Patent Document:

as required , detailed embodiments of the present invention are disclosed herein ; however , it is to be understood that the disclosed embodiments are merely exemplary of the invention , which may be embodied in various forms . therefore , specific structural and functional details disclosed herein are not to be interpreted as limiting , but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure . in an application of the present invention , tooth restoration shall mean facing , filling , replacing , rebuilding , or the like , of a tooth or missing portions thereof caused by decay , breakage , or the like . for discussion purposes and without limiting the application of the present invention , examples are provided herein to demonstrate one or more of the many uses available for applications of the invention . the present invention generally includes imbedding a matrix of ground or pulverized filling material in a binding or adhesive means . the adhesive means is preferably tightly and strongly bonding to tooth enamel and is compatible for use in the human mouth with respect to safety and organoleptic properties such as taste . adhesive means include glass ionomer cement , methyacrylate , or the like . the pulverized filling material comprises tooth enamel which , for purposes of the present invention , may be obtained from animal teeth , including tusks , preferably of bovine origin . bovine teeth not only provide the desired characteristics but are readily available and plentiful . the imbedding of pulverized animal tooth enamel provides substantially greater surface area of tooth enamel which generally forms a stronger bond with the adhesive means than the adhesive means forms with itself . as a result , cross - linking occurs between the adhesive means and the pulverized animal tooth enamel such that the cohesive strength of the restorative is substantially greater than is obtainable from the adhesive means alone . also , the animal tooth enamel provides substantially greater wearability characteristics than is generally obtainable with adhesive means without such imbedded animal tooth enamel . such an arrangement also enhances the abrasion resistance of the restorative . the binder material preferably allows the pulverized tooth enamel contained therein to color the composite composition such that a natural tooth enamel color is presented by the composition in use . it is foreseen that pulverized tooth enamel of various colors may be selected to better match the color of the teeth being restored or , if the color cannot be closely matched with the pulverized tooth enamel , additional pigments of the type currently used may be incorporated in the composition . animal teeth to be used for preparation of the pulverized filling material are obtained from any appropriate source , such as from a meat packing plant . before processing such teeth , they are subjected to a sterilization procedure and may be sorted as to color . in one application of the present invention , the teeth are sterilized by boiling in water for approximately eight hours . this procedure also coagulates proteins in the teeth . following sterilization , the animal teeth are desiccated , such as by placement at an elevated temperature in a drying oven . after sterilization , the animal teeth are crushed into coarse particles to expose dentin and non - enamel material contained in the teeth . in one application of the present invention , the teeth are crushed in a hammermill , with the resulting particles ranging from approximately 1 to 5 millimeters in size . after exposing the dentin and non - enamel material , it is then essential to separate the enamel therefrom . as an example , the teeth particles are boiled in a solution of concentrated sodium hydroxide for approximately 16 - 20 hours in order to hydrolyze the organic bond between the enamel and the dentin in the teeth particles . after boiling , the teeth particles are subsequently allowed to cool , rinsed with water , ph - neutralized with an inorganic acid , and desiccated with acetone . the tooth enamel particles are then further finely crushed or pulverized , such as in a hammermill . in one application of the present invention , the enamel particles are finely crushed into particles ranging from approximately 10 to 200 microns in size . after cleaning and desiccating with acetone , the fine enamel particles are separated from the fine dentin and non - enamel particles . in one application of the present invention , the fine enamel and dentin particles are separated by placing the finely crushed particles in a concentrated , saturated solution of zinc iodide . since the zinc iodide solution has a specific gravity which lies between the specific gravity of the fine enamel particles and the specific gravity of the fine dentin particles , the fine enamel particles sink to the bottom of the container containing the zinc iodide while the fine dentin particles rise to the top of the zinc iodide solution . it is then a simple matter to pour off the zinc iodide solution along with the floating fine dentin particles , leaving the fine enamel particles in the container . the fine enamel particles are then washed with water and dried with acetone . the fine enamel particles are then separated into narrower ranges of particle sizes , with each particular range of particle sizes depending on the type of restoration work to be performed therewith . for example , laboratory sieves may be used to select fine enamel particles ranging from approximately 1 to 100 microns in size for a particular restoration . as an example of preparing material for a tooth restorative using the fine enamel particles with a glass ionomer cement , a mixture is formed by admixing the components and stirring that contains approximately 85 % by weight of a glass ionomer cement in the form of a powder , such as that disclosed in u . s . pat . no . 4 , 342 , 677 , which is incorporated herein by reference , and approximately 15 % or more by weight of fine enamel particles ranging from 1 - 100 microns in size as hereinbefore described . the combined mixture of glass ionomer cement and enamel particles is then mixed with carboxylic acid solution in an approximate ratio of 4 . 5 grams of mixture to 1 gram of acid solution , with the resulting material then applied as a restorative by techniques commonly known and applied in the dental profession . for those applications where it is desired to use a composite comprising a matrix of an acrylic material filled with the fine enamel particles , further processing of the enamel particles is preferred as follows . the fine enamel particles are chemically etched to promote micro - mechanical bonding between the acrylic component and the fine enamel particles . in one application of the present invention , the fine enamel particles are treated with a 30 % by weight phosphoric acid solution for approximately 60 seconds , followed by rinsing with water and then treating with a 1 % by weight sodium fluoride solution for approximately 8 hours . the neutralized particles are then thoroughly rinsed with water and dried with acetone . as an example of preparing material for a tooth restorative using such fine enamel particles in an acrylic matrix , the fine enamel particles are kneaded into an acrylic component such as that disclosed in u . s . pat . nos . 4 , 503 , 169 and 4 , 719 , 149 which are incorporated herein by reference . the resulting material is then applied as a restorative by techniques commonly known and applied in the dental profession . broadly speaking , an application of the present invention first involves preparation of the tooth to be restored , such as by first removing the decayed portion of the tooth and leaving underlying dentin and enamel surfaces exposed . such initial decay removal can be performed by any appropriate technique , such as by the use of caries removal materials which may be advantageous for the reduction of patient discomfort , or by conventional drilling , or the like . the exposed tooth structure is then preferably cleaned of all debris and dried . this is particularly important since surfaces in the oral environment are usually coated with water and organic matter , such as proteins , bacteria , and food residue which are deposited on the surfaces by saliva . washing the exposed tooth structure with a dilute acid solution will generally remove the undesired organic matter , leaving the surface more suitable for bonding . the exposed structure is then rinsed clean of the acid wash and dried , such as with clean , dry compressed air or with a solvent , such as acetone , which carries away water as an azetrope . while bovine teeth have been described herein as a source of enamel for use in the invention , it is foreseen that enamel of other animals , including humans , could be utilized . likewise , it is foreseen that other adhesive agents besides those specifically described could be utilized in the invention provided such adhesive agents bond well to enamel and are not otherwise unacceptable because , for example , the agent is poisonous to humans , does not have acceptable wear even when combined with a hard material such as the enamel , requires too much time to harden after use or has a lingering taste . it is to be understood that while certain forms of the present invention have been illustrated and described herein , it is not to be limited to the specific forms or arrangement of parts described and shown .

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