TOOTHBRUSH FOR PREVENTION AND TREATMENT OF

DENTIN HYPERSENSITIVITY USING LOW LEVEL LIGHT Technical Field [1] The present invention relates to a toothbrush for prevention and treatment of dentin hypersensitivity using low level light, and more particularly to a toothbrush having a donut-shaped head with a hole at the center thereof and low level light sources such as LEDs or laser diodes at the bottom of bristles embedded therein to emit low level light during brushing for the prevention and treatment of dentin hypersensitivity. [2] Background Art [3] The main function of toothbrushes is to remove remaining food debris on teeth surfaces to clean the oral cavity including the teeth and thereby prevent plaque and calculus accumulation that often result in periodontal diseases and caries. [4] Dental hypersensitivity is a painful condition prevalent in the general population. It causes oral discomfort generated by sensitive, painful or loose teeth. Since a short and sharp pain arises from exposed dentin in response to thermal, evaporative, tactile, osmotic or chemical irritation, people suffering from dentin hypersensitivity cannot brush their teeth with usual toothbrushes or maintain normal tooth brushing habits. [5] Exposed dentin has a large sensitivity variation from light symptoms to acute and long-lasting pains. The dentin sensitivity cannot be effectively treated with a painkiller or an anti-inflammatory agent. To address this problem, desensitizing toothpastes containing components such as tricalcium phosphate (microcrystalline hydroxyapatite), [6] The most common factors responsible for dentin hypersensitivity are Bio- stimulation using low level light increases the energy level at the body irradiated with light and activates cells and tissues, thereby producing physiological effects such as promotion of ATP synthesis, cell division, tissue regeneration and cell metabolism. Low level light therapy was first studied at the Mayo Clinic in 1989 using various light sources such as lasers, LEDs or lamps. [7] Mayo Clinic studies have suggested that the results of light therapy are due to the direct effect of light itself, generated at specific wavelengths, rather than to the coherency and polarization associated with lasers. [8] strikingly painful condition that originates from the exposure of dentinal tubules when the thickness of the enamel or root cementum is significantly reduced, et al the efficacy of low level laser therapy (LLLT) in the treatment of patients with dentin hy¬ persensitivity. Their studies suggested that light emitted from a 780 nm or 830 nm diode laser at an output power of 50 mW reduces pain associated with dentin hyper¬ sensitivity and that light from a 632.8 nm helium neon laser at the same low output prevents the inflammation and necrosis of exposed dentinal tubules. [9] The effectiveness of dentin hypersensitivity treatment with diode laser has been reported in various clinical studies such as: The Current Status of Low Level Laser Therapy in Dentistry, Part 1, Soft Tissue Applications, LJ. Walsh, Australian Journal, 1997; The Current Status of Low Level Laser Therapy in Dentistry, Part 2, Hard Tissue Applications, LJ. Walsh, Australian Journal, 1997; Low Level Laser in Dentine Hypersensitivity, Gerschman J A et al., Australian Dent. J. 1994; LLLT in Treating Dentinary Hypersensitivity, A Historical Study on Clinical Application, Aldo Brugnera Junior; Second International Conference on Near-Field Optical Analysis; Pho- todynamic Therapy & Photobiology Effects; Proceedings of the Second International Conference on NOA, Houston, Texas, USA, May 31 to June 1, 2001. [10] Disclosure of Invention Technical Problem [11] Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a toothbrush having low level light sources such as LEDs or laser diodes to emit low level light during brushing for the prevention and treatment of pain associated with dentin hyper¬ sensitivity. [12] Another object of the present invention is to provide an inside- waterproofed toothbrush for prevention and treatment of dentin hypersensitivity using low level light. [13] Technical Solution [14] In order to accomplish the above objects of the present invention, there is provided a toothbrush for prevention and treatment of dentin hypersensitivity using low level light, which comprises: a head having a central hole at the center thereof and bristles arranged in a plurality of rows at the outer periphery of the central hole; a handle connected to the head to form a single body; a printed circuit board mounted in the body and consisting of a light source portion with a plurality of light sources and a controller portion; a toggle switch connected to the printed circuit board; a battery for providing power to the light source portion; and a cover coupled to the rear side of the body. [15] The light source portion is mounted in the head, whereas the controller portion is mounted in the handle. [16] The body and the cover are made of a polycarbonate material and adhered to each other by means of a UV hardener. [17] The printed circuit board is coated with a waterproof coating. [18] The light sources are LEDs or laser diodes having a specific wavelength between 600 nm and 890 nm. Advantageous Effects [19] As can be seen from the foregoing, the toothbrush according to the present invention irradiates low level light to the teeth during brushing to produce photo- biological effects that can treat dentin hypersensitivity. Also, continuous use of the toothbrush can prevent the inflammation or necrosis of exposed dentinal tubules. [20] While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiment and the drawings, however, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims. [21] Brief Description of the Drawings [22] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: [23] FIG. 1 is a front view of a toothbrush for prevention and treatment of dentin hyper¬ sensitivity using low level light according to a first embodiment of the present invention; [24] FIG. 2 is an exploded perspective view of the toothbrush in FIG. 1 ; [25] FIG. 3 is a front view of a toothbrush for prevention and treatment of dentin hyper¬ sensitivity using low level light according to a second embodiment of the present invention; [26] FIG. 4 is an exploded perspective view of the toothbrush in FIG. 3; [27] FIG. 5 is an enlarged cross-sectional view of a waterproof cap and a toggle switch of the toothbrush in FIG. 3; and [28] FIG. 6 is a view showing the usage of the toothbrush according to the present invention. [29] Best Mode for Carrying Out the Invention [30] Reference will now be made in detail to the preferred embodiments of the present invention. [31] FIGs. 1 and 2 illustrate a toothbrush for prevention and treatment of dentin hyper- sensitivity using low level light according to the first embodiment of the present invention. The toothbrush includes a body 10 having bristles 15 embedded in a head thereof, a flexible printed circuit board 30 mounted within the body 10 and a cover 40 for covering the body 10 to sealably mount the printed circuit board 30 inside the body 10. [32] The body 10 consists of a head 23 and a handle 25. Preferably, the body 10 should be made of a polycarbonate material to improve light transmissivity. If the body 10 is made of polycarbonate, a UV hardener should be used to connect the cover 40 to the body 10 because polycarbonate has a property that is not suitable for ultrasonic welding. The head 23 has bristles 15 embedded in a plurality of rows for brushing and a central hole 13 formed at the center thereof for easily removing remaining toothpaste. The handle 25 is provided with a waterproof button 17 at the front side thereof. The button 17 is used to turn on or off a toggle switch of the printed circuit board 30. [33] The integrated body of the head 23 and the handle 25 has a groove 18 formed at the rear side thereof in a shape corresponding to the printed circuit board 30 and suitable to receive the printed circuit board 30. [34] The printed circuit board 30 consists of a light source portion 31 mounted in the head 23 and a controller portion 32 mounted in the handle 25. The light source portion 31 has a hole 34 at the center thereof to correspond to the head 23 and a plurality of light sources 33 at the outer periphery of the hole 34. [35] Preferably, the light sources 33 should be LEDs or laser diodes. Preferably, the LEDs or laser diodes should have a wavelength between 600 nm and 890 nm, a low output power of 1 to 500 mW and a specific cycle. [36] The controller portion 32 connected to the light source portion 31 has a circuit for powering the low level light sources. The controller portion 32 also has a toggle switch 35 that is turned on or off by the pressing of the waterproof button 17, a small battery 36 for supplying power to the light sources 33 and a micom 37 for the on/off control of the light sources 33. [37] The printed circuit board 30 is waterproofed with a transparent waterproof coating. Then the printed circuit board 30 can be colored with a color coating to provide aesthetics. [38] With the flexible printed circuit board 30 being mounted in the groove 18, the body 10 is sealably covered with the cover 40. The cover 40 has a shape corresponding to that of the body 10. In other words, the cover 40 has a head portion 41 with a hole 43 at the center thereof to correspond to the head 23 of the body 10 and a handle portion 45 corresponding to the handle 25 of the body 10. [39] Mode for the Invention [40] Hereinafter, a toothbrush for prevention and treatment of dentin hypersensitivity using low level light according to the second embodiment of the present invention will be explained in detail. [41] The toothbrush according to the second embodiment is identical to that according to the first embodiment, except for the shape of the printed circuit board mounted in the body and the location of the toggle switch. [42] As illustrated in FlGs. 3 and 4, the toothbrush according to the second embodiment of the present invention includes a body 110 having bristles 115 embedded in a head thereof, a printed circuit board 130 mounted within the body 110 and a cover 140 for covering the body 110 to sealably mount the printed circuit board 130 inside the body 110. [43] The body 110 consists of a head 123 and a handle 125. Preferably, the body 110 should be made of a polycarbonate material to improve light transmissivity. If the body 110 is made of polycarbonate, a UV hardener should be used to connect the cover 140 to the body 10 because polycarbonate has a property that is not suitable for ultrasonic welding. The head 123 has bristles 115 embedded in a plurality of rows for brushing and a central hole 113 formed at the center thereof for easily removing remaining toothpaste. [44] The printed circuit board 130 consists of a light source portion 131 mounted in the head 123 and a controller portion 132 mounted in the handle 125. The light source portion 131 has a hole 134 at the center thereof to correspond to the head 123 of the body 110 and a plurality of light sources 133 at the outer periphery of the hole 134. [45] Preferably, the light sources 133 should be LEDs or laser diodes. Preferably, the LEDs or laser diodes should have a wavelength between 600 nm and 890 nm, a low output power of 1 to 500 mW and a specific cycle. [46] The controller portion 132 connected to the light source portion 131 has a circuit for powering the low level light sources. The controller portion 132 also has a toggle switch 135 connected to the circuit and the lower end of the controller portion 132, a small battery 136 for supplying power to the light sources 133 and a micom (not shown) for the on/off control of the light sources 133. [47] The printed circuit board 130 is waterproofed with a transparent waterproof coating. Then the printed circuit board 30 can be colored with a color coating to provide aesthetics. [48] The body 10 with the flexible printed circuit board 130 mounted therein is sealably covered with the cover 140. The cover 140 has a shape corresponding to that of the body 110. In other words, the cover 140 has a head portion 141 with a hole 143 at the center thereof to correspond to the head 123 of the body 110 and a handle portion 145 corresponding to the handle 125 of the body 110. [49] As illustrated in FlG. 5, the toggle switch 135 is provided at the lower end of the printed circuit board 130 and protruded from the bottom of the body 110. Also, the toggle switch 135 is covered with a silicon waterproof cap 134 to prevent water permeation into the bottom of the body 110. The waterproof cap 134 of a silicon material can be bonded to the body 110 of a polycarbonate material using an adhesive for bonding heterogeneous materials. [50] Hereinafter, the usage and function of the toothbrush for prevention and treatment of dentin hypersensitivity using low level light according to the present invention will be explained in detail. [51] Referring to FlG. 6, when a user turns on the toggle switch 35 or 135, the plurality of light sources 33 or 133 emit low level light of a wavelength between 600 nm and 890 nm and a low output of 1 to 500 mW. When the user brushes the teeth using the switched-on toothbrush with a toothpaste, the toothbrush emits light on the top and sides of a tooth being brushed. More specifically, the light is delivered to the enamel, hard tissues of dentine, gingival soft tissues and underlying cementum so that photo- biological effects can effectively prevent and treat dentin hypersensitivity. [52] The micom may store a simple program for operating the light sources. For example, a predetermined light emitting time can be stored to automatically stop the light emission when the predetermined time lapses. It is also possible to store a program for automatically turning on the light sources during brushing and off while the toothbrush is not being used. [53] When the toggle switch 35 or 135 is pressed again, it turns off to stop operation of the light sources. [54] The photobiological effects refer to stimulation in vivo by the light delivered to the body, which enhances activation of cells, growth of activated cells and activation of body tissues. [55] To verify the effectiveness of the toothbrush of the present invention in the prevention or treatment of dentin hypersensitivity, clinical tests were performed during a period from August 1, 2004 to November 30, 2004 on 300 patients who visited the dental clinic of Chonnam National University Hospital. [56] Evaluation by questionnaire indicated that 43% of the patients complained pain from sensitive teeth everyday before using the toothbrush of the present invention, whereas 9% have had little pain. A significant reduction was observed in the pain condition from 43% to 4% after the use of the toothbrush. At the conclusion of the clinical tests, an increased percentage of patients, from 9% to 78%, felt little pain. [57]