In-situ tooth filling system and method utilizing external curing step

An In-situ Tooth Filling System and Method Utilizing External Curing Step. The method and system utilizes the heat-/light-/vacuum-curing process normally available only in a dental laboratory. Like the conventional dental prosthetic production process, the filling is attached to the tooth void utilizing curable cement. Unlike the conventional (indirect) method, however, the instant method is completed totally within a single appointment in the dentist's office. The system utilizes fill stems that are made from curable filling material. These stems will become a part of the filling when the filling is cured. The filling is partially cured and then removed from the tooth for final curing in a vacuum oven that heat- and/or light-cures the filling.

This application is filed within one year of, and claims priority to Provisional Application Ser. No. 61/686,005, filed Mar. 29, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to dental processes and systems and, more specifically, to an In-situ Tooth Filling System and Method Utilizing External Curing Step.

2. Description of Related Art

Conventional tooth repair approaches can typically be grouped into two categories: (1) those conducted in the dentist's office in a single visit (e.g. fillings), and (2) those requiring an intermediate step conducted at a dental lab (e.g. dental prosthetics). As depicted inFIG. 1, the typical in-situ filling method10proceeds through the following steps: the tooth having the cavity is first drilled out to create a clean void that is suitable for filling100. The dentist then injects a filling material (composite, metal or other) into the void previously created in the tooth102. For fillings made from composite, the material must be cured once it has been injected so that it is hard enough to function as a repair for the tooth. The injection and curing of the composite material is typically done in layered steps104. Generally a light-reactive filling material is used, with ultraviolet wavelength being the most common. Once filled and cured, the dentist shapes and polishes the filling106so that the patient has a comfortable bite and no sharp or rough edges. Rosenfeld, U.S. Pat. No. 7,189,076 discusses a typical layered filling and curing method for in-situ tooth filling.

The in-situ filling method is by far the most prevalent approach used to repair a person's tooth because it is completed in a single office visit, and because it therefore tends to be the lowest-cost method available. In-situ tooth fillings are commonly covered by dental insurance. The problems with the in-situ filling method are related to durability and comfort. Because the composite material used to fill the tooth is cured while in the tooth, the dentist cannot use the type of composite material that is heat-cured in an oven, or make sure that the composite material used is totally cured and hardened. The heat-curable/light-curable composite material is used to create one of the hardest and most durable finished dental prosthetics available. Furthermore, during in-situ filling there will be air bubbles and gaps between the filling and the walls of the void created in the tooth during the filling process. These gaps are the result of the slight shrinkage that occurs during the curing process. Any gaps between the filling and the tooth will result in tooth discomfort for the patient and a potential for bacterial impregnation (which further reduces the fillings lifespan).

In cases where filling the tooth in the dentist's office is either not desirable, or it is not feasible, a prosthetic filling (or tooth) is installed.FIG. 2depicts the steps employed in a conventional dental prosthetic installation method12.

First, an impression of the undisturbed tooth is made108. Next,100, the tooth is prepared for filling by drilling a clean void in the tooth. A second impression is then made110; this impression is of the tooth after the void has been drilled. For now, these are the final steps conducted in the dentist's office during this visit (although a temporary filling will usually be installed to prevent undue discomfort for the patient and to keep the void clean.

At the dental prosthetics lab, the first and second impressions are used to make a single prosthetic shaped to fit perfectly into the void created in the patient's tooth112. This prosthetic piece is then cured by heat (and sometimes partially by light) while being held in a vacuum state at the dental lab114.

At a second appointment at the dentist's office, the prosthetic is installed into the void previously formed in the patient's tooth, and is held in place by specialized adhesive cement116. Any shrinkage of the prosthetic that occurred during curing is compensated for by the dental adhesive used to permanently bond the prosthetic to the patient's tooth. The result is a perfectly-fitted repair area that is much less likely to cause the patient future discomfort or to suffer from a short lifespan. Examples of these conventional approaches are discussed in Hewell, U.S. Pat. No. 4,695,254, Rubbert (I), U.S. Pat. No. 7,708,557 and Rubbert (II), U.S. Patent Application Publication No. US12/0064489.

While prosthetic filling methods produce a very high quality result for the patient, they tend to be quite expensive and time-consuming. As a result, they are only chosen infrequently for tooth repair. What is needed is a tooth repair method and system that provides the comfort and durability of a dental prosthetic with the cost and convenience of an in-situ installed filling.

SUMMARY OF THE INVENTION

In light of the aforementioned problems associated with the prior devices and methods, it is an object of the present invention to provide an In-situ Tooth Filling System and Method Utilizing External Curing Step. The method and system should utilize the heat/light-/vacuum-curing process normally available only in a dental implant laboratory. Like the conventional dental implant production process, the filling should be attached to the tooth void utilizing curable cement. Unlike the implant method, however, the instant method should be completed totally within a single appointment in the dentist's office. The system should utilize fill stems that are made from curable filling material. These stems should become a part of the filling when the filling is cured. The filling should be partially cured and then removed from the tooth for final curing in a vacuum oven that heat- and/or light-cures the filling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an In-situ Tooth Filling System and Method Utilizing External Curing Step.

The present invention can best be understood by initial consideration ofFIG. 3.1FIG. 3depicts an example of the elements involved in the implementation of the method of the present invention (further detail is provided herein below in connection with other drawing figures). A conventional method of dispensing liquid filling material for the purpose of creating dental fillings and prosthetics is via the device15depicted inFIG. 3. The dispenser15has a reservoir16filled with filling material28and capped by a head18. The head18is formed with a tubular nozzle20protruding from one end.1As used throughout this disclosure, element numbers enclosed in square brackets [ ] indicates that the referenced element is not shown in the instant drawing figure, but rather is displayed elsewhere in another drawing figure.

The dentist positions the tip of a tubular sacrificial stem22inside of a void26formed in the tooth24. The stem22is preferably made from the same or similar material as the filling material28, but it has been at least partially cured so that it is somewhat hardened. The stem22may still be pliable, but the material is cured enough so that it can be used to dispense the liquid filling material28, and then utilized as a handle later on in the process.

The nozzle20(outside of the patient's mouth) is positioned in the opposing end of the stem22(the nozzle20attaches to the stem22with a click), and the filling material28is extruded out through the nozzle20so that it travels down the stem22and fills the void26. It is not critical that the top surface of the tooth24is in a finished state, since the top of the filling material (in the filled void26) will be shaped an polished during a later step in the filling process of the present invention. Now turning toFIG. 4, we will examine this novel process in detail.

FIG. 4is a flowchart depicting the steps of a preferred embodiment of the in-situ filling method30. As with the prior in-situ filling method, the first step is to prepare the tooth by drilling the proper void100into which the filling material will be place. Next, a conventional mold release material is applied into the void118, and cured if necessary (usually by application of UV or other light). The mold release material is designed to allow for cured (or semi-cured) filling material to be more easily removed from a mold. In this case, the mold release material is applied into the tooth void itself.

A stem is first attached to the end of the head119. The stem is then inserted into the void120(after being attached to the nozzle20). The shape of the stem may vary so that it fits well into the void. Some examples of the possible shapes and features of the various stems are depicted below inFIG. 6. As discussed above, the stem is preferably formed from cured filling material, and is basically an elongate tube.

Non-hardened composite filling material is then injected through the stem and into the tooth void until the void is completely filled122. It should be noted that up to this point, no impression or mold has been made of the tooth (i.e. unlike the prior art dental appliance method discussed previously). Ultraviolet or other specialized light is applied to the void and stem (which is also filled with filling material) until it is partially cured124. Typically only a single fill and cure step will be conducted, since there will be a full curing step later on in the process.

Once the filled void has been partially cured (by light only), the entire assembly of the stem and filled void will be a single, hardened piece of filling material. It is then a simple matter of pulling on the stem (after the nozzle has been removed) until the partially cured filling assembly is released from the void126. This partially cured prosthetic/filling assembly is then placed into a specialized oven in order to bake the assembly until it is fully heat- and light-cured128while under vacuum. This heat-/light-curing step will cause the prosthetic/filling assembly to become just as hard as a conventional lab-prepared prosthetic. The difference is that by following the process described here, it can be done in the dentist's office in a single patient visit, while the patient waits. Furthermore, if the prosthetic/filling assembly experiences shrinkage, all of that shrinkage will have occurred by the time that the assembly is removed from the oven and cooled down.

Once the prosthetic/filling assembly has cooled and trimmed, it can be re-inserted into the tooth void. First, a suitable bonding agent or adhesive is applied to the tooth void and/or the prosthetic/filling assembly, and then the prosthetic/filling is re-inserted into the void130. The bonding agent/cement will fill any gaps between the outside of the prosthetic/filling and the walls of the void, while also creating a virtually permanent bond between the prosthetic/filling assembly and the tooth.

Finally, the protruding portion of the filled/cured stem is cut off and the surface of the tooth (and excess filling material) is polished and shaped so that the patient has a comfortable bite and no interferences.FIG. 5depicts this method in summary form pictorially.

In order to optimize the wide variety of tooth configurations and void shapes, a wide variety of shapes of stems22could be provided. A sample of these shapes and configurations are shown as elements22A-22I inFIG. 6. The feature indicated inFIG. 22Iis a pair of through-holes through that portion of the lower portion of the stem22I. As discussed previously, the upper portion of the stems (generically22) will protrude from the tooth until its removal at the end of the filling process. It is possible that grip features may be added to the outer surface of the upper portion of the stems22to aid the doctor and his or her staff in grasping the prosthetic/filling assembly [36] when removing it from the tooth, or otherwise handling it.