by mass. In addition, SnO ₂ improves and guarantees the chemical durability of Cs ₂ O-containing glasses. As lower limit of SnO ₂ , it is advantageously possible to envisage 3% by weight, preferably 4% by weight, particularly preferably more than 4% by weight. Too much SnO ₂ causes significant devitrification or crystallization tendency. Therefore, it is preferable not to exceed the upper limit of 15% by mass. An upper limit of preferably 13% by weight, advantageously 12% by weight, preferably 10% by weight, particularly preferably 9% by weight of SnO ₂ may also be selected. The SnO ₂ poor embodiment may have an upper limit of 6% or 3% by weight.

  Within the scope of the preferred fluorine-containing embodiment of the present invention, the radiopaque glass comprises fluorine in a proportion of at least 0.3% by weight, preferably at least 0.5% by weight. Advantageously, for fluorine, a maximum of 8% by weight, preferably a maximum of 5.5% by weight, preferably a maximum of 5% by weight, or for some embodiments a maximum of 2.5% by weight is included. Many embodiments have an upper limit for 6 wt% or 3 wt% F. The advantageous range for F is 0.75 to 2.5% by weight, particularly preferably 0.75 to 2.25% by weight, preferably 1 to 2% by weight in the case of advantageous embodiments. Good. In this case, fluorine in this composition is described in atoms with respect to mass. This is used to adjust the refractive index in interaction with the above combination of radiopaque materials and improves the melting behavior of the glass mixture by lowering the melting temperature. It can therefore be advantageously included in the composition at least 0.3% by weight, preferably 0.5% by weight. As an advantageous lower limit, 0.75% by weight, preferably 1% by weight, may also be selected. It is not preferred to exceed the upper limit of 8% by weight, preferably 6% by weight, advantageously 5.5% by weight, advantageously 5% by weight. This is because otherwise this component can be vaporized during the melting process, resulting in a non-uniform refraction value distribution in the glass. Advantageously, fluorine may be included in many embodiments in a proportion of up to 2.5% by weight, advantageously up to 2.25% by weight, preferably up to 2% by weight.

  The fluorine-poor aspect of the present invention contains less than 0.3 wt% F. The fluorine-free embodiment is F-free.

  It will be apparent to those skilled in the art that each stated upper and / or lower limit of one component can be arbitrarily combined with each stated upper and / or lower limit of the other component and Note that included herein.

In a preferred embodiment of the glass aspects corresponding with the SnO ₂ and F, the molar ratio is at least 0.4 for F of SnO _2, preferably at least 0.45, preferably at least 0.49, particularly preferably Is intended to be at least 0.5. The molar ratio of SnO ₂ to F in the case of an advantageous embodiment is at most 0.85, advantageously at most 0.79, preferably at most 0.77, more preferably at most 0.75, likewise The maximum is preferably 0.72, particularly preferably 0.7. This measure makes it possible to accurately adjust the refractive value of the glass with relatively high X-ray absorption at the same time. Furthermore, this precise ratio also has the advantage that the meltability of the glass is guaranteed. If the value is too high, a non-uniform melt is produced.

In X-ray opaque glass, the refractive value and X-ray opacity, i.e. high to aluminum equivalent regulate further improve the thickness, of Cs 2 _O, Cs 2 _O above the impermeable _material, BaO and SnO _It is advantageous if the molar ratio to the sum of ₂ is at least 0.05, preferably at least 0.07, particularly preferably at least 0.1. Advantageously, the upper limit of 0.48, preferably 0.45, particularly preferably 0.41, is not exceeded. If the ratio is too low, the X-ray absorption is too low. If the ratio is too high, chemical durability is reduced.

The radiopaque glass may optionally contain ZrO ₂ in a proportion of 0-2% by weight, preferably 0-1% by weight. This zirconium content improves the mechanical properties, here in particular the tensile and compressive strength, and reduces the brittleness of the glass. However, if the content is too high, the glass can become reactive, especially in the environment of dental plastics. In contrast, the glass should be at least sufficiently inert to dental plastics, especially composites, and should not interfere with its polymerization behavior, for example. In an advantageous embodiment, the glass is free of zirconium (ZrO ₂ free).

  An advantageous embodiment of the radiopaque glass may comprise a limited proportion of alkaline earth consisting of the group of CaO and MgO. The proportion of CaO may be 0-2% by mass. MgO is similarly arbitrary and may be contained at 0 to 2% by mass. A very particularly preferred embodiment contemplates that the glasses of the invention are free of MgO, except for inevitable impurities. MgO can be disadvantageous for dental applications that should exhibit low refraction values and at the same time high radiopacity in the glass. MgO does not increase radiopacity to the same extent as other alkaline earth oxides CaO, SrO and BaO. This is because the X-ray absorption edge of MgO is far below the absorption edge of other alkaline earth oxides and does not have much influence within the range of tungsten X-ray tubes used in the medical field. MgO only increases the refraction value, which can make it difficult to balance between a low refraction value and a high radiopacity.

The glass according to the invention is optionally intended to be free of CeO ₂ and TiO ₂ except for inevitable impurities. CeO ₂ and TiO ₂ shift the UV edge of the glass based on their absorption in the UV region, which can result in undesirable yellowish coloration. In a preferred embodiment, the glass according to the invention is TiO ₂ free.

Particularly preferred embodiments of the glass are free of TiO ₂ and ZrO ₂ .

ZnO and / or WO ₃ and / or Nb ₂ O ₅ and / or HfO ₂ and / or Ta ₂ O ₅ and / or Gd ₂ O ₃ and / or Sc ₂ O ₃ and / or Y ₂ O ₃ and / or Yb ₂ O ₃ is preferably and optionally contained alone or in any combination, in addition from 0 to 2% by weight, respectively.

Within the scope of the present invention, in order to adjust the desired radiopacity in this glass, La ₂ O ₃ is advantageously 0-19% by weight, preferably 0-16% by weight or 0-15% by weight. % May be used. When La ₂ O ₃ is included, the glass generally has advantageously at least 0.1% by weight, preferably at least 0.2% by weight, preferably at least 0.5% by weight or at least 1% by weight. Preferably, the La ₂ O ₃ containing glass contains more than 2% by weight of this component. In many advantageous embodiments, a suitable lower limit may be 4% by weight. An advantageous upper limit for La ₂ O ₃ may be 19% by weight or 18% by weight, preferably 17% by weight, 16% by weight or 15% by weight. In many advantageous embodiments, a suitable upper limit for La ₂ O ₃ is 13% or 11% or 10% or 9% or 8% or 7.5% or 6% or 5%. It may be mass%.

Instead of La ₂ O ₃ containing embodiments, the present invention includes advantageous embodiments having a clearly reduced content of La ₂ O ₃ . This embodiment comprises up to 2% by weight of La ₂ O ₃ , preferably up to 1.5% by weight or up to 1% by weight (a lanthanum-poor embodiment). If La ₂ O ₃ is included in this embodiment, an advantageous lower limit may be 0.1% by weight. The limitation of the La ₂ O ₃ content advantageously does not cause the refractive index of the glass to rise significantly. A preferred embodiment of the glass is La ₂ O ₃ free (La ₂ O ₃ free aspect). This provides a cost advantage and enables the production of low refractive glasses that exhibit high radiopacity.

The radiopaque glass contains 0 to 2% by weight, preferably 0 to 1, of a fining agent selected from the group of at least one fining agent, for example chloride or sulfate, for industrial or optical applications. It is also possible to include it in a mass% ratio. SnO ₂ may be used as a fining agent, which is used in the melting apparatus in comparison with similarly possible fining agents such as As ₂ O ₃ and Sb ₂ O ₃ and the chlorides and sulfates described above. It has the advantage that no contaminants are introduced by other fining agents. This is advantageous when producing further dental glass following industrial glass.

The linear thermal expansion coefficient α _(20-300) of the glass according to the invention, measured in the temperature range from 20 ° C. to 300 ° C., is preferably less than 7 · 10 ⁻⁶ K ⁻¹ . Due to this low coefficient of thermal expansion, the glass according to the invention can compensate for the naturally significant thermal expansion of plastics, especially when applied as fillers in plastics, so that dental plastic compounds result. It exhibits thermal expansion that is better adapted to natural tooth materials.

  As already described, the glass according to the invention is resistant to chemical attack, ie the glass according to the invention is chemically durable. Preferably, the glass according to the invention has a water resistant HGB according to DIN ISO 719 of class 2 or better.

  The glass according to the present invention is superior due to its good chemical durability, which causes a large reaction inertness in the interaction with the resin matrix, thereby resulting in a very good long life of the whole dental material. Cause it to occur.

  In the case of another preferred embodiment of the invention, the glass according to the invention is advantageously free of other components not claimed and / or described herein. This means that in the case of this type of embodiment, the glass consists essentially of the components described. The expression “consisting essentially of” means that in this case the other components are present as impurities, if any, but are not intentionally added as single components to the glass composition.

  However, the present invention also contemplates the use of the glass according to the invention based on another glass, which may have up to 5% by weight of another component added to the glass according to the invention described. In such a case, this glass consists of a glass which, in the case of the present invention, has been described up to at least 95% by weight.

Of course, the color appearance of the glass for optical or other industrial applications can be tailored for this by the addition of conventional oxides. Oxides suitable for coloring the glass are known to those skilled in the art and include, for example, CuO and CoO, which can be added for this purpose, preferably 0-0.5% by weight. Furthermore, an antibacterial function may be imparted to the glass by adding, for example, 0 to 3% by mass of Ag ₂ O.

  The invention further comprises the use of a glass powder comprising the glass according to the invention, or a radiopaque glass according to the invention as a glass powder. The glass powder is produced by a known method, for example, as described in DE 41 00 604 C1 (DE 41 00 604 C1). The glass powder or powder particles according to the invention preferably have an average particle size of up to 50 μm, particularly preferably up to 20 μm. An average particle size of 0.1 μm can be achieved as a lower limit, in which case, of course, smaller particle sizes are also included in the present invention. The glass powders described above can generally be used as starting materials for the use of the glasses according to the invention as fillers and / or dental glasses. Preference is given to the use of radiopaque glasses according to the invention in dental glass containing dental plastic-dental plastic compounds. Such dental compounds are, for example, dental filling materials, inlays, onlay materials, dental cements, crowning materials and bridges, artificial tooth materials, prosthetic, conservative and / or prophylactic Used as other materials for dental treatment.

  In the case of the preferred embodiment, the surface of the glass powder, ie the surface of the glass powder particles, is silanized in a conventional manner. This silanization can achieve improved bonding of the inorganic filler to the plastic matrix of the dental plastic compound.

  The problems imposed at the outset are further solved by the radiopaque glass according to the invention for use as dental glass in the medical field, in particular in the dentistry field, and / or for diagnostic purposes. . Diagnostic purposes include medical applications such as use in contrast agents.

  Furthermore, the challenge imposed at the outset is radiopaque according to the invention for treating cavities in human and / or animal teeth and / or for use as dental glass for dental restorations. It is solved by the glass. This treatment generally involves complete or partial filling of cavities, spaces, gaps, etc. in the teeth.

  The glass according to the invention can preferably be used as dental glass as described. In this case, the dental glass is preferably present in the form of powder particles. Furthermore, it is preferred if the glass is a component of a dental plastic compound containing dental plastic, in particular the glass is a powdery filler. Advantageously, the surface of the powder particles is silanized. In the case of a preferred embodiment, the dental compound contains, in addition to the glass powder, other components such as barium- and / or strontium- and / or lithium-aluminate-glass ceramic powder, radiopaque. Additives for further improving (for example, ytterbium trifluoride and / or yttrium fluoride) and fillers for adjusting the viscosity (particularly pyrogenic silica and / or wet precipitated silica) are added. Good.

Preferably, the dental glass is an acrylate base requiring a particularly chemically inert filler for the treatment of dental cavities, in particular for filling and / or for restoration of teeth. Used as a filler in composites (also referred to as filled composites) for plastics. Likewise, the use of the glass according to the invention as a radiopaque material in dental materials, in particular dental plastic compounds, is also within the scope of the invention. Glass according to the invention is suitable for replacing the X-ray opaque material of expensive crystalline, e.g. YbF _3. Similarly, the glass according to the invention is suitable for use as a filler in dental cements such as glass ionomer cements and is intended for use as a filler in dental cements such as glass ionomer cements. Is. Similarly, the glass according to the invention can also be used as an inert additive in glass ionomer cements. The use as an inert additive in resin reinforced glass ionomer cement is particularly preferred. Resin reinforced glass ionomer cements are a type of material that has been available over the last few years, and this type of material itself exhibits a very long lasting curing reaction of the cement, but it can be cured initially. A resin matrix such as the above composite is also included.

  Correspondingly, the radiopaque glass according to the invention is preferably used for the production of dental glass-plastic composites containing dental plastics. Preferably, the dental plastic is acrylate, methacrylate, 2,2-bis- [4- (3-methacryloxy-2-hydroxypropoxy) -phenyl] -propane (Bis-GMA), triethylene glycol-di UV curable resins based on methacrylate (TEGDMA or TEGMA, both of which are meant here), urethane-dimethacrylate (UDMA), alkanediol dimethacrylate, or cyanoacrylate.

  The invention likewise includes the use of the glass according to the invention as an optical element comprising the glass according to the invention. An optical element is understood to be all articles and in particular parts that can be used for optical applications. This may be a part through which light passes. Examples of such components are cover glasses and / or lens elements, but also supports other components such as mirrors and glass fibers.

  The cover glass is preferably used for the protection of electronic components. This of course includes optoelectronic components as well. The cover glass usually exists in the form of a glass plate with a plane parallel surface and is preferably mounted above the electronic component so that the electronic component is protected from environmental influences, for example light, X-ray Such electromagnetic radiation can pass through the cover glass and interact with electronic components. However, x-rays can also be harmful to many optoelectronic components. Therefore, the cover glass manufactured from the radiopaque glass according to the present invention can be used as an X-ray protective glass in such a case, for example, in a medical device.

  Another application may be the use of the radiopaque glass according to the invention as cover glass and / or substrate glass in display technology with cathode ray tubes (CRT).

  Based on their optical properties, the glasses according to the invention can be used for optical applications as well. This is sufficiently chemically inert so that it can be applied as a substrate glass and / or a cover glass in a photovoltaic device, for example to cover solar cells based on silicon, organic solar cells and / or It is suitable as a support material for a thin film solar cell module. The X-ray absorption of the glass according to the present invention is particularly advantageous when using solar cell modules in spacecraft applications, among others. This is because it may be exposed to particularly intense X-rays outside the atmosphere. The high X-ray absorption properties also make it possible to apply as X-ray protective glass quite generally.

  Due to their high temperature resistance, the glasses according to the invention are suitable both as lamp glasses and in particular for use in halogen lamps and / or fluorescent tubes and similar structures. When X-rays are generated by the mechanism of light emission in the lamp, a particular advantage of the glass of the present invention is that it can be blocked from the surroundings. Furthermore, the glass according to the invention can be used in X-ray tubes.

  Further, the present invention includes vaporizing the glass according to the present invention by a physical method and depositing the vaporized glass on a part. Such a physical vapor deposition method, also called physical vapor deposition method or PVD method for short, is known to those skilled in the art and is described, for example, in DE 102 22 964 (DE 102 22 964 B4). Yes. The glass according to the invention is then used as a target to be vaporized in such a process. Parts deposited with glass according to the present invention can benefit from both the chemical durability of the glass and the X-ray absorption of the glass.

  Furthermore, based on its high durability, the glass according to the invention is likewise suitable as a matrix material for safe intermediate storage and / or final storage of radioactive waste and for embedding of radioactive materials .

  This glass also has advantages in applications as pharmaceutical container glass or packaging. Based on the high durability against the surrounding medium, the interaction with the content substance can be almost eliminated.

The relationship between the refractive index and the relative aluminum equivalent thickness for the examples from Table 1 is shown. Figure 3 shows the relationship between refractive index and relative aluminum equivalent thickness for the examples from Table 1 with advantageous upper and lower limits. FIG. 9 shows the relationship between refractive index and relative aluminum equivalent thickness for examples from Table G1500, with advantageous upper and lower limits. FIG. 9 shows the relationship between refractive index and relative aluminum equivalent thickness for examples from Table G1515, with advantageous upper and lower limits. FIG. 9 shows the relationship between refractive index and relative aluminum equivalent thickness for examples from Table G1525, with advantageous upper and lower limits. FIG. 6 shows the relationship between refractive index and relative aluminum equivalent thickness for examples from Table G1550, with advantageous upper and lower limits.

  Next, the present invention will be described based on examples, but these examples are intended to specifically explain the teaching of the present invention and are not intended to limit the present invention.

Table 1: Example (AB), unit: mass%

Table 1 contains examples of radiopaque glasses with a preferred composition range. All statements regarding the composition are given in mass%. The glass contains a preferred radiopaque combination of Cs ₂ O, BaO and SnO ₂ as well as an additionally defined amount of fluorine. Together with the combination described above, fluorine forms a preferred radiopaque material system, with which the refractive value is in the range of 1.480 to 1.561 and relative to aluminum. The thickness can be adjusted to a range from about 120% to over about 1400%.

All values of relative aluminum equivalent thickness (ALGWD in%) listed in Table 1 corresponding to X-ray absorption (XRO in%) were measured according to DIN ISO 4049. In this case, the gray value obtained from the image was measured using image processing software, and X-ray absorption was determined therefrom. Table 1 further describes the refractive index _nd and density of the examples.

The glasses described in the examples were produced as follows:
Weigh the raw materials for the oxide and continue to mix well. The glass mixture is melted at about 1580 ° C. in a discontinuous melting apparatus and then clarified and homogenized. At a casting temperature of about 1600 ° C., the glass can be cast and processed as a ribbon or other desired dimensions. In large capacity continuous equipment, the temperature can be reduced by at least about 100K.

  For subsequent processing, the cooled glass ribbon was crushed into a glass powder having an average particle size of up to 10 μm using the method known from DE 41 00 604 C1 (DE 41 00 604 C1). . Glass properties were determined using glass lumps that were not crushed into powder. Glass exhibits good chemical durability against water.

  In addition, Table 1 lists the chemical durability of the glass embodiment according to the invention. For two examples, the water resistance class (HGB) according to DIN ISO 719 is described by way of example. However, the glass according to the invention also achieves good values of acid resistance according to DIN 12116 and alkali resistance according to DIN ISO 695.

The following table G1500 represents glass in the vicinity of a region with a refractive index of 1.50. These data are expressed in weight percent:

The following table G1515 represents glass in the vicinity of the region with a refractive index of 1.515. These data are expressed in weight percent:

The following table G1525 represents glass in the vicinity of the region with a refractive index of 1.525. These data are expressed in weight percent:

The following table G1550 represents glass in the vicinity of the region with a refractive index of 1.550. These data are expressed in weight percent:

  The glasses of the indicated tables G1500, G1515, G1525 and G1550 have been experimentally melted and are also completely or at least partly the subject of the present invention. These corresponding examples are correspondingly examples as well.

Table 2: Comparative Example (VB), unit: mass%

Table 3: Comparative Example (VB), unit: mol%

  Tables 2 and 3 list the composition, refractive index, and relative aluminum equivalent thickness in% (ie, X-ray absorption, XRO in%) for comparison, for comparison. These glasses are radiopaque glasses or fillers for use in known dental glasses and dental materials, in which case the radiopaque properties are different from each other with various radiopaque materials. Based on the system (use of a single radiopaque material or a combination of various radiopaque materials).

In FIG. 1, the preferred relationship between refractive index and relative aluminum equivalent thickness for Examples AB1-AB12 is shown graphically:
In the range of the refractive index of 1.480 to 1.561, it is preferable that a relative aluminum equivalent thickness ALGWD (unit:%) is assigned to this refractive index. Can be described by:
Relative _{ALGWD (%) = (15480~15900)} · n d - (23015~22695).

In a first preferred embodiment of the present invention, X-ray opaque glasses exhibiting a refractive index _{n d} of the refractive index range of 1.480 to 1.561 is lowest relative aluminum equivalent thickness (minimum relative ALGWD) Relative aluminum equivalent thickness ALGWD (%) equal to or greater than where the minimum relative ALGWD is represented by the formula:
Minimum relative ALGWD (%) = C · n _d −D (where C = 11000 and D = 16160)
The case where it is calculated | required by is preferable.

Furthermore, X-rays opaque glass exhibiting a refractive index _{n d} of the refractive index range of 1.480 to 1.561 is the maximum of the relative aluminum equivalent thickness (maximum relative ALGWD) and the same or relative below it Aluminum equivalent thickness ALGWD (%), where the maximum relative ALGWD is the equation:
Maximum relative ALGWD (%) = A · n _d −B (where A = 1430 and B = 1632)
The case where it is calculated | required by is preferable.

Thus, in this X-ray opaque glass, preferably, the refractive index of each range _{n d} of from 1.480 to 1.561, the relative ALGWD delimited by the maximum of the relative ALGWD and minimum relative ALGWD Can be assigned. Preferred X-ray opaque glasses exhibiting a specific refractive index n _d is preferably an relative ALGWD within the interval of relative ALGWD, in this case, this interval can be calculated by the above equations.

In this first preferred embodiment, the assignment (n _d ; relative ALGWD) is in the range n _d of 1.480 to 1.561 for the preferred embodiment of the glass and defines two preferred upper and lower limits for relative ALGWD. This is done by building a linear equation. FIG. 2 shows a graph of this linear equation for AB1-AB15. This graph forms a so-called “einhuellende Geraden”. In the region between the upper encircling straight line (maximum) and the lower encircling straight line (minimum), there is a preferred range of relative ALGWD for the preferred embodiment of the glass, which is preferably 1.480-1. assigned to _{n d} range of 561. As can be appreciated, these examples are between “enclosing straight lines”.

In a second preferred embodiment of the present invention, the refractive index range of 1.480 to 1.561, assignment between the glass having a refractive index _{n d} and the relative aluminum equivalent thickness ALGWD (%) is the next interval By description:

This typically means: shows a composition within the scope of the present invention, and the refractive index in the _{n d} a range of less than 1.490 or more 1.510 _(e.g., n d = 1.50 Radiopaque glasses exhibiting a) preferably exhibit a relative ALGWD of at least 260% (corresponding to a minimum ALGWD). At the maximum, the ALGWD of this glass may preferably be 1000% (corresponding to the maximum ALGWD). For X-ray opaque glass contained in the other n _d range, the "minimum ALGWD" and "maximum ALGWD" applies has the values listed each other. "Min ALGWD" thus with respect to a particular _{n d} range, defines the lower limit of the relative ALGWD, and "maximum ALGWD" defines the upper limit.

In another preferred embodiment, the refractive index range of 1.480 to 1.561, assignment between the refractive index of the glass _{n d} relative aluminum equivalent thickness ALGWD (%) is carried out by the following description of the section :

This typically means: shows a composition within the scope of the present invention, and a refractive index that is included in the _{n d} a range of less than 1.480 or more 1.490 (e.g. _n d = 1.485 Radiopaque glasses exhibiting a) preferably exhibit a relative ALGWD of at least 120% (corresponding to a minimum ALGWD). At the maximum, the ALGWD of this glass may preferably be 760% (corresponding to the maximum ALGWD). For X-ray opaque glass in the other n _d range, the "minimum ALGWD" and "maximum ALGWD" applies has the values listed each other. "Min ALGWD" thus with respect to a particular _{n d} range, defines the lower limit of the relative ALGWD, and "maximum ALGWD" defines the upper limit.

In order to collect data, a glass lump was made from the glass composition of the examples and the parameters belonging to it were determined: the relative aluminum equivalent thickness (unit:%) was measured by the method described above. The refractive index _nd was determined by a known method. The number of samples per example was two. Each parameter was measured a plurality of times, and average values were calculated for refractive index and X-ray absorption. Using linear regression, as shown in FIG. 1, the refraction values for the radiopaque glasses according to the invention, for example those containing the preferred radiopaque system of SnO ₂ , BaO, Cs ₂ O and F And the radiopacity can be expressed.

For comparison, the refractive values and relative aluminum equivalent thicknesses are similarly entered in FIG. 1 for the above-described comparative examples based on other radiopaque material systems. It can be recognized that the examples in the refractive index range described in the claims show clearly higher X-ray absorption (on the basis of the respective refractive indices) than the comparative examples. For the same refraction values, much higher x-ray absorption values are achieved in the preferred glass, eg n _d = 1.548, whereas Example AB1 shows a relative ALGWD of 1240%, Comparative Example VB1 only shows 763%, Comparative Example VB10 shows 276%, and Comparative Example VB14 only shows 190%. Even at a low refractive value range of about 1.49, Example AB3 shows a relative ALGWD of 310%, whereas Comparative Example VB19 only shows 80%. Thus, the X-ray visibility of the preferred glass within the scope of the present invention or dental plastic compound made using it is clearly enhanced. Optical elements including preferred glass (such as protective glass) can therefore be designed to be thinner with the same thickness and absorb more X-rays than known elements, or with the same X-ray absorption, Thus, the mass can be reduced.

In the case of glasses exhibiting a low refractive value, so far the radiopacity has been difficult and can only be raised insufficiently. This is because an increase in the ratio of the X-ray opaque material may simultaneously increase the refraction value. With the preferred X-ray opaque material system of SnO ₂ , BaO, Cs ₂ O and F, a clear improvement in X-ray opacity is achieved, even at low refractive values, and higher refractive values In range, the aluminum equivalent thickness is significantly improved over known glasses.

In FIG. 2, Example AB15 shows a similar composition and similar high relative ALGWD to Example AB7 for the radiopaque components Cs ₂ O, BaO, and SnO ₂ , but with a refractive index of 1.504. Thus, the refractive index is clearly lower than that of Example AB7 (n _d = 1.525). This is due to the favorable influence of the component fluorine, which allows the refractive index to be intentionally adjusted and thus reduced here. Thereby, it is possible to intentionally produce a glass that exhibits a high relative ALGWD and a relatively low refractive index.

Similarly, the comparison of Examples AB13 and AB14 shown in FIG. 2 is approximately due to the appropriate choice of radiopaque material in the preferred radiopaque material system of SnO ₂ , BaO, Cs ₂ O and F. It reveals that it is possible to produce glasses that exhibit the same refractive index but different relative ALGWDs.

  The above-mentioned advantageous equations, graphs and intervals for the assignment between the refractive index of the glass and the relative aluminum equivalent thickness are also for the embodiments of the invention listed in Tables G1500, G1515, G1525 and G1550. This applies accordingly (see FIGS. 3-6). Also in these figures, advantageous upper and lower limits (“enclosing straight line”) and comparative examples for comparison are entered.

The invention can also be described by the following:
1. Dental materials or dentistry comprising radiopaque glasses according to the invention as fillers for the treatment of cavities in human and / or animal teeth, in particular for filling and / or for restoration of teeth raw materials.

  2. A glass powder comprising powder particles made of radiopaque glass according to the present invention.

  3. The glass powder according to item 2, wherein the surface of the powder particles contained is silanized.

  4). Filling material for dental plastic compounds for treatment of cavities in human and / or animal teeth, in particular for filling and / or for dental restoration, comprising a glass according to the invention.

  5. A dental plastic compound comprising a glass powder comprising a radiopaque glass according to the invention or a glass according to the invention.

  6). Dental glass / plastic composite comprising a glass powder comprising a radiopaque glass according to the invention or a glass according to the invention.

  7). The dental plastic is preferably acrylate, methacrylate, 2,2-bis [4- (3-methacryloxy-2-hydroxypropoxy) -phenyl] -propane (Bis-GMA), triethylene glycol-dimethacrylate. (TEGDMA or TEGMA, both of which are meant here), a dental curable resin according to item 6, which is a UV curable resin based on urethane-dimethacrylate (UDMA), alkanediol dimethacrylate or cyanoacrylate Glass / plastic composite.

  8). Dental glass / plastic-glass ionomer cement comprising a glass powder comprising a radiopaque glass according to the invention or a glass according to the invention.

  9. Dental glass containing dental plastic for treating, in particular filling cavities in human and / or animal teeth and / or for dental restorations-dental glass for producing dental plastic compounds As a use of the radiopaque glass according to the invention.

  10. Use of the radiopaque glass according to the invention as glass powder.

  11 Item 11. Use according to item 10, wherein the surface of the obtained powder particles is silanized.

  12 Dental glass containing dental plastics-Use according to item 10 or 11 in dental plastic compounds.

13.
As a radiopaque material in dental plastic compounds and / or as an element for optical applications and / or as a cover glass and / or substrate glass in display technology in cathode ray tubes (CRT) And / or as cover glass and / or substrate glass in photovoltaic devices and / or as lamp glass in X-ray tubes and / or as material for embedding radioactive materials
Use of radiopaque glass according to the invention.

14 Oxide-based mass%, the following:
SiO ₂ 35~75
B ₂ O ₃ 2-16
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~14
BaO 0-24
Cs ₂ O 1~30
SnO ₂ 0~15
F 0-8
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the and preferably has a _La 2 _{O 3} of 0 to 19, a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.480 to 1.561, X-ray opaque Glass.

15. Oxide-based mass%, the following:
SiO ₂ 40-70, especially 50-65
B ₂ O ₃ 5-15, especially 6-15
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0-10, especially 2-6
BaO 0-24, especially 0-17
Cs ₂ O 1-30, especially 7-24
SnO ₂ 0-15, especially 0-3
F 0-8, especially 0-6
La ₂ O ₃ 0-8, especially 0-5
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10, especially 13-35
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.480 to 1.510, X-ray opaque glass.

16. Oxide-based mass%, the following:
SiO ₂ 42-65, especially 47-64
B ₂ O ₃ 5-15, especially 6-15
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0-10, especially 2-6
BaO 0-15, especially 2-10
Cs ₂ O 5-30, especially 6-26
SnO ₂ 0-10, especially 0-3
F 0-5, especially 0-3
La ₂ O ₃ 0-9, especially 0-7.5
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 9, especially 11-35
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of 1.505-1.520, X-ray opaque glass.

17. Oxide-based mass%, the following:
SiO ₂ 42-65, especially 45-61
B ₂ O ₃ 5-15, especially 7-15
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0-14, especially 1.5-7
BaO 0-18, especially 6-14
Cs ₂ O 5-25, especially 6-19
SnO ₂ 0-6, especially 0-3
F 0-5, especially 0-3
La ₂ O ₃ 0-19, especially 0-17
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 8, especially 10-35
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.519 to 1.542, X-ray opaque glass.

18. Oxide-based mass%, the following:
SiO ₂ 37-56, especially 40-53
B ₂ O ₃ 2-16, especially 3-14
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0-14, especially 0-12
BaO 0-24, especially 4-24, preferably 4-21
Cs ₂ O 9~25, especially 10 to 19
SnO ₂ 0-6, especially 0-3
F 0-5, especially 0-3
La ₂ O ₃ 1-19, especially 4-17
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10, especially 15-42
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.542 to 1.561, X-ray opaque glass.

19. Oxide-based mass%, the following:
SiO ₂ 35-75, especially 38-70
B ₂ O ₃ 2 to 16, especially 5 to 15, preferably 6 to 15
Al ₂ O ₃ 0.8-7.5, especially 0.8-6
K ₂ O 0 to 14, especially 0-10, preferably 0-7
Cs ₂ O 1-30, especially 6-28, preferably 7-24
SnO ₂ 0-15, especially 0-6, preferably 0-3
F 0-8, especially 0-6, preferably 0-3
La ₂ O ₃ 0-19, especially 0-16
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO and BaO-free with the exception of unavoidable impurities, and the refractive index _{n d} of 1.480 to 1.561, X-ray opaque glass.

The described radiopaque material combination (SnO ₂ , BaO, Cs ₂ O), and preferably the defined addition of fluorine, adjusts the desired refractive value on the one hand in the glass and on the other hand is as high as possible X-ray absorption can be adjusted. According to the present invention, in the refractive index range of 1.480 to 1.561, a relative aluminum equivalent thickness range of about 120% to over 1400%, for example, 1600% can be realized.

These examples, refractive index _{n d} of the glass system according to the invention, in particular, in the range of 1.480 to 1.561, without compromising the required ALGWD, also demonstrate that can be tailored to the application purpose . Thereby, it can preferably be used especially as a filler in dental materials and also for other applications where high demands are imposed, especially with regard to purity and chemical durability and high temperature resistance. This glass system can be produced industrially on a large scale at a low cost.

  The glass according to the invention can be melted relatively easily and can therefore be produced effectively. In particular, by changing the individual components, the refractive index can be adjusted within the stated limits, depending on the application requirements, for example the requirements for dental filling materials, and the resulting glass has an improved ALGWD. The glass system shown was found. The possible refractive index variations included in the present invention are relatively wide. This glass system allows a particularly rational industrial production of the glass within this glass system. This is because, in particular, only a defined selection of raw materials has to be maintained, and the proportion within the quantities stated in this selection is changed. Therefore, the method management during the melting of the glass is very similar within this glass system.

Claims (19)

X-ray opaque glass, in oxide-based mass%, the following:
SiO ₂ 35~75
B ₂ O ₃ 2-16
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~14
BaO 0-24
Cs ₂ O 1~30
SnO ₂ 0~15
F 0-8
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of 1.480 to 1.561, X-ray opaque glass. Oxide-based mass%, the following:
SiO ₂ 35~75
B ₂ O ₃ 4-15
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~10
BaO 0.6-24
Cs ₂ O 1~30
SnO ₂ 0~15
F ≧ 0.3
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.480 to 1.561, according to claim 1 X-ray opaque glass according. Oxide-based mass%, the following:
SiO ₂ 35~75
B ₂ O ₃ 4-15
Al ₂ O ₃ 0.8~7.5
K ₂ O 0~10
BaO 0-24, especially 0.6-24
Cs ₂ O 1~30
SnO ₂ 0~15
F 0 or more and less than 0.3, but BaO + Cs ₂ O + SnO ₂ + F ≧ 10
, And the a PbO-free with the exception of unavoidable impurities, and the refractive index _{n d} of from 1.480 to 1.561, according to claim 1 X-ray opaque glass according. F in a proportion of up to 5.5% by weight, preferably up to 2.5% by weight and / or La ₂ O ₃ in a content of 0-19% by weight, preferably 0-16% by weight, and / or _B 2 _{O 3} containing at a content of 5 to 15 wt%, X-ray opaque glass according to any one of claims 1 to 3. Oxide-based mass%, the following:
SiO ₂ 38~70
B ₂ O ₃ 6-15
Al ₂ O ₃ 1-7
K ₂ O 0~7
BaO 0.8-20
Cs ₂ O 1~28
SnO ₂ 1-15, preferably more than 4 and 15 or less F 0.75-2.5
With the exception of BaO + Cs ₂ O + SnO ₂ + F ≧ 10
The radiopaque glass according to claim 1 or 2, wherein The sum of the proportions of BaO, Cs ₂ O, SnO ₂ and F is 12% or more, preferably 14% or more, particularly preferably 17% or more in terms of mass% of the oxide base. The radiopaque glass according to claim 1. The molar ratio of SnO ₂ to F is at least 0.4, advantageously at least 0.45, preferably at least 0.49, particularly preferably at least 0.5 and / or at most 0.85, preferably at most 7 to 9, more preferably at most 0.77, likewise preferably at most 0.75, particularly preferably at most 0.72 and even more preferably at most 0.7. The radiopaque glass according to any one of the above. Of Cs _{2 O,} molar ratio of the sum of Cs ₂ O + BaO + SnO 2 is at least 0.05, preferably at least 0.07, particularly preferably at least 0.1, and / or at most 0.48, preferably up to The radiopaque glass according to claim 1, which is 0.45, particularly preferably 0.41 at the maximum. Furthermore, the following component ZrO ₂ 0 to 2 in mass% of oxide base
ZnO 0-2
MgO 0-2
CaO 0-2
WO ₃ 0~2
Nb ₂ O ₅ 0-2
HfO ₂ 0-2
Ta ₂ O ₅ 0-2
Gd ₂ O ₃ 0-2
Sc ₂ O ₃ 0~2
Y ₂ O ₃ 0-2
Yb ₂ O ₃ 0-2
La ₂ O ₃ 0-2
The radiopaque glass according to claim 1, comprising at least one of the following. From Na ₁ O and / or Li ₂ O and / or MgO and / or CeO ₂ and / or TiO ₂ and / or La ₂ O ₃ and / or ZrO ₂ , excluding inevitable impurities The radiopaque glass according to any one of 9 to 9. Said glass exhibiting a refractive index _{n d} of the refractive index range of 1.480 to 1.561, the minimum relative aluminum equivalent thickness (minimum relative ALGWD) equal to or exceeds that the relative aluminum equivalent thickness ALGWD ( %) Where the minimum relative ALGWD is the equation:
Minimum relative ALGWD (%) = C · n _d −D (where C = 11000 and D = 16160)
The radiopaque glass according to any one of claims 1 to 10, which is obtained by: Said glass exhibiting a refractive index _{n d} of the refractive index range of 1.480 to 1.561, the maximum relative aluminum equivalent thickness (maximum relative ALGWD) equal to or below which the relative aluminum equivalent thickness ALGWD ( %) Where the maximum relative ALGWD is the equation:
Maximum relative ALGWD (%) = A · n _d −B (where A = 1430 and B = 1632)
The radiopaque glass of Claim 11 calculated | required by these. In the refractive index range of 1.480 to 1.561, between the refractive index _{n d} and the relative aluminum equivalent thickness ALGWD of the glass (%), the following assignment:
n _d Min ALGWD and preferably up ALGWD
1.480 or more and less than 1.490 120% and preferably 700%
1.490 or more and less than 1.510 260% and preferably 1000%
1.510 or more and less than 1.530 520% and preferably 1200%
1.530 or more and less than 1.550 780% and preferably 1500%
1.550 to 1.561 850%, preferably 910% and preferably 1600%
The radiopaque glass according to claim 1, wherein: In the refractive index range of 1.480 to 1.561, between the refractive index _{n d} and the relative aluminum equivalent thickness ALGWD of the glass (%), the following assignment:
n _d Min ALGWD and preferably up ALGWD
1.480 or more and less than 1.490 120% and preferably 760%
1.490 or more and less than 1.500 240% and preferably 875%
1.500 or more and less than 1.510 360% and preferably 990%
1.510 or more and less than 1.520 475% and preferably 1105%
1.520 or more and less than 1.530 590% and preferably 1220%
1.530 or more and less than 1.540 705% and preferably 1335%
1.540 or more and less than 1.550 820% and preferably 1450%
1.550-1.561 935% and preferably 1565%
The radiopaque glass according to claim 1, wherein:   A radiopaque glass comprising at least 95% by mass of the oxide-based glass of any one of claims 1-14.   16. Radiopaque glass according to any one of claims 1 to 15, for use as a dental glass in the medical field, in particular in the dentistry field, and / or for diagnostic purposes.   16. Treatment according to cavities in human and / or animal teeth, in particular for filling and / or for use as dental glass for dental restorations. Radiopaque glass.   Said dental glass is a component of a dental plastic compound that is present in the form of powder particles and is preferably silanized on the surface and contains dental plastic, in particular in the form of a filler of a filling composite, 18. Radiopaque component according to claim 16 or 17, which is a component in the form of a filler or inert additive in dental cement, preferably in the form of an inert additive in resin reinforced glass ionomer cement. Glass. As a radiopaque material in dental plastic compounds and / or as an element for optical applications and / or as a cover glass and / or substrate glass in display technology in cathode ray tubes (CRT) And / or-as a cover glass and / or substrate glass in a photovoltaic device and / or-as glass in an X-ray tube and / or-as a material for embedding radioactive material
Use of the radiopaque glass according to any one of claims 1 to 15.