Abstract:
This invention relates to a curing light device capable of curing dental composites with a means to blow air. The blown air is directed from the curing light onto the tooth that is exposed to the curing light. The blown air has the effect of cooling the surface of the tooth to maintain patient comfort and efficient curing of dental composites

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to any device suitable for photocuring, or photobleaching in general. Particularly, it relates a photocuring, or photobleaching device suitable for curing dental composites or acting on a whitening gel, respectively, having a fan to blow air to cool the tooth surface. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the field of dentistry, tooth restoration and repaired, dental cavities are often filled and/or sealed with compounds that are photosensitive, either to visible and/or ultraviolet light. These compounds, commonly known as light-curable compounds, are placed within dental cavity preparations or onto dental surfaces and are cured when exposed to light from a dental curing light device. 
         [0003]    Heat generated on the tooth surface by any curing lights during operation can be problematic. The radiometric power of light needed for the fastest cure times is enough to cause oral tissue to heat up. The higher the intensity of light, the more heat generated. Additionally, composites can also exotherm as they cure. In deep cavities where there is the need for the longest curing times and the most power, extensive dentin has been removed and decay removal can approach the pulpal chamber. Therefore, there is concern over damage to pulp. The industry standard used for pulpal temperature increase is less than 5° C. This same kind of problem is also encountered in photobleaching lights. Therefore, any efficient way of removing heat from the tooth surface is desirable for both curing and photobleaching lights. 
         [0004]    Various ways have been attempted to manage the heat generated on the teeth from high intensity curing lights. Such methods includes limiting the exposure time and/or pause between exposure to allow the oral tissue to cool. 
         [0005]    Another method is the operator attempting to prevent the high intensity curing light from directly contacting unprotected gingival, oral mucuous membrane or skin. However, this is often difficult as the user&#39;s vision of the cured area is often obstructed. The user is also unable to look at the curing area while the curing light is activated as the light is too bright to look at with the naked eye. 
         [0006]    Another way to manage heat is to place wet cotton rolls on the tooth crown opposite the side of exposure to lessen temperature rise. 
         [0007]    The curing light can also be used at low power levels to reduce heat generation. While low power levels reduce heat, curing times may be increased and curing perforamce may be reduced due to the lower power levels. 
         [0008]    All of the approaches listed above have drawbacks associated with them. Such drawbacks includes extending the time it takes to complete the procedure, increase patient discomfort, increase the risk of patient injury and decreasing the efficacy of the composite cure. 
         [0009]    Therefore, there remains a need for a device that will effectively manage or remove heat from the tooth surface while maintaining high intensity power levels to ensure efficient curing or photobleaching of compounds. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention relates to a portable dental curing light suitable for curing light curable dental composite materials with a means for cooling the surface of the teeth. The curing light device may be “pen” style, “gun” style or convertible between “pen” and “gun” style. The curing light will include a housing having a handle portion towards its distal end, a front portion towards its proximal end, and a light module inside the front portion. The light module houses one or more light sources, which may include, for example, light emitting diodes (LEDs). The LEDs may emit wavelengths having a single or multiple peaks, one or both is in the range of most photosensitizers used in the curable composites such as dental composites. Also located in the device is a fan or other air circulation device which blows air out through the tip of the device, thereby cooling the tooth surface. 
         [0011]    The housing of the curing light may be substantially cylindrical, with a slight taper from the distal end to the proximal end, for example. The proximal end of the housing may be straight or may be angled. In addition, the housing may have a vent leading to an air channel so that air is pulled into the housing by the fan. As air passes through the fan, it passes through another air channel that leads to the exhaust vent, which is proximate to the tip. Air exists the tip and contacts the tooth surface and has a cooling effect on the tooth surface. 
         [0012]    The housing of the curing light may have a substantially hollow interior with at least one heat sink located therein, as discussed above. The heat sink may take on various shapes, and/or may include at least one phase change material, some of which may facilitate the arrangement of the light sources for a longer runtime device. 
         [0013]    The curing light includes a light module housing having a distal end and a proximal end. The light module housing may have a substantially cylindrical shape defining a substantially hollow interior, a handle, a head and neck portion, with at least one elongated heat sink located therein. The head portion may be angled with respect to the rest of the housing. At least one mounting surface is located towards the proximal end of the elongated heat sink. An air channel with runs through the light module housing with an exit vent located proximate the head portion. 
         [0014]    Light sources may include semiconductor light emitting devices, light-emitting chips such as an LED, a solid state LED, an LED array, edge emitting chips, a fiber optic bundle and so on. 
         [0015]    A thermistor may also be present to provide temperature control of the light source wherein one end of the thermistor is attached to a control circuit board, and the other end may be inserted into the heat sink. When the temperature of the LEDs is higher than certain set point of the thermistor, a signal to shut off the curing light may be transmitted to the control circuit board to cool down the curing light for a period of time, which may not only prevent the curing light device from overheating, but may also protect patients from discomfort. 
         [0016]    In one embodiment, the mounting surface may include an optical element, which may be concave or convex, and for directing and/or focusing light from a light source to a desired location, such as the mouth of the patient. In one aspect, the optical element may include lenses that are individually aligned with the corresponding LEDs to direct and/or focus light therefrom, to generate a high intensity round beam with less heat dissipation. 
         [0017]    In one aspect, a heat sink made of a solid block of thermally conductive material, such as metal, may be used to efficiently remove or divert heat from a light source or sources. In another aspect, the heat sink may be configured to have fins, corrugations, or other geometric features adapted to provide a larger surface area for convective cooling of the heat sink. In a further aspect, the heat sink may include a substantially hollow interior which may be partially filled with at least one suitable phase change material including organic materials, inorganic materials and combination thereof, as noted before. These materials can undergo substantially reversible phase changes, and can typically go through a large, if not an infinite number of cycles without losing their effectiveness. A capping device may be used to cap off the heat sink after filling with the phase change material. The capping device may be compression fit. Any fitting may be sufficient to withstand any expansion and/or contraction force during cycling of the phase change material. In still another aspect, the heat sink may be constructed by hollowing out a thermally conductive material, such as metal, and at least partially filling the space with at least one phase change material prior to capping it to secure the phase change material inside, such that at least one phase change material is substantially contained or surrounded by a thermally conductive material such as a metal normally used in the construction if a conventional metal heat sink. 
         [0018]    The light module housing may have a substantially cylindrical shape defining a substantially hollow interior, a handle, a head and neck portion, which may be angled with respect to the rest of the housing. At least one mounting surface is located towards the proximal end of the elongated heat sink. The light source may be located at the distal end of the heat sink. Within the housing is a fan. The fan is connected to an intake channel which draws air from the exterior to the fan, and an outlet channel which sends air from the fan to the exit vent. The exit vent is angled such that air leaving the exit vent is directed to the tooth surface. 
         [0019]    The curing light of the present invention is compact, light weight, cordless and portable. 
         [0020]    Any of the curing lights described above may provide light at single or multiple wavelengths commonly used for restorative compounds, as noted above. In one aspect, for multiple wavelengths, the light source may emit multiple wavelengths. In another aspect, the light source may emit one wavelength and the optical element may include a wavelength transformer having a chemical capable of absorbing the incident light and emitting light having a longer wavelength. 
         [0021]    The curing light may be un-tethered and powered by, for example, a portable energy source, such as a battery, capacitor and/or combinations thereof. The battery can be removable or non-removable. A charger may be provided for charging the portable energy source during off cycle. In one aspect, the charger base may include an electric motor mechanically coupled to a fan or turbine. The fan or turbine may be adapted to draw or urge ambient air across a surface of the heat sink to provide cooling of the heat sink. In one embodiment, this cooling may occur when the curing light is at rest or being recharged. In another embodiment, the cooling means is present inside a charger base or cradle, for recharging the curing light. In other embodiments, the charger base or cradle may not have a fan or cooling means, but instead or additionally, many include a display panel for displaying a condition of the battery. 
         [0022]    Another embodiment of this invention is a curing light device which can convert between a “pen” style curing light and a “gun” style curing light. In this embodiment, the handle itself can switch configurations. An alternative embodiment will have interchangeable handles for the various configurations. 
         [0023]    Yet another embodiment of this invention is removable smart tips. The tips that are attached to the curing light devices have a variety of parameters, such as length, diameter, curvature and shape, which affects the light output. The removable smart tips transmit parameter information to the curing light device. The curing light device is able to use the information transmitted to it and adjust the light output so that each removable smart tip outputs the same level of light. This embodiment ensures that the curing light is emitting the proper intensity of light for each particular use. Also, but varying the intensity of light, battery life is improved. 
         [0024]    The present invention together with the above and other advantages may best be understood from the following detailed description of the embodiments of the invention illustrated in the drawings below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  illustrates a perspective view of a curing light of the present invention. 
           [0026]      FIG. 2  illustrates an exploded view of the curing light of the present invention. 
           [0027]      FIG. 3  illustrates a sectional view of the curing light of the present invention. 
           [0028]      FIG. 4  illustrates cross-sectional views of a light module of the curing light in the present invention. 
           [0029]      FIG. 5  illustrates a cross-sectional view of the fan module in the present invention. 
           [0030]      FIG. 6  illustrates a cooling fan of the present invention. 
           [0031]      FIG. 7  illustrates a perspective view of the lens cap engaging with the light emitting end with a pair of engaging units. 
           [0032]      FIG. 8  illustrates a perspective view of the curing light with a pulse circuit. 
           [0033]      FIG. 9  illustrates the pulse circuit electrically connecting with the thermistor and the LED circuit. 
           [0034]      FIGS. 10 and 11  illustrate a charger base of the curing light in the present invention. 
           [0035]      FIG. 12  illustrates an exploded view of the heat sink and portion of the light module attached to the heat sink. 
           [0036]      FIG. 13  illustrates a perspective posterior view of the handle portion of the curing light in the present invention. 
           [0037]      FIG. 14  illustrates a perspective anterior view of the handle portion of the curing light in the present invention. 
           [0038]      FIG. 15  illustrates a perspective view of a “gun” style curing light of the present invention. 
           [0039]      FIGS. 16   a - c  illustrates a perspective view of a curing light of the present invention which is capable of being converted from a “pen” style curing light to a “gun” style curing light. 
           [0040]      FIGS. 17   a - c  illustrates a perspective view of a curing light of the present invention which is capable of being converted from a “pen” style curing light to a “gun” style curing light. 
           [0041]      FIG. 18  illustrates a perspective view of a removable smart tip. 
           [0042]      FIG. 18   a  illustrates a series of removable smart tips contained in a kit. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    The detailed description set forth below is intended as a description of the presently exemplary device provided in accordance with aspects of the present invention and is not intended to represent the only forms in which the present invention may be prepared or utilized. It is to be understood, rather, that the same or equivalent functions and components may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. 
         [0044]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the exemplary methods, devices and materials are now described. 
         [0045]    All publications mentioned herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the designs and methodologies that are described in the publications which might be used in connection with the presently described invention. The publications listed or discussed above, below and throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention. 
         [0046]    A curing light device useful for curing or activating light-activated materials is disclosed. The present invention has applications in a variety of fields, including but not limited to medicine and dentistry, where light-activated materials including a photoinitiator or photoinitiators are used. As an example, a photoinitiator absorbs light of a particular wavelength and initiates the polymerization of monomers into polymers. 
         [0047]    In an exemplary embodiment, light-activated materials including a single photoinitiator or multiple photoinitiators may be applied to a surface, such as a tooth surface, and later cured by light of a wavelength or wavelengths that activates or activate the photoinitiator or photoinitiators. The light used is not only of a wavelength to which the photoinitiator is sensitive, but also of a power level adapted to cause curing over certain durations of time. Although the light used to activate the photoinitiator is of a wavelength to which a photoinitiator is sensitive, the light may come from a variety of sources, for example, a lamp, an arc lamp such as a halogen light source, semiconductor light emitting devices, light-emitting chips such as an LED, a solid state LED, an LED array, a fluorescent bulb, a fiber optic bundle and so on. Further for example, the present invention comprises light sources including semiconductor chips, LED dies, solid state LEDs, LED arrays, edgec emitting chips, or combinations thereof. The light source may include an emitting surface or at least one emitting edge as in the case of an edge emitting chip noted above, for a compact curing light device. 
         [0048]    The typical sensitizers used in composite curing include Camphorquinone (CQ), which absorbs at about 465 nm and phenyl-propanedione (PPD), which absorbs at about 390 nm. Dental curing lights having multiple wavelengths suitable for curing curable composites usually comprise output wavelengths encompassing both of the absorbing wavelengths of these two typically used photo-initiators. The output wavelengths generally include a composite spectrum generated by LEDs or LED arrays emitting different wavelengths. The present invention comprises a curing light capable of curing all typical dental composites using, for example, light sources mentioned above, including semiconductor chips, LED dies, solid state LEDs, LED arrays, edge emitting chips, fiber optic bundles or combinations thereof, mounted on mounting platforms configured on at least one heat sink. 
         [0049]    According to one embodiment, as illustrated in  FIG. 1 ,  2  or  3 , a handheld curing light  10  of the present invention includes a longitudinal housing having a distal end  11  and a proximal end  13  with a substantially hollow interior. In the present embodiment, the housing may include two portions, as depicted in the figures, a handle portion  12  and a front portion  14 . LCD screen  500  displays status updates for the procedures, as well as permits the user to control different functions of the handheld curing light  10  if LCD screen  500  is a touchscreen. In the alternative, function buttons  502  permits the user to control different functions of the curing light. Intake vents  501  are connected to the intake channel  504  as seen in  FIG. 3 . It is noted, however, that a one-part housing may also be contemplated as part of the present invention. The front portion  14  may also be an extension of the housing, especially if an integral housing is present. 
         [0050]    The portions  12  and  14  may be joined together by any attachment means, with the proximal end of handle portion  12  abutting the distal end of the front portion  14 . Suitable attachment modes include, but are not limited to, friction fit, mating bayonet formations, tongue and groove type formations, interesting pin and pinhole formations, latches and other interconnecting structures. 
         [0051]    As shown in  FIG. 1 , front portion of housing  14  of the curing light of the present invention also has a neck section  15 , and this neck portion may be configured such that an emitting end  16  substantially coincides with the terminal end of the mounting deck, surface, platform or member of the light source  20 , as shown in  FIG. 3 . The neck portion may also be angled with respect to the longitudinal portion of the housing. As shown in  FIG. 3 , the fan module  503  is located within the curing light device  10 . Fan module can be located in either front portion  14  or handle  12 . Air is drawn into the curing light device  10  through the intake vents  501  through the intake channel  504  into the fan module  503 . Fan module  503  blows the air through output channel  505  where the air exits the curing light device through exit vent  506 . 
         [0052]    In one embodiment, as shown, for example, in  FIG. 4 , the front portion of the housing  14  may include a light module  120  in a desirable position in the interior of the front housing portion  14 . The light module may include at least one light source  20 , which, for example, may include LEDs or a fiber optic bundle. In another embodiment, the lens  461  may be inter-connected to form a continuous structure. At least one heat sink  60  may be located inside the light module  120  to conduct heat away from the light source  20 . The proximal end  14  of the housing may further include a lens cap  47 , which may be transparent, as exemplified, to provide an exit aperture for light from light source  20  and to serve as a protective cover to close the light emitting end  16  of the curing light. The lens cap  47  may also include other optical properties for focusing the light, etc., as discussed above, and in more detail below. Output channel  505  is proximate to the light module  120 . Output channel  505  can be located on the exterior or interior of the housing portion  14  and is connected to the fan module  503 . 
         [0053]    The optical element  46  may be made of any substantially transparent material, including materials such as polycarbonate (Lexan®), polyacrylics, or any of the materials mentioned below that is substantially transparent. 
         [0054]      FIG. 2  shows fan module  503 . Air enters the intake channel  504  through intake vent  501 . There is going to be at least one intake vent  501 , although, multiple intake vents  501  can lead to the same intake channel  504  to increase the amount of air flowing to the fan. Air is pulled into the intake vent  501 , through the intake channel  504  by the fan  507 . After the air passes through the fan  507 , it is pushed through output channel  505  and leaves the fan module  503  through exit vent  506  towards the tooth surface. There is at least one exit vent  506 , although, multiple output vents  506  can be utilized. 
         [0055]      FIG. 6  shows a fan  507 . Fan  507  can be any standard cooling fan known to those skilled in the art that will fit within the fan module  503 . At least one fan  507  will be mounted within the fan module  503 , however, multiple fans  507  can be utilized depending on the size of fan module  503 . Fan module  503  will be located in either the handle portion  12  or a front portion  14 . Although, it is preferred that the fan module  503  be located as close to the distal end  11  of the curing light device  10  as possible, so the air will not need to travel as far before contacting the tooth surface. Fan  507  should be able to move enough air to cool the tooth surface such that the temperature of the tooth surface does not increase by more than 5° C. 
         [0056]      FIG. 7  is an embodiment with three exit vents  506 . However, any number of exit vents  506  can be utilized in different arrangements.  FIG. 7  also shows a removable lens cap  47 . In this embodiment, lens cap  47  may include a pair of engaging units  475  symmetrically located at the periphery of the lens cap  47 , to be connected to a resilient material, so that the user may slightly press the engaging units  475  inwardly to engage the receiving slot  476  located at the light emitting end  16 . However, the actual attachment and detachment mechanism for removable lens cap  47  can be any number of ways known to those skilled in the art. 
         [0057]    In one embodiment, the heat sink  60  may be elongated and positioned inside the front portion  14 , in close-proximity to the light source  20 , to conduct, or dissipate heat there from. In one aspect, as illustrated in  FIG. 4 , the light source  20  (on the substrate  22 ) is attached or glued, with thermal adhesive including thermosetting or structural adhesives, to the mounting surface  61  of the heat sink  60 . A thermistor  62  may also be attached or glued to the outer surface of the heat sink  60  with the same material noted above, wherein one end of the thermistor  62  may be attached to the control circuit board  50  to control on/off of the curing light  10 , and the other end may be inserted into the heat sink  60 . When the temperature of the LEDs is higher than certain set points of the thermistor, a feedback signal may be generated and transmitted to the control circuit board  50  to shut off the curing light device  10  for a period of time to bring the temperature down to the set point. This feedback control scheme not only prevents the curing light device  10  from overheat, but also protects patients from discomfort. 
         [0058]    In one embodiment, the optical element  46  and the front portion  14 , or at least portions of the front portion  14  may be, for example, made out of the same material, similar material, or different material having little or no difference in the coefficients of thermal expansion. With the presence of different coefficients of thermal expansion, hoop stress may result, which may lead to premature failure of the unit. Such failure is minimized or eliminated by the present embodiment of the invention. 
         [0059]    For example, a polymer useful in the present invention may be a polymer that may be molded or cast. Suitable polymers include polyethylene, polypropylene, polybutylene, polystyrene, polyester, acrylic polymers, polyvinylchloride, polyamide, or polyetherimide like ULTEM®; a polymeric alloy such as Xenoy®. resin, which is a composite of polycarbonate and polybutyleneterephthalate or Lexan®. plastic, which is a copolymer of polycarbonate and isophthalate terephthalate resorcinol resin (all available from GE Plastics), liquid crystal polymers, such as an aromatic polyester or an aromatic polyester amide containing, as a constituent, at least one compound selected from the group consisting of an aromatic hydroxycarboxylic acid (such as hydroxybenzoate (rigid monomer), hydroxynaphthoate (flexible monomer), an aromatic hydroxyamine and an aromatic diamine, (exemplified in U.S. Pat. Nos. 6,242,063, 6,274,242, 6,643,552 and 6,797,198, the contents of which are incorporated herein by reference), polyesterimide anhydrides with terminal anhydride group or lateral anhydrides (exemplified in U.S. Pat. No. 6,730,377, the content of which is incorporated herein by referfence) or combinations thereof. 
         [0060]    In addition, any polymeric composite such as engineering prepregs or composites, may also be used. For example, a blend of polycarbonate and ABS (Acrylonitrile Butadiene Styrene) may be used for the housing. Generally, materials usable in housing include, for example, polymeric materials or composites having high temperature resistance. 
         [0061]    A liquid crystal polymer or a cholesteric liquid crystal polymer, such as one that can reflect rather than transmit light energy, may be used in various embodiments of the invention. (For example, in U.S. Pat. Nos. 4,293,435, 5,332,522, 6,043,861, 6,046,791, 6,573,963, and 6,836,314, the contents of which are incorporated herein by reference). 
         [0062]    The lens cap  47  is generally transparent, as noted above. Thus, any material that can produce a transparent lens cap may be used. 
         [0063]    The lens cap  47  may in general be disposable, so that it may be replaced when it becomes too dirty or has too many scratches on the surface to assure the quality and intensity of the light exiting from the lens cap  47 . 
         [0064]    Referring to  FIG. 2 , the curing light  10  may further include an internal connector  80  which is adapted to connect the handle portion  12  and the heat sink  60 . In one embodiment, the handle portion  12  engages with the distal end  81  of the connector  80 , while the heat sink  60  engages with the proximal end  82 . Furthermore, a control circuit board  50  adapted to control the substrate  22  is received in the hollow interior  81  of the internal connector  80 . 
         [0065]    It is worth mentioning that the connector  80  may also assist the alignment between the substrate  22  and the optical element  46  by limiting the movement of the heat sink  60 . For example, the proximal end  82  of the connector  80  may include an opening  83 , which are received in an engaging portion  65  of the heat sink  60 . The engaging portion  65  may also include an opening  66  and when the connector  80  engages with the heat sink  60 , the openings  66  and  83  are aligned with each other, as shown in  FIG. 2 . When the heat sink  60  slightly rotates to misalign the openings, the heat sink  60  disengages the connector  80 . In other words, the rotational movement of the heat sink  60  is so limited when engaging the connector  80 , such that the precision of the alignment of between the substrate  22  (located at the mounting surface  61  of the heat sink  60 ) and the optical element  46  is achieved. 
         [0066]    In one aspect, a guiding slot  67  is located at the side wall of the front portion of the heat sink  60 . The guiding slot  67  matches with a guiding protrusion  141  inside the front portion  14 , such that the substrate  22  at the heat sink  60  can be located at the appropriate position when slid onto the guiding protrusion  141 , and thus precisely align with the optic element  46 . 
         [0067]    In one aspect, a pulse circuit  51  may provide electrical current to the LEDs in a pulsed manner, meaning that the current is steadily provided for a period of time, and then rest for a period of time, etc, as shown in  FIG. 8 . When the current is consistently provided to the LEDs, the heat is likely to buildup to decrease the intensity of the lights. If the electrical current is input into the LEDs in a pulsed manner, the heat can be dissipated or released at the time without electrical current. This pulsed current input scheme is surmised to improve the efficiency of heat dissipation, and thus increase the runtime and intensity of the curing light device  10 . 
         [0068]    In another aspect, the pulse circuit  51  may include a microprocessor, for controlling the on/off cycle, or the input or output power level. 
         [0069]    In still another aspect, the pulse circuit  51  may include an input for receiving signals from the thermistor  62  and an output for controlling the intensity of the LEDs to minimize heat generation, as shown in  FIG. 5   a.  More specifically, when the temperature of the LEDs is higher than certain set point of the thermistor  62 , a feedback signal may be generated and transmitted to the pulse circuit board  51  to provide a pulse current to the LEDs to minimize the heat generation, as discussed above, and to further increase the runtime of the curing light device  10 . It is surmised that the intensity of the curing light device  10  may be increased as well with pulsing. 
         [0070]    In a further aspect, the pulse circuit  51  may monitor the output power level of the LEDs in a similar manner as illustrated above, and make corresponding adjustment of the electrical current to minimize heat generation, and further improve the runtime of the curing light device  10 . 
         [0071]    The pulsing is not limited to on and off, but to different levels of input power or output power. For example, a rest cycle may give off one half of the power of the on cycle, etc. In another example, the pulsing may be a half sinusoidal signal, like a bell-shape curve, going from zero to a maximum and down to zero again, etc. 
         [0072]    Generally speaking, the heat sink  60  may be constructed by hollowing out a thermally conductive material, such as metal, and at least partially filling the void with at least one phase change material prior to capping it to secure the phase change material inside, such that the at least one phase change material is substantially contained or surrounded by a thermally conductive material such as metal normally used in the construction of a conventional heat sink. 
         [0073]    In another embodiment, the heat sink may include a block of thermally conductive material such as metal having a bore or void space which is at least partially filled with a phase change material. 
         [0074]    In a further embodiment, the heat sink  60  may be configured to have fins, corrugations, or other geometric features adapted to provide a larger surface area for convective cooling of the heat sink, whether the heat sink is a solid metallic block, partially filled with a phase change material, so on. 
         [0075]    In still another embodiment, the curing light device  10  may include an electric motor mechanically coupled to a fan or turbine (as shown in  FIGS. 10 and 11 ). The fan or turbine may be adapted to draw or urge ambient air across a surface of the heat sink  60  to provide cooling effect thereof. 
         [0076]    The heat sink  60  may be made of any material that has good thermal conductivity, and/or dissipation properties, such as a metal or non-metal, for example, copper, aluminum, silver, magnesium, steel, silicon carbide, boron nitride, tungsten, molybdenum, cobalt, chrome, Si, SiO 2 , SiC, AlSi, AlSiC, natural diamond, monocrystalline diamond, polycrystalline diamond, polycrystalline diamond compacts, diamond deposited through chemical vapor deposition and diamond deposited through physical vapor deposition, and composite materials or compounds. 
         [0077]    Exemplary phase change materials are generally solid at ambient temperature, having melting points between about 30° C. and about 50° C., or between about 35° C. and about 45° C. Also, the exemplary materials may have a high specific heat, for example, at least about 1.7, more for example, at least about 1.9, when they are in the state at ambient temperature. In addition, the phase change materials may, for example, have a specific heat of at least about 1.5, more for example, at least about 1.6, when they are in the state at the elevated temperatures. 
         [0078]    Some of the phase change materials mentioned above may be recyclable in that they may undergo phase changes for an almost infinite number of times. Others may be more endothermic agents and thus may have a limited life cycle unless handled under a controlled environment. These endothermic agents may lose their effectiveness as a phase change material even when handled under a controlled environment. 
         [0079]    Thermal conductivity of the materials is a factor in determining the rate of heat transfer from the thermally conductive casing to the phase change material and vice versa. The thermal conductivity of the phase change material may be, for example, at least about 0.5 W/m° C. in the state at ambient temperature and at least about 0.45 W/m° C. in the state at elevated temperature. 
         [0080]    Heat sinks having a phase change material may more efficiently remove or divert heat from a light source or sources with a given weight of heat sink material when compared to a heat sink made of a solid block of thermally conductive material such as metal. Such a heat sink may even efficiently remove or divert heat from a curing light device when a reduced weight of the material is used. Using a phase change material enclosed inside a hollow thermally conductive material such as a metal heat sink instead of a conventional solid metal heat sink can decrease the weight of the curing light and increase the time the heat sink takes to reach the “shut off” temperature, as it is called in the dental curing light industry. The period prior to reaching the shut off temperature is called the “run time”. Increasing the “runtime”, i.e., the time that the light can remain on, increases the time when a dentist can perform the curing or whitening procedure. 
         [0081]    Suitable phase change material may include organic materials, inorganic materials and combinations thereof. These materials can undergo substantially reversible phase changes, and can typically go through a large, if not an infinite number of cycles without losing their effectiveness. Organic phase change materials include paraffin waxes, 2,2-dimethyl-n-docosane (C.sub.24H.sub.50), trimyristin, ((C.sub.13H.sub.27COO).sub.3C.sub.3H.sub.3), and 1,3-methyl pentacosane (C.sub.26H.sub.54). Inorganic materials such as hydrated salts including sodium hydrogen phosphate dodecahydrate (Na.sub.2HPO.sub.4.12H.sub.2O), sodium sulfate decahydrate (Na.sub.2SO.sub.4.10H.sub.2O), ferric chloride hexahydrate (FeCl.sub.3.6H.sub.2O), and TH29 (a hydrated salt having a melting temperature of 29.degree. C., available from TEAP Energy of Wangara, Australia) or metallic alloys, such as Ostalloy 117 or UM47 (available from Umicore Electro-Optic Materials) are also contemplated. Exemplary materials are solids at ambient temperature, having melting points between about 30.degree. C. and about 50.degree. C., more for example, between about 35.degree. C. and about 45.degree. C. Also, the exemplary materials have a high specific heat, for example, at least about 1.7, more for example, at least about 1.9, when they are in the state at ambient temperature. In addition, the phase change materials may, for example, have a specific heat of at least about 1.5, more for example, at least about 1.6, when they are in the state at the elevated temperatures. 
         [0082]    A perspective posterior view and an anterior view of an embodiment of the handle portion  12  are shown in  FIGS. 13 and 14 , respectively. At the distal end of the handle may be an end cap  30 , including, according to one embodiment, electrical contacts  31 ,  32 ,  33  so that the curing light may be seated in a charger base (shown in  FIGS. 10 and 11 ) for recharging the battery  70 , if the curing light is battery powered. The end cap  30  and/or the charger base (as exemplified in  FIG. 10 ), may also be so constructed as to provide means for diverting heat away from the curing light after use. 
         [0083]    The housing, including its handle portion  12  and front portion  14 , may be constructed of a high temperature polymer or composite, such as ULTEM®., which is an amorphous thermoplastic polyetherimide or Xenoy®. resin, which is a composite of polycarbonate and polybutyleneterephthalate or Lexan®. plastic, which is a copolymer of polycarbonate and isophthalate terephthalate resorcinol resin, all available from GE Plastics, or any other suitable resin plastic or composite. At the same time, high impact polystyrene, some polyesters, polyethylene, polyvinyl chloride, and polypropylene may also be suitable. 
         [0084]    Polymeric composites, as mentioned above, such as engineering prepregs or composites are also suitable for the composition of the housing. The composites may be filled composites, filled with conductive particles such as metal particles or conductive polymers to aid in the heat dissipation of the device. 
         [0085]    An on/off button or switch  18  may be located on the handle portion  12 , near the junction between the handle portion  12  and the front portion  14 , for manually turning on/off of the curing light. The button may be a molded part, made out of a polymer such as high temperature plastics or polymers used in other parts of the housing, as discussed above. It may also be of the same or different color from the housing. A different color may also help to accentuate its presence and make it easier to find. 
         [0086]    LCD screen  500  may also be located on the handle portion  12 . LCD screen  500  can be used to display information about the procedure or the curing light device  10  itself. For example, some information that may be displayed can include light wavelength, runtime, battery charge left and a timer. In addition, function buttons  502  can be used to control different aspects of the device. For example, the buttons can control the procedure type, light wavelength, timer settings, and any other function that the curing light device  10  can perform. Additionally, LCD screen  500  can be a touchscreen allowing the user to control the curing light device  10  functions by interfacing directly with the LCD screen  500  and making function buttons  502  unnecessary. 
         [0087]    It is also worth to mention that the electrical and control components may be received within the housing portions  12  and  14  towards the distal end  13  of the curing light  10 . The curing light  10  may be battery powered or tethered to a power source or a transformer. Battery powered curing lights may offer better portability. 
         [0088]    Referring to  FIG. 3 , a battery  70  may provide electrical power for operating the light source  20  via battery contacts  70   a  and pin connector  40 . In one embodiment, a single rechargeable battery such as a lithium ion battery may be used to power the curing light  10 . The on/off button  18  may serve to manually operate the curing light by providing a user input signal through a shaft or post  17 , which interfaces with a printed control circuit board  50 , may also be located within the handle portion  12 , and is mounted close to the battery  70 , for example. In one embodiment, a control circuit board  50  includes a device, which may or may not include a microprocessor, which monitors battery life, LED temperature, or system functionality. The battery can be removable or non-removable and mounted inside of the curing light device  10  or be mounted externally. 
         [0089]    The end cap  30  is cylindrical in shape and may be attached to the distal end of the handle portion  12 . It may be molded as part of the handle portion  12 . It may also be attached by other means, such as adhesive bonding, heat bonding, or threaded attachment. 
         [0090]    In one embodiment of the invention, as shown in  FIG. 10 , the charger base may include an electric motor mechanically coupled to a fan or turbine  201 . The fan or turbine  201  may be adapted to draw or urge ambient air across a surface of the heat sink  60  to provide cooling of the heat sink  60 . In one embodiment, this cooling may occur when the curing light is at rest or being recharged. In another embodiment, the cooling means is present inside a charger base or cradle  200 , for recharging the curing light. In other embodiments, the charger base or cradle  200  may not have a fan  201  or cooling means, but instead or additionally, many include a display panel (not shown) for displaying a condition of the battery. In another embodiment, the heat dissipation device may include a compressed air cooling system. 
         [0091]    Still referring to  FIG. 10 , a separate battery charger module  2200  is included in one embodiment. The charger module  2200  is adapted to receive AC power into a plug  400  from a traditional wall socket and provide DC power to the curing light for battery charging. 
         [0092]    The battery charger module  2200  illustrated in  FIG. 10  has a cable  428  for conducting electricity from the plug  400  to the charger module  2200 . The battery charger module  2200  includes circuitry  430  for controlling battery charging of batteries. 
         [0093]      FIG. 15  is an alternative embodiment to the invention, which is a dental curing light in a “gun” configuration. The gun style curing light device  600  will have a housing  602 . On the housing  602  is LCD screen  500 . The housing will also have intake vents  501 . Extending from the housing is tip  603 . Handle portion  601  is angled away from housing  602 . The angle at which handle portion  601  protrudes from housing  602  is such that the user can hold handle portion  601  and manipulate the on/off button or switch  18  and function buttons  502  comfortably without needing to change hand position. 
         [0094]    Tip  603  can be removable. Exit vent  506  will be located near the end of the tip, so that air exiting the gun style curing light device  600  will be directed towards the teeth being exposed by the curing light. 
         [0095]    The light source can be any number of light sources known to those skilled in the art, such as, but not limited to lamps, LEDs and fiber optic bundles. The light source can be located within housing  602 , with tip  603  acting as a light guide to direct the light towards the teeth to be treated. On the other hand, the light source can be mounted at the end of tip  603 . 
         [0096]    LCD screen  500  can display information about the procedure or the gun style curing light device  600  itself. The function buttons  502  can be used to control different aspects of the device. The LCD screen  500  can be a touchscreen as an alternative to using function buttons  502 . 
         [0097]    The fan module  503  that is located within housing  602  will work as shown in  FIG. 5 . Air is drawn into housing  602  through the intake vent  501 . At least one intake vent  501  will located on the housing  602 , although more intake vents  501  can be added. Air drawn from the intake vents  501  pass through the intake channel  504  to the fan  507 . Fan  507  will then blow the air through the output channel  505  where the air exits the gun style curing light device  600  through exit vent  506  located at the end of tip  603 . 
         [0098]    Handle portion  601  will contain rechargeable battery  70 . In addition, heat sink  60  will be located either in the handle portion  601  or the housing  602 . Heat sink  60  can be any number of types of heat sinks, such as a phase change heat sink, a fan or a solid metallic block. 
         [0099]      FIGS. 16   a - 17   c  is yet another alternative embodiment to the invention where the curing can be converted between a “pen” configuration and a “gun” configuration.  FIGS. 16   a  and  17   a  shows convertible curing light device  700 . LCD screen  500  displays information relevant to the procedure or the status of the convertible curing light device  700 . LCD screen  500  is on the housing  702 . Also located on housing  702  is on/off button or switch  18 . On/off button or switch  18  is located on housing  702  such that the user can operate it easily when the convertible curing light device  700  is either in the pen or gun configuration. 
         [0100]    Tip  703  extends from housing  702 . Tip  703  can be removable. Exit vent  506  will be located near the end of the tip, so that air exiting the convertible curing light device  700  will be directed towards the teeth being exposed by the curing light. 
         [0101]    The light source can be any number of light sources known to those skilled in the art, such as, but not limited to lamps, LEDs and fiber optic bundles. The light source can be located within housing  702 , with tip  703  acting as a light guide to direct the light towards the teeth to be treated. On the other hand, the light source can be mounted at the end of tip  703 . 
         [0102]    The fan module  503  that is located within housing  702  will work as shown in  FIG. 5 . Air is drawn into housing  702  through the intake vent  501 . At least one intake vent  501  will located on the housing  702 , although more intake vents  501  can be added. Air drawn from the intake vents  501  pass through the intake channel  504  to the fan  507 . Fan  507  will then blow the air through the output channel  505  where the air exits the convertible curing light device  700  through exit vent  506  located at the end of tip  703 . 
         [0103]    In the convertible curing light device  700  embodiment that is displayed in  FIG. 16   a,  handle  701  is rotatably coupled to housing  702 . In  FIG. 16   b,  handle  701  rotates with respect to housing  702 . By rotating handle  701 , the angle of handle  701  with respect to housing  702  changes such that the convertible curing light device  700  changes from being held as a “gun” style curing light device to a “pen” style curing light device.  FIG. 16   c  shows Configuration A of convertible curing light device  700  as being a “gun” style curing light device and Configuration B of convertible curing light device  700  as being “pen” style curing light device following the handle  701  rotation shown in  FIG. 16   b.    
         [0104]    In the convertible curing light device  700  embodiment that is displayed in  FIG. 17   a,  gun style handle  704  is removably coupled to housing  702  and interchangeable with pen style handle  705 .  FIG. 17   b,  shows that gun style handle  704  and pen style handle  705  are attached to housing  702 , depending on the user&#39;s desired configuration.  FIG. 17   c  shows Configuration A of convertible curing light device  700  with gun style handle  704  attached to housing  702 .  FIG. 17   c  show Configuration B of convertible curing light device  700  as being a “pen” style curing light device with pen style handle  705  attached to housing  702 . 
         [0105]      FIG. 18  discloses an embodiment where the removable tip is a smart tip  550 . Smart tip will have a distal end  551  and a proximal end  552 . Proximal end  552  is removably coupled to the housing  602 . In the alternative, proximal end  552  can be coupled to housing  702 . Proximal end  552  of the smart tip  550  will have a connector  553 . Connector  553  corresponds to opening  554  on the housing  602 . The connector  553  and corresponding opening  554  can utilize any number of removable attachment means known to those skilled in the art such as, but not limited to, friction fit, a screw and nut arrangement, or a pin and jack arrangement. 
         [0106]    Housing  602  will contain a sensor which can determine certain parameters of the smart tip  550  when it is inserted into the housing  602 . Some of the detectable smart tip  550  parameters includes, but is not limited to, diameter, length, curvature and shape. The sensor can be, but is not limited to, mechanical, optical or magnetic. For example, one possible embodiment is that the connector  553  is comprised of an arrangement of pins. The sensor in housing  602  will identify the parameters of the smart tip  550  based on the pin arrangement that it detects when the smart tip  550  is attached to housing  602 . 
         [0107]    The advantage of the curing light device being able to detect the parameters of the smart tip  550  that is attached to it is that the curing light device can adjust the power output based on the parameters of the smart tip  550 . If the curing light device does not adjust the power output based on the parameters of the tip that is attached to it, then light output will vary according to the tip that is attached to the curing light device. Generally, if the radiometric power on the input side of the tip remains constant, light output per unit area will increase as the tip size decreases. The problem that results is that dental professionals may end up using a tip which emits the proper area light spot, but the radiometric power is not ideal. 
         [0108]    However, since the smart tip  550  will communicate the parameters of the tip to the device, the device can automatically adjust the power output depending on the smart tip  550  attached to the housing  602 . The advantage to that is that the light output per area will remain consistent no matter which smart tip  550  is attached to the housing  602 . Another benefit is that the battery life of the device will be extended. The battery life is extended because certain smart tip  550  parameters will utilize a lower power draw to project the same constant output. For example, a tip with a smaller diameter will draw less power to have the same constant output as a tip with a larger diameter. 
         [0109]    In another embodiment, a variety of smart tips  550 , covering a wide range of parameters could be packaged together as a kit.  FIG. 18   a  is a sample arrangement of smart tips  550  which may be included in a smart tip  550  kit. In this sample arrangement of smart tips, each tip has a different diameter: 
         [0000]                                                Diameter                           550a    2 mm           550b    8 mm           550c    9 mm           550d   13 mm           550e    4 mm           550f   11 mm                        
It is important to note that smart tips  550  are not limited to the aforementioned diameters, this listing is for illustrative purposes only. A kit can contain any number of smart tips  550  covering any combination of smart tip  550  parameters.
 
         [0110]    Having described the invention by the description and illustrations above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Accordingly, the invention is not to be considered as limited by the foregoing description, but includes any equivalents.