MXPA02010753A - Dental composite restorative material and method of restoring a tooth. - Google Patents

Abstract

A dental composite material includes a hardenable resin matrix and a filler component. The filler component includes (a) a first plurality of preferably glass particles having an average particle size of from about 1 to about 10 micrometers; (b) a second plurality of preferably glass particles having an average particle size of from about 0.1 to about 1 micrometers; and (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 micrometers. A method according to the invention includes compacting a dental composite material into a prepared tooth cavity, wherein the material has a packability index above about 300 g/mm2.

Description

COMPOSITE DENTAL RESTORATION MATERIAL AND METHOD TO RESTORE A TEETH TECHNICAL FIELD The present invention relates to a dental material composed of the type that is useful in dental restoration and the like, such as, for example, as an alternative to a conventional dental composite or amalgam. More specifically, the invention relates to a material having a hardenable matrix component and a filler component. Specifically, the invention relates to a material wherein said filler component includes fillers having three different particle sizes. A method according to the invention includes compacting a composite dental material within a prepared tooth cavity, wherein the material has a packing capacity index in excess of about 300 g / mm2.

BACKGROUND OF THE INVENTION Certain practical considerations apply to the formulation and application of dental restoration, such as resin-based posterior dental restorations. Accordingly, it is widely preferred that the composition is effectively homogeneous in such a way that bubbles or structural discontinuities are substantially prevented from penetrating into the structure of the tooth. Additionally, it is preferred that the material be can "pack" or "condense" and be able to deform a matrix band during the course of the tooth filling. Said materials must also be able to withstand the physical stresses existing in the posterior region of the mouth and that do not crumble, fracture or erode under such conditions. The use of metal amalgams in the restoration of posterior teeth has been known for some time. Said amalgam materials have been shown to have good resistance to the physical stresses supported by the posterior teeth and which have small coefficients of thermal expansion. Said amalgams have also shown that they have good "packing capacity" and have demonstrated other properties necessary for the subsequent restoration. However, these materials suffer from uncertainty as to the biological effect of the introduction of mercury and other materials into the oral cavity for long periods of time. Those skilled in the art of dental restoration will appreciate that certain posterior restorations, such as Class II restorations, require the use of a matrix for the proper application. This is to ensure that the replacement of the natural structure of the tooth is replaced and restored in close contact with the adjacent tooth. In this way, it will be appreciated that the use of a matrix band surrounding the tooth to be repaired is generally necessary. These bands are necessary when the tooth to be repaired must be excavated in such a way that the preparation of the resulting cavity is communicated from the upper surface to one or more lateral surfaces of the tooth. In such a case, the matrix band is placed around the tooth and held tightly in place while the restoration material such as the amalgam is put in place. A measure of the packing capacity of a material and the values of the packaging capacity measured for conventional dental amalgams is described, for example, in U.S. Patent No. 4,226,622 which is incorporated herein by reference for said description. Until now, commercially and conventionally available composite materials, although durable, have suffered from low packing capacity values. This results in a less than effective distension of the matrix band, very often resulting in a "bounce" or recovery of the original shape of the band and finally a less than ideal contact. Therefore, there is a need for a durable back composite dental material which has a high packing capacity.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a composite dental material. It is another object of the present invention to provide a composite material as mentioned above, which has a high packing capacity. It is another object of the present invention to provide said composite material, which is durable when used in dental restorations. It is yet another object of the present invention to provide an alternative dental material to conventional amalgams and composites. It is yet another object of the present invention to provide restorative dental material that can be placed where desired and then can be sculpted or scraped for aesthetic purposes. These and other objects of the present invention, which should be apparent from the following description, will be carried out by the invention as will be described and claimed herein.

BRIEF DESCRIPTION OF THE INVENTION In general, a composite dental material comprises a hardened resin or "compomer" matrix and a filler component. The filler component comprises (a) a first plurality of glass particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of glass particles having an average particle size of from about 0.1 to about 1 micrometer; and (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns. One embodiment of the invention comprises about 12 percent to about 25 percent by weight of said matrix. resin and about 75 to 88 percent by weight of said filler component. A method according to the present invention for restoring a tooth includes selecting a tooth that needs to be restored, the tooth having an original configuration must have at least a top surface and lateral surfaces. A portion of the tooth is removed to form a preparation cavity. The preparation cavity can communicate from the upper surface to at least a first lateral surface of the tooth. At least, the first side surface is surrounded by the substantial matrix band and completely covering the cavity where it communicates with the first side surface. A composite dental material according to the invention as discussed above and preferably having a packing capacity index of approximately 300 g / mm2 is applied to the cavity. The composite dental material is compacted to deform the matrix band, and the material hardens, preferably by exposure to actinic light. The original configuration of the tooth with this is substantially restored.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a package for photosensitive materials, in accordance with the concepts of the present invention, and showing, with dotted lines, a dose unit of material contained therein.

Figure 2 is a perspective view of an alternative embodiment of the package as shown in Figure 1. Figure 3 is a view like that of Figure 1, showing the release layer removed from it, thereby exposing the unit of dose of material contained therein. Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3. Figure 5 is a perspective view of a portion of the package of Figure 1, shown being used on a surface of support, and showing a dental instrument for environmental purposes. Figure 6 is a top plan view of a plurality of packages like those of Figure 1, which are shown contiguously attached and showing a release layer in dotted lines. Figure 7 is an elevation, side view of the plurality of packages of Figure 6, showing the release layer removed from these. Figure 8 is a top plan view of an alternative embodiment of the plurality of packages of Figure 6. Figure 9 is an elevation, side view of the two packages of Figure 7, shown attached back to back and each having a release layer shown in dotted lines and removed from them. Figure 10 is a cross-sectional view like that of Figure 4, showing an alternative embodiment of the invention.

PREFERRED MODALITIES FOR CARRYING OUT THE INVENTION A dental composition or "compomer" material according to the present invention includes a hardenable resin and a filler component. The material can be placed in place with respect to the tooth to be restored and then sculpted and carved as necessary due to its non-flow characteristics. A preferred filling material is a radiopaque dental glass. More preferably, the filler component comprises at least one and preferably three components (a), (b) and (c) as follows: (a) a first plurality of glass preferably, more preferably barium glass, with particles having an average particle size of from about 1 to about 10, more preferably from about 5 to about 9 microns; (b) a second plurality of glass preferably, more preferably barium glass, with particles having a particle size of from about 0.1 to about 1, more preferably from about 0.5 to about 0.9 microns; and, (c) a plurality of filler particles, preferably fumed silica, having an average particle size of from about 0.01 to about 0.04 microns. The fillers (a) and (b) can be the same or different materials. It has been found that this inventive material has improved the packaging capacity much more than materials hitherto known in the art. The Inventive materials can be used as intraoral dental restorative, but can also be used by the laboratory technician in extra-oral dental applications such as in the production or restoration of crowns, inlays or the like. The invention will be exemplified and will be discussed here, for simplicity, with respect to intra oral applications, it should be understood that extra-oral applications are within the scope of use of the invention. The material may be contained in a primary dose unit protective package, which has an opaque, polymeric cup, heat sealed with a similar opaque polymeric lid or metallized paper film. The inverted suction cup can be used to protect light-sensitive material during use. The material can also be packed in a bag or bag (not shown) having the characteristics of the package described below. For example, a package exemplifying the concepts of the present invention is generally represented by the number 10 in the accompanying drawings. As will be discussed in its entirety below, package 10 is useful for storing, transporting and using photo sensitive materials such as material 11, which is the composite dental material for restoration discussed herein. Package 10 includes a container with an open top generally indicated by the number 20 having a base 21 and at least one vertical wall 22 and having an open area 23 therein. (Figure 4). Package 10 does not need to have a size or particular shape. However, it is preferred that the package 10 be configured to closely maintain a dose unit of material 11. A configuration of the package 10 is generally rectangular, such that the four side walls 22 contiguously formed with each other and with the base 21 form the container 20 (Figures 1, 3-5). Any other form is within the field of use of the invention, including a single round side wall 22 as shown in Figure 2 as is package 10b. An example of a dosage unit of the present inventive composite material is about 0.3 grams. With said dose unit, a package 10 having an open area 23 of about 300 mm2 is useful. However, smaller or larger sizes are very well within the field of use of the invention. Similarly, material 11 does not need to have any particular form, and may include flat or oblong shapes as shown in Figures 1 and 4, or more rounded shapes as shown in Figure 2. The equipment (not shown) that is used to form the dose unit of material 11 or others criteria, normally it will dictate the form, and a specific configuration for package 10 will be selected based on this. Ways leading to efficient material handling have been imagined, and all are within the scope of use of the invention. It is preferred that the vertical side wall 22 have a sufficient height for allowing the user to effectively secure the package 10. The side wall 22 is preferably a vertical wall having a first end 30 near the base 21 and an end 31 remote from the base 21 (Figure 4). The distal end 31 of the side wall 21 is close to an open top 32, which opens to form the open area 23. The distal end 31 of the side wall 22 is preferably contiguously formed with a laterally extended band or shelf 40. In the characterization of the invention as shown in Figures 1 and 5, the band 40 has four portions 40a-40d. In the invention, as shown in Figure 2, a single band 40 extends from the side wall 22. The band 40 has several functions, including providing a convenient surface for the user to be able to hold it. Additionally, the band 40 provides an extended surface to have an adhesive contact with the release layer which will be described below. The band 40 also provides a connection between a plurality of contiguously formed packets 10 as shown in Figure 6-9 and as will also be discussed in detail below. A release layer 50 is fixed removably and preferably adhesively to the band 40. The release layer 50 closes the open area 23 standing in an opposite relationship to the open top 32. It is also preferable to configure the release layer 50 to have a shape and dimension similar to the band 40, although this is not necessarily required. Any releasable adhesive, which does not adversely affect the dosage unit of the material 11 is useful. Additionally it will be appreciated that the release layer 50 can be selectively removed from the package 10 and then replaced over it to reseal the package 10. Although an adhesive releasable release layer 50 is preferred, it is also within the range of use of the invention a release layer that can be broken, cut or otherwise removed. All are within the field of employment of the term "release layer". To facilitate removal of the release layer 50 from the container 20, a user simply holds a release layer portion 50 and detaches it from the web 40 at the distal end 31 of the side wall 22. To assist the user in this procedure , a portion of the release layer 50 can be left exposed. This can be achieved by any means, such as providing a flange 51 (Figure 2), which does not contact the band 40, or removing (or without forming) a portion 52 of the band 40 such that the section 50a ( Figure 1) of the release layer 50 is not in physical contact with the band 40 at that location. Any of these means or others are within the field of use of the invention. As another example, as shown in Figure 10, the band 40 may terminate in a lip or catch protrusion 41, which also normally does not contact the proximal portion 50b of the release layer 50. This provides an area where a user can hold the release layer 50 to remove it. The package 10 is preferred and substantially non-transmitting of at least a portion of the light spectrum to which the material 11 is photo-sensitive. It may be substantially non-transmitting of the entire light spectrum by being made of an opaque material, or it may transmit all portions of the spectrum other than those to which the material 11 is photo-sensitive. The latter is desirable when it is desired to see the contents of packet 10 for any reason. Likewise, it is imagined that one portion of the package 10 may be opaque while another portion may transmit all or part of the spectrum light. For example, the container 20 may be opaque, while the release layer 50 is partially transmissive, or vice versa. The package 10 is preferably thermoformed from a dark or black pigmented plastic material, providing a barrier against light. Examples of such materials include polystyrene, polyethylene terephthalate, polyethylene (preferably high density polyethylene), polypropylene, and the like. The release layer 50 may be formed of a similar material or may be formed of a flexible material such as a metallized substrate or sheet of paper and metal (preferably aluminum), having a release coating or a permanent sealing liner. With a permanent sealing liner, the package 10 may have to be destroyed, or a portion destroyed to open it. The release layer 50 and the container 20 can also be individually formed of laminated materials. For reasons that will be explained below, the release layer 50 may be flexible or rigid. Figures 3 and 4 depict a more flexible release layer 50, partially removed from the package 20. A flexible release layer may be formed of a metallized substrate or a paper / metal laminate. A stiffer release layer 50 is shown in Figure 1 and may be formed of a more rigid or heavy plastic material. It will also be appreciated that the package 10 may be formed with a lid attached by a living hinge, a sliding hinge, or any other useful cover, although these are not shown in the drawings. During use, the dose unit 11 of the photosensitive material is provided in the package 10. The dose unit of the material 11 is protected from premature exposure to light because the package 10 substantially does not transmit at least that portion of the light spectrum to which the material 11 is photo sensitive. When it is desired to use the material 11 for its intended purpose, the user will first remove the release layer 50. At this point, the user can remove all or a portion of the dose unit 11 from the package 10. it is removed and a portion is left unused, the release layer 50 can temporarily placed again on the container 20, whereby continuous exposure to light is limited. This is also facilitated if the release layer 50 is more or less rigid. Alternatively, the user can also remove the entire dose unit from the material 11 of the package 10. In this case, the material 11 can be placed on a support surface 60 (Figure 5). A dental 61 used to work with the material 11 is depicted in Figure 5 for environmental purposes. To limit the exposure of the material 11 to the exposure of the light in this case, the container 20 can be inverted over the material 11 in such a manner as to cover the material 11 as the material 11 rests on the support surface 60. In addition , the release layer 50 can be placed on the support surface 60 and then the material 11 can be placed on the located release layer 50 (not shown) before the package 20 is placed on the material 11. This provides a Additional work surface convenient for the user and once again, it can be facilitated by a relatively rigid release layer 40. The package 10 can be provided as an Individual unit, as shown in Figures 1 and 2. However, the package 10 can also be joined with one or more packages 10 as shown in Figures 6-9. Any number of packages 10 joined in this manner, and in any relationship, is within the scope of use of the invention. For example, Figure 6 represents five contiguously formed packages 10 when being joined along a portion of band 40. Networks 40 between individual packages 10 may be provided with perforations 70, scored portions (not shown) or the like, to facilitate the removal of one. or more packages 10 of the rest for its use. Alternatively, as shown in Figure 8, the perforations are not necessary and the attached packages 10 can be cut or detached from the others. A separation during use is not necessarily required. The joining of a plurality of packages 10 can be achieved by any means other than means conventional in the art. Other configurations for joining a plurality of packages 10, such as the joining of the bases 21 (Figure 9) are also within the field of use of the invention. Similarly, a plurality of packages 10 can be joined in rows and columns (not shown), or other configurations without limit. Returning now to the discussion of composite restorative dental material, the present materials are useful for many types of dental restorations, including but not limited to Class I, II, and IV types and the like. In such restorations, the tooth to be restored is identified by the clinician and then excavated to remove caries or the like. It is a common practice in the restoration of posterior teeth to use a band of matrix that surrouthe tooth to be filled. These baare usually sheets of plastic or metal thin and malleable shaped to fit over the tooth. The use of said bands and a general description of the restoration of the tooth with which the present invention is useful are described, for example, in the patent of E.U.A. No. 4,514,174 which is incorporated herein by reference for said descriptions. By having an improved packing capacity over the previously known composite dental materials, a person skilled in the art will appreciate the improvement in the dental restorations that the inventive materials can make possible. The composite materials according to the research can be inserted into a cavity preparation by any conventional technique, including those described in the US patent. No. 4,514,174 which is incorporated herein by reference. Those techniques similar to the management and placement of dental amalgams, which are well known in the art, are particularly useful with the present invention. Examples of resins useful for components are those materials having as the main functional ingredient, the polymerizable unsaturated acid monomers, such as an acid-substituted butane portion or a functionality derived from acid reagent. An example of an acid or a functionality derived from acid reagent includes those having the general formula (RO2C) x-C4H6- (CO2R ')? where R is an acid radical or an acid reagent derivative and R 'is an unsaturated polymerizable radical having from 2 to about 13 carbon atoms, x from 2 to 3 y, and from 1 to 2. A description of said materials is provided in the U.S. patent. No. 5,218,070, which is incorporated herein by reference for said description. Any hardenable resin matrix useful for intra oral or extra oral applications is within the scope of use of the invention. Preferred resins include those that are curable, more preferably curable by exposure to actinic light. Examples of such resins include ethoxylated bisphenol-A dimethacrylate; glycidyl methacrylate Bisphenol-A; triethylene glycol dimethacrylate; and mixtures of these. A preferred inventive material includes from 12 to about 25 and more preferably from 12 to about 18 percent by weight of the resin matrix component and from about 75 to about 88, more preferably from about 80 to about 88 percent by weight of the component. of filling. Optionally, a shading pigment or other additives may also be employed, such as, for example, fluoride releasing agents, antibacterial materials, anticaries agents, and the like. A preferred resin material is the reaction product of glycidyl methacrylate bisphenol-A (Bis-GMA) and a chain initiator, such as hexamethylene diisocyanate (HMDI). The reaction may also include other reactive components. For example, the urethane component can be the product reaction of about 27 to about 31 percent by weight of Bis-GMA as a reactive resin, more preferably approximately 29 percent by weight; from about 29 to about 33 weight percent of triethylene glycol dimethylacrylate (TEGDMA) as diluent reagent, more preferably about 31 weight percent; and from about 29 to about 33 weight percent of ethoxylated bisphenol-A dimethylacrylate (EBPADMA) also as a diluent reagent, more preferably about 31 weight percent; a useful amount of HMDI (preferably about 8 percent by weight). The reaction is preferably catalyzed with, for example, a catalyst such as dibutyltin dilaurate, and uses an inhibitor such as butylated hydroxytoluene. From about 97 to about 99 percent by weight of the urethane component, and more preferably about 98 percent by weight, is used to form 100 percent by weight of the activated resin component. The rest of the constituents of the activated resin include inhibitors, photoinitiators, UV absorbers, accelerators, fluorescers, and the like. While the preferred material is photo curable, a chemical curing package can also be used, including any of those well known in the art for dental use, including peroxide, amine, and ascorbic acid derivatives, a metal ionic salt, and the similar ones. Other useful resins that may be employed include those described in the U.S.A. Nos. 4,514,342, 4,675,941, 4,816,495, 5,338,773 and 5,710,194, which are incorporated herein by reference for said description. The filler component preferably comprises one or more constituents, and more preferably comprises components (a), (b) and (c) as discussed above. It is believed that the mechanical interaction between these filler components, and particularly the increased contiguity of the contact between them, increases the packing capacity of the inventive materials. Examples of useful glass particles include barium-aluminum borosilicate glass, barium-aluminum fluorosilicate glass; mixtures of these and the like. In these materials, barium can also be replaced with strontium and the like, and may also contain fluoride. Other useful materials include calcium hydroxide ceramic, and others such as those fillers described in the U.S. Patents. Nos. 5,338,773, 5,710,194, 4,758,612, 5,079,277, and 4,814, 362, which are incorporated herein by reference for said description. These materials may have any morphology or shape, including spheres, regular or irregular shapes, filaments or fibers, and the like. Any form of particle having the other characteristics of the invention as described herein, including for example, average particle size, is within the scope of use of the invention. Preferred glasses are also silanados although this does not it is an absolute limitation of the invention. The filler particles can be treated with silanes (bound with silane) or provided with other treatments as is conventional for dental fillings. A preferred composition making up to 100 percent by weight of the filler component, is composed of from about 10 to about 30, more preferably from about 12 to about 25 percent by weight, even more preferably about 15-20 percent by weight , of barium glass particles (a); from about 50 to about 65, more preferably from about 58 to about 62 percent by weight, more preferably about 60 percent by weight of barium glass particles (b); and, from about 10 to about 30, more preferably from about 12 to about 25 percent by weight, even more preferably about 15-20 by weight, of fumed silica particles (c). In addition to improvements in packaging capacity, the materials according to the invention, when compared to the already known composite dental materials, exhibit similar or improved physical characteristics. For example, these include cure depth, diametral tensile strength, transverse tear strength, flexural modulus, radio opacity, hardness, fracture strength, opacity, polymerization shrinkage and wear. These characteristics and their Comparisons with the known compositions will be explained in detail later. It has also been found that the present materials can be polished, to shine more, with conventional polishing techniques. It will be shown that certain features, especially the packing capacity and the wear resistance have been improved compared to the materials of the prior art. Those skilled in the art will appreciate that the "packing capacity" as the term is used herein, is a quality possessed to a relatively greater or lesser degree among products that include dental restorative. It is difficult to attribute an exact quantitative measure for "packaging capacity", but a useful packaging capacity index has been imagined. By "packing capacity index" is meant a measured value that describes the amount of force required, grams per square millimeter (g / mm2), to condense or deform the restoration material. The test procedure simulates the clinical procedure of compressing the restoration material and packing the material into a cavity preparation to form a dense mass, substantially free of vacuum. While more force is required to compact the material, the "packaging capacity index" is much higher, and therefore, the material has a much higher "packing capacity". A material according to the present invention has a packing capacity index above about 300 and more preferably above of approximately 800 g / mm. It has been found that compositions according to the invention have good or improved aesthetic characteristics. The materials can be polished to a high gloss despite being highly filled. It has also been found that the products have an excellent radio opacity that approaches that of gold and amalgam products. Additionally it has been found that the inventive materials have equal or higher polymerization shrinkage characteristics after curing. This will be explained in its entirety below. A method according to the present invention for the restoration of a tooth includes selecting a tooth in need of restoration, the tooth having an original configuration having at least an upper surface and a lateral surface. A portion of the tooth is removed by excavating it to form a cavity preparation. The cavity preparation can be communicated from the top surface to at least the first side surface of the tooth. In the case where a matrix band is required, at least the first side surface is surrounded with a matrix band covering substantially and completely the cavity where it communicates with the first side surface. A composite dental material according to the invention, as discussed above and preferably having a packing capacity index above about 300 g / mm2, is applied to the cavity. The composite dental material is packaged for deforming the matrix band, and the material hardens, preferably by exposure to actinic light. The original conformation of the surface and anatomy of the tooth, with this is substantially restored.

GENERAL EXPERIMENTATION In order to demonstrate the effectiveness of the inventive materials in carrying out the objects of the invention, a composite material was prepared with the following components and as described above: Quantity Resin Activated 14.95 p / p% Inorganic Filler 85.00 p / p% Pigments of Matiz 0.05 p / p% 100.00 Activated Resin: Amount Reactive Methacrylate Resin EBPADMA Urethane Resin (Bisphenol-A Ethoxylated Dimethylacrylate): 98.0 p / p% BHT Inhibitor (Butylated Hydroxytoluene); Photo started r-CQ (Camphorquinone); UV Absorbent (Phenyl Metanone); Accelerator-EDAB (Ethyl, NN Dimethylamino Benzoate); and, Fluorescent Agent-2,5 Dihydroxy Terephthalate Acid Diethyl Ether 2.0 p / p% 100,000 EBPADMA Urethane Resin: Bis-GMA Reactive Resin (Glycidyl Methacrylate Bisphenol-A): 28.9 p / p% Reagent Diluent-TEGDMA (Triethylene Glycol Dimethacrylate): 31.3 p / p% Reagent Diluent-EBPADMA (Bisphenol Dimethacrylate- A Ethoxylate): 31.2 p / p% Chain Initiator-HMDI (Hexamethylene Diisocyanate): 8.2 p / p% Catalyst - Dibutyltin dilaurate 0.3 p / p% Inhibitor-BHT (HydroxyToluene Butylated): 0.1 p / p% 100.0 Inorganic filler particles: (a) silanated barium-aluminum fluorosilicate glass (BAFG) 20.0 p / p% (b) BAFG silanado 60.0 p / p% (c) fumed silica 20.0 p / p% 100.0 As stated above, it is intended that the present compositions are, inter alia, an alternative or replacement for dental amalgams and conventional compounds. It has been found that dental compositions according to this invention are equal to or superior to conventional dental amalgam products such as DISPERSALLOY available from Dentsply International Inc. of York PA. This includes, for example, the wear characteristics of the material. To determine the wear properties of the inventive material, a standard wear test can be employed. Preferably, the test is a three-body wear test, which is closer to the effects of chewing teeth in normal use. One of the tests uses the three-body cyclic abrasion wear machine, in vitro Leinfelder / University of Alabama. The analysis system Profilometer / Surface Rank Taylor Hobson, used to measure volume loss of the Leinfelder University of Alabama wear machine, performs two different functions: 1) The Form Taysurf profilometer employs a transverse recording needle to construct a 3D topographic map of the worn area by means of a unit interface interface to a host computer, 22) A surface analyzer program installed on the main computer graphically represents the worn area and calculates its volume. This volume, expressed in cubic millimeters, is taken as the "loss of Volume wear "of the tested material The higher the volume loss, the more the material wears.After running a wear cycle of 400k, a Dispersalloy (amalgam) test sample showed a wear volume of 0.024 mm3; Alert (compound available from Jeneric / Pentron Incorporated) had a wear volume of 0.041 mm3, Solltaire (composed of Kulzer) had 0.054mm3, and Tetrlc Ceram (composed of Vivadent) had (at 250k wear cycles only) 0.090 mm3 In comparison, the material according to the present invention showed a volume loss of less than 0.024 mm 3. These data clearly show the improved wear resistance (expressed in volume loss) for the material according to the invention in relation with conventional amalgam materials and conventional dental compounds.The physical properties of this material, as already discussed above, were tested by conv techniques. As a comparison, the same physical properties were tested for Solitaire and Alert. The results of these tests are reported as follows: The depth of the curing is determined by preparing a small amount of material to be tested by packing it into a cylindrical mold and radiating it with light, exposing the upper surface of the cylinder to light. The specimen is then removed from the mold and the lower surface of the sample is sanded to a determined hardness such as Barcol 7.0 on a medium scale. The thickness of the specimen is then measured. Other test parameters are measured according to conventional techniques for handling materials. For example, diametral tensile strength was tested in accordance with ADA 27; other properties were tested in accordance with ISO 4049. Fracture hardness was tested according to Ruse et al., "Novel fracture toughness test using notchless triangular primsm (NTP) specimen", Journal of Biomedical Materials research, Vol. 31 (1996 ), pages 457-463, John Wiley & Sons, publisher. The procedure used to determine the packing capacity index may vary. As an example, the procedure used for the packaging capacity index numbers reported above, employed an Instron Model 1123 Universal Test Machine with a Series IX Data Acquisition System.

The sample holder included six cylindrical vessels with 6.5 mm (millimeters) in diameter and 4.5 mm in depth (designed to simulate the cavity of a tooth). They were mounted on a solid block of Plexiglas. The penetrator used was a carbon steel pin with a rounded tip of 3.15 mm in diameter and 6.25 mm in length, vertically placed in an Instron UTM device. The procedure used was as follows: A. Packet Capacity Access Test on the Instron computer and verify the following test parameters: Total Scale Load: 0.5kg (kilograms) Crosshead Speed 200mm / minute Extension Measure 2.5mm down with automatic return B. Using a plastic spatula, fill each glass container to the edge with the material to be tested. Gently fill the test material in the container to avoid voids, clean excess material from the top of the container so that the surface material is level with the edge of the container. Allow the sample holder to reach an ambient temperature of 23 ° C (plus or minus 1) before testing, usually for at least a minimum hour. C. Place the filled sample holder in the Instron's load cell and calibrate it to achieve a load reading of 0.00 kg. in the "Load" digital display window.

D. Center the first full container under the Penetrator and slowly lower the Instron cross head until the Penetrator makes contact with the surface of the material (without penetrating it). E. Adjust the extension measure so that it reads O.OOmm in the digital display window "Extension" (extension). F. Press the appropriate computer key (s) to cause the cross head to go down (2.50mm) and return. G. Record the value of the Packing Capacity Index (maximum grams / mm2) by pressing the appropriate computer key (s). H. Repeat the steps for the five remaining containers in the sample holder. I. Press the appropriate computer key (s) to summarize and statistically analyze the test data. The Packing Capacity Index is calculated using the following equation: Packing Capacity Index = Maximum Resistance Obtained in qr. Area (mm) of the Penetrating Tip (7.9mm2) The Instron Series IX computer program automatically calculates the packaging capacity index values and prints the average Packaging Capacity Index expressing the value in gr / mm2 (up to an accuracy of 1g / mm2). The results of the tests do not have a coefficient of variation (CV) greater than 10%. The containers with the specimens were cleaned with methanol between uses.

Other examples of the inventive composition as exemplified above showed the following physical characteristics: In another example of the inventive composition, a sample was prepared as prepared above but with a filling component with 25 percent by weight of (a), 60 percent by weight of (b) and 15 percent by weight of ( c) Tests like the previous ones were conducted and showed a compressive strength (MPa) of 302 (plus or minus 26); a resistance to diametral tension (MPa) of 48 (± 4); a transverse resistance (MPa) of 127 (± 12); a flexural modulus (Gpa) of 11 (± 0.5); a loss of wear volume (mm3 to 400,000 cycles) of 0.0183; a packing capacity (grams / mm2) of 765 (± 42); a curing depth (mm) of 7.3; and, a Barcol hardness on a median scale of 99. Yet another test employing this filler component showed a compressive strength (MPa) of 354; a diametral tensile strength (MPa) of 47; a flexural modulus (MPa) of 11,814; a loss of wear volume (mm3 to 400,000 cycles) of 0.0167; a packing capacity (grams / mm2) of 747; a curing depth (mm) of 5.4; and, a Barcol hardness on a medium scale above 100. This test sample also showed a curing post curing of 2.41 percent. It should be appreciated that the inventive material shows similar or improved physical characteristics compared to commercially available products. Most notably, the inventive material exhibits an improved packing capacity index and an improved local wear index and the like. The above description illustrates the preferred embodiments of the invention. However, the concepts used can, based on the description, be used in other modalities without departing from the field of use of the invention.

Claims (8)

1. A method for restoring a tooth comprising the steps of: preparing a tooth to receive a dental restoration; pack a quantity of the restoration material inside the prepared tooth; and, cure restorative dental material; wherein the restorative dental material comprises a polymer matrix and filler component; the filler component comprises (a) a first plurality of particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of particles having an average particle size of from about 0.1 to about 1 micrometer; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns.

2. A packaged photo sensitive material comprising in combination: a photo sensitive material formed in a unit of dose and content within a container; the photo-sensitive material comprises a polymer matrix and a filler component; wherein the filling component comprises (a) a first plurality of particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of particles having an average particle size of about 0.1 to about 1 micrometer; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns.

3. A packaged material according to claim 2, wherein the container is a container with the top part open and has a base and at least one vertical wall and has an open area therein; the vertical wall has a first end proximal to the base and an end close to the open top; the end next to the open upper part is contiguously formed with a laterally extended band; a release layer removably attached to the band and covering the open area; the container and the release layer are substantially non-transmitting of at least a portion of the light spectrum to which the material is photo-sensitive; where the dose unit of the material is contained within the open area.

4. A packaged material according to claim 2, wherein the container is made of polystyrene, polyethylene terephthalate, polyethylene, polypropylene and mixtures thereof.

5. A method for working with a photo-sensitive material dose unit comprising the steps of: providing the dose unit of the material in a package, wherein the material comprises a polymer matrix and a filler component; wherein the filler component comprises (a) a first plurality of particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of particles having an average particle size of about 0.1 to about 1 micrometer; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns; the package has an open top container having a base and at least one vertical wall and having an open area therein; the vertical wall has a first end proximal to the base and an end close to the open top; the end next to the open upper part is contiguously formed with a laterally extended band; a release layer removably attached to the band and covering the open area; the container and the release layer are substantially non-transmitting of at least a portion of the light spectrum to which the material is photo-sensitive; remove the release layer of the package; Remove the dose unit from the package material and place the dose unit of the material on a support surface; Repeatedly remove a selected portion of the dose unit from the material and invert and place the package on the unit of material dose; in such a way that the light is prevented from making contact with the dose unit of the material under the package as the selected portion is used for its intended use.

6. A method according to claim 5, wherein the release layer is placed on the support surface, and the dose unit of the material is placed on the release layer placed before the invert step and placing the package on the dose unit of the material.

7. An intra oral or extra oral restorative dental material having improved wear properties comprising: a polymer matrix and a filler component; wherein the filler component comprises (a) a first plurality of particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of particles having an average particle size of about 0.1 to about 1 micrometer; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns.

8. An intra oral or extra oral restorative dental material having improved wear properties comprising: a polymer matrix and a filler component; wherein the filler component comprises (a) a first plurality of particles having an average particle size of from about 1 to about 10 microns; (b) a second plurality of particles having an average particle size of about 0.1 to about 1 micrometer; and, (c) a plurality of filler particles having an average particle size of from about 0.01 to about 0.04 microns; where the material is used as dental crown, incrustation, or top layer of wear.