Dentistry – Method or material for testing – treating – restoring – or... – By filling – bonding or cementing
Reexamination Certificate
2002-06-28
2004-08-10
O'Connor, Cary E. (Department: 3732)
Dentistry
Method or material for testing, treating, restoring, or...
By filling, bonding or cementing
C433S226000
Reexamination Certificate
active
06773261
ABSTRACT:
TECHNICAL FIELD
This invention relates to processes for forming dental materials from hardenable dental compositions involving generally sequential hardening.
BACKGROUND
Hardenable polymeric materials are used in a wide variety of dental applications, including composites, filling materials, restoratives, cements, adhesives, and the like. Often, such materials shrink upon hardening. This is particularly problematic when the material is in a constrained environment, as in a dental filling or restorative, for example. Dimensional changes upon shrinkage while in a constrained environment can generate a strain within the material that is typically converted into a stress on the surrounding environment (e.g., tooth). Such forces can result in interfacial failures between the tooth and the polymeric material resulting in a physical gap and subsequent microleakage into the tooth cavity. Alternatively, such forces can lead to fractures within the tooth and/or the composite.
Generally, conventional processes of hardening polymeric dental materials involve a composite held in place on an oral surface with an adhesive and involve hardening the adhesive and then subsequently hardening the composite material. More specifically, conventional methods utilize one or more of the following steps: surface treatment of the tooth (e.g., etching, priming), application of a hardenable adhesive to the tooth surface, curing of the adhesive, placement of a composite material (e.g., restorative) on the hardened adhesive, and curing of the composite material. Such methods also typically utilize a blue light source emitting between approximately 380 nm to 520 nm to induce hardening.
Thus, there is a need for methods of hardening dental materials, e.g., dental adhesives and dental composites, that reduce the amount of stress placed on the dental material and the surrounding environment during or after hardening.
SUMMARY OF THE INVENTION
The present invention provides processes for hardening (e.g., curing by polymerization, crosslinking, ionic reaction, or other chemical reaction) hardenable compositions involving a generally sequential hardening of the compositions. Such processes are particularly useful in dental applications, such as dental sealants, dental adhesives, dental cements, dental composites, dental restoratives, and dental prostheses, for example. The processes of the present invention typically result in a reduction in the amount of stress placed on the dental material and surrounding environment during and/or after hardening of the material.
Generally, the processes of the present invention involve applying a radiation source and irradiating a hardenable dental composite that includes at least two adjacent regions with different concentrations of a photoinitiator, at least two adjacent regions with different photoinitiators, or both. Preferably, hardening of a region furthest from the radiation source is initiated first. These regions can be in the form of layers, although they do not necessarily need to be.
The dental composite is adhered to a surface through a dental adhesive that is in contact with a dental surface (e.g., tooth surface or bone). In certain embodiments, either while the dental composite is hardening (e.g., polymerizing) or after it is substantially completely hardened, the processes involve initiating hardening of a hardenable dental adhesive that is in contact with the dental composite and the surface. In certain embodiments, the dental adhesive can be partially or substantially completely hardened prior to applying a hardenable dental composite to it. Typically, hardening of the dental adhesive can be carried out through a chemical curing mechanism or a photopolymerization mechanism, for example.
In one embodiment, the present invention provides a process for forming a dental material adhered to a surface that includes: applying a hardenable dental adhesive to the surface; applying a hardenable dental composite to the hardenable dental adhesive on the surface, wherein the hardenable dental composite includes at least two adjacent regions with different concentrations of a photoinitiator; applying a radiation source to irradiate the hardenable dental composite, wherein hardening of a region furthest from the radiation source is initiated first; and hardening the hardenable dental adhesive to adhere the dental composite to the surface through the adhesive. In certain embodiments, the photoinitiator is a phosphine oxide and in others, the photoinitiator is a monoketone, a diketone, or a combination thereof.
In another embodiment, a process for forming a dental material adhered to an oral surface includes: applying a hardenable dental adhesive to the surface; at least partially hardening the hardenable dental adhesive; applying a hardenable dental composite to the at least partially hardened dental adhesive on the surface, wherein the hardenable dental composite includes at least two adjacent regions with different concentrations of a photoinitiator; and applying a radiation source to irradiate the hardenable dental composite and adhere it to the surface through the adhesive, wherein hardening of a region furthest from the radiation source is initiated first.
In yet another embodiment, a process for forming a dental material adhered to an oral surface includes: applying a hardenable dental adhesive to the surface; applying a hardenable dental composite to the hardenable dental adhesive on the surface, wherein the hardenable dental composite includes at least two adjacent regions with different photoinitiators; applying a radiation source to irradiate the hardenable dental composite; and hardening the hardenable dental adhesive to adhere the dental composite to the surface through the adhesive. Optionally, the hardenable dental composite can further include at least two adjacent regions of different concentrations of a photoinitiator. Preferably, hardening of a region furthest from the radiation source is initiated first.
In still another embodiment, a process for forming a dental material adhered to an oral surface includes: applying a hardenable dental adhesive to the surface; at least partially hardening the hardenable dental adhesive; applying a hardenable dental composite to the at least partially hardened dental adhesive on the surface, wherein the hardenable dental composite comprises at least two adjacent regions with different photoinitiators; and applying a radiation source to irradiate the hardenable dental composite and adhere it to the surface through the adhesive. Optionally, the hardenable dental composite can further include at least two adjacent regions of different concentrations of a photoinitiator. Preferably, hardening of a region furthest from the radiation source is initiated first.
Each of the above embodiments includes a hardenable dental composite that includes at least one photoinitiator. In contrast, the hardenable dental adhesive can include at least one photoinitiator or not.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention provides processes for forming dental materials adhered to a surface. The surface is typically an oral surface such as the surface of a tooth or a bone, although other surfaces are encompassed, such as the surface of a fixture used to prepare a prosthetic device, for example.
The dental materials can be used for example, as dental adhesives, artificial crowns, anterior or posterior fillings, casting materials, cavity liners, cements, coating compositions, mill blanks, restoratives, composites, prostheses, and sealants. In a preferred aspect, the dental material is a dental restorative. The restoratives of the invention can be placed directly in the mouth and cured (hardened) in situ.
The processes involve applying a radiation source and irradiating a hardenable dental composite that includes at least two adjacent regions with different concentrations of a photoinitiator, at least two adjacent regions with different photoinitiators, or both. Preferably, hardening of a region furthest from the radiation sourc
Craig Bradley D.
Kalgutkar Rajdeep S.
Oxman Joel D.
3M Innovative Properties Company
Edman Sean J.
O'Connor Cary E.
LandOfFree
Processes for forming dental 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 Processes for forming dental materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processes for forming dental materials will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3313279