Patent Description:
In particular, the invention pertains to a dental crown as defined in claims <NUM> and <NUM>, and to a method for forming a dental crown as defined in claim <NUM>.

Some aspects of the present disclosure provide a dental crown. The dental crown could include a metal shell shaped to cover a portion of a tooth of a patient; a coating retention metal layer diffusion bonded to the metal shell, wherein an interface between the coating retention layer and the metal shell comprises a plurality of interstitial regions; and a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal shell.

Some other aspects of the present disclosure provide another dental crown. The dental crown could include a continuous, nonporous metal shell shaped to cover a portion of a tooth of a patient; a coating retention metal layer of elongated metal strands diffusion bonded to the metal shell, wherein there are apertures between the elongated metal strands, wherein the apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer, and wherein an interface between the coating retention layer and the metal shell comprises a plurality of interstitial regions; and a polymeric composition on the coating retention layer and within a plurality of the interstitial regions to bond the coating composition to the metal shell.

Some aspects of the present disclosure provide a method of forming a dental crown. The method includes diffusion bonding a metal base layer to a coating retention layer to form a dental crown blank, wherein the coating retention layer comprises a plurality of apertures wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions; coating a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal base layer; and forming the dental crown blank into a dental crown shaped to cover at least a portion of a tooth of a patient.

Some other aspects of the present disclosure provide a method of forming a dental crown. This method which is not according to the invention and present for illustrative purposes only may include bonding a continuous, nonporous metal base layer to a coating retention layer to form a dental crown blank, wherein the coating retention layer comprises a plurality of apertures wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions, wherein the plurality of apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer; and coating a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal base layer; and forming the dental crown blank into a dental crown shaped to cover at least a portion of a tooth of a patient.

The details of one or more examples of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of this disclosure will be apparent from the description and drawings, and from the claims.

There has been a long-standing need for both temporary and permanent esthetic metal crowns for dental patients. Traditionally, dental patients have received dental crowns made from stainless steel because they are very durable and provide reliable restorations for the patient's tooth. However, stainless steel crowns have an unattractive appearance. Thus, there is a need for stainless steel dental crowns that have a more natural look with preferably a tooth-like color. Attempts have been made using resins, such as polyesters, epoxies, acrylics, and high-density polyethylene, to form an esthetically pleasing appearance on the outside of the crown. But, as illustrated by <FIG>, as these crowns <NUM> contact other teeth or dental work, as well as food items placed in the mouth, the outside coatings <NUM> tend to be sheared off because of this contact and the resultant forces of occlusion.

<FIG> illustrate exemplary examples of the esthetic dental crown of the present invention. Dental crown <NUM> is being shown in <FIG> as it is being placed in the mouth to cover a prepared tooth <NUM>. The prepared tooth <NUM> is shown as having its surface ground away sufficiently for the placement of the crown <NUM> thereon.

The scale of the teeth shown and the crown <NUM> to be placed thereon is for ease of illustration and should not be considered to be at the correct scale. Furthermore, the portion of the tooth <NUM>, which has been ground away, is also for illustration purposes only.

<FIG> are convenient for illustrating the various layers that are used to create a laminate used in the dental crown <NUM>. The dental crown has an occlusal surface <NUM> and an open end <NUM> opposite the occlusal surface <NUM> for receiving the prepared tooth <NUM>. The dental crown is shaped to resemble the original tooth it replaces, and the open end <NUM> is for placement over the prepared tooth <NUM>. It is sized to fit comfortably over the portion of the tooth <NUM> on which the dental procedure is being performed. The crown is trimmed so that the bottom edge of the crown meets the gum line in a comfortable manner approximating the placement of the tooth when the crown <NUM> is applied. The crowns <NUM> are manufactured in various size and shapes to fit different types of teeth. The crown <NUM> is malleable so it can be crimped around the base of the tooth and shaped on the occlusal surface to provide a comfortable bite with the opposing tooth. However, the coating <NUM> is retained on the crown <NUM> during this crimping and shaping steps. Proper tooth preparation includes removing all caries and proper shaping the remaining natural tooth to receive the dental crown <NUM>.

The dental crown <NUM> has a metal layer or foil <NUM>, shown as a metal shell. The metal for the shell <NUM> is preferably stainless steel, but also could be aluminum, tin, silver, gold and any alloys thereof. The metal layer is preferably a continuous layer and nonporous. This is to prevent the coating material from seeping into the interior of the crown, which might interfere with the crown preparation and placement. The dental crown <NUM> has a coating retention layer <NUM>. The retention layer <NUM> is preferably stainless steel, but also could be aluminum, tin, silver, gold and any alloys thereof. The retention layer keeps the coating <NUM> highly retained on the metal shell <NUM>, even after long periods of use. Due to the mechanical structure of the retention layer, the coating <NUM> is strongly adhered to the metal shell <NUM>, as described in more detail below relative to <FIG>. When the dental crown <NUM> is shaped and crimped prior to placement, the esthetic coating layer <NUM> does not delaminate or sheer off. Likewise, as the dental crown <NUM> receives various occlusal forces from the opposing teeth or food, the esthetic coating layer <NUM> does not delaminate or shear off from the crown <NUM>.

In one exemplary embodiment, the coating retention layer <NUM> is made from a mesh of intermingled, elongated strands of metal. The metal strands <NUM> may be woven into a variety of patterns. Examples of some patterns are illustrated in <FIG>. Alternatively, the metal strands <NUM> may be arranged in a nonwoven mesh. Regardless, the open spaces between adjacent metal strands <NUM> create apertures <NUM> within the coating retention layer <NUM>.

<FIG> shows a molar crown <NUM>. <FIG> shows an eyetooth crown <NUM>. However, it is understood that the present invention is applicable to both anterior and posterior crowns as well. The present invention provides a dental crown <NUM> that may be suitable for all types of crowns that could be used by a prospective dental patient, which are long lasting.

<FIG> is convenient for illustrating the various layers used for making the laminate in the dental crown <NUM> of the present invention during the diffusion bonding portion of the method. A metal layer or foil <NUM> is brought into contact with a coating retention layer <NUM>. A separator sheet <NUM> is brought into contact with the coating retention layer <NUM>. A stack <NUM> of these three layers is then heated in a furnace while being forced together in a press, as illustrated in <FIG> and discussed more below, to bond the metal layer <NUM> and coating retention layer <NUM>. Thereafter, the separator sheet <NUM> is removed, and thus a laminate for a dental blank is created.

<FIG> shows a magnified view of the metal layer <NUM> and coating retention layer <NUM> prior to this diffusion bonding process and <FIG> shows a magnified view after the diffusion bonding process.

As illustrated in <FIG> and <FIG>, when the metal layer <NUM> is adjacent to the coating retention layer <NUM>, the interface between the two creates a plurality of interstitial regions <NUM>. These open spaces provide regions for conveniently receiving the polymeric composition <NUM>, when it is applied over the coating retention layer <NUM>, described in more detail below. The interstitial regions <NUM> underlie at least a portion of the metal strands <NUM>, but ideally underlie the majority of the metal strands <NUM>.

One exemplary embodiment for diffusion bonding the metal layer <NUM> to the coating retention layer <NUM> is shown in <FIG>. The stack <NUM> of metal layer <NUM>, retention layer <NUM>, and separator sheet <NUM> put into a hot press furnace having two opposing plates <NUM>, <NUM>. The stack <NUM> is heated by the furnace and the plates <NUM> and <NUM> apply pressure. The time and temperature is picked to allow the metal layers <NUM>, <NUM> to diffuse into each other at the points of contact, but to still maintain the interstitial regions <NUM>. For example, if the metal layer <NUM> is made of stainless steel and the retention layer <NUM> is made of stainless steel, the furnace may be heated within a range of <NUM> to <NUM>. Other metals, temperatures, pressures, and times may be selected by known by one skilled in the art.

Alternatively, other bonding processes not according to the invention may be used, other than diffusion bonding. For instance, welding or brazing may be used to bond the coating retention layer <NUM> to the metal base layer <NUM>, while still maintaining the interstitial regions <NUM> between the two layers.

<FIG> shows a magnified picture of the retention layer <NUM> and the metal base layer <NUM> after the diffusion bonding step. As illustrated, the portion of the metal strands <NUM> adjacent to the metal base layer <NUM> have melted with the metal base layer to create bonded areas <NUM>. Adjacent the top surface of the metal base layer <NUM> and underlying the metal strands <NUM> are the interstitial regions <NUM>.

<FIG> illustrates a magnified picture of the layers after the bonding process described above. Each of the metal strands <NUM> in the coating retention layer <NUM> are bonded to the base metal layer <NUM> in areas <NUM>. Between the metal strands <NUM> are apertures <NUM>. In one embodiment, the coating retention layer <NUM> is selected so that the plurality of apertures <NUM> contribute <NUM> to <NUM> percent of the total area of the coating retention layer <NUM>. In another embodiment, the coating retention layer <NUM> is selected so that the plurality of apertures <NUM> contribute <NUM> to <NUM> percent of the total area of the coating retention layer <NUM>. In one example, a coating retention layer <NUM> with an <NUM> mesh with a <NUM>-mil (<NUM> micrometer diameter) wire gauge provides <NUM>% area of apertures or open area. The number of apertures <NUM> may be optimized to allow enough open area for the composition <NUM> to sufficiently bond to the metal layer <NUM> and to flow into the interstitial regions <NUM> for additional bonding areas and around the metal strands <NUM>. The number of apertures <NUM> may also be optimized to provide enough metal strands <NUM> to sufficiently bond with the metal layer <NUM>. The gauge of the metal strands <NUM> may also be optimized to sufficiently bond with the metal layer <NUM>.

After the dental blank is created, it is then formed into a dental crown by deep drawing the blank with a series of forming dies. One exemplary process for deep drawing is according to process DIN <NUM>-<NUM>.

A deep-drawing die illustrated schematically in <FIG>, which is convenient for illustrating the method step for converting the dental blank into a dental crown <NUM>.

The deep-drawing die set <NUM> includes a base plate <NUM>, a drawing punch <NUM> arranged stationarily on the upper side of the base plate <NUM>, and a sheet-metal holder <NUM> which surrounds the drawing punch <NUM> in a ring shape and is arranged on a supporting plate <NUM> which likewise surrounds the drawing punch <NUM> in a ring shape and is borne by spindle sleeves <NUM> which can be moved vertically be means of a hydraulic moving device ( not illustrated) so that the supporting plate <NUM> can be moved with the sheet metal holder <NUM> arranged thereon along the vertical direction drawing <NUM>.

The deep-drawing die set <NUM> also includes a drawing member <NUM> which is arranged above the drawing punch <NUM> and the sheet metal holder <NUM> and comprises, for its part, a ring-shaped drawing ring support <NUM> and a drawing ring <NUM> held on its underside.

The drawing ring support <NUM> is held at its upper side on a holding plate <NUM> which can be moved by means of a hydraulic moving device (not illustrated) along the direction of drawing <NUM> relative to the drawing punch <NUM> and the sheet metal holder <NUM>.

The drawing member <NUM> forms the first deep-drawing die part <NUM> of the deep-drawing die set <NUM>; the drawing punch <NUM> forms the second deep-drawing die part <NUM> of the deep-drawing die set <NUM>.

A first deep-drawing process is carried out as follows with the deep-drawing die set <NUM> described above.

First, the drawing member <NUM> and the sheet metal holder <NUM> are displaced into their respective upper starting positions by means of the respective hydraulic moving devices (not illustrated).

In the upper starting position of the sheet metal holder <NUM>, the essentially flat upper side of the sheet metal holder <NUM>, the essentially flat upper side of the sheet metal holder <NUM> is arranged above the upper side of the drawing punch <NUM>.

In this position, the dental blank <NUM>, from which the drawn part is intended to be produced, is inserted into the deep-drawing die set <NUM> such that the edge of the blank <NUM> rests on the sheet metal <NUM>, as illustrated in <FIG>.

Subsequently, the deep-drawing die set <NUM> is closed in that the drawing member is displaced by means of the hydraulic moving device (not illustrated) downwards out of its upper starting position to such an extent along the direction of drawing <NUM> until the underside of the drawing ring <NUM> on the upper side of the blank <NUM> and the edge of the blank <NUM> is clamped between the drawing ring <NUM> and the sheet metal holder <NUM>, as illustrated in <FIG>.

In the subsequent method step, the blank <NUM> is formed into a drawn part <NUM> in that the spindle sleeves <NUM> with the supporting plate <NUM> arranged thereon and the sheet metal holder <NUM> as well as the drawing member <NUM> are moved downwards by means of the hydraulic moving device (not illustrated) along the direction of drawing <NUM> relative to the drawing punch <NUM> by the drawing depth, wherein the blank <NUM> held securely at its edge between the drawing ring <NUM> and the sheet metal holder <NUM> fits closely along the outer contours of the drawing ring <NUM> and the drawing punch <NUM>, as illustrated in <FIG>.

Once the desired drawing depth for the first deep-drawing process is reached, the spindle sleeves <NUM> are moved back into their upper starting position with the supporting plate <NUM> arranged thereon and the sheet metal holder <NUM> and the deep-drawing die set <NUM> is opened in that the drawing member <NUM> is moved further along the direction of drawing <NUM> upwards into its upper starting position, as illustrated in <FIG>.

As a result, the drawn part <NUM> formed during the first deep-drawing process is accessible from outside the deep-drawing die set <NUM> and can be removed from it. There are often successive deep drawing die sets that continue to form the drawn part <NUM> to the final desired dimensions. The drawn part <NUM> may then be converted into a dental crown <NUM> of the present invention by trimming the excess flange around the portion that contacted the sheet metal holder <NUM>.

After the retention layer <NUM> and metal base layer <NUM> are bonded, they are coated with a polymeric composition to form a dental blank <NUM>. <FIG> illustrates a cross section of the finished dental blank <NUM>. The polymeric composition is applied over the top of the retention layer <NUM>, into the interstitial regions <NUM>, around the metal strands <NUM> and in contact with the metal base layer <NUM> to form a coating <NUM>. Afterwards, the coating <NUM> may be hardened to mechanically bond the coating to the metal base layer <NUM>, especially via retention layer <NUM>. The hardened composition in the interstitial regions <NUM> adjacent the metal strands <NUM> and metal layer <NUM> assist in adhering the coating to the base layer. After hardening, the coating is mechanically bonded to the metal layer <NUM> by the coating being locked into place within interstitial regions <NUM> and around the metal strands <NUM>. However, the coating, mesh, and base combination are still flexible enough to be shaped and crimped easily by a dentist. The retention layer <NUM> also provides strength and flexibility.

Optionally, to increase the bonding of the coating <NUM> to the retention layer <NUM> and to metal base layer <NUM>, both layers may be sandblasted or primed prior to the coating process.

One way to apply the esthetic layer <NUM> is to electrostatically apply powder to the metal retention layer <NUM> and base layer <NUM>. One example of suitable powder is ALESTA epoxy-polyester hybrid, which is commercially available from Axalta Coating Systems based in Houston, Texas.

The hardenable compositions of the present disclosure are typically hardenable due to the presence of a polymerizable component. As used herein, the term "hardenable" refers to a material that can be cured or solidified, e.g., by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking, or the like.

In some embodiments, the compositions can be hardened (e.g., polymerized by heat, conventional photopolymerization and/or chemical polymerization techniques) after it has been applied to the surface of a dental article.

In certain embodiments, the compositions are photopolymerizable, i.e., the compositions contain a photoinitiator system that upon irradiation with actinic radiation initiates the polymerization (or hardening) of the composition. In other embodiments, the compositions are chemically hardenable, i.e., the compositions contain a chemical initiator (i.e., initiator system) that can polymerize, cure, or otherwise harden the composition without dependence on irradiation with actinic radiation. Such chemically hardenable compositions are sometimes referred to as "self-cure" compositions.

In other embodiments, the compositions are thermally polymerizable, i.e., the compositions contain a thermal initiator system that upon heating or other application of thermal energy initiates the polymerization (or hardening) of the composition.

As used herein, the term "(meth)acrylate" is a shorthand reference to acrylate, methacrylate, or combinations thereof, and "(meth)acrylic" is a shorthand reference to acrylic, methacrylic, or combinations thereof. As used herein, "(meth)acrylate-functional compounds" are compounds that include, among other things, a (meth)acrylate moiety.

The polymerizable component typically comprises one or more ethylenically unsaturated compounds, with or without acid functionality. Examples of useful ethylenically unsaturated compounds include acrylic acid esters, methacrylic acid esters, hydroxy-functional acrylic acid esters, hydroxy-functional methacrylic acid esters, and combinations thereof. The polymerizable component may comprise one or more ethylenically unsaturated compounds, with or without acid functionality that is phosphorylated, such as a phosphorylated methacrylate. In some embodiments, the polymeric composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.

One suitable coating is taught as microparticle coating in <CIT>, "Dental Articles include a Ceramic and Microparticle Coating, and Method of Making the Same".

In one embodiment, the composition is a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof. In another embodiment, the composition may be a thermoplastic polymer. If so, the thermoplastic polymer could be from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE or combinations thereof.

Preferably, the coating composition is retained on the metal shell with a minimum bond strength of at least <NUM> MPa. This is to provide a dental crown that will endure the various forces applied to it while the patient is chewing.

In one preferred embodiment, the metal shell has a thickness in the range of <NUM> to <NUM> micrometers. In a more preferred embodiment, the metal shell <NUM> has a thickness in the range of <NUM> to <NUM> micrometers. In another preferred embodiment, the coating retention layer <NUM> has a thickness in the range of <NUM> to <NUM> micrometers. Overall, the dental crown <NUM> has a thickness in the range of <NUM> to <NUM> micrometers. Such preferred thickness ranges provide flexibility and durability.

<FIG> show examples of dental crowns <NUM> after the deep drawing process step described above, but prior to the coating process step. <FIG> show examples of dental crowns after both the deep drawing process and coating process steps. Typically, the top or occlusal surface of the dental crown <NUM> will include grooves, indentations and or dimples (not shown), similar to normal dentition. The occlusal surface is shaped into the metal base layer <NUM> as part of the deep drawing process described in <FIG>, prior to the bonding and coating processes described above.

<FIG> illustrate several examples of exemplary coating retention layer <NUM> having different wire mesh weave styles. <FIG> illustrates a plain weave style. For example, the mesh layer <NUM> shown in <FIG> and 7A have a plain weave style. <FIG> illustrates a twill square weave style. <FIG> illustrates a reverse plain Dutch weave style. <FIG> illustrates a plain Dutch weave style. The coating retention layer <NUM> in <FIG> has apertures <NUM> that comprise between <NUM> and <NUM> percent of the area of the coating retention layers. The coating retention layer <NUM> in <FIG> has apertures <NUM> that comprise between <NUM> and <NUM> percent of the area of the coating retention layers.

The following embodiments are intended to be illustrative of the present disclosure and not limiting.

Embodiments <NUM> to <NUM>, <NUM> to <NUM> and <NUM> are not according to the invention and are present for illustrative purposes only.

Embodiment <NUM> is a dental crown comprising: a metal shell shaped to cover a portion of a tooth of a patient; a coating retention metal layer diffusion bonded to the metal shell, wherein an interface between the coating retention layer and the metal shell comprises a plurality of interstitial regions; and a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal shell.

Embodiment <NUM> is the dental crown of embodiment <NUM>, wherein the coating retention layer comprises an interwoven mesh, the mesh comprising a plurality of elongated metal strands, and the interstitial regions underlie at least a portion of the strands.

Embodiment <NUM> is the dental crown of embodiment <NUM>, wherein a plurality of apertures between the plurality of elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer.

Embodiment <NUM> is the dental crown of embodiment <NUM>, wherein the open spaces between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer.

Embodiment <NUM> is the dental crown of Embodiments <NUM>, <NUM> and <NUM>, wherein the coating retention layer comprises a nonwoven mesh of elongated metal strands, and the interstitial regions underlie at least a portion of the strands.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.

Embodiment <NUM> is the dental crown of claims <NUM>-<NUM>, wherein the composition comprises a thermoplastic polymer.

Embodiment <NUM> is the dental crown of Embodiment <NUM>, wherein the composition comprises a thermoplastic polymer chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE and combinations thereof.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the metal shell and/or the coating retention layer comprise stainless steel alloys.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating composition is retained on the metal shell with a minimum bond strength of <NUM> MPa.

Embodiments <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition comprises a polymerizable component selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the metal shell has a thickness in the range of <NUM> to <NUM> micrometers.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating retention layer has a thickness in the range of <NUM> to <NUM> micrometers.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the dental crown has a thickness in the range of <NUM> to <NUM> micrometers.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the metal shell is a continuous, nonporous layer of metal.

Embodiment <NUM> is the dental crown of claims <NUM>-<NUM>, wherein the composition comprises powder.

Embodiment <NUM> is a dental crown comprising: a continuous, nonporous metal shell shaped to cover a portion of a tooth of a patient; a coating retention metal layer of elongated metal strands bonded to the metal shell, wherein there are apertures between the elongated metal strands, wherein the apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer, and wherein an interface between the coating retention layer and the metal shell comprises a plurality of interstitial regions; and a polymeric composition on the coating retention layer and within a plurality of the interstitial regions to bond the coating composition to the metal shell.

Embodiment <NUM> is the dental crown of Embodiment <NUM>, wherein the plurality of apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating retention layer comprises an interwoven mesh, the mesh comprising a plurality of elongated metal strands, and the interstitial regions underlie at least a portion of the strands.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating retention layer comprises a nonwoven mesh of elongate metal strands, and the interstitial regions underlie at least a portion of the strands.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM> wherein the composition is photocurable.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the coating composition comprises a thermoplastic polymer.

Embodiment <NUM> is the dental crown of Embodiment <NUM>, wherein the coating comprises a thermoplastic polymer chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE and combinations thereof.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition is retained on the metal shell with a minimum bond strength of <NUM> MPa.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the polymeric composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition comprises powder.

Embodiment <NUM> is a method of forming a dental crown, comprising: diffusion bonding a metal base layer to a coating retention layer to form a dental crown blank, wherein the coating retention layer comprises a plurality of apertures wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions; coating a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal base layer; and forming the dental crown blank into a dental crown shaped to cover at least a portion of a tooth of a patient.

Embodiment <NUM> is the method of Embodiment <NUM>, wherein the forming step comprises pressing the blank through a die.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the forming step comprises deep drawing the blank according to DIN <NUM>-<NUM>.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating retention layer comprises a mesh of interwoven elongate metal strands, and wherein the plurality of interstitial regions is between the metal strands and the base layer.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, further comprising hardening the coating composition to form a coating overlying at least a portion of the coating retention layer.

Embodiments <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating step includes electrostatically powder coating the retention layer and heating.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the composition is hardened or cured by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation-induced polymerization or crosslinking.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the thermoplastic composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating comprises a thermoplastic polymer.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein composition comprises a thermoplastic polymer, and wherein the thermoplastic polymer is chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE, and combinations thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the plurality of apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein at least one of the metal base layer and the coating retention layer comprise a stainless-steel alloy, or wherein both the metal base layer and the coating retention layer comprise stainless steel alloys.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating retention layer comprises a nonwoven mesh of elongate metal strands, and the interstitial regions underlie at least a portion of the strands.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating composition is retained on the metal shell with at least a bond strength of <NUM> MPa.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, further comprising: selecting the dental crown of claim <NUM> to cover a tooth portion of a patient; customizing the dental crown for the patient; and attaching the dental crown to the tooth of the patient.

Embodiment <NUM> is a method of forming a dental crown, comprising: bonding a continuous, nonporous metal base layer to a coating retention layer to form a dental crown blank, wherein the coating retention layer comprises a plurality of apertures wherein an interface between the metal base layer and the coating retention layer comprises a plurality of interstitial regions, wherein the plurality of apertures between the elongated metal strands comprise <NUM> to <NUM> percent of the area of the coating retention layer; and coating a composition on the coating retention layer and within the plurality of the interstitial regions to bond the coating composition to the metal base layer; and forming the dental crown blank into a dental crown shaped to cover at least a portion of a tooth of a patient.

Embodiment <NUM> is the method of Embodiment <NUM>, wherein the plurality of apertures comprises <NUM> to <NUM> percent of the area of the coating retention layer.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the forming step comprises pressing the blank through a die.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating retention layer comprises a mesh of interwoven elongate metal strands, wherein the plurality of apertures is between the plurality of metal strands, and wherein the plurality of interstitial regions between the metal strands and the base layer.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, further comprising hardening the composition on the coating retention layer.

Embodiment <NUM> is the dental crown of Embodiments <NUM>-<NUM>, wherein the composition comprises a polymerizable component is selected from the group consisting of phenoxyethyl methacrylate, urethane dimethacrylate, polyethylene glycol methacrylate, polypropylene glycol methacrylate, triethyleneglycol dimethacrylate, the diglycidyl methacrylate of bisphenol A, and combinations thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the composition comprises a polymer or copolymer chosen from epoxy, polyester, and hybrids thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating composition comprises a thermoplastic polymer, and wherein the thermoplastic polymer is chosen from polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenolsulfones, polyethersulfones, polyacrylamide, PTFE, and combinations thereof.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating composition is retained on the metal shell with a minimum bond strength of <NUM> MPa.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the bonding step includes diffusion bonding the metal base layer to the coating retention layer.

Embodiment <NUM> is the method of Embodiment <NUM>, wherein diffusion bonding comprises heat and pressure.

Embodiment <NUM> is the method of Embodiments <NUM>-<NUM>, wherein the coating step includes electrostatically powder coating the retention layer and heating.

Embodiment <NUM> is the method of claim <NUM>-<NUM>, further comprising: selecting the dental crown of Embodiment <NUM> to cover a tooth portion of a patient; customizing the dental crown for the patient; and attaching the dental crown to the tooth of the patient.

Advantages and embodiments of this invention are further illustrated by the following examples. All parts and percentages are by weight unless otherwise indicated.

A <NUM> x <NUM> square piece of the diffusion bonded stainless steel foil/mesh laminate was coated with <NUM> FILTEK Supreme Ultra Flowable Restorative and light cured using a <NUM>-<NUM> visible curing light. The cured restorative composite material adhered well to the substrate.

Dental crown structures were simulated in the form of simple hemispherical caps, such as those shown in <FIG>. A <NUM> x <NUM> square piece of the diffusion bonded stainless steel foil/mesh laminate was formed into a hemispherical cap using a simple punch die to simulate a deep-drawing process. The deep-drawing process is used in manufacturing to create commercially available preformed stainless-steel crowns from <NUM>-L SS foils. These formed caps were dry-powder coated with an electrostatic spraying process and using the following powder: RAL <NUM> Cream - Polyester TGIC Weather Resistant Powder Coating. The caps were first washed with cleaning solution and rinsed with water prior to electrostatic coating. After the application of the powder coating, the caps were baked at <NUM>°F (<NUM>) for <NUM> minutes. The final coating was approximately <NUM> micrometers thick.

The mesh side of a <NUM> x <NUM> square piece of the diffusion bonded stainless steel foil/mesh laminate was cleaned with acetone. The disc mold was lined with a gelatin capsule through the hole of the PTFE mold and then cut flush with a razor to the top and bottom surface of the mold, thus making a gelatin sleeve to line the mold. The gelatin sleeve will dissolve when exposed to water and this will facilitate easy removal later of the mold without disrupting the cured composite material. The disc-shaped mold with gelatin sleeve was clamped onto the mesh side of the foil/mesh laminate the metal piece. Then, FILTEK Supreme Ultra Flowable Restorative composite material was directly extruded from the syringe (with the tip immersed in the material to prevent bubbles) into the mold hole and onto the mesh side of the foil/mesh laminate. The composite material was then pressed with a spatula to make it the same level as the mold. The excess composite material was removed with spatula. The composite material was cured using the <NUM> ELIPAR DeepCure-S LED curing light for <NUM> seconds. Then the composite material bonded to the mesh side of the laminate was placed in <NUM> water for <NUM> hours before testing the bonding strength. The final test object of Example <NUM> was a <NUM> square piece of the SS foil/mesh laminate with a circular button/disc (<NUM> millimeter in diameter and <NUM>-millimeter-thick) of composite material bonded to the mesh side of the SS foil/mesh laminate.

Comparative Example <NUM> was prepared in the same manner as Example <NUM> except that the foil side of the foil/mesh laminate was cleaned with acetone and the FILTEK Supreme Ultra Flowable Restorative composite material was applied and cured to thefoil side of a stainless-steel foil/mesh laminate sheet.

Comparative Example <NUM> was prepared in the same manner as Comparative Example <NUM>, except that the foil side of the foil/mesh laminate was first sandblasted with <NUM> ROCATEC- PLUS sandblasting material and then cleaned with acetone. Finally, FILTEK Supreme Ultra Flowable Restorative composite material was applied and cured to the sandblasted prepared foil side of a stainless-steel foil/mesh laminate sheet.

Comparative Example <NUM> was prepared in the same manner as Comparative Example <NUM>, except that after the foil side of the foil/mesh laminate was sandblasted and then cleaned with acetone and dried, and then further a primer layer of <NUM> RelyX Ceramic Primer was applied for <NUM> seconds to the sandblasted, cleaned foil side of the laminate, followed by air drying of the primer. Finally, FILTEK Supreme Ultra Flowable Restorative composite material was applied and cured to the sandblasted and primer prepared foil side of a stainless-steel foil/mesh laminate sheet.

Shear bond strength of the composite material to the metal substrate was measured for Example <NUM>, and Comparative Examples <NUM>-<NUM> according to the following procedure. Each example was prepared and tested with <NUM> replicates. Prior to the shear bond strength testing the PTFE disc mold was removed. The shear bond strength of a cured test examples was evaluated by clamping one end of the metal laminate in the jaws of an INSTRON testing machine (Instron <NUM>) with the metal surface oriented parallel to the direction of push. A notched-edge fixture (hemispherical in shape, designed to fit and engage one half of the composite button/disc) was placed around the cured composite material button adjacent to the metal surface. After alignment, the notched-edge fixture was clamped in the travelling jaw of the INSTRON apparatus and pushed at a crosshead speed of <NUM> millimeter per minute, thereby placing the adhesive bond in shear stress, with a pushing force. The force in kilograms (kg) at which the bond failed was recorded, and this number was converted to a force per unit area (units of kg/cm<NUM> or MPa) using the known surface area of the button. Additionally, each surface was observed to determine the mode failure where it was characterized as "adhesive" when there was no remnant of the cured composite material left on the metal surface, or "cohesive" when there was remnant of the cured composite material left on the metal surface. Each reported value of adhesion represents the average of <NUM> replicates. The values in the parentheses show the standard deviation of the five replicate measurements of shear bond strength for each example.

Claim 1:
A dental crown (<NUM>), comprising:
a metal shell (<NUM>) shaped to cover a portion of a tooth (<NUM>) of a patient;
a coating retention metal layer (<NUM>) diffusion bonded to the metal shell, wherein an interface between the coating retention metal layer and the metal shell comprises a plurality of interstitial regions (<NUM>); and
a composition (<NUM>) on the coating retention metal layer and within the plurality of the interstitial regions to bond the composition to the metal shell.