Patent Application
20170333158
Not Applicable
A dental crown wherein the crown is made with a fiberglass or quartz fiber embedded with cosmetic resin composite.
Dental crowns may be made of molded zirconia but are quite expensive and their pricing limits its acceptable throughout the general population. Stainless steel crowns are less expensive but require the use of a protective “unnatural” color crown restoration for primary teeth. The stainless steel construction has a major problem, that the “silver” color of the steel crown is not acceptable, and the issue with the use of a zirconia cosmetic crown involves beyond the necessary thus excessive grinding of tooth structure to compensate for the lack of flexibility thus leading to some retention, adaptability and strength problems.
There is a need for an excellent dental crown that is lower cost, in particular for pediatric dentistry where cost may be even more of an issue and baby teeth would eventually fall out.
The invention provides a dental crown that is an inexpensive and affordable solution for restorations in pediatric and adult dentistry utilizing crowns, with added cosmetic value not allowed with the stainless steel crowns and not affordable with zirconia type crowns. The invention utilizes either fiberglass or quartz filaments/fibers imbedded with an outer cosmetic composite resin material embodying the crown has a similar structure observed on fiberglass dental posts already widely used in dentistry for endodontic/restorative purposes for decades. The strength and bio-compatibility with a degree of flexibility is much closer to tooth structure then stainless steel and zirconia crowns.
The invention as shown in the Figures is a dental crown using fiberglass, aramid, carbon or quartz filaments/fibers imbedded with an outer cosmetic composite resin material. As shown in
As shown in
The fiberglass or quartz fiber containing dental crowns of the invention may be made with the same materials currently used in FiberKleer® Posts from Pentron Clinical of Orange, Calif. which use fiberglass within a mixture of cured copolymers bisphenol A-glycidyl methacrylate (BISGMA), urethane dimethacrylate (UDMA) and HDDMA. The Safety Data Sheet for Pentron lists 1,6-hexanediyl bismethacrylate from 10-30%, 7,7,9(or 7,9,9)-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-diylbismethacrylate from 5-10%, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide from 0.1 to 1% and 2-(Diethylamino)ethyl methacrylate from 0.1 to 1%.
The fibers of FiberKleer posts may be barium borosilicate glass, glass fibers. In this invention, quartz fibers may be used alone or in addition to other dentally acceptable fibers. Other acceptable glass fibers include Reforpost Glass Fibers from ANGELUS INDÚSTRIA DE PRODUTOS ODONTOLÓGICOS S/A sociedad anonima (sa) BRAZIL Rua Waldir Landgraf, 101 Lindóia, Londrina, PR, BRAZIL which makes glass fiber infraradicular posts with conical tips. ParaPost® Fiber Lux from Coltène/Whaledent Inc. of Cuyahoga falls, Ohio also makes an acceptable glass-filled composite.
The fibers are embedded within dentally acceptable composite resins, also already used in dentistry for decades, to form the dental crowns according to standard procedures for creating dental crowns. The outer surface of the dental crowns is a cosmetic resin composite substrate which can provide the appropriate color and good mouth feel.
Fiber-reinforced composites for dental materials are discussed in U.S. Pat. No. 7,673,550 to Karmaker et al., the disclosure of which is incorporated herein by reference. Contrary to that patent, this invention does not contemplate the need to form rods or sheaths and instead forms the dental crowns from a mixture of fiberglass/quartz fibers and resin without orienting into solid rods.
The methods includes roughening the outer surface of the tooth (teeth) to be restored, applying a bonding agent in the crown of the invention to be seated on the tooth/teeth to be restored tooth with then mechanical/chemical retention.
The dental crowns may include from 25 to 85% fibers and more preferably between 30 to 70%, with the remainder being the resin and fillers. The outer layer is a cosmetic resin composite bonded to the main body of the dental crown which is formed from the fiber/resin mixture.
As shown in
Note that if more than one mesh sheet 30 is used each successive sheet is preferably rotated form the first sheet as shown in
A mold (not shown) is used for each dental crown to be formed and the fibers are layered, preferably in different directions and the mold is closed and resin is injected into the mold under pressure to embed the fibers and provide great strength. The fiberglass layers may be in a mat but surprisingly, individual layers of fiberglass sheets provided better strength at a better cost point. The fiberglass is saturated with the resin through the dental crown and is trimmed as need after removed from the mold.
The resin may be a suitable dental resin as used in the industry. It may be an epoxy resin such as EPO-TEK 301 from Epoxy Technology, Inc., 14 Fortune Drive, Billerica, Mass. 01821 USA. Its EPO-TEK 301, as with all epoxies, is a two component epoxy with Part A and Part B. Part A contains a Bisphenol A Diglycidyl Ether Resin and a reactive diluent. Part B contains trimethyl-1,6-Hexanediamine. Any dentally accepted resin including epoxies may be used, the Epo-Tek 301 has been tested and works well.
Dentistry involves working with patients that have a wide range of tooth colors. A colorant may be added to the resin to produce the color that best matches the tooth which will receive a crown. Dental colorants are well known. A suitable and typical colorant is titanium oxide, TiO2. Titanium oxide is typically from 0.3 to 1.2 micrometers in size. Iron oxide (FeO2) may be used to impart a yellowing color.
multiplier for ratio calculation: 128.2051282
Testing of sample dental crowns made without fiberglass or TiO2 were conducted and the average force before breaking was 27.9 pounds. A stainless steel dental crown test failed with ductile fracturing at 160 pounds. A zirconia dental crown test failed with a brittle fracture at only 75 pounds. Failed zirconia crowns are brittle and sharp shards are created which is a problem. A dental crown of the invention made with epoxy and fiberglass didn't fail until a force of 199 pounds was applied and then with a plastic deformation. Thus, the fiberglass dental crowns of the invention absorbed 2 to 2.5 times the force of the zirconia crowns. The fiberglass dental crowns of the invention are therefore safer and less hazardous than zirconia crowns. Human bite strength on chewing yields about 72 pounds of force which is close to the failure point for zirconia and well below the failure point of the inventive crowns.
Fibers have referenced fiberglass but other fibers may be used including quartz fibers, carbon fibers and aramid fibers such as DuPont Kevlar® brand fibers. Use of the terms “fibers” and “fiberglass” herein are intended to encompass a wide range of fibers that may be woven into mesh sheets that will impart strength into a dental crown of the invention.
Dental crowns are primarily used in humans but may be used in veterinary applications as well.
While this invention may be embodied in many different forms, there are shown in the drawings and described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.
This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.
This application claims priority to U.S. Provisional patent application 62/338,809 filed on May 19, 2016, the disclosure of which is incorporated herein by reference as permitted.
| Number | Date | Country | |
|---|---|---|---|
| 62338809 | May 2016 | US |
