METHOD AND APPARATUS FOR WHITENING TEETH

The present invention relates to the treatment of teeth, in particular teeth whitening. More specifically, it relates to a method and apparatus for whitening teeth, e.g. for cosmetic purposes.

Dental treatment to whiten teeth, particularly for cosmetic reasons, has become increasingly popular in recent years.

Teeth whitening is a bleaching process that removes or hides discolouration or stains on teeth. Stains may be present on or in the enamel and dentine of the teeth. Discolouration of teeth may be caused by chromogens, particularly polyphenols.

Various compositions for teeth whitening are known, such compositions generally contain a bleaching agent such as hydrogen peroxide.

The composition may provide oxygen radicals which can react with polyphenols on or within the teeth.

Typically, the composition may be in the form of a solution or a gel. Examples of suitable compositions for teeth whitening are disclosed in the applicant's earlier British patent application GB 0709418.8, the entire disclosure of which is incorporated herein by reference. It is known that enamel and dentine within the teeth are porous and semipermeable.

Accordingly, compositions for teeth whitening may travel, e.g. by diffusion, into and around the body of the teeth.

The effectiveness of a teeth whitening treatment will, therefore, be dependent on the rate of diffusion of the active, i.e. bleaching, agent within the teeth whitening composition.

The rate of diffusion will, in turn, depend on the concentration of the bleaching agent within the composition and also the temperature of the gel.

However, while increased temperatures may increase the efficacy of a teeth whitening treatment by boosting the rate of diffusion, it is known that higher temperatures may result in pulpal damage to an individual's teeth and/or discomfort to the individual.

For example, Zach and Cohen (Oral. Surg. Oral Med. Oral. Pathol. : 19; pp 515-530 (1965)) reported that a temperature rise of 5.6 ⁰ C of the pulp caused 15% of the pulp to lose vitality, and an 11.2 ⁰ C rise caused 60% to lose vitality.

Thus, it is a non-exclusive object of the present invention to provide an apparatus for use in the whitening, e.g. cosmetic whitening, of teeth, which provides heat to increase the diffusion rate of a composition for teeth whitening located on or around a person's to-be-whitened tooth or teeth in a safe and measurable way, thus avoiding, or at least significantly reducing, the possibility of causing damage to the tooth or teeth and/or discomfort to the person.

According to a first aspect of the invention, there is provided an apparatus for use in teeth whitening, e.g. cosmetic teeth whitening, comprising a heat source comprising at least one electrically heatable panel.

According to another aspect of the invention, there is provided an apparatus for use in teeth whitening, e.g. cosmetic teeth whitening, the apparatus comprising a body housing a source of heat, support means for adjustably locating the body, in use, at a location in front of a person's mouth, the support means preferably being wearable on at least a part of the person's body, e.g. head, wherein the source of heat comprises a heatable panel.

The panel may be electrically heatable, e.g. resistively heatable.

Preferably, the panel has a major surface which faces, in use, the person's mouth.

Preferably, in use, said major surface of the panel may be exposed at least partially to the air. For instance, in use, said major surface of the panel may be substantially uncovered. The panel may comprise a metallic material.

Preferably, the panel may comprise polyimide, e.g. a polyimide film such as Kapton ^® .

The panel may be substantially flat.

Alternatively, the panel or a portion thereof, may be curved. For instance, the major surface, which faces, in use, the person's mouth may be curved to at least partially reflect the curvature of the person's teeth.

A plurality of panels may be provided.

The panel or panels may be of substantially uniform thickness. For instance, the panel or panels may be from 1 to 10 mm, preferably from 2 to 8 mm, more preferably from 3 to 7 mm thick,

The body may comprise a discrete article or capsule comprising the source of heat and a casing. Preferably, the casing may provide a removable jacket for the article or capsule.

Advantageously, the body or casing may be flexible.

The body or casing may be made primarily from a polymeric material such as silicone. The support means may be provided by a retractor or a part thereof.

The retractor may comprise one or more spigots on which the body or casing may be mountable. The or each spigot may be substantially straight or hook-shaped.

The retractor may be made from a plastics material.

Alternatively, the support means may comprise a band or strap for passing around the back of a wearer's head, e.g. over the wearer's ears.

Alternatively, the support means may comprise arms akin to those of a pair of spectacles.

According to another aspect of the invention, there is provided an apparatus for teeth whitening, e.g. cosmetic teeth whitening, the apparatus comprising a support means, locatable, at least partially, within a wearer's mouth, the support means comprising a pair of spigots extending therefrom, in use, outwardly from the wearer's mouth such that the longitudinal axes of the spigots are not parallel, the apparatus further comprising a body comprising a housing for a heat source, the body comprising a pair of passages therethrough, one or more sides of the passages being engagable with the spigots to hold the body in place. Preferably, the support means may be a retractor for at least partially holding open the person's lips. Preferably, the retractor may comprise a pair of lip-receiving portions.

Preferably, in use, the longitudinal axes of the spigots may be divergent from each other.

Preferably, in use, the longitudinal axes of the spigots may be located substantially within a single plane.

Preferably, the spigots may be longer than the passages. For example, the spigots may be between 10 and 50 mm, preferably 15 and 45 mm, most preferably 18 and 40 mm, long.

Preferably, the spigots may extend from diametrically opposed, in use, points on the support means.

Optionally, the spigots may comprise, at their distal ends, a deformable knob for helping to prevent the body and retractor from becoming separated when in use.

The spigots may have substantially uniform cross-sections along their length. Alternatively, the cross-sectional shape and dimensions of the spigots may vary continuously or discontinuously. The spigots may be rectangular in cross-section, although other shapes may also be suitable. The spigots may be integrally formed with the support means.

Alternatively, the spigots may be adhered or otherwise attached to the support means.

The spigots may be made from the same or a different material from the support means.

Preferably, the body may be shaped and dimensioned so as to substantially occlude the opening maintained by the support means, e.g. retractor.

Advantageously, the body may be resiliently flexible to at least some degree.

The body may be made primarily from a polymeric material, e.g. silicone.

The body may comprise a pair of wing portions. The wing portions may be connected to, and extend from, a central portion of the body, preferably on opposite sides of the central portion.

The passages may be rectangular in cross-section, although other shapes may also be suitable.

Preferably, the passages may pass through the wing portions. The retractor may be a self-spanning mouth retractor.

The retractor may be made from a plasties material.

The retractor may comprise a member which connects the two lip-receiving portions.

Preferably, the member may be resiliently flexible.

Preferably, the member may comprise a curved portion.

Preferably, the member may be substantially flat, i.e. wider than it is thick.

Other cross-sections may also be suitable, e.g. circles, semi-circles, ellipses, triangles, squares and other polygonal or curvilinear shapes.

In use, the member may be located for the most part outside the mouth, e.g. it may be substantially u-shaped and pass by, near or around the wearer's chin.

Alternatively, in use, the member may be located for the most part within the wearer's mouth.

According to another aspect of the invention, there is provided an apparatus for teeth whitening, e.g. cosmetic teeth whitening, comprising a support means, preferably a head-worn support means, and a body housing a source of heat, the body being connected to the support means and, in use, being adjustably locatable in front of a wearer's mouth, wherein the source of heat comprises a heatable panel.

The panel may be electrically heatable, e.g. resistively heatable.

Preferably, the panel has a major surface which faces, in use, the person's mouth.

Preferably, in use, said major surface of the panel may be exposed at least partially to the air. For instance, in use, said major surface of the panel may be substantially uncovered.

The panel may comprise a metallic material.

Preferably, the panel may comprise polyimide, e.g. a polyimide film such as Kapton ^® .

The panel may be substantially flat.

Alternatively, the panel or a portion thereof, may be curved. For instance, the major surface, which faces, in use, the person's mouth may be curved to at least partially reflect the curvature of the person's teeth. A plurality of panels may be provided.

The panel or panels may be of substantially uniform thickness. For instance, the panel or panels may be from 1 to 10 mm, preferably from 2 to 8 mm, more preferably from 3 to 7 mm thick.

The body may be attached to a first end of at least one elongate member, which, at its second end is attached to the support means.

Preferably, the at least one elongate member and the support means are pivotably connected.

Optionally, the body may be rotatable relative to the at least one elongate member.

The support means may comprise a head band for passing round the back of the wearer's head and over the wearer's ears.

At each end of the head band there may be a node point. The elongate member and the support means may be mutually pivotable about the node point.

The at least one elongate member may comprise a curved portion. Preferably, the apparatus comprises two elongate members. For example, a. first elongate member may extend from a first side of the body to a first node point and a second elongate member may extend from a second side of the body to a second node point. The second side of the body may be opposite the first.

Preferably, at least one of the support means and the at least one elongate member may be adjustable to accommodate different head sizes and/or to locate the body at varying distances from the wearer's mouth.

The body may be substantially elliptical in shape.

The body may be rigid or it may be flexible to some degree. The body may be made from a plastics material.

According to another aspect of the invention, there is provided an apparatus for teeth whitening, e.g. cosmetic teeth whitening, the apparatus comprising a support means, locatable, at least partially, within a wearer's mouth, the support means comprising a pair of spigots extending therefrom, each spigot having a longitudinal axis which extends, in use, outwardly from the wearer's mouth such that the longitudinal axes are not parallel.

Preferably, in use, the longitudinal axes of the spigots may be divergent from each other. Preferably, in use, the longitudinal axes of the spigots may lie substantially within a single plane.

The spigots may be between 10 and 50 mm, preferably 15 and 45 mm, most preferably 18 and 40 mm, long.

Preferably, the spigots may extend from diametrically opposed, in use, points on the support means.

Optionally, the spigots may comprise, at their distal ends, a deformable knob for helping to prevent the body and retractor from becoming separated when in use.

The spigots may have substantially uniform cross-sections along their length. Alternatively, the cross-sectional shape and dimensions of the spigots may vary continuously or discontinuously. The spigots may be rectangular in cross-section, although other shapes may also be suitable.

The spigots may be integrally formed with the support means.

Alternatively, the spigots may be adhered or otherwise attached to the support means.

The spigots may be made from the same or a different material from the support means. The support means may be made from a plastics material.

The support means may comprise a retractor, e.g. a self-spanning mouth retractor.

The retractor may comprise a pair of lip-receiving portions.

The retractor may comprise a member which connects the two lip-receiving portions.

Preferably, the member may be resiliently flexible.

Preferably, the member may comprise a curved portion.

Preferably, the member may be substantially flat, i.e. wider than it is thick.

Other cross-sections may also be suitable, e.g. circles, semi-circles, ellipses, triangles, squares and other polygonal or curvilinear shapes.

In use, the member may be located for the most part outside the mouth, e.g. it may be substantially u-shaped and pass by, near or around the wearer's chin.

Alternatively, in use, the member may be located for the most part within the wearer's mouth. Another aspect of the invention provides a support for securely and/or releasably locating a device adapted for engagement therewith at a position in front of a person's mouth, the support being locatable, in use, at least partially within the person's mouth, wherein the support comprises a pair of spigots, the spigots each having a longitudinal axis, which, in use, extends in a direction outward from the person's mouth, whereby the longitudinal axes are not parallel with each other.

Preferably, in use, the longitudinal axes of the spigots may be divergent from each other.

Preferably, in use, the longitudinal axes of the spigots may lie substantially within a single plane.

The spigots may be between 10 and 50 mm, preferably 15 and 45 mm, most preferably 18 and 40 mm, long.

Preferably, the spigots may extend from diametrically opposed, in use, points on the support.

Optionally, the spigots may comprise, at their distal ends, a deformable knob.

The spigots may have substantially uniform cross-sections along their length. Alternatively, the cross-sectional shape and dimensions of the spigots may vary continuously or discontinuously. The spigots may be rectangular in cross-section, although other shapes may also be suitable.

The spigots may be integrally formed with the support.

Alternatively, the spigots may be adhered or otherwise attached to the support.

The spigots may be made from the same or a different material from the support.

The support may be made from a plastics material.

The support may comprise a retractor, e.g. a self-spanning mouth retractor.

The retractor may comprise a pair of lip-receiving portions.

The retractor may comprise a member which connects the two lip-receiving portions.

Preferably, the member may be resiliently flexible.

Preferably, the member may comprise a curved portion.

Preferably, the member may be substantially flat, i.e. wider than it is thick. Other cross-sections may also be suitable, e.g. circles, semi-circles, ellipses, triangles, squares and other polygonal or curvilinear shapes.

In use, the member may be located for the most part outside the mouth, e.g. it may be substantially u-shaped and pass by, near or around the wearer's chin.

Alternatively, in use, the member may be located for the most part within the wearer's mouth.

In another aspect of the invention, there is provided an apparatus for teeth whitening, e.g. cosmetic teeth whitening, the apparatus comprising a body housing a source of heat and an air displacement means, wherein, in use, the body is locatable in front of a person's mouth and the air displacement means blows or otherwise urges air heated by the source of heat towards the person's mouth.

Preferably, the apparatus may further comprise support means for engagement with the body or a portion thereof, in use, at a location in front of the person's mouth, the support means preferably being wearable on at least a part of the person's body, e.g. head.

Preferably, the body may be releasably and/or securely engagable with the support means. Alternatively, the body may be connected to the support means.

Alternatively, the body may be fixed to a wall, floor or ceiling of a room. The body may be mounted on a static or mobile stand or trolley.

Alternatively, the body may be part of a hand-held unit.

Preferably, in use, the air displacement means may be located or locatable between the source of heat and the to-be-treated tooth or teeth.

The air displacement means may comprise a fan. The fan may be a small, electrically-powered fan. The fan may be a low power, high current fan.

The source of heat may be any suitable source of heat, e.g. an incandescent bulb or heat lamp.

Preferably, the source of heat may comprise a heatable panel.

The panel may be electrically heatable, e.g. resistively heatable.

Preferably, the panel has a major surface which faces, in use, the person's mouth. Preferably, in use, said major surface of the panel may be exposed at least partially to the air. For instance, in use, said major surface of the panel may be substantially uncovered.

The panel may comprise a metallic material.

Preferably, the panel may comprise polyimide, e.g. a polyimide film such as Kapton ^® .

The panel may be substantially flat.

Alternatively, the panel or a portion thereof, may be curved. For instance, the major surface, which faces, in use, the person's mouth may be curved to at least partially reflect the curvature of the person's teeth.

A plurality of panels may be provided.

The panel or panels may be of substantially uniform thickness. For instance, the panel or panels may be from 1 to 10 mm, preferably from 2 to 8 mm, more preferably from 3 to 7 mm thick.

Advantageously, the body may be flexible.

The body may be made primarily from a polymeric material such as silicone. The support means may be provided by a retractor or a part thereof.

The retractor may be made from a plastics material.

Alternatively, the support means may comprise a band or strap for passing around the back of a wearer's head, e.g. over the wearer's ears.

Alternatively, the support means may comprise arms akin to those of a pair of spectacles.

In an apparatus according to any of the preceding aspects of the invention, the or a body may comprise a cavity for housing the source of heat.

Preferably, the cavity may be substantially open, i.e. the internal volume of the cavity is not enclosed on all sides.

Preferably, in use, heated air passes from the source of heat towards the to-be-treated tooth or teeth through the "open" side of the cavity or portion thereof.

The cavity may be defined, at least partially, by a base and a wall, e.g. a perimeter wall.

For example, the cavity may be defined by a base and an inner surface of a continuous perimeter wall. The base may be curved or bowed. Alternatively, the base may be substantially flat.

The base may be solid. Alternatively, it may have one or more apertures therethrough, comprise a mesh or be in the form of a film.

The inner surface of the wall may extend substantially perpendicularly, at an acute or oblique angle, from the base.

The wall may be from 5 to 20 mm, preferably from 8 to 15 mm, high.

Preferably, the wall may be of substantially uniform height. Alternatively, its height may vary continuously or discontinuously.

The wall may be between from 4 to 20 mm, preferably from 5 to 15, most preferably from 6 to 10 mm, thick.

The wall may be of substantially uniform thickness. Alternatively, its thickness may vary continuously or discontinuously over its height or its length.

Alternatively, the source of heat may be mounted on a body or part thereof, e.g. such that it stands proud of said body or part thereof. Optionally, the apparatus may further comprise a mesh or screen having one or more apertures therethrough, the mesh or screen being locatable between the source of heat and the surface of the tooth or teeth being whitened.

Optionally, the mesh or screen having apertures therethrough may be located or locatable across at least a portion of the "open" side of the cavity.

The apertures may be from 1 to 10 mm, preferably from 1 to 5 mm, more preferably from 1 to 3 mm in diameter.

The body housing the source of heat may comprise means for holding, e.g. releasably holding, the mesh or screen in place, e.g. retaining beads.

One or more pairs of retaining beads may be provided, in which the location of one of the beads of each pair is diametrically opposed to that of the other bead.

Preferably, the retaining beads may be spaced at regular intervals along the wall, e.g. at regular intervals around the continuous perimeter wall.

A protective cap may also be provided for covering, at least partially, the source of heat and/or the cavity when the apparatus is not in use. The body housing the source of heat may comprise means for holding the protective cap in place, e.g. retaining beads.

The means for holding the mesh or screen in place when required in use may be the same as the means for holding the protective cap in place, when the apparatus is not in use.

For example, two or more retaining beads for retaining a screen having apertures therethrough, a mesh or a protective cap may protrude, e.g. into the cavity, from the inner surface of the wall.

The apparatus may comprise a plurality of sources of heat, e.g. an array of heatable panels.

The source or sources of heat may be variable.

For instance, where the source of heat comprises a panel heatable by electrical filaments, the current passing through the filaments may be variable to alter the output power of the source of heat.

Further, different areas of the source or sources of heat, e.g. heated panel(s), and/or different sources from within a plurality of sources of heat, may be operated at different powers. The source of heat and/or the or an air displacement means may be operably connected to a control unit.

In use, the control unit may be remote from the support means and/or the body housing the source of heat.

The control unit may be pre-programmable to follow an appropriate teeth whitening regime, which may have been selected following pre-treatment analysis of at least one of a number of factors including the porosity of the tooth or teeth to be treated and/or the person's age and/or the extent of discolouration.

Examples of suitable methods of selecting an appropriate teeth whitening regime are disclosed in two earlier patent applications belonging to the present applicant, GB 0701979.7 and GB 0514965.3, the entire disclosures of which are incorporated herein by reference.

The control unit may be operable to provide a plurality of pre-set power settings to cater for different types of teeth and treatment cycles.

The control unit may comprise an in-built timer for monitoring the course of a treatment session. For instance, the timer mechanism may countdown during a treatment session and may provide visual and/or audible signals or indications at pre-determined points within the session. For instance, the in-built time may be pre-set for a given period, e.g. five, 10, 15 or 20 minutes. Alternatively or additionally, the in-built timer may be programmable by a user for a given treatment.

Advantageously, the apparatus may comprise one or more temperature sensors.

The one or more temperature sensors may be locatable in close proximity to the tooth or teeth being whitened so as to monitor, in use, the temperature of the composition and/or the surface of the tooth.

Preferably, the one or more temperature sensors may be in communication with at least one of the control unit, the source of heat and the means for moving heated air.

The one or more temperature sensors may be adapted to send a signal, e.g. an electrical, infra red or radio signal, to the control unit.

Preferably, the one or more temperature sensors may be adapted to cause the transfer of heat from the source to the tooth or teeth undergoing whitening to be reduced or stopped, e.g. by sending a signal to the control unit, the source of heat and/or the means for moving heated air, if the temperature at the surface of the tooth or teeth reaches a pre-determined temperature, e.g. 50 ⁰ C or 45 ⁰ C. An apparatus according to any aspect of the invention may further comprise a component attachable to the body housing the source of heat and/or the support means for creating a substantially enclosed environment. The component may provide a passage, tube or tunnel, from the source of heat to close to the to-be-treated tooth or teeth.

A kit of parts for teeth whitening, e.g. cosmetic teeth whitening, may comprise :-

• an apparatus as described herein; and

• a composition for teeth whitening.

Preferably, the composition may comprise a bleaching agent, e.g. hydrogen peroxide or carbamide peroxide.

Preferably, the composition may be in the form of a solution or a gel.

Examples of preferred compositions for teeth whitening may be disclosed in the applicant's earlier British patent application GB 0709418.8, the entire disclosure of which is incorporated herein by reference.

In still another aspect of the invention there is provided a method of whitening, e.g. cosmetic whitening, of teeth, the method comprising the steps of:- • applying a composition, e.g. a solution or a gel, to a surface of a person's tooth or teeth;

• holding apart, at least partially, the person's lips, preferably with a retractor, to provide an opening onto the tooth or teeth to which the composition was applied;

• locating a heat source in front of the opening to heat the air between the source and the composition; and

• blowing or otherwise urging heated air towards the composition, e.g. by use of a fan.

The method may comprise a preliminary assessment in order to select an appropriate teeth whitening regime. The following factors may be taken into account: the age of the subject; the discolouration of the tooth or teeth to be treated; and the porosity of the tooth or teeth to be treated.

Examples of suitable methods of selecting an appropriate teeth whitening regime are disclosed in two earlier patent applications belonging to the present applicant, GB 0701979.7 and GB 0514965.3, the entire disclosures of which are incorporated herein by reference.

Prior to applying the composition it may be advantageous to remove any plaque or other unwanted matter or debris from the surface of the to-be- treated tooth or teeth. Advantageously, the method may comprise the step of at least partially dehydrating the to-be treated tooth or teeth before applying the composition.

The method may further comprise the preliminary step of selecting a teeth whitening regime following an assessment of the person's to-be-treated tooth or teeth.

The method may further comprise the step of measuring, periodically or continuously, the temperature of the composition during the teeth whitening regime.

The method may further comprise pre-programming a selected teeth whitening regime into a control unit operably connected to the heat source and/or fan or other air displacement means.

An apparatus comprising the heat source and/or fan may be attachable, in use, to support means.

The support means may be provided on the retractor or a part thereof.

The support means may be head-worn and/or locatable at least partially within the wearer's mouth. Alternatively, the apparatus comprising the heat source and/or fan may be separate from the support means, e.g. the retractor.

For instance, the apparatus comprising the heat source and/or fan may be mounted on a stand or in a separate handheld unit.

The distance between the heat source and the composition on the surface of a to-be-whitened tooth may be between 5 and 50 mm, preferably between 10 and 40 mm, most preferably between 15 and 35 mm.

The composition for teeth whitening may be applied to the tooth or teeth by any suitable method, e.g. by a syringe, by brushing or using a dental tray. ,

Examples of suitable dental trays are disclosed in the applicant's earlier patent applications, GB 0514966.1 and GB 0800739.5, the entire disclosures of which are incorporated herein by reference.

Advantageously, one or more barrier layers, e.g. compositions, sheets or films, or partial or complete dental trays, may be provided to shield any teeth which do not require whitening from the heated air.

Another aspect of the invention provides a heat source for use in teeth whitening, e.g. cosmetic teeth whitening, comprising at least one heatable panel, e.g. a resistively heatable panel. Preferably, the panel comprises polyimide, e.g. a polyimide film such as Kapton ^® .

A heatable panel provides means of applying a uniform and/or spatially and/or temporally consistent heat to the surface of the to-be-treated tooth or teeth. Advantageously, it may be more controllable and/or energy efficient and/or safer and/or more reliable and/or quieter and/or more cleanable than other means for the application of heat. For example, lamps are effectively point sources which can be broken.

Advantageously, a heatable panel provides energy efficient delivery of heat without generating large amounts of unwanted heat. Hence, for instance, no cooling means, e.g. a cooling fan, need be provided within the apparatus.

Another aspect of the invention comprises use of any of the devices described herein for teeth whitening, e.g. cosmetic teeth whitening.

In order that the invention may be more fully understood, it will now be described by way of non-limiting example only with reference to the following drawings in which :-

• Figures IA, IB and 1C show a housing for a source of thermal energy according to the invention; • Figures 2A and 2B show a retractor suitable for use with the housing of Figures IA, IB and 1C;

• Figures 3A, 3B and 3C show an alternative embodiment of an apparatus according to the invention;

• Figure 4 shows a housing for a source of thermal energy according to another preferred embodiment of the invention;

• Figure 5 shows the housing of Figure 4 from another perspective;

• Figure 6 shows a preferred embodiment of a body containing a heat source;

• Figure 7 shows a preferred embodiment of a casing suitable for use with the body shown in Figure 6;

• Figure 8 shows a retractor suitable for use with the items shown in Figures 4, 5, 6 and 7;

• Figure 9 shows a preferred embodiment of a control unit according to the present invention; and

• Figure 10 shows a preferred embodiment of a teeth whitening apparatus according to the invention. Referring now to Figures IA, IB and 1C there is shown a housing 1 for a source of thermal energy, i.e. heat.

The housing 1 comprises a central body portion 2 having a pair of wing portions 3 extending from opposite edges thereof.

In plan view, as will be appreciated from Figure IB, the body portion 2 has an outline shape defined by a pair of substantially straight parallel sides 2a joined together at their ends by a pair of curved portions 2b, e.g. semicircles.

The wing portions 3 extend from the curved portions 2b at opposite ends of the body portion 2.

In plan, the outline shape of the housing 1 has two perpendicular lines of symmetry, one which bisects the substantially straight parallel sides 2a and a second which bisects the curved portions 2b.

The housing 1 has a wingspan, i.e. the distance from the tip of one wing portion 3 to the other, of 104 mm. Preferably, this distance may be from 90 to 130 mm, more preferably from 95 to 120 mm, most preferably from 100 to 110 mm.

In a side elevation, as will be appreciated from Figure IA, the body portion 2 is bowed with the top 2c and bottom 2d edges having substantially the same radii of curvature. In use, the top edge 2c will face towards a wearer's mouth.

With reference to Figures IA and IB, further features of the housing 1 will now be described. The body portion 2 comprises a base 6 and a continuous upstanding perimeter wall 4, the base 6 and wall 4 defining a cavity 8.

A pair of flat retaining beads 5 protrude from the wall 4 into the cavity 8. The retaining beads 5 are each located across the wall 4 from one of the wing portions 3.

The wing portions 3 extend from the body portion 2 and each comprise a tapered portion 3a and a non-tapered portion 3b, the tapered portion 3a being located between the body portion 2 and the non-tapered portion 3b of the wing portion 3 to provide a smooth, contiguous connection of the wing portion 3 to the body portion 2.

The non-tapered portion 3b is thicker from top 3c to bottom 3d than the tapered portion 3a.

Each wing portion 3 comprises a passage 7 therethrough.

Each of the passages 7 is rectangular in cross-section and passes from the top 3c to the bottom 3d of each wing portion 3. The line of symmetry bisecting, in plan view, the semi-circular end sections, runs parallel to the longer sides and bisects the shorter sides of the rectangular cross-section of the apertures 7.

In the embodiment shown in Figures IA, IB and 1C, the cross-sectional dimensions of each of the passages 7 are around 8 mm and 2 mm.

As will be appreciated, the cross-sectional dimensions of the passage may vary, in particular to reflect the dimensions of any spigots or protrusions which the passage may be adapted to receive, in use, and the length of the passages.

For example, the passages may be from about 5 to 15 mm, preferably from about 7 to 12 mm, in length.

Figures 2A and 2B show a retractor 21 suitable for use with the housing 1.

The retractor 21 is made from a plastics material and comprises a pair of arcuate channel portions 22. The arcuate channel portions 22 provide a channel which is substantially curved in cross-section and which extends around, and is open to, the outside of an arch. In use, portions of a wearer's lips are received within the channels so as to provide an opening to revea) a surface of the to-be-treated tooth or teeth. The two arcuate channel portions 22 are joined together by a member comprising two curved resiliently flexible portions 25 either side of a central relatively rigid portion 24.

The member extends from a point in the vicinity of the "top" of the arch of one of the channel portions 22 to an equivalent point on the other channel portion 22.

The resiliently flexible portions 25 are substantially flat, i.e. they are wider than they are thick.

At their ends distal from the channel portions 22 the resiliently flexible portions 25 are connected by a central, lozenge-shaped, relatively rigid portion 24.

The resiliently flexible portions 25 each comprise a curved portion. As shown in Figure 2A, the arcuate channel portions 22 face downwards substantially in parallel and the curved portions 25 extend upwards from the arcuate channel portions 22 and then downwards towards opposite sides of the central portion 24.

The retractor 21 further comprises spigots 23. A spigot 23 extends substantially perpendicularly outwardly from a point in the vicinity of the "top" of the arch of each of the channel portions 22. The spigots are substantially uniform in cross-section along their length. The spigots are substantially rectangular in cross-section.

In the embodiment shown in Figures 2A and 2B, the spigots are around 15 mm long and 8 mm wide. As will be appreciated, the dimensions of the spigots may be altered, e.g. to reflect the size and shape of the passages.

It will be appreciated that Figures 2A and 2B show the retractor 21 when it is not in use.

In use, i.e. holding apart at least partially a portion of a wearer's lips to provide an opening on to the to-be-treated tooth or teeth, the retractor 21 is manipulated, as allowed by the resilient portions 25, such that the two channel portions 22 turn inwards towards each other. The channel portions 22 each receive a portion of a person's lips, typically part of the upper lip and part of the lower lip. The member is located substantially within the wearer's mouth.

Hence, the spigots 23 extend in a direction outward from the person's mouth.

In an alternative embodiment, a substantially similar retractor may be provided, except that the member connecting the arcuate channel portions for receiving a person's lips is substantially u-shaped and extends from a lower portion of each of the arcuate channel members such that, in use, it is located outside the wearer's mouth and passes close to the wearer's chin.

As will be appreciated these designs of retractor have certain advantages over a fixed, rigid "flat" retractor which does not have the in-built flexibility of the retractors according to the present invention.

First, such fixed retractors tend to keep a wearer's rnouth open in a stretched flat plane. This may be relatively uncomfortable for the wearer.

With the present design, the wearer's lips and mouth can adopt a more comfortable, more natural curved configuration when the retractor is in place. Consequently, for instance, longer whitening procedures may be performed without causing undue discomfort for the wearer.

As will be appreciated, the fact that in such a natural curved configuration, the two arcuate channel portions are not turned inwards to the extent that they face each other and are located in the same plane, means that the spigots 23 do not protrude in parallel to one another. In this configuration, the longitudinal axes of the spigots are located substantially in a single plane and are divergent from each other.

In use, the housing 1 is mounted on the retractor 21 by the spigots 23 being received in the passages 7. The spigots 23 will be longer than the passages 7, such that they can pass entirely through the passages and, further, such that the housing can be located at varying distances from the wearer's mouth, i.e. at varying points along the spigots.

As the spigots are not parallel, but are divergent, they can be thought of as providing a geometric wedge.

Accordingly, each spigot will pass through one of the passages at an angle, such that it bears on one side of the passage on entry thereto and another side, e.g. an opposite side, of the passage on exit therefrom.

Thus, the housing 1 will be maintained at a desired distance from the to-be- treated tooth or teeth.

When one or both parts, i.e. the spigots and the passages are made from a polymeric, preferably rubber-like material, such as silicone, there will also be a "gripping" action as a result of friction between the surfaces.

Further, when the body for housing the heat source is made primarily from a flexible, preferably polymeric material such as silicone, the versatility of the apparatus is increased.

Moreover, the wearer is able to move his head without the housing 1 moving significantly relative to the retractor. It will readily be appreciated that the same effect may be achieved by providing a traditional flat-style retractor with a pair of divergent spigots protruding therefrom.

Advantageously, the "geometric wedge" means that hooks or other more complex-shaped protrusions may not be required to secure the body to the retractor, which increases ease of manufacture.

Further, as will be appreciated this arrangement offers increased versatility. For example, it may be possible to locate the body at different distances from the to-be-treated tooth or teeth without having to change the apparatus. In addition, interoperability of the bodies and retractors may be increased, e.g. the same body may be used with a number of different retractors and vice versa.

Further features of the apparatus will now be described with reference to Figure IB.

The cavity 6 is provided to house a source of heat along with various other associated components.

In one embodiment the source of heat comprises a panel having a metallic major surface. A number of electrical wires pass through the panel to resistively heat it. In use, the metallic major surface faces the wearer's teeth. Heat is transferred from the metallic major surface to the air between it and the wearer's teeth.

In a preferred embodiment, the major surface of the panel, which, in use, faces the wearer's teeth, comprises a polyimide film.

The transfer of heat to the composition is mainly due to convection of heated air, although some radiation will also occur. Accordingly, the heating may be relatively gentle.

In use, the warm air heats a composition for teeth whitening, e.g. a gel located on or around a person's tooth or teeth, in order to speed up the whitening process.

In preferred embodiments, the housing may also contain a small electric fan (not shown), e.g. a low power, high current fan.

The fan serves to direct a stream of warm air from the source of heat towards the wearer's teeth.

The amount of heat transferred to the surface of the tooth or teeth is controllable, e.g. by varying the temperature of the source of heat and/or the speed of the fan.

Further, a screen (not shown), having one or more apertures therethrough may be placed between the heat source and the tooth or teeth to be treated to provide an element of directional control, e.g. so as to preferentially heat certain areas of the tooth or teeth.

The screen (not shown) may be retained by the retaining beads 5.

The heating regime may be pre-programmed pursuant to a selection of an appropriate teeth whitening regime.

One or more temperature sensors may also be provided, locatable in close proximity to the tooth or teeth being whitened. The temperature sensors provide information about the temperature of the gel on the tooth or teeth being whitened, which can be communicated to the controls for the source of heat and/or the fan. The source of heat and/or the fan may automatically react to information from the one or more temperature sensors. Alternatively, the reaction to the information from the one or more temperature sensors may be controlled manually.

Preferably, the apparatus may have an automatic shut-off, whereby the source of radiant heat and/or the fan are automatically switched off, if the temperature of the gel gets close to or reaches a temperature that could damage the wearer's tooth or teeth, e.g. 50 ⁰ C or 45 ⁰ C.

A control panel (not shown) for the apparatus may be provided integrally of the apparatus or a part thereof, e.g. the housing. Alternatively, it may be provided remotely from the wearer, e.g. as part of a separate, preferably hand-held unit or on a computer.

Such a remotely-located control panel may communicate with the apparatus through a wire or wirelessly, e.g. using infrared or radio waves.

Preferably, the control panel may be "intelligent". For instance, once an appropriate teeth whitening regime has been selected and inputted into the control panel, e.g. by a qualified dentist, a program may guide the user, e.g. a relatively unskilled dental assistant or home user of the apparatus, through the process in a step-by-step manner, e.g. by on-screen or other visual cues or audio prompts.

A protective cap (not shown) may be provided to protect the heat source and other components within the housing. For example, the cap may be held in place by the retaining beads 5 when the apparatus is not in use.

Referring now to Figures 3A, 3B and 3C, there is shown an alternative embodiment of an apparatus according to the invention.

Figure 3A shows the apparatus 30, positioned as it would be in use, e.g. during a teeth whitening regime. Figure 3B shows the apparatus 30 in a position, which may be adopted when the apparatus is not in use, but the apparatus is still being worn by the wearer.

Figure 3C shows the apparatus 30 in isolation along with a separate control module 35.

Referring to Figure 3C, the apparatus 30 comprises a band 32 for passing over both of a person's ears and around the back of his head. The band 32 has, connected to both of its ends, a node portion 34.

Also attached to each node portion is an end of an elongate member 33. The elongate members 33 and band 32 are pivotably movable relative to each other about the node portions 34.

Referring to Figure 3C, the apparatus comprises a pair of elongate members, one attached to the node portion at a first end of the band, the other being attached to the node portion at the second end of the band.

The elongate members 33 each extend from one of the node portions 34 and each comprise in series a first substantially straight portion and a curved portion. The curved portions are such that the ends of the elongate members 33 distal from the node portions 34 are closer together than the node portions 34 and face each other.

Each distal end of each of the elongate members 33 is connected to a body 31 which houses a source of heat.

Referring to Figure 3A, it will be appreciated that, in use, the body 31 is locatable in front of a wearer's mouth.

Figure 3B demonstrates that the body 31 may be moved away from in front of the wearer's mouth due to the pivotable movement about the node points, without having to remove the apparatus from the wearer's head.

This is clearly advantageous for both dental practitioners and wearers alike. For example, it saves time in the surgery by allowing the dentist access to the wearer's mouth, e.g. to apply a composition for teeth whitening to one or more of the wearer's teeth.

It also offers similar advantages to the wearer using the apparatus at home.

Additionally, or alternatively, the body 31 may be rotatable about an axis between the elongate members 33 such that the source of heat may be directed away from the wearer's mouth. Referring again to Figure 3C, the body 31 is elliptical in shape and is sized and dimensioned such that when it is in front of the wearer's mouth, it occludes substantially all of the wearer's mouth even when the mouth is held open, e.g. using a retractor.

The body 31 has much of the same functionality as the housing shown in Figures IA and IB and described above.

Indeed, the body 31 contains many of the same or similar components as the housing 1.

Accordingly, the body 31 provides a cavity in which is located a source of heat along with various other associated components.

In one embodiment the source of heat comprises a panel, e.g. a resistively heatable panel, having a metallic major surface. A number of electrical wires pass through the panel to heat it up. In use, the metallic major surface faces the wearer's teeth. Heat is transferred from the metallic major surface to the air between it and the wearer's teeth.

In a preferred embodiment, the panel, e.g. a resistively heatable panel, comprises a polyimide film, preferably over or adjacent at least a substantial portion of the major surface, which, in use, faces the wearer's teeth. The transfer of heat to the composition is mainly due to convection of heated air, although some radiation will also occur. Accordingly, the heating may be relatively gentle.

In use, the warm air heats a composition for teeth whitening, e.g. a gel located on or around a person's tooth or teeth, in order to speed up the whitening process.

In addition to a source of heat, in preferred embodiments the housing also contains air displacement means such as a fan (not shown), e.g. a small electric fan, preferably a low power, high current fan.

The air displacement means serves to direct a stream of warm air from the housing towards the wearer's teeth.

Advantageously, the amount of heat transferred to the surface of the tooth or teeth may be controllable, e.g. by varying the temperature of the source of heat and/or the speed of the fan.

Further, a screen (not shown), having one or more apertures therethrough may be placed between the heat source and the tooth or teeth to be treated to provide an element of directional control, e.g. so as to preferentially heat certain areas of the tooth or teeth. The screen (not shown) may be attachable to the body 31 or one of the elongate members 33.

A protective cap (not shown) may be provided to protect the heat source and other components within the housing. For example, the cap may be attachable to the body or a portion thereof.

One or more temperature sensors may also be provided, locatable in close proximity to the tooth or teeth being whitened. The temperatures sensors provide information about the temperature of the gel on the tooth or teeth being whitened, which can be communicated to the controls for the source of heat and/or the fan. The source of heat and/or the fan may automatically react to information from the one or more temperature sensors. Alternatively, the reaction to the information from the one or more temperature sensors may be controlled manually.

Preferably, the apparatus may have an automatic shut-off, whereby the source of radiant heat and/or the fan are automatically switched off, if the temperature of the gel gets close to or reaches a temperature that could damage the wearer's tooth or teeth, e.g. 50 ⁰ C or 45 ⁰ C.

Also shown in Figure 3C is a control unit 35 for controlling the source of heat and/or the air displacement means, such as a fan. The control unit 35 may be operably connected to the apparatus 30 either by wire or remotely, e.g. wirelessly by radio waves or infra red.

For instance, a wire from the control unit 35 may be connected to a point on the body 31 or to a point in the vicinity of one of the node portions 34.

Alternatively, one or more antennae for receiving signals from the control unit 35 may be located at points on or within the apparatus 30.

Preferably, the apparatus 30 may also comprise a transmitter or signal generator to enable two-way communication between the apparatus 30 and a separate control unit 35.

Alternatively, there may be no separate control unit, the required controls, e.g. on/off switch, a dial to alter the output power of the radiant heat source being located on one or more parts of the apparatus.

The apparatus 30 and/or the control unit 35 may comprise indicator lights, such as one or more LEDs for example, to indicate that the heat source is turned on.

Preferably, the control panel may be "intelligent". For instance, once an appropriate teeth whitening regime has been selected and inputted into the control panel, e.g. by a qualified dentist, a program may guide the user, e.g. a relatively unskilled dental assistant or home user of the apparatus, through the process in a step-by-step manner, e.g. by on-screen or other visual cues or audio prompts.

As will be appreciated, where the body housing the source of heat is connected to or engagable with a head-worn support means, advantageously, the person having his or her teeth whitened may be able to move his or her head relatively freely without adversely affecting the treatment.

Some examples of methods according to the invention will now be described.

The exemplary methods may be carried out using one or more of the apparatus described herein.

In an exemplary embodiment of a method according to the invention, an initial assessment of a person's to-be-treated tooth or teeth is carried out in order to select the most appropriate teeth whitening regime.

The initial assessment may be carried out in accordance with the methods and techniques disclosed in the applicant's earlier patent applications GB 0514965.3 and GB 0701979.7, the entire disclosures of which are incorporated herein by reference. Following any preparatory assessments and/or treatment, e.g. to remove plaque or other debris from the to-be-treated tooth or teeth, a retractor 21 as shown in Figures 2A and 2B is placed in the patient's mouth.

The arcuate channel portions 22 receive portions of the patient's lips and the retractor serves to hold open the patient's lips to provide an opening onto the patient's teeth.

A teeth whitening gel is then applied to the tooth or teeth or portions thereof which are to be whitened.

The teeth whitening gel is sufficiently viscous and tacky such that it stays in place at the desired location.

Care must be taken to ensure that the gel does not come into contact with sensitive areas, e.g. around the gingival margin and the soft tissue of the gums, as these may be irritated by the gel.

If any gel does come into contact with such areas, it should be removed, e.g. wiped away, immediately.

With the gel in place and the retractor providing 22 an opening, the body housing the source of heat is then located in position. The housing 1, as shown in Figures IA, IB and 1C is positioned by passing the spigots 23 on the retractor 21 through the passages 7 provided in the wing portions 3 of the housing 1.

The divergence of the longitudinal axes of the spigots 23 provides a geometric wedge to keep the housing 1 in position. Typically, the source of heat will be facing the tooth or teeth to which the gel has been applied and will be located from 10 mm to 30 mm therefrom.

The source of heat is then turned on, heating the air close to it.

The fan within the housing 1 is also turned on in order to increase the flow of warm air from the source of heat towards the gel.

After a certain time period, say from 5 to 20 minutes, or once a certain temperature is reached, the fan and the source of heat are turned off.

The housing 1 will then be removed from the retractor 21.

The retractor 21 will also be removed from the patient's mouth.

The process may be repeated as necessary in order to achieve the desired whitening of the teeth. A method using the apparatus shown in Figures 3A, 3B and 3C will now be described.

In this method, following any initial assessments and/or preparatory treatment, a retractor is placed in the patient's mouth to provide an opening on to the patient's tooth.

A teeth whitening gel is then applied to the tooth or teeth or portions thereof, which are to be whitened.

Any gel which is inadvertently applied where it shouldn't be, should be removed, e.g. wiped away, immediately.

The apparatus 30 is then located onto the patient's head, initially in the position shown in Figure 3B.

The body 31 in which the source of heat is located is then brought into position in front of the patient's mouth, by virtue of pivotable relative motion around the node portions 34 of the elongate members 33 and the band 32.

The source of heat and the fan within the body 31 are operated using the control unit 35 to provide a stream of warm air on to the tooth or teeth where the gel is located. When no more heating is required, e.g. because a certain time has elapsed or a certain temperature has been reached, control unit 35 is operated to turn off the source of heat and the fan.

The apparatus 30 and retractor will then be removed from the patient.

Alternatively, e.g. if another warming cycle is to be carried out shortly afterwards, the apparatus 30 may be returned to the configuration shown in Figure 3B without being removed from the patient's head.

The process may be repeated as necessary in order to achieve the desired whitening of the teeth.

Figures 4 and 5 show another preferred embodiment of a housing 4 for a source of thermal energy, e.g. a heatable panel.

The housing 4 comprises two principal components: a casing 41 and a capsule 42. The casing 41 provides a removable jacket for the capsule 42.

The casing 41, which is also shown in isolation in Figure 7, is made from silicone and is generally oval-shaped. Materials other than silicone may be used. The casing 41 has a front 41a and a back 41b connected by a side wall 41c. In use, the front 41a of the casing 41 faces away from a wearer's mouth. The front 41a and the back 41b both have central substantially oval-shaped apertures 410a, 410b therethrough. The aperture 410b through the back 41b of the casing 41 may be larger than the aperture 410a through the front 41a of the casing 41. Alternatively, the apertures 410a, 410b may be similarly or substantially identically sized and dimensioned. The aperture 410a through the front 41a of the casing 41 is optional.

As can be seen in Figure 4, the back 41b of the casing 41 is provided with a pair of slots 43, the two slots 43 being positioned diametrically opposite each other either side of the minor axis of the oval-shaped casing 41.

Each slot 43 comprises a channel set into the casing 41, having a substantially flat base 431 and a pair of parallel sides 432 and extending from the top 430a to the bottom 430b of the casing 41. At around the midpoint of each channel 43, a bridge 433 thereover is provided by a section of the back 41b of the casing 41. Accordingly, the central portion of each channel 43 comprises a tunnel-like passage.

As shown in Figure 7, an aperture 44 is provided in the side wall of the casing 41. The aperture 44 is located at or towards the bottom of the casing 41. The aperture 44 allows a cable or the like to be connected to a device held within the casing 41.

Figures 4 and 5 show the capsule 42 in place within the casing 41. The capsule 42 is shown in isolation in Figure 6. The capsule 42 contains or is a source of thermal energy (not shown) in the form of a resistively heatable panel, typically comprising a polyimide film or layer, and feedback control circuitry, which may be connected to temperature sensing means.

The capsule 42 comprises a substantially oval-shaped body having a front 42a and a back 42b. The front 42a has a central region 46 bearing a logo, in this case a registered trade mark used by the applicant, which lights up when the apparatus 40 is operating. Additionally or alternatively, other indicia may be provided.

A major portion of the back 42b is made up of a surface of the heatable panel. Optionally, a mesh or screen may be fitted to or next to the back 42b of the capsule, which mesh or screen will be located, in use, between the heatable panel and a wearer's mouth.

Referring to Figures 4 and 5, it will be appreciated that the central apertures through the front 41a and the back 41b of the casing permit, in use, the sometime-illuminated central region 46 to be seen and heat transfer towards the to-be-treated tooth or teeth respectively.

The capsule 42 also comprises an inlet socket 45 for an electrical cable or the like. The socket 45 is positioned such that it is in registry with the aperture 44 when the capsule 42 is held within the casing 41. Figure 8 shows a retractor 50 suitable for use with the housing 40, more particularly with the casing 41.

The retractor 50 is of the same general type as the retractor 21 shown in Figures 2A and 2B. Hence, it comprises a pair of opposed C-shaped lip receiving portions 51, joined together by a member comprising two curved resiliency flexible portions 52 either side of a central relatively rigid lozenge-shaped portion 53. Conveniently, the member, in particular, the central portion 53, serves, in use, to prevent the wearer's tongue from moving into the anterior portion of the oral cavity, i.e. into the vicinity of the tooth or teeth which are being treated.

The retractor 50 further comprises a pair of hook-shaped spigots 54. A hook-shaped spigot 54 extends substantially perpendicularly outwardly from a point in the vicinity of the "top" of the arch of each of the lip receiving portions 51.

Each hook-shaped spigot 54 has a first portion and a second portion inclined relative to the first portion, the first portion being between the lip receiving portion 51 from which the spigot 54 extends and the second portion. As shown in Figure 8, the second portion may be substantially perpendicular to the first portion. The retractor 50 also comprises four support lugs 55, two of which are located at spaced-apart locations on the non-lip receiving side and towards the front of each of the lip receiving portions 51.

When the retractor 50 is in place in a user's mouth, the housing 40 is brought into position by engaging the hook-shaped spigots 54 with the slots 43. The support lugs 55 abut the housing 40, thereby helping to keep the housing 40 in the correct position relative to the user's to-be-treated tooth or teeth.

Figure 9 shows a control unit or console 60 suitable for use with the capsule 42. The console 60 is operable to control the source of heat within the capsule 42.

The console 60 contains control circuitry (not shown) and is powered by a rechargeable battery (not shown), e.g. a 3.7V lithium-polymer battery, which can be charged from the mains electricity supply via a cable inlet 62. A cable outlet 63 is provided for connecting the console 60 to socket 45 of the capsule 42. Inlet 62 and outlet 63 are provided in a side wall of the console 60.

A front wall of the console 60 is provided with a number of buttons and indicators: an activity indicator 61, which lights up when the console 60 is turned on; one or more, e.g. five, timing LEDS 64 arranged in a line, which may be illuminated at the start of a pre-selected treatment regime and go out one by one at regular intervals as the treatment progresses; a master on/off switch 65 for the console; a switch 66 for selecting a high power setting; a switch 67 for starting a treatment regime; and a switch 68 for selecting a low power setting. Variable power setting controls may be provided.

Figure 10 shows an exemplary set-up of apparatus according to the invention, in which the console 60 is connected to the capsule 42 by cable 69, the capsule 42 being held within the casing 41 thereby forming a two- part housing 40 for the source of heat. The casing 41 is then attached to the retractor 50 by engagement of the hook-shaped spigots 54 (Figure 8) with the slots 43 (Figure 4).

The apparatus according to the invention may be quickly and easily cleaned, e.g. between uses. For example, the console 60 and the capsule 42 may simply be wiped clean using a damp cloth and can be disinfected, preferably using non-alcohol based disinfectants. The retractor 50 and casing 41 are autoclavable.

Conveniently, apparatus according to the invention may be supplied, preferably for use in professional teeth whitening practices, in the form of kits, which may be relatively easy to use, even for less-experienced practitioners or technicians. For instance, a kit may contain the articles shown in Figure 10. In the preferred embodiment, the console contains an in-built countdown timer of 10 minutes (+/-2%) and has a choice of two modes - high power and low power - to cater for different types of teeth.

All five of the timing LEDs 64 illuminate when a 10-minute treatment cycle is started. Every two minutes, one of the LEDs 64 will go off, thereby giving the operator a visual indication as to the timing of the treatment cycle.

One minute before the session ends, the console will emit a first audible signal, a second audio signal being emitted at the end of the 10 minutes.

It has been found that the temperature at the surface of a to-be-treated incisor when a retractor is in place is in the region of 31 ⁰ C. The low power setting is adapted to increase the temperature of the tooth surface to around 37 ⁰ C, say from 35 ⁰ C to 39 ⁰ C. The high power setting is adapted to increase the temperature of the tooth setting to around 42 ⁰ C, say from 40 ^O C to 44 ⁰ C.

Hence, it will be appreciated that a wide range of treatment regimes may be carried out by selecting the appropriate power mode and the number of times the treatment cycles. An appropriately trained operator, typically a skilled dentist should be able to specify an effective treatment regime taking into account the extent of discolouration and the structure of the to-be- treated tooth or teeth. For example, it has been found that, using a system as shown in Figure 10, at low power setting, a treatment period of 40 minutes, i.e. four 10-minute cycles, gives excellent results on medium density teeth.

The applicant has found that the use of a heatable panel source to accelerate the rate of diffusion can reduce the treatment time by up to 40%.

As will be appreciated, better results may be achieved if any plaque or other readily removable matter is removed from the teeth before carrying out the cosmetic method or methods of the invention.

While the invention has been described having regard to a small number of preferred embodiments, it will be appreciated that a number of modifications could be made without departing from the scope of the invention.

For instance, the body housing the source of heat may be of any suitable shape. It is preferred that the body covers at least a major portion of the mouth opening that is maintained by a retractor, in use.

For example, the person skilled in the art will appreciate that the steps of the various methods disclosed herein may be carried out in different orders or certain steps may be omitted as appropriate. Also, the person skilled in the art will readily appreciate that the apparatuses and parts thereof disclosed herein may be combined in many other ways without departing from the scope of the invention.

> Further, while the invention has been described in respect of the whitening, preferably cosmetic whitening, of the teeth of humans, it is envisaged that it may also have utility in the dental treatment of animals, especially the cosmetic dental treatment of domestic animals and pets.

i In this specification, the terms panel and heatable panel and the like refer to bodies adapted not to emit any light. Hence, it will be appreciated that these terms do not encompass any forms of lamp, bulb, LED, or collections or arrays thereof.