Dentistry – Method or material for testing – treating – restoring – or... – By filling – bonding or cementing
Reexamination Certificate
1999-05-18
2001-11-13
Lucchesi, Nicholas D. (Department: 3732)
Dentistry
Method or material for testing, treating, restoring, or...
By filling, bonding or cementing
C433S226000, C433S212100
Reexamination Certificate
active
06315567
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for restoring a defect in a tooth by using a curable composite material.
BACKGROUND
Teeth with dental decays such as cavities are generally restored by removing the decayed area and applying a restorative thereon. Traditionally, amalgam material has been used for filling and repairing teeth. Because the amalgam material tends to harden as it is being worked, and its thick, lumpy consistency necessitates using specialized tools for pushing the materials into corners and crevices to facilitate adaptation to the tooth, its use is inconvenient and causes great discomfort to the patient. Moreover, the retention of an amalgam resotative in a tooth is by bulk. For repairing a small decayed area, often an amount of healthy tool structure many times the decayed area has to be removed to provide toom to receive the amalgam material.
The concern of the presence of mercury in amalgam material has led to the introduction of other restoratives that do not contain mercury. For example, “Universal Paste” composites, such as P-SO and Z-100 sold by 3M Company, have been used for restoring teeth. Examples of other composite materials that can be used for repairing teeth include the compositions disclosed in U.S. Pat. No. 4,553,940 (Koblritz, et al) and U.S. Pat. No. 5,228,907 (Eppinger, et al).
Generally, composite materials for repairing teeth are thick and sticky, making them difficult to work with and highly technical skill is required of the operator to properly place such materials in teeth for restoration purposes. Universal paste type composites are generally used by trowelling an amount of the paste into position in a hollow (or void or cavity), tamping the paste down to improve contact with the surface of the cavity, carving the excessive paste into a rough outline of the desired shape, and polishing the cured composite to a desired shape and smoothness.
Because a composite material, similar to amalgam material, is generally applied as a lump in the prepared location in a tooth, voids and porosities are often incorporated into the material during placement because of the difficulty in manipulating the material into corners and crevices in the tooth. Furthermore, if a composite material is light curable, because of the thickness of the composite material applied, incomplete polymerization often results.
Another kind of restorative material that does not contain mercury is a film-forming composition that is generally used as a sealant, glaze, or adhesive. Typically, such a film-forming dental composition contains resins with little or no filler materials. Such filmforming dental compositions are typically used for sealing the tooth against cracks adjacent to fillings. Such compositions generally have low viscosity and can be applied to the tooth by using a brush. An example of a sealant is disclosed in U.S. Pat. No. 4,001,483 (Lee, Jr., et al.). Such a composition is generally applied as a thin coating and when cured, forms a sealing coat on the tooth. Yet another kind of coating composite is used for masking stains and discolorations. For example, U.S. Pat. No. 4,150,485 (Lee, Jr., et al) discloses a brushed on dental restorative coating composition used for covering surface imperfections. This composition has a higher viscosity than conventional sealants. Such film-forming and coating compositions have not been applied in restoration of tooth decays such as filling cavities.
SUMMARY
The present invention provides a method of restoring a tooth that has a defect. The method includes dispensing a curable composition through a needle with a lumen into a hollow on the tooth to achieve a desired shape and curing the curable composition. As used herein, the term “needle” refers to a slender, hollow, stiff instrument which may be straight, curved or bent, with or without a sharp point. The composition contains a curable liquid resin portion and an inorganic filler portion. The curable liquid resin portion has a polymerizable binder resin. As used herein, a “hollow” refers to a void area or cavity that results after a tooth has been prepared to receive a restorative by a cutting or abrasive tool such as a dental bur.
In another aspect, the present invention provides a method of restoring a tooth having a decayed portion including the steps of removing the decayed portion to form a hollow in the tooth, coating the surface in the hollow with a curable bond and curing the bond, dispensing a curable composition from a needle in the hollow to achieve a desired shape, curing the curable composition, and repeating the dispensing of the curable composition and curing the curable composition until a cured structure of desired shape and smoothness is obtained. In removing the decayed portion, an amount of an adjacent healthy portion or the tooth is removed with the decayed portion. The volume of the healthy portion removed is about zero to three times, preferably 0.5 to 3 times the decayed portion. The composition contains a curable liquid resin portion and an inorganic filler portion. The curable liquid portion has a polymerizable binder resin and a polymerizable diluent monomer less viscous than the polymerizable binder resin.
The present invention provides yet another method for restoring a tooth using a composition that contains a curable liquid resin portion and an inorganic filler portion. The method includes the steps of dispensing a curable composition from a needle as one of a layer and a drop in the hollow, curing the curable composition wherein the one of a layer and drop shrinks when it is cured, dispensing the curable composition as one of a layer and drop on top of the cured composition and in the void space resulted from the shrinkage to compensate for the shrinkage, and repeating the dispensing and curing of the composition in the hollow until a cured structure of desired shape and smoothness is obtained. The method of the present invention can be advantageously utilized to restore defects in teeth. Because of the composition of the present invention can be applied using a hypodermic needle like tubular structure, the composition can be applied into a small hollow in hard to-reach places on a tooth. By laying the curable composition as a thin layer or small drop, substantially complete curing by light (as compared to relatively incomplete curing when conventional universal paste-type of composite is used) can be realized. Such substantial complete curing leads to improved mechanical integrity and chemical resistance of the restorative material in the tooth. Better curing leads to less stress cracking taking place in the restorative material.
The use of conventional composite material often leads to a great amount of shrinkage as the material is cured. Such shrinkage can lead to many problems, such as accelerated wear, open margins between the tooth surface and the filling material, leakage of foreign material into the unfilled area, thereby causing degradation and subsequent development of caries. In the present invention, by depositing the composition as thin layers, curing, and repeating the process the void area left by the shrinkage of a previous cured area can be filled with a subsequent layer with the composition, thereby eliminating or greatly reducing the presence of unfilled areas caused by shrinkage.
The thixotropic characteristic of the restorative curable composition of the present invention greatly facilitates the restoration of tooth without having to shape the composition using a scraping tool. The thixotropic substance can be forced through a syringe and needle and carefully deposited in a desired location and cured. By gradually building up the cured structure, there is no need to remove excess composite material to achieve a desired shape. The relatively low viscosity of the composition helps to spread the composition into crevices and corners to greatly reduced amount of void area so that a strong bond can result between the composition and the tooth without depending on retention of the restorative materi
Abco Research, LLC
Dorsey & Whitney LLP
Lucchesi Nicholas D.
LandOfFree
Method of restoring a tooth does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of restoring a tooth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of restoring a tooth will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2578877