Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-09-12
2003-06-17
Yoon, Tae H (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S115000, C523S116000, C433S226000, C433S228100, C433S215000
Reexamination Certificate
active
06579919
ABSTRACT:
FIELD OF THE INVENTION
The present invention describes a paste with application as a try-in paste (i.e., trial paste) useful for assisting in the determination of the correct choice of a dental cement used to apply a dental prosthesis to a tooth.
BACKGROUND
Try-in pastes (i.e., trial pastes) are used in assisting a dentist in the selection of an appropriate dental cement for bonding a dental prosthesis (e.g., veneer, in-lay, on-lay, etc.), which is often translucent, to a tooth. This selection depends on the optical properties of the final polymerized cement and the dental prosthesis compared to the optical properties of the other teeth of the patient.
Typically, a try-in paste, which is matched to a dental cement with respect to optical properties (often just color-matched), is used to apply temporarily the dental prosthesis to a prepared tooth surface. The dentist determines if the optical properties (at least color) would be esthetically desirable for the combination of the prosthesis and underlying cement. If so, the prosthesis is removed and try-in paste is washed away and the appropriately matched dental cement is used to apply the prosthesis. If not, the prosthesis is removed and try-in paste is washed away and this is repeated with a different try-in paste appropriately matched to a different dental cement.
Traditionally, such try-in pastes are based on glycerin. They typically either have poor handling characteristics or leave a residue after water cleanup. Additionally, because glycerin is transparent optically, some difficulty is encountered in preparing pastes whose optical properties closely match those of the polymerized cement. Thus, additional try-in pastes are desired that are capable of better shade matching.
SUMMARY OF THE INVENTION
The present invention provides a try-in paste (i.e., trial paste) suitable for shade matching to a corresponding polymerized dental cement, so that a dental cement of the correct shade can be selected for bonding a dental prosthesis to a tooth of a patient. As used herein, “shade matching” refers to the use of a try-in paste for guiding a dentist in the selection of a shade-matched dental cement for use in bonding a dental prosthesis to a tooth of a patient. The selection of an appropriate dental cement shade depends on the optical properties (typically, color, and preferably, color and opacity) of the polymerized cement and the dental prosthesis compared to the optical properties of the other teeth of the patient.
In a preferred embodiment, the present invention provides try-in paste that includes: a polyalkylene glycol that is liquid at room temperature; a polyalkylene glycol that is solid at room temperature; and particulate material; wherein the polyalkylene glycols are present in amounts to provide a paste having a consistency of about 20 mm to about 50 mm; and wherein the particulate material is present in an amount to provide a try-in paste having a shading (i.e., shade) that matches the shading of a corresponding polymerized dental cement.
Preferably, the shading match includes a color match, and more preferably, a color match and an opacity match. That is, for particularly preferred embodiments, particulate material is present in an amount to provide a try-in paste having a color and opacity that matches the color and opacity of a corresponding polymerized dental cement. Preferably, the color match is within a Delta E* of three units or less. Preferably, the shading match is within a Delta CR of five units or less.
Preferably, the polyalkylene glycols are polyethylene glycols. Preferably, the liquid polyethylene glycol has a weight average molecular weight of about 100 g/mol to about 600 g/mol and the solid polyethylene glycol has a weight average molecular weight of about 700 g/mol to about 20,000 g/mol. Preferably, the ratio of liquid to solid PEG is within a range of about 1/1 to about 10/1, and more preferably, about 2/1 to about 5/1.
In another preferred embodiment, the present invention provides a kit for selecting a dental cement for bonding a dental prosthesis to a tooth of a patient. The kit includes: a dental cement; and a corresponding try-in paste, wherein the try-in paste is as described above. The kit typically and preferably includes more than one try-in paste and their corresponding cements. The try-in paste includes particulate material in an amount to provide a try-in paste having a shading that matches the shading of a corresponding polymerized dental cement. Preferably, the shading match between the try-in paste and the corresponding polymerized dental cement includes a color match and an opacity match. Preferably, the color match is within a Delta E* of three units or less. Preferably, the opacity match is within a Delta CR of five units or less.
Another preferred kit includes a dental cement and a corresponding try-in paste, wherein the try-in paste includes: a polyethylene glycol that is liquid at room temperature and has a weight average molecular weight of about 100 g/mol to about 600 g/mol; a polyethylene glycol that is solid at room temperature and has a weight average molecular weight of about 700 g/mol to about 20,000 g/mol; and particulate material that includes a pigment and an optional filler; wherein the polyethylene glycols are present in amounts to provide a paste having a consistency of about 20 mm to about 50 mm; wherein the particulate material is present in an amount to provide a try-in paste having a shading that matches the shading of a corresponding polymerized dental cement.
The present invention also provides a method of selecting a dental cement for bonding a dental prosthesis to a tooth of a patient. The method includes: selecting a first try-in paste; applying the dental prosthesis to the tooth of the patient using the first try-in paste; comparing the shading of the dental prosthesis and the first try-in paste to the shading of the other teeth of the patient to determine if there is an appropriate match; removing the first try-in paste; and bonding the dental prosthesis to the tooth using a corresponding dental cement. The try-in paste includes: a polyalkylene glycol that is liquid at room temperature; a polyalkylene glycol that is solid at room temperature; and particulate material; wherein the polyalkylene glycols are present in amounts to provide a paste having a consistency of about 20 mm to about 50 mm; wherein the particulate material is present in an amount to provide a try-in paste having a shading that matches the shading of a corresponding polymerized dental cement. Preferably, comparing the shading includes comparing the color and opacity of the dental prosthesis and the try-in paste to the color and opacity of the other teeth of the patient. Preferably, the method further includes selecting a different try-in paste if the match using the first try-in paste is not appropriate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
This invention provides dental try-in (i.e., trial) pastes that include a mixture of liquid and solid polyalkylene glycols, preferably, polyethylene glycols (PEGs). Such try-in pastes are used to shade match (typically, match the color, and preferably match the color and opacity) of final polymerized dental cements used to apply a dental prosthesis (i.e., restorative such as a veneer, in-lay, on-lay, etc., whether it be made of porcelain, ceramic, or a composite material). The dental cements typically can be resin cements, ionomeric cements, or resin-modified ionomeric cements. Preferably, the present try-in pastes are used to match the optical properties of (meth)acrylate-based resin cements.
Such pastes have a consistency (defined below) such that they are semi-solid. Such properties provide good handling characteristics (e.g., little or no slump). Preferred pastes are homogeneous. Preferred pastes are also shelf-stable such that there are no significant changes in handling, homogeneity, color, or opacity while stored at room temperature in the dark for at least one year, and preferably for at least two years. Alternatively, preferred pastes
Konings Mark S.
Winters Edward J.
3M Innovative Properties Company
Gwin Doreen S. L.
Yoon Tae H
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