Dentistry – Apparatus – Having means to emit radiation or facilitate viewing of the...
Reexamination Certificate
1999-02-23
2001-09-18
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Having means to emit radiation or facilitate viewing of the...
C433S216000, C362S804000, C132S323000
Reexamination Certificate
active
06290496
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of oral hygiene and more particularly to devices and methods for selective photo-thermal destruction of oral bacteria.
BACKGROUND OF THE INVENTION
Various forms of periodontal disease in humans are caused by oral bacteria. Oral bacteria create plaque, a sticky, colorless film of bacteria that constantly forms on the surface of teeth and may lead to periodontal diseases. Plaque, if allowed to stay on the tooth's surface will eventually lead to gingival irritation also known as gingivitis, which may be accompanied by gum swelling, bleeding and by fibrous enlargement of the gingiva.
The plaque forming bacteria create toxins which irritate the gums and result in breakdown of the attachment of gum tissues to teeth. Over time, these toxins can destroy gum tissues, allowing the infection to progress to bone loss.
Plaque that is not timely removed can combine with other materials and harden into a rough, porous deposit called calculus or scale. If the plaque and scale builds up and are not removed by professional cleaning, the gums will start to move away from the teeth. This is the start of periodontal gum disease. Pockets form between the teeth and gums. If the gums are allowed deteriorate further, the gums recede and the bone and other supporting tissues around the teeth start deteriorating and the teeth may eventually become loose.
Calculus on the tooth's surface, above the gum-line, does not contribute to periodontal diseases. However, calculus on the root surface, below the gums, makes removal of new plaque and bacteria more difficult. Unlike plaque, which can be removed by tooth brushing, calculus must be removed by a dentist or dental hygienist.
Prevention and treatment of periodontal gum disease must be based to a large extent on the control of bacterial plaque. This requires a considerable effort on the patient's part. In addition, routine professional oral hygiene techniques, through professional cleaning of the teeth and frequent reassessment of the patient's periodontal tissues to provide early detection and treatment of new or reoccurring abnormalities or of destruction of supporting periodontal tissues.
By far the most important aspect of controlling periodontal diseases is the practicing of daily oral hygiene techniques that needs to be initiated at pre-adolescence and carried on for the rest of the patient's life. Daily maintenance schedules ideally require full patient's compliance with instructions and an ideal tooth cleaning technique. Far too often, token attempts at dental bacterial control are inadequate and unsuccessful in one or more sites of the dentition leading to inflammatory changes at these sites and further loss of periodontal attachment.
Products sold for the prevention of periodontal diseases include toothpaste, mouth rinsing solutions, Manual toothbrushes, dental floss and powered toothbrushes and oral irrigators.
Chemical antibacterial agents are increasingly being used in prophylactic and therapeutic regimes for plaque-related diseases. As these agents can be rendered ineffective by the development of resistance in the target organisms there is a need to develop alternative anti-microbial treatments. Light from high-power lasers is known to be bactericidal and investigations have shown that it is effective against organisms implicated in carries and inflammatory periodontal diseases. However, the adverse effects of such light on dental hard tissues argues against its use solely as an antibacterial agent.
U.S. Pat. No. 4,784,135 to Blum et al. discloses a method for treating tooth decay, by far UV radiation generated by an argon fluoride (ArF) laser, which is based on ablative photo-decomposition of organic biological material. No staining of the material is disclosed.
U.S. Pat. No. 5,658,148 to Neuberger et al. discloses a method and a device for cleaning teeth by a low power diode laser applying the principle of photodynamic therapy. This method is based on using a photosensitizer compound. The photosensitizer compound produces singlet oxygen upon irradiation by the laser light. The singlet oxygen thus produced destroys oral bacteria.
U.S. Pat. No. 5,611,793 to Wilson discloses a method of disinfecting or sterilizing tissues, wounds or lesions of the oral cavity. The method comprises applying a photosensitizing compound to the tissues and irradiating the tissues with laser light at a wavelength absorbed by the photosensitizing compound. The helium-neon laser or the gallium aluminum arsenide diode laser used by Wilson are expensive and may not be suitable for home use.
There is a widely recognized need for a simple, inexpensive and selective method for killing oral bacteria which is suitable for home use.
SUMMARY OF THE INVENTION
It is therefore an object of some preferred embodiments of the present invention to provide a device and method for destroying oral bacteria.
An aspect of some preferred embodiments of the present invention involves the pre-staining of the bacteria using bacterial selective dyes or stains.
An aspect of some preferred embodiments of the present invention involves the use of incoherent broad band light for irradiating the preferably pre-stained bacteria.
As aspect of some preferred embodiments of the invention involves a dentifrice containing a bacterial stain. This dentifrice is preferably used to stain the bacteria during normal brushing so that they can be destroyed.
There is thus provided, in accordance with a preferred embodiment of the invention, oral hygiene apparatus for destroying sensitized oral bacteria, comprising:
an incoherent light source; and
a light directing member, adapted for directing light from said light source onto at least part of a surface of at least one tooth within an oral cavity.
Preferably, the light directing member comprises a light guide removably coupled to a housing containing the light source.
Preferably, the light directing member comprises a reflective layer coating light passage. Preferably, the reflective layer coated light passage comprises a hollow passage whose radial extent is defined by a light reflecting surface.
In a preferred embodiment of the invention, the light guide comprises an elongated member, having at least one peripheral surface uncoated by a reflecting material, said light guide directing light entering it at one end by internal reflection from said at least one peripheral surface to a second end.
In a preferred embodiment of the invention, the incoherent light source includes a lamp, a reflector which directs at least part of the light produced by said lamp to said light directing member. Preferably, the lamp is an arc discharge lamp or a flash lamp. Preferably, reflector is a parabolic reflector, a spherical reflector, a quasi-spherical reflector or an ellipsoidal reflector.
In a preferred embodiment of the invention the light source further includes at lease one lens disposed between said flash lamp and said light directing member for directing light onto said light directing member.
Preferably, the apparatus includes at least one filter which passes light to which said bacteria has been sensitized. Preferably, the at least one filter substantially blocks light at wavelengths at which oxyhemoglobin absorbs substantial energy.
In a preferred embodiment of the invention, the light is directed to said tooth surface from an exit port of the light directing member.
In a preferred embodiment of the invention, the apparatus a tooth brush like member adjacent to or surrounding said exit port. Preferably, the tooth brush like member comprises a plurality of bristle like members arranged peripherally around said exit port to enable said light exiting said port to reach said at least part of a surface of at least one tooth within said oral cavity while teeth are being brushed by said tooth brush like member.
In a preferred embodiment of the invention the apparatus includes a plurality of bristles coupled to said light directing member such that a first end of said plur
Azar Zion
Shalev Pinchas
Fenster & Company Patent Attorneys Ltd.
Lewis Ralph A.
Radiance Inc.
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