WO1994012118A1

WO1994012118A1 - Apparatus and method for lightening teeth

Info

Publication number: WO1994012118A1
Application number: PCT/US1993/011430
Authority: WO
Inventors: Mark G. Fontenot
Original assignee: Fontenot Mark G
Priority date: 1992-11-24
Filing date: 1993-11-24
Publication date: 1994-06-09
Also published as: AU5677394A

Abstract

A disposable non-porous, polymeric dental appliance (2) which has a trough containing a premeasured quantity of lightening or bleaching agent (3) and a method for use thereof, wherein the dental appliance (2) is applied upon the dental arches such that at least a partial seal is formed about the gingiva and soft tissue surrounding the teeth.

Description

APPARATUS AND METHOD FOR LIGHTENING TEETH

Field of the Invention

The apparatus and method of this invention are drawn toward a disposable dental appliance for lightening teeth.

Background of the Invention

Recently, home bleaching has been introduced into the dental health care market for the management of stained teeth. Home bleaching is a technique 'utilizing weak oxidizing agents such as 6 to 15 percent carbamide peroxide or other peroxy compound which are delivered to the dental arch by the patient using a rigid dental appliance which is custom fabricated by the dentist or dental laboratory. Protocols outlined by dental professionals for the treatment of stained teeth employing the home bleaching technique generally recommend that the patient wear a rigid custom dental appliance for periods of up to 120 minutes per day usually over the course of several weeks, totalling between 20 to 40 hours of home bleaching time.

All currently available bleaching agents are either viscous liquids or gels. Bleaching agents are commercially available and packaged in separate dispensing containers such as bottles, syringes, and tubes. The bleaching agent is self-administered by the patient, who dispenses an estimated quantity of bleaching agent to the rigid custom dental appliance.

The exact origin of the home bleaching procedure is unclear. The earliest reports of this technique occurred in the mid-1960's when two dentists in Arkansas reported Glyoxide™, which is commercially available from Marion Merrel Dow, Inc. Glyoxide is an agent used in a custom dental appliance, or dental splint, for soft tissue wound healing, resulted in the desirable side effect of whitening teeth. Glyoxide™ is an over-the-counter preparation containing 10% carbamide peroxide in glycerine. These dentists switched to Proxigel™, which is commercially available from Reed & Carnrick Pharmacy after its introduction into the over-the-counter market in 1972. Proxigel™ is a combination of water, glycerine, Carbopol™ (thickening agent) and 10% carbamide peroxide.

The first report of the home bleaching procedure was published in 1989, when Haywood and Heymann reported successful bleaching using Proxigel™ in a custom fabricated dental appliance to be worn at night. In the Haywood and Heymann procedure, the bleaching agent was placed in a soft plastic, vacuum formed dental appliance for an average of 7.5 hours per night for 2 to 5 weeks. Also, in 1989, White and Brite™, which is marketed by Omni International, became the first commercially available dental bleaching agent specifically for whitening teeth. White and Brite™ is a preparation containing 10% carbamide peroxide in glycerine which is sold exclusively to dentists and sold in conjunction with custom-fitted or prescription dental appliances. Since its introduction into the dental health care market, over 20 companies have marketed similar products.

The aforementioned home bleaching techniques require two dental office visits and the fabrication of a rigid custom dental appliance. During the first office visit, impressions of the dental arches are taken, from which rigid custom-fitted dental appliances are fabricated. The use of thermoplastic films are recommended for the fabrication of rigid custom dental appliances which function to carry and deliver various home bleaching agents to the dental arches. Thermoplastic films are sold as rigid or semi-rigid sheeting and are available in various sizes and thicknesses. Some manufacturers also offer laminations of porous foams or low modulus plastics to rigid thermoplastic films.

Fabrication of rigid custom dental appliances to stone models of the dental arches necessitates heating and vacuum forming a rigid thermoplastic sheet to the stone models of a patient's dental arches. The excess sheeting is subsequently removed and the resulting rigid custom dental appliance polished and provided to the dentist for fitting to the patient's dental arches.

Dentists have traditionally utilized one of three types of dental appliances for bleaching teeth. The first type is a rigid appliance which is fitted precisely to the patient's dental arches. A second type of rigid custom dental appliance frequently practiced by dentists is the delivery of home bleaching agents in an "oversized" rigid custom dental appliance. The dental laboratory fabrication technique for the oversized rigid dental appliance involves augmenting the facial surfaces of the teeth on the stone models with materials such as die spacer or light cured acrylics. Next, thermoplastic sheeting is heated and subsequently vacuum formed around the augmented stone models of the dental arch. The net effect of this method results in an "oversized" rigid custom dental appliance.

Unfortunately, there exist many problems with the oversized rigid custom dental appliance, including, but not limited to, occlusion, increased fabrication time and cost, irritation and the lip of the appliance contacting the gingival region, and decreased retention to the bleaching agent within the target area of the dental arches. The most serious drawback results from spilling of the^' agent out of the dental appliance, which may cause ingestion of the bleaching agent, which may reach toxic levels, and, at a minimum, cause the patient great discomfort. A third type of rigid custom dental appliance, which is used with less frequency, is a rigid bilaminated custom dental appliance fabricated from laminations of materials, ranging from soft porous foams to rigid, non- porous thermoplastic films. The non-porous, rigid thermoplastic shells of these bilaminated dental appliances encases and supports an internal layer of soft porous foam.

After consultation with the dentist and fabrication of the aforementioned dental appliance, a teeth whitening procedure utilizing the dental appliance is practiced by the patient, who then typically applies the bleaching agent on a daily basis. The patient dispenses the home bleaching agent into the rigid custom dental appliance and then places the appliance over the dental arch. Generally, the recommended treatment period ranges from 30 to 120 minutes per day. At the end of the treatment period, the dental appliance is removed, cleaned with water to remove any remaining bleaching agent, and then stored until the next application.

Obtaining rigid custom-fabricated dental appliances involved significant problems, including the time and expense of making dental impressions, which necessitated dental laboratory work, two office visits, and possibly reshaping poorly fitted appliances. Moreover, the bilaminated appliances have several downfalls, including problems with occlusion and retention of the bleaching agent in the target area. Furthermore, cleaning and maintenance of the foam-lined dental appliance is difficult, due to its high surface area and pore volume.

Such problems triggered the development of a fourth and final type of treatment regimen employed to deliver home bleaching. That regimen replaces rigid custom dental appliances with an individually packaged disposable U-shaped soft foam tray saturated with a premeasured quantity of bleaching agent, such a device is commercially available from Cadco Dental Products in Oxnard, California under the tradename VitalWhite™. Recommended treatment protocol described in the product's package insert instructs the patient to fit the device around his or her teeth and to keep the tray in position for sixty minutes after which time it is removed and discarded. Cadco suggests that fourteen sixty

Unfortunately, however, the ineffective design of the foam appliance used in home bleaching systems such as that provided by Cadco has proven to be replete with problems. That is primarily because the porous foam tray of such a system is bulky, lacks adequate structural rigidity to fit securely over the dental arches, and causes excessive salivation.

As a result, the design of the foam appliance fails to direct and confine the application of home bleaching agents on the surfaces of a patient's teeth, which is critical to the safety and efficacy of any dental appliance, or other medical device used in or on the human body. Furthermore, the surfaces of the foam device, which are saturated with bleaching agent, are open and exposed to the oral cavity, and allow the elution of large, potentially toxic quantities of bleaching agent from the device, enter the oral cavity, and be ingested by the patient. In addition, because of the discomfort associated with the moisture buildup resulting from foaming of the bleaching agent and salivation, patient compliance and acceptance is low. In summary, it can thus readily be seen that there are a multitude of problems with devices for delivering home bleaching agents which are presently available. Conventional rigid, custom-fabricated dental appliances require time-consuming and expensive dentist office visits, dental laboratory tests and fitting of each patient's dentition. Furthermore, any changes in the surface of the patient's teeth, such as fillings, crowns, and other accidental or therapeutic alterations of the dentition, would affect the fit of the rigid custom dental appliance and warrant repeating the entire fabrication procedure. Refabrication of the splint may also be required in the event that subsequent rebleaching becomes necessary in the future.

Additional problems result from the errors introduced by the patients, who are typically inexperienced and unaware of the importance of precision and infection control when self-administering medicinal agents. The patients' lack of aseptic technique increases the risk of contaminating the bleaching agent or dental splint. Patients may fail to provide the careful maintenance, cleaning, and storage which is necessary for a rigid custom dental appliance to reach its intended service life while performing adequately. Yet a further problem results from patients' frequent dispersion of excessive bleaching agent into the rigid custom dental splint which is subsequently displaced from the appliance into the oral cavity and spilled into the digestive system. The resulting application of excessive bleaching agent and leakage of bleaching agent from the dental carriers or retainers may cause gingival irritation, burning, edema, nausea and other allergic reactions. The patient is thus subjected to potentially hazardous quantities of bleaching agent which pose a potential health hazard, particularly after the multiple treatments typically required to attain acceptable clinical results. Moreover, as further discussed above, although individually packaged, disposable foam trays addressed some of the problems associated with treatment regimens employing foam trays, the sponge-like permeability of such devices merely amplified the problems associated with lack of retention or confinement of the bleaching agent to the target area and ingestion of toxic levels of the agent. These problems are not exhaustive but are mere examples of difficulties encountered with present devices. Therefore, it is apparent that there is a need for substantial improvement in devices to deliver bleaching agents.

Summary of t.h Invention

The above-noted and other drawbacks of the prior art are addressed by the device and method for effecting delivery of bleaching agents to a dental arch according to the present invention. The present invention provides a prefabricated disposable device for lightening teeth, comprising a dental appliance composed of a non-porous polymeric material having a trough for immersing the teeth and gingiva of the dental arch, the dental appliance being capable of forming at least a partial seal about the gingiva and soft tissue surrounding the teeth, and a premeasured amount of active bleaching agent disposed within the trough of the disposable dental appliance.

A typical embodiment of the present invention features a dental appliance wherein an open cell foam containing the active bleaching agent is affixed to an inner wall of the trough. Preferably, the open cell foam containing the active bleaching agent is affixed to the wall of the trough facing the anterior surface of the dental arch subject to treatment.

Yet another aspect of this invention includes a trough which is shaped such that the target area of the teeth with which the active bleaching agent comes into contact is concentrated in the anterior portion of the dental arch subject to treatment.

The present invention may also include a buffer region in the area around the gingiva and soft tissue surrounding the teeth subject to treatment, the buffer region containing material to prevent the gingiva and soft tissue from coming into contact with the active bleaching agent . In one embodiment of the present invention, the buffer region contains a chemical compound capable of neutralizing the active bleaching agent. In another embodiment of the invention, the buffer region contains an adhesive, such as zinc oxide eugenol .

The method for lightening teeth according to the present invention includes the steps of selecting a prefabricated dental appliance composed of a non-porous polymeric material having a trough for immersing the teeth and gingiva and soft tissue of the dental arch which contains an active bleaching agent, and applying the dental appliance upon the dental arches such that at least a partial seal is formed about the gingiva and soft tissue surrounding the teeth and the active bleaching agent is delivered and confined to the target area of the teeth to be lightened.

The apparatus and method of the present invention provides many advantages which have not heretofore been available. When seated about the dental arch, the dental appliance forms a tight seal between the gingiva and soft tissue with which it comes into contact and the perimeter of the device, thereby confining the bleaching agent to the dentition and minimizing seepage of the bleaching agent from the trough into the oral cavity. The new device requires and delivers less bleaching agent since it confines the bleaching agent within the target area and minimizes seepage into the oral cavity.

In addition, the new device may be prescribed by the dentist in one short appointment, thereby eliminating the need for dental impressions and fabrication of a custom dental appliance. A still further advantage emanates from the sterile packaging and single use of the present invention insofar as the problems associated with bacterial contamination and cleaning are minimized. Brief Description of the Drawings

FIG. 1 depicts a perspective view of the dental appliance in accordance with the present invention;

FIG. 1A provides a cross-sectional view of the device of the present invention, taken across line 1-1 shown in relation to teeth positioned for immersion therein;

FIG. 2 provides a transverse cross-sectional view of the present invention as actually applied to teeth;

FIG. 3 depicts a transverse cross-sectional view of the dental appliance of the present invention which contains a buffer region;

FIG. 4 depicts a transverse cross-sectional view of the dental appliance of the present invention having an open cell foam containing a bleaching agent affixed to an inner wall of the trough; and

FIG. 5 illustrates a transverse cross-sectional view of the dental appliance of the present invention having a trough which is shaped such that bleaching agent is concentrated on the anterior of the teeth.

Detailed Description of the Preferred Embodiments

Referring to the drawings, the device shown consists of a U-shaped dental appliance 2 having a trough along the long, horizontal axis of the dental appliance 2 containing a premeasured quantity of bleaching agent 3 for immersing the teeth 4 which are subject to treatment. The dental appliance 2 is fabricated from a non-porous polymer in a U-shaped configuration.

FIGS. 3-4 depict the dental appliance 2 as it appears in relation to the teeth 4 of the dental arch in actual practice. In the procedure utilized in practicing the present invention, first, an appropriate prefabricated, disposable dental appliance 2 which approximately fits around the relevant patient's dental arches is selected. The dental appliance 2 may be packaged in a preferably sterile container with a premeasured quantity of bleaching agent 3 disposed in the trough. The dental appliance 2 next may be removed from the packaging and delivered to the teeth 4. Delivery of the dental appliance 2 is effected by positioning the dental appliance 2 intraorally with the trough aligned in a parallel fashion to the edges of the teeth 4 as shown in FIGS. 1A and 2. In order to correctly place the dental appliance 2 over the teeth 4 in a dental arch, the trough is pushed in the direction of the gingiva 6 and soft tissue 8 surrounding the dental arch toward and then around the edges of the teeth. Placement of the dental appliance 2 is complete at the point when the dental appliance 2 is seated and creates at least a partial seal with the gingiva 6 and soft tissue 8 surrounding the dental arch subject to treatment. Correctly placed, the dental appliance 2 covers the teeth 4 gingiva 6 of the dental arch as illustrated in FIG. 3 and provides a drug delivery system whereby the dental appliance 2 delivers a premeasured quantity of bleaching agent 3 to the teeth of the dental arch subject to treatment.

As shown, the teeth 4 and gingiva 6 are embedded and intimately interface with the bleaching agent 3. The gingival seal is subsequently formed about the orifice of the trough which results from the correct placement of the dental appliance 2 and thus confines the bleaching agent 3 within the target area 5.

FIG. 4 depicts an embodiment of the present invention in which buffer region 7 neutralizes bleaching agent 3, thereby protecting against the toxic effects of any bleaching agent 3 which might leak outside of the trough.

FIG. 5 illustrates one embodiment of the present invention in which an inner wall of the dental appliance 2 is laminated or otherwise affixed to an open cell foam 10 containing a premeasured quantity of the bleaching agent 3. The open cell foam 10 thus forms a matrix for application of the bleaching agent 3.

FIG. 6 depicts a preferred embodiment of the present invention wherein the dental appliance 2 is formed so that the bleaching agent 3 is confined to the interior wall of the dental appliance 2 adjacent to the target area 5 of the anterior surface of the teeth 5. As previously explained, a seal is thus created between the gingiva 6 and soft tissue 8 and the dental appliance 2, which consequently forms a reaction vessel which confines the bleaching agent 3 to the anterior surfaces of the teeth 4 and minimizes leakage or seepage of the bleaching agent 3.

It is to be understood that the present invention is not intended to be limited to the exact details of construction, operation, exact materials or embodiments shown and described herein, as obvious modifications and equivalents will be apparent to one skilled in the art. For example, the dental appliance of the present invention could be applied to facilitate the delivery to the teeth of other therapeutic agents, such as fluoride. This disclosure is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

The following claims represent the scope of this invention to the extent that it is subject to such delimitations. It will be appreciated by those skilled in the art that the anticipated uses and embodiments of the present invention are not amenable to precise delineation, but may vary from the exact language of the claims. Thus, the following claims are drawn not only to the explicit limitations, but also to the implicit embodiments embraced by the spirit of the claims.

Claims

ClaimsI claim:

1. A disposable device for lightening teeth, comprising:

(a) a prefabricated dental appliance composed of a non-porous polymeric material having a trough for immersing the teeth and gingiva of the dental arch, the dental appliance being adaptablea to fit a range of variously sized dental arches and forming at least a partial seal about the gingiva and soft tissue surrounding the teeth;

(b) a premeasured amount of active bleaching agent predispensed within the trough of the prefabricated dental appliance .

2. The prefabricated dental appliance of claim 1, wherein an open cell foam containing the active bleaching agent is affixed to an inner wall of the trough.

3. The prefabricated dental appliance of claim 1, wherein an open cell foam containing the active bleaching agent is affixed to an inner wall of the trough for facing the anterior portion of the dental arch subject to treatment.

4. The prefabricated dental appliance of claim 1, wherein the trough is shaped such that the target area of the teeth with which the active bleaching agent comes into contact is concentrated in the anterior portion of the dental arch subject to treatment.

5. The prefabricated dental appliance of claim 1, further comprising a buffer region in the area around the gingiva and soft tissue surrounding the teeth subject to treatment, the buffer region containing material to prevent the gingiva and soft tissue from coming into contact with the active bleaching agent.

6. The prefabricated dental appliance of claim 5, wherein the buffer region contains a chemical compound capable of neutralizing the active bleaching agent.

7. The prefabricated dental appliance of claim 5, wherein the buffer region contains an adhesive.

8. The prefabricated dental appliance of claim 5, wherein the buffer region contains zinc oxide eugenol .

9. A method for lightening teeth, comprising the steps of:

(a) selecting a prefabricated, disposable dental appliance adapted to fit a range of variously sized dental arches within which a premeasured amount of bleaching agent is predispensed, the dental appliance being composed of a non- porous polymeric material having a trough for immersing the teeth and gingivae of the dental arch; and

(b) applying the dental appliance upon the dental arches such that at least a partial seal is formed about the gingivae and soft tissue surrounding the teeth.