Dental composite materials

Details Dental composite materials Dental composite materials

2000-09-12

2002-07-09

Michl, Paul R. (Department: 1714)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S493000

Reexamination Certificate

active

06417246

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to composite materials for restorative dentistry. More particularly, it relates to composites which are useful as crown and bridge materials, either with or without an alloy substrate; as reconstructive materials, restorative materials, filling materials, inlays, onlays, laminate veneers, dental adhesives, cements, sealants and the like.
2. Brief Description of the Related Art
In recent years, materials used for dental restorations have comprised principally acrylate or methacrylate polymers. Typical acrylate resinous materials are disclosed in U.S. Pat. No. 3,066,112 to Bowen, U.S. Pat. No. 3,179,623 to Bowen, U.S. No. 3,194,784 to Bowen, U.S. Pat. No. 3,751,399 to Lee et al. and U.S. Pat. No. 3,926,906 to Lee et al. An especially important methacrylate monomer is the condensation product of bisphenol A and glycidyl methacrylate, 2,2′-bis[4-(3-methacryloxy-2-hydroxy propoxy)-phenyl]-propane (hereinafter abbreviated “Bis-GMA”). Polyurethane dimethacrylates (hereinafter abbreviated to PUDMA) are also commonly used principal polymers in dental restorative materials of this type. Since Bis-GMA is highly viscous at room temperature, it is generally diluted with an acrylate or methacrylate monomer having a lower viscosity such as trimethylol propyl trimethacrylate, 1,6-hexanediol dimethacrylate, 1,3-butanediol dimethacrylate, and the like. Other dimethacrylate monomers, such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate, are also in general use as diluents.
Because acrylic materials exhibit high coefficients of thermal expansion relative to the coefficient of thermal expansion for the tooth structure, these substances by themselves proved to be less than satisfactory. The disparity in thermal expansion, coupled with high shrinkage upon polymerization, resulted in poor marginal adaptability and ultimately led to secondary decay. Furthermore, the wear and abrasion characteristics and the overall physical, mechanical, and optical properties of these unfilled acrylic resinous materials were quite poor. Composite dental restorative materials containing methacrylate resins and fillers were thus developed, the fillers generally comprising inorganic materials based on silica, silicate glass, or quartz. Particularly suitable improved inorganic filler materials include those disclosed in commonly assigned U.S. Pat. No. 4,547,531 to Waknine, and U.S. Pat. No. 4,544,359 to Waknine. Despite their suitability for their intended purposes, there nevertheless remains a perceived need in the art for dental resin materials with even more advantageous physical properties.
SUMMARY OF THE INVENTION
The drawbacks and deficiencies of the prior art are remedied by a dental composite comprising a resin composition and a filler composition, wherein the filler composition comprises a nanostructured, bound silica. Preferably, the bound silica comprises colloidal, nanosized particles having their largest dimensions in the range from about 10 to about 50 nanometers (nm). The silica particles are preferably bound in the form of chains having lengths in the range from about 50 nm to about 400 nm.
These filled compositions are useful for a variety of dental treatments and restorative functions including crown and bridge materials, fillings, adhesives, sealants, luting agents or cements, denture base materials, orthodontic materials and sealants, and other dental restorative materials.
Detailed Description of the Preferred Embodiments
The present dental composite comprises a resin composition and a filler composition, wherein the filler composition comprises a nanostructured, bound silica, preferably in the form of nanosized particles having their largest dimensions in the range from about 10 to about 50 nanometers (nm). silica particles are preferably bound so as to result in chains having lengths in the range from about 50 nm to about 400 nm. Also within the scope of the invention described herein are methods for use of the preceding materials. Resin Composition
Resin compositions are well known in the art, generally comprising viscous acrylate or methacrylate monomers such as those disclosed in U.S. Pat. No. 3,066,112 to Bowen, U.S. Pat. No. 3,179,623 to Bowen, U.S. Pat. No. 3,194,784 to Bowen, No. 3,751,399 to Lee et al., U.S. Pat. No. 3,926,906 to Lee et al., and commonly assigned U.S. Pat. Nos. 5,276,068 and Pat. No. 5,444,104 to Waknine, all of which are incorporated herein by reference. Other resin materials include, but are not limited to, urethane dimethacrylate (UDMA), diurethane dimethacrylate (DUDMA), and other monomers and oligomers known in the art. A useful oligomer is disclosed in U.S. Pat. Nos. 5,276,068 and U.S Pat. No. 5,444,104 to Waknine, being a polycarbonate dimethacrylate (PCDMA) which is the condensation product of two parts of a hydroxyalkylmethacrylate and
1
part of a bis(chloroformate). Another advantageous resin having lower water sorption characteristics is an ethoxylated bisphenol A dimethacrylate (EBPDMA) as disclosed in U.S. Pat. No. 6,013,694. Included within the scope of the resin compositions herein are the resin compositions suitable for use with glass ionomer cements, including polycarboxylic acids such as homo- and copolymers of acrylic acid and/or itaconic acid.
In addition to the aforementioned monomers and oligomers, the resin compositions can further include a diluent acrylate or methacrylate monomer to increase the surface wettability of the composition and/or to decrease the viscosity of the polymerization medium. Suitable diluent monomers include those known in the art such as hydroxy alkyl methacrylates, for example 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; ethylene glycol methacrylates, including ethylene glycol methacrylate, diethylene glycol methacrylate, tri(ethylene glycol) dimethacrylate and tetra(ethylene glycol) dimethacrylate; and diol dimethacrylates such as butanedimethacrylate, dodecanedimethacryalte, or 1,6-hexanedioldimethacrylate. Tri(ethylene glycol) dimethacrylate (TEGDMA) is particularly preferred.
The more viscous monomers, i.e., UDMA, Bis-GMA, and the like are generally present in an amount in the range from 30 to about 100 percent by weight of the total resin composition, preferably in an amount in the range from about 50 to about 90 percent by weight of the total resin composition, and even more preferably in an amount from about 50 to about 80 percent by weight of the total resin composition. Diluent monomers, when present, are incorporated into the resin composition in an amount from about 1 to about 70 weight percent of the total resin composition.
In addition to the above monomers and oligomers, the resin compositions also typically include polymerization initiators, polymerization accelerators, ultraviolet light absorbers, antioxidants, and other additives well known in the art.
Suitable polymerization initiators are those conventional initiators known in the art. For example, visible light curable compositions employ light-sensitive compounds such as benzil diketones, and in particular, DL-camphorquinone in amounts ranging from about 0.05 to 0.5 weight percent. Self-curing compositions will generally contain free radical polymerization initiators such as, for example, a peroxide in amounts ranging from about 2 to 6 weight percent. Particularly suitable free radical initiators are lauryl peroxide, tributyl hydroperoxide and, more particularly benzoyl peroxide.
Polymerization accelerators suitable for use are the various organic tertiary amines well known in the art. In visible light curable compositions, the tertiary amines are generally acrylate derivatives such as dimethylaminoethyl methacrylate and, particularly, diethylaminoethyl methacrylate (DEAEMA) in amounts ranging from about 0.05 to 0.5 weight percent. In the self-curing compositions, the tertiary amines are generally aromatic tertiary amines, such as dimethyl-p-toluidine,

Affiliated with

Also associated with

Rating

Dental composite materials does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dental composite materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dental composite materials will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2879088