Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-01-03
2003-09-02
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, C523S118000, C523S120000, C523S212000, C523S217000, C433S226000, C433S228100
Reexamination Certificate
active
06613812
ABSTRACT:
TECHNICAL FIELD
The present invention provides a dental composition with high loading of reactive glass. In particular, the composition contains, among other components, treated reactive glass, such as fluoroaluminosilicate glass, and a fatty acid additive. Even with a high loading of reactive glass, the composition is stable during storage, does not phase separate, and has good physical properties making it suitable in various dental applications.
BACKGROUND
Fluoroalumuniosilicate (FAS) glass has been used widely in dental compositions. They are known fluoride releasing materials. The glass can be treated with surface treating agents such as silanes. Some skilled in the art have used treated fluoroaluminosilicate glass in dental cements and liners, among other applications.
U.S. Pat. No. 5,883,153 (Roberts et al.) discloses a dental composition comprising a resin composition made of (a) radical polymerizable compound, (b) a curing agent, and (c) fluoride-ion sustained release preformed glass ionomer filler. The glass ionomer filler may be surface treated with agents such as silane compounds.
Some skilled in the art have used fatty acids in dental compositions for various reasons. For example, U.S. Pat. No. 5,154,613 (Cohen) discloses a dental cement for a temporary dental prosthesis. The cement is in the form of a paste. The paste consists of metal a oxide and a metal hydroxide. Preferably, the metal oxide is the oxide of zinc, calcium, mercury, copper, silver, and barium. The paste may also include a fatty acid in an amount between 0.1 and 25 weight percent, preferably those chosen from C
8
to C
18
saturated acids. It is stated that the fatty acids function to (1) increase the adhesion of the cement by etching the temporary prosthesis, and (2) reduce the adhesion of the cement to dentin.
UK Patent Application No. 2 108 132 discloses a dental cement containing first and second components. The first component is a powder of fine particles of zinc oxide, calcium hydroxide, magnesium oxide or magnesium hydroxide. None of the particles is a reactive glass. The particles of the first component are surface treated with a fatty acid such as stearic or oleic acid. The second component is an organic liquid, such as eugenol. It is stated that providing a fatty acid surface coating on the particles facilitates and speeds up mixing and allows a higher proportion of the metal oxide or hydroxide to be incorporated into a dental cement of a given consistency.
While the foregoing technology may be useful, other dental compositions are sought.
SUMMARY
The present invention provides, for the first time, a dental composition having, among other components, treated acid-reactive filler and a fatty acid as an additive. The inventive material has a viscosity at which it can be easily dispensed from a device, such as a syringe, without being stringy.
In brief summary, the dental composition comprises (a) a part A comprising fluoroaluminosilicate glass that has been surface treated with agents selected from the group of silane and silanol, and at least one fatty acid; and (b) a part B comprising at least one polyacid. The composition further comprising at least one resin and at least one initiator, the resin and initiator residing in either part A or part B. Kits and methods of using the dental composition are also disclosed.
One illustrative method comprises the acts of (a) providing a dual barrel syringe of a dental composition recited in the immediate paragraph above stored in the barrels such that part A resides in a first barrel and part B resides in a second barrel; (b) dispensing an amount of the dental composition onto a mixing pad; (c) mixing parts A and parts B together to form the dental composition; (d) supplying a sufficient amount of water; and (e) applying the dental composition to a patient's dental structures.
One advantage of the present invention is that the composition can be formulated and packaged such that parts A and B are both pastes or one being a paste (typically part A) and the other a liquid (typically part B). The paste-paste or paste-liquid combination allows for easy mixing of the two parts prior to use. Previously, some dental compositions have typically been supplied in powder-liquid form. For example, the dental cement in UK Patent Application No. 2 108 132 uses a zinc oxide powder. The powder presents drawbacks during the mixing process because more skill and care is required to dispense adequate amounts of the powder and liquid in making the dental composition.
Another advantage of the present invention is that the acid-reactive filler, in particular, the fluoroaluminosilicate (FAS) glass, is treated with a silane or silanol solution. Such treatment allows for increase FAS glass loading in the inventive composition and provides for increase in working time, both being desirable attributes in a dental composition. As an additional benefit, the high loading of the reactive glass fillers yield a radiopaque dental composition.
Yet another advantage is that the inventive composition is stable and does not settle during storage. The fillers can settle out of a dental composition during storage. Because of the size and density of the treated FAS glass filler, maintaining a homogeneous system can present a challenge. It is believed that the use of fatty acids minimizes, if not nearly eliminate, the filler from settling. The fatty acid imparts a yield stress to the dental composition thereby keeping the reactive glass particles from settling.
Yet with such a high loading of reactive glass, the physical and rheology properties of the inventive material remain well suited for dental applications. In particular, the inventive composition has good adhesion to dental structures and good compressive strength.
The inventive dental composition can be used in various applications. Such applications include dental adhesives, artificial crowns, anterior or posterior fillings, casting materials, cavity liners, cements, coating compositions, mill blanks, adhesives and cements for affixing orthodontic brackets and appliances, endodontic cements, restoratives, prostheses, and sealants. The materials can be placed in the mouth and cured in situ. Alternatively, it may be fabricated into a prosthesis outside the mouth and subsequently adhered in place in the mouth.
DETAILED DESCRIPTION OF THE INVENTION
The inventive composition can be visually described as similar to whip cream (such as Cool Whip®, from Kraft Foods), shaving cream or hair mousse dispensed from a pump. The composition has adhesion to dentin greater than about 5 MPa when tested according to the Adhesive Test Method, as described below in the Examples. The treated FAS glass has the ability to release useful amounts of fluoride ion when made into a cured dental composition. Fluoride release can be measured using the procedure set out in Example 18 of EP 0 323 120 B1. The composition has a compressive strength greater than about 10,000 psi when tested according to Compressive Strength Test Method, as described below in the Examples.
As stated, in one embodiment, the inventive composition is supplied as a two-part system, a part A and a part B. The viscosity of part A is typically greater than about 50,000 cps, preferably between 150,000 to 300,000 cps when measured at or near room temperature (about 25° C.) using a Brookfield viscometer using a T-D spindle with a conversion factor equal to 32,000. Typically, a dental practitioner mixes the two parts immediately prior to use. As the two parts are mixed, the acid-base FAS curing reaction begins. Subsequent curing of the ethylenically-unsaturated groups or the curable resin is done by curing agents and/or by light. Each component used to formulate parts A and B are discussed in detail below. Certain components such as the curable resin and the initiator may reside in either part A or part B, as further explained below.
Acid-Reactive Filler
Part A comprises about 5% to 90%, preferably about 40% to 80% by weight acid reactive filler, based on the total weight of the componen
Bui Hoa T.
Kolb Brant U.
Mitra Sumita B.
3M Innovative Properties Company
Gwin Doreen S. L.
Yoon Tae H.
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