The present invention relates to the use of photosensitizers with irradiation by light energy and/or sonic energy to kill the microbes involved in a number of oral diseases including inflammatory periodontal disease, dental pulp disease and caries, and in disinfecting or sterilizing wounds and other lesions in the oral cavity.
Chronic periodontitis, a form of inflammatory periodontal disease, is the major cause of tooth loss in adults. Patients with chronic periodontitis have inflamed pockets in the gum tissue, or gingiva, surrounding the affected tooth. Layers of bacteria build up in biofilm within these gingival pockets, leaving behind calcified accretions called calculus attached to the tooth and root surfaces. As the bacterial infection progresses, inflammatory exudates from the biofilm as well as host tissue responses can cause progressive breakdown of the hard and soft tissue structures supporting the tooth, ultimately resulting in tooth loss. Bacterial infections of the oral cavity are also gaining recognition as a source of infection in the rest of the body (e.g., bacteremias [infections of the blood], infective carditis, pulmonary disease, etc.) Such infections have also been implicated in implant rejection and may complicate the prognosis for diabetes mellitus and other autoimmune disorders.
Conventional methods of treating bacterial infections of the oral cavity include removal of the pockets of subgingival plaque, calculus and biofilms by dental scaling and applications of antibiotics. Dental scaling is performed on patients with periodontal diseases several times a year, in some cases every three months or more frequently. An ultrasonic dental scaler generates ultrasound vibrations in a fluid (e.g., water, saline or the like) that remove subgingival plaque, calculus and biofilm from the gum tissues. The ultrasound vibrations cause cavitation exerting high shear forces directly on the fluid, the calculus, and the plaque surrounding or within the gum tissue, resulting in the detachment of such calculus, plaque and associated biofilm from the gum tissues. The principles of dental scalers are well described in the patent literature. See U.S. Pat. Nos. 2,990,616; 3,089,790; 3,703,037; 3,990,452; 4,283,174; 4,804,364; and 6,619,957. These patents are all hereby incorporated by reference.
Unfortunately, dental scaling by itself has had limited success in eliminating bacteria in the oral cavity and long term applications of antibiotics could lead to resistance rendering the antibiotics clinically ineffective. Moreover, applications of antibiotics may not be desirable for immunocompromised patients and patients with denture stomatitis.
In addition to treatment of inflammatory periodontal diseases, elimination of microbes in the oral cavity is also preferable in drilled out carious cavities prior to conventional filling and during other forms of dental surgery including endodotic operations involving the interior of the tooth itself.
Photodynamic therapy for killing microbes in the oral cavity was disclosed by Wilson, et al. in U.S. Pat. No. 5,611,793 and European Patent No. EP 0637976B2. These patents are herein incorporated by reference. As discussed in these patents, laser light in a certain wavelength and intensity range is used to illuminate a photosensitive compound that has been applied to the infected tissue(s). The laser activates the compound causing the formation of free radicals and other elements that are toxic to microbes residing in the oral cavity.
Because photodynamic therapy has been shown to be effective in killing infectious microbes in the oral cavity, it would be highly desirable if it were incorporated into routine dental care (e.g., dental scaling or the like). It is an objection of the present invention to provide methods that can conveniently and efficiently disinfect a treatment region of the oral cavity while cleaning and removing calculus, plaque and biofilm from such a region.
The present invention provides methods that use a photosensitizing composition in conjunction with irradiation by light and/or sonic energy to kill microbes in the oral cavity, a process hereinafter termed “sonophotodynamic therapy”. As described below, the combined administration of light and sonic energy in the presence of a fluid and a photosensitizing compound has a synergistic effect in the killing of microbes in the oral cavity.
The application of sonic energy in a fluid can create acoustic cavitation. Acoustic cavitation involves the nucleation, growth and collapse of gas/vapor filled bubbles in a fluid. Cavitation can effectively kill microbes by physical disruption. For example, the mechanical energy in acoustic cavitation can disrupt and disperse plaque (and the microbes surrounding it) by the violent shear forces produced around the bubbles. Free radicals in a fluid have also been detected as a direct result of acoustic cavitation. These free radicals can kill microbes via cell wall disruption and/or lipid peroxidation. The collapse of the bubbles during acoustic cavitation can be accompanied by a simultaneous emission of light (“sonoluminescence”). The light emitted by sonoluminescence is very broadband and may contain ultraviolet light, which can also be directly detrimental to microbes. Light emitted via sonoluminescence, when applied to a photosensitizing composition in the oral cavity, can release more free radicals, causing further killing of microbes.
In an aspect of the invention, a method for killing microbes in an oral cavity is disclosed comprising: applying a photosensitizing composition to a locus; applying a fluid and sonic energy to the locus; and irradiating the locus with a light source at a wavelength absorbed by the photosensitizing composition so as to destroy microbes at the locus.
In another aspect of the invention, a method for killing microbes in an oral cavity is disclosed comprising: applying a photosensitizing composition to a locus; applying sufficient sonic energy to the locus in order to provide acoustic cavitation so as to destroy microbes at the locus.
In yet another aspect of the invention, a method for promoting wound healing is disclosed comprising: applying a photosensitizing composition to a wound; applying a fluid and sonic energy to the wound; and irradiating the wound with a light source at a wavelength absorbed by the photosensitizing composition so as to destroy microbes at the wound.
In another aspect of the invention, a method for promoting wound healing is disclosed comprising: applying a photosensitizing composition to a wound; applying sufficient sonic energy to the locus in order to provide acoustic cavitation so as to destroy microbes at the wound.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portion of the specifications and the drawings.
The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims, and drawings, of which the following is a brief description:
The present invention provides methods of killing microbes in the oral cavity by delivering and activating a photosensitizing composition in the oral cavity in conjunction with sonic energy, usually (but not necessarily) provided by ultrasound or sonic dental scaling.
I. Definitions
The following terms are intended to have the following general meanings as they are used herein.
1. Microbes: any and all disease-related microbes such as virus, fungus, and bacteria including Gram-negative organisms, Gram-positive organisms or the like.
2. Light: light at any wavelengths that can be absorbed by a photosensitizing composition. Such wavelengths include wavelengths selected from the continuous electromagnetic spectrum such as ultraviolet (“UV”), visible, the infrared (near, mid and far), etc. The wavelengths are generally preferably between about 160 nm to 1600 nm, more preferably between 400 nm to 800 mm, most preferably between about 500 nm to 850 nm although the wavelengths may vary depending upon the particular photosensitizing compound used and the light intensity. The light may be produced by any suitable art-disclosed light emitting devices such as lasers, light emitting diodes (“LEDs”), arc lamps, incandescent sources, fluorescent sources, gas discharge tubes, thermal sources, light amplifiers or the like.
3. Locus: any tissue, carious cavity, endodontic chamber, wound, or lesion in the oral cavity where anti-microbial treatment is desired.
4. Wound: any wound or lesion outside of the oral cavity where anti-microbial treatment is desired.
5. Photosensitizing composition: a composition comprising at least one suitable art-disclosed photosensitizer. Arianor steel blue, toluidine blue O, crystal violet, methylene blue and its derivatives, azure blue cert, azure B chloride, azure 2, azure A chloride, azure B tetrafluoroborate, thionin, azure A eosinate, azure B eosinate, azure mix sicc., azure II eosinate, haematoporphyrin HCl, haematoporphyrin ester, aluminium disulphonated phthalocyanine are examples of suitable photosensitizers. Porphyrins, pyrroles, tetrapyrrolic compounds, expanded pyrrolic macrocycles, and their respective derivatives are further examples of suitable photosensitizers. Photofrin® manufactured by QLT PhotoTherapeutics Inc., Vancouver, B.C., Canada is yet another example of a suitable photosensitizer. Other exemplary photosensitizers may be found in U.S. Pat. Nos. 5,611,793 and 6,693,093. U.S. Pat. No. 6,693,093 is hereby incorporated by reference. The photosensitizers mentioned above are examples are not intended to limit the scope of the present invention in any way.
6. Sonic energy: ultrasound, sonic waves or energy produced by a sonic or ultrasonic device (e.g., dental scaler or the like). It is preferred that the tip vibration of the sonic device is between the range of about 3 KHz to about 5 MHz, more preferably between about 10 KHz to about 1 MHz, even more preferably between about 20 KHz to about 50 KHz, and most preferably between about 25 KHz to about 40 KHz.
II. Exemplary Apparatus for Sonophotodynamic Therapy
i. Description of the Apparatus
Referring to
In the embodiments shown herein, the probes of the present invention are typically illustrated to integrate plural members into a single probe wherein the plural members are configured for guiding light, providing sonic energy, delivering fluid or a combination thereof. It should be understood, however, that these members may be divided amongst multiple probes if desired. It should be further understood that the probe of the present invention may integrate members according to a variety of configurations within the scope of the present invention.
The probe 12 of
With reference to
In the illustrated embodiment, the tube 44 extends centrally along substantially the entire insert 34, the probe 12 or both and substantially defines the body portion 38 of the insert 34. The tube 44 defines a passageway or tunnel 50 that also extends along substantially the entire insert 34, the probe 12 or both. Typically, the tube 44 is in fluid communication with therapeutic fluid source 26 via tubes or other members.
The optical fiber 46 is located within the tunnel 50 and is substantially coextensive with the tube 44. As shown in
The scaler tip 42 is attached to the tube 44 at one end of the tube 44. The scaler tip 42 defines its own tunnel 56, which is preferably in fluid communication with the tunnel 50 of the tube 44. The scaler tip 42 is preferably arced or curved, although not required.
Various tips or members may be employed for delivery of sonic energy and the use of the various tips or members contemplates that fluids may be delivered by those tips or members or delivered adjacent the tips or members using a variety of passageways. It is contemplated that a tip or other member may include one hole or multiple holes (e.g., arranged radially) for delivery of light, fluid or both or a tip may be formed of a porous (e.g., a microporous) structure for the delivery of light, fluid or both.
As shown in the example of
It is contemplated that the skilled artisan may be able to employ a variety of sonic energy sources within the scope of the present invention. Typically, the sonic energy source 20 includes an actuator material that assist in the creation and/or transmission of sonic energy to the member (e.g., the scaler tip) configured for delivery of the sonic energy and an activator for activating the actuator material. As an example, the sonic energy source could comprise a piezoelectric material in electrical communication with an electrical energy source wherein the piezoelectric material converts energy from the electric energy source into ultrasonic vibrations deliverable by a member such as the scaler tip. In particular, the piezoelectric material may deform or vibrate in response to the application of an electrical field at an ultrasonic frequency.
Generally, the actuator material may be configured in variety of shapes, sizes or other configurations. For example, the material could extend down the center of the probe and fluid delivery openings or other components of the probe may be outside the actuator material. Alternatively, the actuator material could comprise a plurality of rods and may or may not be tubular in configuration.
In the embodiment shown, there is an actuator material 60 integrated into the proximal portion 36 of the insert 34. The material 60 has a tubular configuration and substantially surrounds a portion of the tube 44 and a portion of the waveguide or fiber 46 of the insert. The particular actuator material 60 illustrated is a magnetostriction material that converts energy from an electric energy source 62 into ultrasonic vibrations deliverable by a member such as the scaler tip.
In the particular embodiment shown, the electrical energy source 62 includes excitation drive circuitry 64 configured for communicating the electrical energy from the electrical energy source 62 to the actuator material 60. In turn, the electrical energy exposes the actuator material 60 to a magnetic field that excites and vibrates the actuator material 60, which sonically or ultrasonically vibrates the tube 44 the scaler tip 42 or both. It is contemplated that the actuator material may be directly or indirectly connected to the member or tip for initiating the vibration.
Preferably, the apparatus 10 includes a controller 70 in signaling communication with the fluid sources 24, 26, 28 the light source 22 and the sonic energy source 20. The controller 70 will typically allow a user of the apparatus 10 to control the delivery of fluids, the delivery of light, the delivery and frequency of ultrasonic vibrations of the actuator material 60, the member or scaler tip 42, or both by the probe 12. The apparatus 10 can also include an activation device or switch 72 (e.g., an on/off foot controlled switch) for allowing the user to determine when ultrasonic vibrations, fluid, light or a combination thereof are to be delivered. It will be understood that a variety of different controllers and switches can be developed for controlling the probe and other components of the apparatus 10 within the scope of the present invention and depending upon the degree and type of control desired.
In the particular embodiment illustrated, the activation device 72 (e.g., switch or the like) can be linked to the excitation drive circuitry 64 and/or the control circuitry and can be used to control (1) the activation of electrical excitation to the sonic source 20 producing sonic energy; (2) the activation of light from the light source 22; and (3) the flow of fluid(s) (e.g., liquid, photosensitizing composition, gas) from the fluid sources 24, 26, 28 to the probe 12 or a combination thereof. The excitation drive circuitry 64 can also be configured for controlling amplitude of the electrical excitation to the sonic source 20, the light source, as well as the flow rate of fluid(s) to the probe 12. Fluid communication tubes 78 are connected and controlled by a switching device 80. The switching device 80 determines which of the fluid sources 24, 26, 28 (e.g., the liquid source 28, the therapeutic source 26 or the gas source 24) is delivered to the probe 12 via the tubes 78 and can be controlled by the controller 70. The switching device 80 can be any art-disclosed switching device and it can be optionally incorporated into the excitation drive circuitry 64. Thus the switching device 80 can comprise a single switch or solenoid in communication with two or all of the fluid sources, multiple switches or solenoids in connection with respective fluid sources or the like. Moreover, it is possible to have the switching device at least assist in controlling fluid flow rates.
In
Advantageously, the insert 34 can be removed from the housing and cleaned and sterilized between uses.
ii. Operation of the Apparatus
In use, the therapeutic fluid source delivers the fluid to the member configured for dispensing the fluid to an area of tissue. Thereafter, the light source communicates electromagnetic radiation to the member configured for delivering light to an area of tissue. Additionally, and typically at a close proximity in time to delivery of the photosensitizing composition or delivery of the light, the sonic energy source provides sonic energy to the member configured for delivering that sonic energy to an area of tissue. It should be understood that the areas of tissue to which the sonic energy, the fluid and the light are delivered are typically one single area of tissue, but such areas may be merely adjacent each other or only partially overlapping as well.
With reference to
Photosensitizing composition flows from its source 26 through a tube 78 and passage 104 of the connector 86 to and through the tunnel 50 of the tube 44 of the probe 12 for delivery to an area of the tissue. In the particular embodiment shown, the fluid flows from the passage 104 to and through the opening 56 in the member or tip 42 of the probe 12.
In an alternative embodiment, it is contemplated that a member such as a tube may be connected to the source of therapeutic fluid and may be separate from the members used for delivery of light and/or sonic energy. In such an embodiment, the therapeutic fluid may be applied to tissue and then a probe including both a waveguide and a sonic scaling tip may be employed to provide light and sonic energy to the tissue.
In the illustrated embodiment, electrical energy is typically provided via a bus 110 (e.g., a wire or other electrical conductor) to the electrically conductive material 98, which in turn creates a magnetic field for exciting the actuator material 60. The actuator material then vibrates at an ultrasonic frequency and, in turn, vibrates the scaler tip 42 at an ultrasonic frequency.
It is additionally contemplated that the apparatus 10 may include a source 28 of cooling and/or lavage fluid (e.g., coupling fluid, water or saline) that can flow the fluid to and through the probe for delivery of the fluid to an area of tissue. In the particular embodiment shown, fluid is delivered through a tube 78 and a passage 112 in the connector and is delivered to a passage 114 defined within the probe 12 between the conductive material 98 and the actuator material 60. The fluid is then delivered to the scaler tip 42 and emitted to the area of tissue. It is particularly preferred, but not required, for the sonic energy to be provided to the tissue in the presence of such cooling and/or lavage fluid.
It is additionally contemplated that the cooling and/or lavage fluid, the photosensitizing composition or both may include one or more additives, which can provide therapeutic advantages. For example, the cooling and/or lavage fluid, the photosensitizing composition or both may include bubbles (e.g., microbubbles) trapped in shells for enhancing acoustic cavitation, sonoluminescence or both when the probe is used to perform sonophotodynamic therapy. These bubbles can be produced using art-disclosed means such as the use of hydrocarbons, fluorcarbons, perfluorochemicals, sulfur hexafluoride etc. The addition of bubbles with gas in them (e.g., air, nitrogen, helium, argon, xenon, or the like) has been reported to emit light at higher intensity during sonoluminescence. The size of the bubbles is optimized to have a natural resonance at the frequency of sonic energy employed. The frequency resonance of a gas bubble (fr) is known to be approximately related by the following equation: fr=(3gPo/r)1/2/(2πa) where: g=the ratio of specific heats for a bas bubble, Po=ambient hydrostatic pressure, r=density of the surrounding media, and a=radium of the bubble in meters. Producing acoustic cavitation and sonoluminescence with lower applied acoustic intensity (e.g., tip vibration in the KHz ranges) is generally desired because of the potential problems with high intensity acoustic energy and non desired tissue effects.
It is also contemplated that gas (e.g., air, nitrogen, helium, argon, xenon, or the like) may be provided from the gas source 24 to any of the tunnels, openings, passageways or the like for purging or other purposes.
As suggested, the system apparatus 10 of the present invention may be employed for performing sonophotodynamic therapy upon a variety of tissue of nearly any organism, but that, the apparatus is particularly suited for performing dental sonophotodynamic therapy.
iii. Alternative Embodiments
As suggested previously, the members and other components of the apparatus of the present invention may be arranged, integrated and connected to each according to a variety of protocols within the present invention. As such,
In
The probe 120 preferably includes a member such as a tube 144 for delivering photosensitizing composition to and through the scaling tip 132. The optical fiber 136 is located within and extends along a wall 146 of the housing portion 130. As such the fiber 136 is substantially coextensive with the actuator material 138. In the embodiment shown, the fiber 136 extends outward from the housing portion 130 and is arced to emit light toward the scaling tip 132. It may be desirable to provide a protective encasing 150 about at least the end 152 of the section 134 of fiber 136. The attachment 124 is also shown to include a covering 158 for protecting a linkage portion that connects the actuator material 138 to the scaler tip 132.
With reference to
Upon attachment of the attachment portion 124 to the base portion 122, the section 134 of waveguide of the attachment portion 124 aligns with the section 170 of waveguide of the base portion 122 such that light can be transmitted down the lengths of the sections to the end 152 of the member or completed waveguide 180. Also upon attachment, the actuator material 138 is located in the hollow portion 166 of the conductive material 162 such that the actuator material 138 may be sonically vibrated as previously described.
In another alternative embodiment and with reference to
It is additionally contemplated that any of the fluids may be separately delivered rather than through the probe. For example, a syringe or a tube and pump assembly may be employed to deliver photosensitizing composition, cooling or lavage fluid or air or other gasses and then the probe may be used at the location of delivery of the fluid.
Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components can be provided by a single integrated structure. Alternatively, a single integrated structure might be divided into separate plural components. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention.
III. Sonophotodynamic Therapy
Referring to
The light applied during the irradiating step 106 can be supplied by a single light emitting device or a plurality of light emitting devices. Any suitable art-disclosed light emitting device(s) such as lasers, light emitting diodes (“LEDs”), arc lamps, incandescent sources, fluorescent sources, gas discharge tubes, thermal sources, light amplifiers or the like may be used to provide the wavelength(s) that can be absorbed by the photosensitizing composition. Lasers include any art-disclosed lasers such as diode lasers, gas lasers, fibers lasers or diode pumped solid state laser or the like. LEDs include any art-disclosed LEDs such as semiconductor LEDs, organic LEDS or a combination thereof. Fluorescent sources include any art-disclosed fluorescent sources such as fluorescent tubes, LED pumped fluorescent devices, cold cathode fluorescent panels or the like. Light amplifiers include devices that produced an amplified amount of input light (e.g., fiber amplifiers, gas amplifiers, etc.) or devices that produce wavelength shifted version of incident radiation or harmonics of incident radiation.
The light applied during the irradiating step 106 provides the wavelength(s) that can be absorbed by the photosensitizing composition. Such wavelength(s) include wavelengths selected from the continuous electromagnetic spectrum such as ultra violet (“UV”), visible, the infrared (near, mid and far), etc. The wavelengths are generally preferably between about 160 nm to 1600 nm, more preferably between 400 nm to 900 nm, most preferably between about 500 nm to 850 nm although the wavelengths may vary depending upon the particular photosensitizing compound used and the light intensity.
Referring to
For methods 100 and 200, the time required for each of the steps (102, 104, 106, 202, 204) on a locus may vary depending on the existing conditions (e.g., the microbes, the photosensitizing composition, the amount of calculus and plaque, the sonic energy source, the light source, etc.). For example, in one embodiment of the present invention, the time for completion of each of these steps may range preferably from about 1 second to about 1 hour, more preferably from about 1 second to 10 minutes and most preferably from about 1 second to 5 minutes. It is preferred that the photosensitizing composition is left in contact with the locus for a period of time to enable the microbes located near or at the locus to take up some of the photosensitizing composition and become sensitive to it. A suitable duration will generally be from about 1 second to about 10 minutes, preferably about 5 seconds to about 5 minutes, more preferably about 10 seconds to about 2 minutes and most preferably about 30 seconds although this may vary depending upon various factors such as the particular photosensitizing composition used, the target microbes to be destroyed, the reaction time required for any other compound(s) that may be added into the photosensitizing composition, etc.
The photosensitizing composition of the present invention is not limited to the use of one photosensitizer during the sonophotodynamic therapy. Depending on the desired application, multiple and/or different photosensitizers can be used simultaneously or separately during such therapy. The photosensitizing composition is preferably in a fluid form and the amount or concentration of the photosensitizer(s) contained in the photosensitizing composition may vary depending upon the desired application, the particular photosensitizer(s) used, and the target microbes to be destroyed. In one embodiment of the present invention, the concentration of the photosensitizer(s) is preferably from about 0.00001% to about 50% w/v, more preferably from about 0.0001% to about 25% w/v, still more preferably from about 0.001% to about 10% w/v, and most preferably from about 0.01% to about 1% w/v. Furthermore, the photosensitizing composition may comprise addition components such as pharmaceutically compatible carriers (e.g., solvent, gelling agents or the like), buffers, salts for adjusting the tonicity of the solution, antioxidants, preservatives, bleaching agents, antibiotics, or the like.
The sonic energy can be applied at any suitable art-disclosed level using any suitable art-disclosed devices such as a conventional dental scaler. For a list of exemplary dental scalers, see Introduction to Automated Scaler Comparison (Comparison of 16 Ultrasonic and 7 Sonic Scalers), June 1998 CRA Newsletter (Vol. 20, Issue 6), which is hereby incorporated by reference. It is preferred that the tip vibration of the sonic device is between the range of about 3 KHz to about 5 MHz, more preferably between about 20 KHz to about 3 MHz, and most preferably between about 25 KHz to about 1 MHz.
The methods (100, 200) of the present invention are useful for many purposes including, but is not limited to, (a) destroying disease-related microbes in a periodontal pocket in order to treat chronic periodontitis; (b) destroying disease-related microbes in the region between the tooth and gingiva in order to treat inflammatory periodontal diseases; (c) destroying disease-related microbes in the pulp chamber of a tooth; (d) destroying disease-related microbes located at the peri-apical region of the tooth including periodontal ligament and surrounding bone; (e) destroying disease-related microbes located in the tongue; (f) destroying disease-related microbes located in soft-tissue of the oral cavity; (g) disinfecting drilled-out carious lesions prior to filling; (h) sterilizing drilled-out carious lesions prior to filling; (i) destroying cariogenic microbes on a tooth surface in order to treat dental caries; (j) destroying cariogenic microbes on a tooth surface in order to prevent dental carries; (k) disinfecting dental tissues in dental surgical procedures; (l) disinfecting gingival tissues in dental surgical procedures; (m) sterilizing dental tissues in dental surgical procedures; (n) sterilizing gingival tissues in dental surgical procedures; (o) treating oral candidiasis in AIDS patients; (p) treating oral candidiasis in immunocompromised patients; and (q) treating oral candidiasis in patients with denture stomatitis.
The apparatus and the methods (100, 200) of the present invention discussed above also can be use for destroying disease-related microbes in wounds in other parts of the body (i.e., not just in the oral cavity) and disinfection of such wounds. In fact, it is believed that the present invention can promote wound healing. For such treatments of wounds, the apparatus and the methods described above would be the same except that instead of “locus” within the oral cavity, the methods would involve a wound.
The preferred embodiment of the present invention has been disclosed. A person of ordinary skill in the art would realize however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.
IV. Example
The present invention will be illustrated by the following example. This example is not intended to limit the scope of the present invention in any way.
E. coli ATCC 25922 at a concentration of 1×106 CFU were put in a ˜0.5 ml well (TiterTek 96 well plate) with 50 ug/ml methylene blue (CAS number 61-73-4) in sterile water. Laser light at a wavelength of 670 nm was applied through a 200/240 micron cleaved optical fiber positioned so that light was emitted from the fiber and impinged upon the surface of the well at measured distances above the well. The light output of the cleaved fiber for each run was measured with an optical wattmeter. The spot size of the main beam at the surface of the fluid in the well was estimated by measuring the diameter of the brightest region with a scale then calculating the area from this diameter. Further, the intensity in the spot was calculated by dividing the measured power by the area of the spot.
Sonic energy was produced by a Parkell Turbo Sensor Ultrasound Scaler (25-30 KHz) with a Cavitron 30 KHz periodontal scaler insert (FSI-SLI). The power control on the unit has a low, medium, and high setting. These settings have peak to peak tip vibratory displacement amplitude in air of 34, 74, and 86 micrometers respectively. See Introduction to Automated Scaler Comparison (Comparison of 16 Ultrasonic and 7 Sonic Scalers), June 1998 CRA Newsletter (Vol. 20, Issue 6). A cylindrical wave emitted from a 1 mm diameter, 30 kHz vibrating wire at these peak-to-peak displacements would produce an emitted power, in air, per 1 cm wire length of 0.14, 0.48 and 0.85 watts respectively (utilizing equation 7.3.5, PM Morse & KU Ingard's Theoretical Acoustics [1968, McGraw-Hill, pp 358]) If this same amplitude of vibration was achieved in water, the emitted power would be 5.1, 18.5, and 32.7 W/cm respectively. Since a length of only about 2 mm of the tip would in fact be vibrating at the measured amplitudes, it is estimated that in air 0.028, 0.098, and 0.17 Watts, respectively, would be emitted at those displacements. In water, an estimated 1.0, 3.7, and 6.54 Watts would be emitted for the 2 mm tip length at those displacements. The relative amplitude of sound generated at the low, medium, and high settings in water were measured with a small microphone (Radio Shack Model No. 33-3028) covered with a latex membrane held at 3 mm from the vibrating tip under water. The RMS voltage amplitudes measured were 3.3, 5.7, and 10 volts at the respective settings. The square of these amplitudes is related to power being radiated. The square of each voltage reading provides 11, 32.8, and 100.8 V2, respectively. A plot of the square of these microphone measurements compared to the calculated emitted power (based on the peak-to-peak tip vibratory measurements) is shown below, demonstrating fairly a proportional relationship between the expected emitted power in water, given the tip displacements and emitted power estimated from microphone measurements. This result indicates the equipment used in this study was operating in a proportional manner to that as reported in the literature.
Each trial was conducted with a new well containing the suspension of bacteria and dilute photosensitizer solution. The ultrasound tip was sterilized by gently agitating the tip in Sporicidin® solution for 30 seconds per manufacturer's recommendations between each trial. Four trials were conducted for each exposure condition. The ultrasound tip was placed about 3 mm into the solution in the well for each trial. Exposures of light with no applied sonic energy and exposures with sonic energy and light were made. Time of exposure was standardized to 30 seconds per trial. The power control of the Parkell Turbo Sensor Ultrasound Scaler was set at the medium setting.
Results with light and sonic energy:
*CFU/ml refers to colony forming units per ml.
**Due to low sample volume exact counts could not be calculated. Replicate was excluded from
analysis.
Results with light alone without sonic energy:
Comparing the results of with and without sonic energy:
As shown above, without ultrasound there was no significant killing of bacteria with light intensities of 14 mw/cm2, 282 mw/cm2 and 478 mw/cm2. However, with ultrasound present at these light intensities, the surviving bacteria decreased respectively, 0.92, 0.63, and 0.19 compared to the results with no ultrasound. Furthermore, when the light was increased to 3,184 mw/cm2 there was a significant amount of bacteria killed by only the light and photosensitizer. In spite of this, with ultrasound on at these optical intensities, more bacteria were killed (0.02 less bacteria survived than when no ultrasound was on). These results demonstrate that there is a synergistic effect of ultrasound, light and photosensitizer in killing bacteria.
This application claims the benefit of U.S. Provisional Application Ser. No. 60/590,421 titled: “Dental Photocidal Therapy by Means of Dental Scalers” filed on Jul. 22, 2004 and U.S. Provisional Application Ser. No. 60/622,463 titled: “Improved Dental Scaler for Use in Photocidal Therapy” filed on Oct. 27, 2004.
Number | Date | Country | |
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60590421 | Jul 2004 | US | |
60622463 | Oct 2004 | US |