US3840932A

US3840932A - Ultrasonic toothbrush applicator

Info

Publication number: US3840932A
Application number: US00318430A
Authority: US
Inventors: R Meyer; L Balamuth; M Rutten
Original assignee: Ultrasonic Systems Inc
Current assignee: Ultrasonic Systems Inc
Priority date: 1972-12-26
Filing date: 1972-12-26
Publication date: 1974-10-15
Anticipated expiration: 1991-10-15

Abstract

An applicator in the form and/or a configuration adapted to be ultrasonically vibrated to transmit mechanical vibrations from one end thereof to bristle elements positioned at approximately the other end thereof for use in the oral cavity.

Description

United States Patent 1m Balamuth ct al.

1 1 ULTRASONIC TOOTHBRUSH APPLICATOR [75] Inventors: Lewis Balamuth, Southampton; I

Michael R. Rutten, East lslip; Robert Meyer, Huntington Station, all of NY.

[73] Assignee: Ultrasonic Systems, Inc.,

Farmingdale, NY.

[22] Filed: Dec. 26, 1972 [21] Appl. N0.: 318,430

[52] U.S. Cl. 15/167 R, 15/22 R, 15/195, 300/21, 128/62 A [51] Int. Cl. A46b 9/04, A46b 13/02 [58] Field of Search 15/167 R, 22 R, 192, 193, 15/195; 300/21; 128/62 A [56] References Cited UNITED STATES PATENTS 2,397,471 4/1946 Cox 15/159 R X 7 2,878,069 3/1 9 5 9 wessel, 300/2 1 I451 Oct. I5, 1974 3,335,443 8/1967 Pzlrisi ct ill. [5/167 R X 1375,2420 4/1968 Kuris C1211 3,471,202 10/1969 Lewis. Jr 3,488,788 1/1970 Robinson 15/22 R X Primary Examiner-Peter Feldman [57] ABSTRACT An applicator in the form and/or a configuration adapted to be ultrasonically vibrated to transmit mechanical vibrations fromone end thereof to bristle elements positioned at approximately the other end thereof for use in the oral cavity.

34 Claims, 28 Drawing Figures PATENTEU 1 Sim 3.840.932

SHEET 2 BF 8 F/G. 3 v F/G', 4

24d /Zd /2ci /06 g; l /2e :"i M we NODE LOOP E PHASE SHIFT (EQUIVALENT TO 2 26% A QUARTER WAVE 26f LENGTH OF HOMOGENEOUS I A=vvAvE LENGTH 0 (LONGITUDINAL VIBRATION) IN Z0 30 EACH SECTION OF THE I.INE SHOWN TRANSMISSION LINE) PAIENIEDBBT I 51914 3.840.932

SHEU 7 [IF 8 PATENTEDUEI 1 saw SHEET 8 OF 8 PROVIDING BRUSH WITH APERTURES INSERTING BRISTLE CLUSTERS IN BRUSH ELEVATI NG TEMPERATURE OF BRUSH STAPLING EACH CLUSTER TO BRUSH ELEVATING TEMPERATURE OF BRUSH APPLYING SO LVENT TO BRUSH DRYING OF BRUSH TRIIVIIVIING OF BRISTLES FINISHING BRISTLE TIPS ULTRASONIC TOOTHBRUSH APPLICATOR CROSS-REFERENCE TO RELATED APPLICATIONS In a co-pending patent application of Lewis Balamuth, Arthur Kuris, and Manual Karatjas, Ser. No. 318,428, filed Dec. 26, 1972, for Ultrasonic Motor- Converter Systems, and assigned to the assignee of the present invention, an ultrasonic system that may be used as for oral cleaning is shown having a brush applicator that may be designed in accordance with the present invention BACKGROUND OF THE INVENTION This invention relates to the dental field and more particularly to a toothbrush designed for and compatible with an automatic toothbrushing system which is powered in the sonic and ultrasonic range for inducing vibrations therein.

The applicants have found that for commercial application of their invention it would be desirable for home use to utilize a brush head made substantially of plastic and not of a metallic material as disclosed in US. Pat. No. 3,335,443. In order to achieve the assembly of brushes having a plastic body on a mass production basis, they required certain novel procedures and designs in order to obtain these results.

OBJECTS OF THE INVENTION One object of the invention is to provide a novel applicator to be used in the ultrasonic energy range.

Accordingly, another object of this invention is to provide a toothbrush especially designed for use with a sonic-ultrasonic powered system in order that improved cleaning and polishing may be achieved at the same time gingival health benefits are obtained.

Another object of the invention is to provide a toothbrush head designed for compatible use from an ultrasonic power source.

Another object of the present invention is the provision of a brush head in which plastic tip bristles and plastic head brushes are coupled together for the transmission of ultrasonic and sonic energy for the individual bristle elements.

Other objects of the invention will become apparent as the disclosure proceeds.

SUMMARY OF THE INVENTION The present invention provides for an interchangeable toothbrush assembly that when coupled to an ultrasonic motor is adapted to be vibrated at an ultrasonic rate and simultaneously therewith at a sonic rate while the motor may be hand held and the bristle clusters of the brush are utilized for the removal of foreign deposits from teeth. In order to assure the proper transmission of high frequency energy from the body portion of the brush to the individual bristles, appropriate securing means are employed such that the relation of the plastic bristles to the plastic body portion are properly matched and energy is transmitted.

As hereinafter discussed, there is a defined relationship between the spacing of the bristle clusters and the selection of the material from which the body portion of the brush is fabricated so as to assure a proper vibratory energy transmission. The applicator means or brushes of the present invention may have individual bristle diameters and a resistance factor to obtain maximum cleaning cfficiency. For example, it has been found that a brush having bristle clusters that range in the diameter of 0.004 inch to 0.020 inch and having approximately bristles per cluster at 0.008 diameter generally form a bristle configuration to which the energy may be properly transmitted and yet also properly clean.

Another aspect of the invention resides inthe fact that the output end of the bristle clusters may be contoured so as to accept the configuration of the teeth as same is positioned within the oral cavity for use by the user such that the brush may be placed, if desired, in relatively fixed positionagainst the teeth so as to maintain it in a relatively fixed position as the energy from the bristle tufts is transmitted to obtain the cleaning re sults.

BRIEF DESCRIPTION OF THE DRAWINGS Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself, and the manner in which it may be made and used, may be better understood by referring to thefollowing description taken in connection with the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout the several views and in which:

FIGS. 1-5 are diagrammatic views of applicators to help illustrate the theory of the present invention;

' FIG. 6 is a diagrammatic view of applicator means in which the bristles are curled;

FIG. 7 is 'a diagrammatic view to help illustrate the present invention; 3

FIG. 8is a diagrammatic view to help illustrate the theory of the presentinvention;

FIG. 9 is a perspective view of an ultrasonic home oral unit in accordance with the present invention;

FIG. 10 is an enlarged sectional view illustrating applicator means in accordance with the present invention;

FIG. 11 is an end view of the applicator means illustrated in FIG. 10;

FIG. 12 is a fragmentary elevational view of a portion of the applicator means in accordance with the present invention;

FIG. 13 is an enlarged fragmentary sectional view taken substantially along the line 13-13 in FIG. 12;

' FIG. 14 is an enlarged fragmentary sectional view taken substantially along the line 14-14 in FIG. 12;

FIG. 15 is an enlarged fragmentary sectional view illustrating the individual bristles secured in position;

FIG. 16 is an enlarged fragmentary view illustrating the rounded bristle ends;

FIG. 17 is a front view of another form of applicator means in accordance with the present invention;

FIG. 18 is a bottom view of the applicator means in FIG. 17;

FIG. 19 is a top view of the applicator means in FIG. 17;

FIG. 20 is an enlarged side view in cross-section of the applicator means of FIG. 17;

FIGS. 21 and 22 are enlarged diagrammatic views of bristle elements;

FIGS. 23-26 illustrate the cleaning system of the present invention in relation to a set of human teeth and are helpful in explaining the process of the instant invention; and

FIG. 27 is a block diagram illustrating the method of manufacturing the brush of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS The ultrasonic applicator means of the present invention, as hereinafter discussed with respect to FIGS. 1-6, is dependent upon an interrelated number of characteristics in order to function in a desired manner.

Prior art disclosure of ultrasonic toothbrush design requires that the ultrasonic activity of each bristle cluster pair diminishes proportionately to their position or distance from said bristle holding toothbrush section or element. Thus, it was desirable to make the applicator means operate at the lowest possible ultrasonic frequency so that the wave length of waves in the body section would be as long as possible, thereby diminishing the effect of displacement from the free end. It was recognized that this frequency limitation seriouslyhampered the freedom to design the most effective brush head for optimal cleaning and other effects inherent in the use of ultrasonic energy for the care of teeth and gingiva.

As FIG. 1 shows diagrammatically in accordance with the prior art for a toothbrush a having a body section 12a of a metallic material which forms the bristle cluster base which shows the greater ratio of the cluster base, 1, to the loop-node (7/4) distance, the more will the amplitude of vibration of the bristle cluster base 12a diminish from its free maximum vibration end 14a as illustrated by the curve 16a which represents the amplitude of vibration from the node at the vertical plane at 18a in at which there is no longitudinal vibration to a loop of longitudinal vibration where the amplitude of vibration is maximum as indicated at the vertical plane 22a.

Now, the physical demands of toothbrush dynamics require a number of bristle clusters a each having a bristle base 20a and elements 21a of finite size (each cluster might have a base diameter of about 3/32 inch). Furthermore, these demands mean that to achieve ordinary toothbrush capacity, one must provide a length of vibratory base material which is at least of the order of a half inch up to one inch in magnitude. Now applicants recognized that conventional electric toothbrushes operating in the 60 vibrations per second range do not encounter the above problem because the wave length, so to speak, becomes relatively infinite or at least so large that all the bristle clusters bases move in phase with the same reciprocating stroke.

Now, in order to enjoy the unique advantages and easy adaptability of the ordinary tooth form, applicants have discovered a way of desinging a toothbrush to satisfy these requirements. The essence of applicants invention resides in the discovery that there are acoustically efficient plastic materials with extremely low speeds of sound (or what is the same thing, low speeds of longitudinal vibrations). For example, a polycarbonate such as Lexan, has a speed of longitudinal waves in a rod of about one fourth the value of the speed of such waves in steel or aluminum at the same high frequency (i.e., above 20 KHz). This results from the fact of the extremely low value of the Youngs Modulus'of this increase in Youngs Modulus. This still further lowers the speed of longitudinal waves in such an element.

As a result, an analysis is provided in FIGS. 2A in which a steel rod, or body section 12b is illustrated as vibrated, at 40 KHz and compare it with a Lexan rod in FIG. 2B or body section 120 at the same frequency. Steel has a wave length of about 5 inches at 40 KHz and therefore a 7/4 of 1.25 inches.

The Lexan corresponding 'r/4' will be approximately one fourth of the value for steel /r 1.25 inches 0.36 inch.

FIGS. 2A and 2B shows the difference of vibration as indicated by curve 16b for steel in distribution at 40 KHz for a steel rod with bristles and a Lexan rod as indicated by curve 160 with bristles. As will be seen later, the presence of the bristle clusters modifies the curves 16a (same as 16b) and 160 in opposite senses, whereby optimal distribution of ultrasonic power density in the bristle clusters is favored in the case of curve 16c and is worsened in the case of curve 160. Clearly the steel rod body section 12b shows a significant reduction in amplitude of the bases 20b of the bristle clusters 15b in going from point B to point A over an approximately /5; inch distance. The Lexan body section 126 on the other hand shows a distribution of nodes and loops of vibration as illustrated by curve 16c within the same approximately inch section at the same frequency. As a result, it is possible to distribute the bristle clusters so as to take advantage of such sites as a, b, c and d (see FIG. 2B). In fact, it is evident that by simple design it 1 is possible to obtain an extended toothbrush complemerit of bristle clusters so that the vibration amplitude (and hence the efficiency of action) of all clusters may be monitored at about the same level.

This is a novelconcept to this art and enables one to produce efficient, inexpensive toothbrushes operating in the ultrasonic frequency range. In addition, new design possibilities arise in relation to the transmission line design, which did not exist before, because the distance between bristle clusters is of the same order as the 1/4 of the transmission line. It is intended to take advantage of all such possibilities within the scope of this invention. For example, consider a structure such as FIG. 3, which accomplishes the results desired by the use of a body section 12d having enlarged radial sections 24d with bristle clusters 15d extending radially therefrom.

FIG. 4 illustrates the invention in which bristle clusters 152 may be in radial arrays from the body section 122 in such a manner that a multiple number of clusters exist in each plane of the brush l0e.

Now, applicants have discovered, that in order to be able to produce a home oral device together with its necessary electronic converter, the most basic questions to be answered were those permitting increased efficiency of operation, adequate safety in home use in the mouth, and especially simplicity of design permitting low production costs for a mass-production product. One important part of this effort in the case of the applicator means or brush head wasto guarantee good vibration energy transfer from the base to the bristle clusters without having recourse as in the prior art to relatively expensive epoxy bonding of such cluster in a metal base. Also, the effect shown in FIG. 3, and hereinafter discussed in greater detail, was to be made as simply as possible so as to achieve optimum spacing of bristle clusters relative to the standing wave pattern set up in the base during operation. This was done by a combination of factors whereby every element in the design entered into experimental work. For example, bristle diameters were selected which would produce a visible fog-like spray of water from the wet bristle head when vibrating in the motor-converter system of the in vention. Also, a maximum number of bristles per cluster was used compatible with the cross-sectional dimensions of the base portion. In addition, specific advantage was taken in inserting a bristle cluster by employing a well known mass production technique which caused a bristle cluster to be composed of a bundle of U-shaped plastic filaments, which are pushed into an aperture with the aid of a metal staple which stays with the bristle cluster after insertion. This mechanical technique is extremely fast and is preferably carried out with the thermoplastic base in a heated condition just below its creep temperature, so as to minimize static residual stresses due to the insertion. But, such mechanical insertion still leaves voids in the region of insertion which serve to lessen the transmitting efficiency of the bristles to the base insofar as vibration transmission is concerned. This difficulty was obviated by the simple expedient of dipping the brush head, after being formed, into a solution which acts as a better solvent for the thermoplastic base material than for the thermoplastic bristle material. For example, a preferred embodiment of the head would include Nylon bristles staple-mounted into a Lexan (polycarbonate plastic) base and blended with a solution of methylene chloride. The solvent can be applied either by a brief dip after mechanical fabrication or can be incorporated into the staple mounting operation by addition of a small amount of said solvent at that time.

In any case, the results achieved are typically hereinafter illustrated with respect to FIGS. 9-22, which shows the U-shaped bristle elements, in place with the cross-section of the metal staple showing. In addition, the spaces between the bristles are filled with the base material which has flowed into place due to the action of the added solvent, which is volatile and vanishes after performing its job. Thus a number of effects are simultaneously achieved whereby excellent acoustic or high frequency vibration coupling is achieved with minimal losses. For example, in practice, it has been found that, with an eight bristle cluster applicator head is mechanically coupled onto the motor output, a definitely visible spray from the bristles in a water wetted condition may be produced on the 30KH2 range with input of only 2 watts into the motor. This recital of facts alone will illustrate to anyone skilled in the art that the instant type of brush head and body is extraordinarily efficient.

In addition, the construction of FIG. 5 serves to bring about in part the condition shown in FIG. 3, without the alterations r, and r, of cross-section shown in FIG. 3. This is because the bristle clusters as shown, for example, at b in FIG. 6 together with the metal staple, act as an increased mass in the section of the transmission line where it is inserted.

In order to understand this matter and its importance, we will consider in FIG. 5 a quarter wave transmission line for longitudinal or torsional vibrations as composed of two

sections

26f and 28f of equal length.

The line is shown as cylindrical for mathematical convenience, which in no way affects the force of the following argument. Now, the radii r,, and r, and the length 1 and the length 1 are easily shown to be connected in the following equation tan (21TI,,/ r) u/ l) a In the case of a non-cylindrical line, then we may use the cross-sectional areas A, and A and in this case a= A /A in the above equation. From the equation a simple table of values may be made as follows:

Table l (1 Degrees As may be seen from the equation and the table, when r, is about one third of r,, then the value of 21r1 /r is l7.8 as compared with 45 when the two crosssections are equal. This is equivalent to the conclusion that the 1-r/2 phase shift shown in FIG. 5 takes place in a distance which is (17.8/45) 0.4 of the distance required for uniform cross-section. Thus, in the previous example given in connection with FIG. 2, at 40 KHz, the value of 7/4 was shown to be 0.36 inch in Lexan. With the alternating reduced cross sections of the FIG. 5 presentation, the equivalent 7/4 or 1r/2 shift in phase would occur in a distance of 0.4 X 0.36 0.144 inch. The bristle clusters would still further reduce this phase shift distance. Thus, it'is shown that the novel design features disclosed herein do in fact allow bristle cluster locations at region of uniformly high activity.

In order to understand better the relation between frequency of operation of the disclosed home oral device and the various dimensions of the bristle cluster arrangement and the total toothbrush head herein described for rigid detachable fastening to the ultrasonic motor, we will take a few examples. Let us consider operation first at 30Kl-Iz. With a polycarbonate (Lexan) thermoplastic head, we have the wave length, 1, equals 1.86 inches, and so a quarter wavelength corresponds to 0.46 inches. Now, as has been taught herein through FIG. 5 and Table I, the presence of the metal staple elements, together with the bristle clusters, produces an a value substantially less than one. This means that the spacing of bristle clusters relative to the phase of the standing longitudinal waves in the brush head is substantially reduced to a value determined by the numerical value of a. For example, with two bristle clusters, b, as shown in FIG. 6, the a-effect is magnified and it is readily possible to reduce the phase shift distance, d, by at least 50 percent, which in our 3OKHz example becomes equal to 0.23 inch, or about a quarter of an inch. The distance, d, may be still further controlled and decreased by varying the cross-section of the

thermoplastic toothbrush bases

12g and 12h as shown in FIGS. 6 and 7 respectively.

For a frequency of 40KI-Iz, 1' equals 1.4 inches and a quarter wavelength corresponds to 0.35 inch. In this case, distance, d, between the bristle clusters 15g and 15h as described in relation to FIGS. 6 and 7 would be about 0.18 in or about 3/16 of an inch.

If the base were metal, such as aluminum or stainless steel then at 30KI-Iz, 'r=6.67 inches, 'r/4 1.6 inch. But

when we consider the distance, d, the a-effect (not considered in the prior patents) would be reversed, because the acoustic impedance of the metal is so much greater than that of the bristle cluster and its epoxy base. In this case, the holes in the metal are filled with a lighter, lower mechanical impedance element and the distance, d, is substantially 1/4 or greater, or at BOKHZ, equal to or greater than I .6 inch. Now, it is evident that this is greater than the whole length of a brush head normally used for toothbrushing and so the novel art disclosed in the instant invention may not be practiced in the prior art disclosed toothbrushes.

The correspondence between FIGS. 6 and 7 and the design structure of a toothbrush in the present invention may be clearly seen in FIGS. 10-17, inclusive, FIG. 6 illustrating bristle elements 21g having a curled like configuration.

As can be seen in FIG. 8, the design has been accomplished whereby the toothbrush 10j has bristle clusters in regions on the base 1 2], P, along the verticle plane defined by line 22 are in regions of peak amplitude of vibration as in the curve 16 due to the transmission line effects discussed above. In particular radial sections 24j are in effect the equivalent of the combined mass at the base or the bristle clusters 15]. It will be noted that, in order to conform with the theory, it is desirable to place the bristle clusters 15j at the very end of the toothbrush base 12j so that the portion 30j is shorter in length than the portion, 24j as shownJAlso the distance D is equal to a half wavelength in the thermoplastic toothbrush transmission member, needed to screw on the brush to the motor. Accordingly, d' is a quarter wave, which in turn as we have shown is larger than the distance, d, which in its turn depends on the value of a which may be chosen in the various ways disclosed. For Lexan at BOKI-Iz, a half-wave length, D, is about 0.93 inch. Therefore, in making a usable toothbrush according to the teaching of this invention, the size and depth of the mouth (oral cavity) must be at least three inches,'and so must incorporate a number of half-wavelengths (180 phase shift) or a number of 90 phase shifts in the node to loop distribution in going from the attachment point to the end of the brush head. A typical Lexan head with nylon bristles operating at about BOKI-Iz would include 1 l or 12 90 phase shift elements in the 3-inch length of the disclosed detachable toothbrush. A toothbrush head having a metallic base is designed and is therein taught as a fraction of a 90 phase shift.

Thus, applicants believe they have shown the sophisticated design features of the disclosed invention herein, and have adequately related it to the prior art. To summarize, applicants have found the sophisticated approach herein described with the whole interrelated combination of production and design features to be essential to the creation of an ultrasonic toothbrush which can be mass-produced with associated motorconverters within a cost basis making possible for the first time to have an effective toothbrush at consumer prices. This is the essential step to making oral hygiene control in the home possible, with benefits inherent in the ultrasonic approach and which benefits cannot be otherwise created.

PREFERRED EMBODIMENTS FIG. 9 illustrates the ultrasonic system 40 which includes instrument means 42 in combination with converter means 44 that work in unison to perform a variety of applications as for example that of tooth brushing. The ultrasonic system 40, for example, is designed to permit the daily use by a person in the home of a toothbrush, whose bristles are mechanically vibrated in a dual frequency in that there is introduced a very low level of high frequency mechanical vibration and, the total power level introduced into the bristles being considerably less than one watt.

In addition to the functionsperformed by an ordinary nonelectric traditional toothbrush, the ultrasonic system 40 provides a local action, due to the invisible very low speed microscopic excursions of the individual bristles 45. These low speed invisible reciprocal motions, in combination with saliva or saliva assisted with a suitable dentifrice, provide beneficial stimulation of the gingiva, especially at the tooth-gingiva junction regions, as well as a removal of plaque, which is generally recognized as a principal source of calculus formation and possibly subsequent loss of teeth due to periodental disease.

Thus, to recapitualte, the purpose of the ultrasonic system 40 when used with bristle elements is to provide a person with a device to use in the home and thereby assist the dentist in achieving a significant care of the teeth and gums, in order to help prevent the onset of periodental disease.

The instrument means 42 includes handle means 46 adapted to be heldby the user in a conventional manner, and also having the detachable applicator means or assembly 10 containing the bristle clusters or stimulants 15 to be ultrasonically vibrated. Extending from one end of the instrument means 40 thereof is supply means 48 which supplies to the instrument means 42, power from the'generator or power means 44 which may have an electrical cord 49 connected to a plug 50 adapted to be plugged into a standard electrical outlet; Le, cycles per secondfSwitching means 52 of the generator 44 includes a switch 54 for providing power for energizing the ultrasonic transducer or motor contained within the instrument casing or housing means 46 of the hand held instrument means 42. The energy from the generator 44 is transmitted to the ultrasonic motor by wires extending through the flexible conduit 56 of the power supply means 44. There exists a multi frequency form of vibrations at the bristle clusters 15 and in the high frequency range illustrated by the double headed arrow 60 which forms a synergistic cooperation of a number of special properties inherent in the total system.

The complete assembly for use in the home includes the generating means 44, for example, a transistorized oscillator capable of producing electrical oscillation at a frequency in the ultrasonic range, as defined herein and the sonic range as defined herein. In practice, the generator 44 may be as small from 1 to 4 watts arid generally in the range of l to 10 watts, and is preferably of The electrical assembly 44 automatically activates the ultrasonic motor in the handpiece housing 46, which in turn transmits modulated high frequencyultrasonic vibrations to the bristle clusters 15 at the end of the applicator means in the form of a plastic transmission line connected detachably to the ultrasonic motor input. The modulation of the high frequency vibrations is, for example, a cycle component which is supplied through the electric converter assembly 44 directly to the bristle clusters 15. The low rate of vibration may be in the range of 10 cycles to 1,000 cycles per second.

By way of example for home consumer application in a tooth brush, the power drawn by the electric converter assembly 44 may be in the range of l to 10 watts. The power delivered to the ultrasonic reciprocal motor 45 in the handpiece is under two watts. The mechanical power delivered to the bristles and subsequently into the gingiva and teeth of the user is variable depending upon the pressure and movement of the bristles by the hand of the user. But, in any case, this power under maximum conditions is but a minute fraction of the power delivered to the handpiece is consumed in overcoming electrical and mechanical dissipation of the motor reciprocal motion and toothbrush element.

Essentially, the motor construction, as hereinafter described, is designed depending upon the use thereof to accept a variety of applicator means 10 and the magnitude of ultrasonic mechanical vibrations to be imparted thereto may be selected by proper motor design. The motor includes a transmission member which has a rear section within the housing 46 and a front section 62 extending beyond the casing 46.

The ultrasonic motor in conjunction with the applicator means 10 is longitudinally dimensioned so as to have lengths which are generally whole multiples of half-wavelengths of the compressional waves established therein at the frequency of the combines longitudinal length of the components so that longitudinal loops or other components of motion occur at the end of the applicator means 10. Thus, the optimum amplitude of longitudinal vibration and hyperaccelerations of transmission is achieved, and such amplitude is determined by the relationship of the motor and applicator means 10.

Now referring more particularly to FIGS. 10-13, there is illustrated the applicator means 10 which is designed to be used with the ultrasonic instrument means 40 as previously illustrated with respect to FIG. 9. The applicator means 10 includes a base or body section means 12 with a longitudinally spaced apart ends 63 and 64 and having a brush head or head portion 65.

which is the upper section in which the bristle clusters 15 are contained and a spaced lower portion or end 66 with a middle section or portion 68 extending therebetween. The body portion 12 which is preferrably made out of a thermo-plastic material such as Lexan has asso ciated therewith securing means 70 at the lower portion 66 in the form of a securing member 72 inserted at one end thereof having a mating portion 74 in the form of threads which is adapted to mate with a complimentary threaded portion 76 of the lower portion 66. To be maintained firmly in place, a bonding material or cement 77 is used to secure and maintain intimate coupling between the threaded portion 74 and the surrounding lower portion 66.

The securing member 72 includes a gripping section 78 which is shown to be of a hexogonal shape so as to be readily grasped between fingers of the user or a wrench for obtaining the disengagement of the applicator means 10 from the oral device. A stud 80 extends from the opposite end of the gripping section 78 and has a thread that may be of a quick type in that it is not a fine thread so that a minimal number of turns of the applicator means 10 is required before the bottom edge 82 abuts the complimentary surface of the instrument means. A sleeve 88 of a plastic material is positioned over the gripping section 78 and the lower portion 66.

The middle section 68 of the body portion 61 may be designed in'a manner in which it has an axially extending bore 84 which extends longitudinally therethrough such as to properly balance the mass of the brush to maintain maximum amplitude of vibration at the output end or tips 85 of the respective bristle clusters 15. The bristle clusters 15 are positioned in a plane substantially normal to the longitudinal axis of the body portion 12 but each individual cluster includes a plurality of bristles 21 that are essentially folded over as seen in FIG. 13 and retained in place by retaining means in the form of a staple 92 having spaced apart prong portions 94 with tips 95 and a connecting portion 96.

Accordingly, each bristle cluster 15 is assembled into an aperture 98 generally of a circular cross-sectional area having an opening 100 at the face surface 102 of the head portion 65 and extending axially the distance generally in the range of 0.10 inch to 0.250 inch in depth such that each bristle element 21 is formed in a U-shaped manner and held in place by the rib portion 96 of the staple 92 as the prongs 94 are imbedded into the plastic material of the head portions 65. In this manner, by automatic assembly equipment, the bristle clusters 15 are inserted within the respective apertures 98 and initially held in place. The head portion 65 may have a rectangularcross-section as seen in FIG. 11

whereasthe middle portion 68 maybe or a circular cross-sectional area with a radius 104 blending the two sections together.

Applicants discovered that the mere introduction or retention of the bristle clusters 15 within an aperture 98 was not sufficient to permit a transmitting of the ultrasonicenergy to the respective bristle elements or strands 21 so as to affectuate efficient ultrasonic motion at the bristle tips 85. It is for this reason that applicants discovered that transmitting means 105 was required in order to permit proper acoustical transmission of the vibrational energy waves from the head portion 65 to the respective individual bristles 21. To accomplish this, applicants devised a process wherein the bristles 21 were exposed to a chemical solution 106 having the ability to form a bond for transmission of the energy waves.

Accordingly, to obtain the proper transmission of mechanical vibratory energy both in the sonic range generally in the frequency range of 0.01 KHz to l KHz and in the ultrasonic range of 5 KHZ to 50 KHZ, applicants utilize the process of manufacture in which the aperture 98 to receive the bristle clusters 15 are generally approximately 30 percent larger than those used in standard brush manufacturing procedures to allow for lesser yield of the thermoplastic material which may be a polycarbonate of various types; i.e., Lexan, Merlon or Polycarbatil. The next step of the manufacturing procedure is to elevate the temperature of the thermoplastic material to a temperature which prevents fracturing of the material upon the insertion of the bristle cluster and the staple'92. Applicants have found that for Lexan material, that the Lexan may be just heated as by inserting in boiling water prior to the insertion of the combined staple 92 and bristle cluster 15 with the temsection or portion 68j extending'therebetween. The

body portion 12j which isrpreferrably made out of a thermoplastic material such'as Lexan has associated .therewith securing means 70j at the lower portion 66j in the form of a securing member 7'2j inserted at one end thereof having a mating portion 74j which is adapted to be secured as by moulding in the lower portion 66j. 200' the To be maintained firmly in' place, an

the bristle thereby reducing its energy transmission,

properties. To assure that the energyis transmitted, the coupling agent which may be in the form of a solvent which 7 causes a flow of the aperture wall-as seen in FIG; 15 to p the interstices as by the formation of a plurality of tingers 106 that secure eachbristle 'll for energy coupling. Accordingly, the solvent is used and causes a flow of the thermoplastic material in the aperture 98 around the staple 92 and bristles 21 thereby assuring proper coupling of the vibratory energy. One type sol ventused is Methylene Chloride which is applied when the brush head 61 is at an elevated temperature in the annular recess or depression 108] is provided to maintain intimate coupling between the portion 74] and the surrounding lower portion 66j.

The lower portion 66; includes a gripping section 78) I which is shown to be of a shape with inclents 1l0j so as to be readily grasped between fingers of the user for obtaining the dis'engagementof the applicator means 10j from the oral device, A stud 80j extends from the securing means 70j approximate the gripping section 78] and has a thread that may be of a quick type in that it is not a fine thread so that a minimal number of turns of, the applicator means 10j is required before the bot tom edge'64j abuts the complimentary surface of the instrument means. i i I y The bristle clusters I5j may be coupled in position as discussed above. Y Y l V Along the line of improved efficiency factors belongs theproviding on the brush head 65j with a material which prevents' transmission of high frequency 'vibratory energy into liquids 'orteeth orgurnstThis is readily accomplished, for example, witha' closed cell, rubber guard or insulating' neans l15j which may be in the form of a cap 116]. The insulating means'may be made range of I0OF.' to 250F. As seen, ,this flow of the brush head portion 65 causes an interlocking relationship such that essentially major air gaps are eliminated, In this way the mechanical vibratory energy is properly transmitted to the individualbristles 21 head 65. i I i A further novel feature of the present invention is that theends 85 of each bristle 21 as seen in .FIG. 16

are rounded such that the sharp points and burrs produced by cutting to size are eliminated. The process from the brush of a foam polystyrane or closed cell rubber which presents-to'the vibratingsurface an acoustic impendance equivalent to that of an air film. The. acoustic impedance of airis'so mismatched (i.e.-, so. much-smaller) than the acoustic impedance of the brush head 65j that all ultrasonicene'rgy' waves arriving at'the brush heads closed cell f lm interface will be almost totally reflected back into the plastic thereby making more energy available to the bristle clusters 15j to :do their work. The cap I 116 may be moulded in place and cover substantially foreliminating the sharp points can be attained by ei- I ther abrasive blasting in that an abrasive compound driven by air pressure being directed against the bristle ends 85 occurs, or another approach is a heating of the bristle ends 85 to cause a momentary softening of the. bristle ends and the bristle ends 85 tends to flow and just the brush head 6'5j or the complete brush 10j. 'If desired the cap or cover ll6j may be of a snap-tit onto the brush head 65j as shown with spaced apart side walls 1 17], end-walls 'l 18 end top wall 1 19j integrally formed with each other.

produce a ball-type end 86 to avoid the sharp edge. Ap- I plicants have found that the useof Nylon material proves to be most satisfactory for the material from which the bristles 21 are made. The bristle diameter may be in the range of 0.004 inch to 0.020 inch and extend fromthe brush head a lengthfrom 0.30 inch to 0.60 inch. For example, for a bristle cluster that includes eighty ends, the bristle element may have a di- Turning now to FIGS. 21 and 22 we have illustrated one of the desired objectives of the invention which re.- lates to the individual bristles of each cluster to deliver their ultrasonic' vibrati'onal energy to the load (i.e. gingival and tooth surfaces) as efiectively as possible; This means, in detail, that we are trying to deliver a number of types of transfers relating to:-

ameter of 0.008 inch and the aperture 98 a diarnater of f 0.093 inch and a depth of approximately 0.120-irich. Now referring more particularly to FIGS. 17-20, there is illustrated the applicator means 10] which may be manufactured as byinjection moulding and.isdesigned to be used with the ultrasonic instrument means as previously illustrated. The applicator means 101' inl. Cavitation (for pervasiveinterproxi'mal effects) 2. Microrriassage (for stimulation of local tissue inicrostructures) I I l 3. Other sonochemical and sono -physiological effects such as desensitizing, anaesthetizingmouth wash psychological action, fluoride penetration,

e tc.-)-.}. Y r It isfound that the overall effectiveness of. a straight I bristle21k as illustratedin FIG. 21 incertain, instances,

cludes a base or body section means 12j with a longitudinally spaced apart ends 63j. andi 64jand having a brush head or. head65j portion which is the upper section in which the bristle clusters 15; are contained and a spaced apart lower portion or end-661' with a middle is less than a crimped bristle 21m of the type illustrated in FIG. 22 forthe same-basic diameter. The technical reasons for the differencelin behavior are difficult to pinpoint because of the complex character of the vibration'transfer from the base of the bristle cluster to the individual bristle of the cluster. But essentially the longitudinal motion of the brush head 65k and 65m as indicated by the double headed

arrow

60k and 60m is translated into a flexural type motion at the bristle tips as indicated by double headed

arrows

111k and 111m.

With respect to cavitation effects, the increased surface area is undoubtedly a cause for increased efficiency. The curliness" also provides a more universal field of motional vibration components which increases the overall effectiveness of the various actions. Especially in connection with cleaning out alba (the white matter between teeth due to food) and plaque (the gellike'substance produced by salivary bacteria) which are both soft, the crimped or curly cluster of bristles 21m has a spring-back action characteristic of springy curls or spiral springs, which is a combination of the stick-slip effect due to the pulsed on-off bursts of ultrasonic energy packets and the low frequency action consequent on this effect and referenced elsewhere in this specification.

Thus, although the crimped bristles are not essential to the operation of the disclosed invention, they nevertheless represent a novel feature of the invention itself, being one of the many disclosed items which increases the effectiveness of the tooth hygiene desired.

Turning now to FIGS. 23-26, there is illustrated the applicator means in use in a dental cleaning procedure in accordance with the invention in operative position in the oral cavity 120 against the teeth 122. In accordance with the invention, the brush bristles 21 of the applicator means 10 is positioned against the teeth 122 in the usual manner during the brushing operation. That is, the bristle clusters 15 are inserted in the mouth and positioned adjacent the tooth surfaces 124 with a relatively light pressure. The bristle clusters 15 may be moved manually to pass the brush portion across all of the tooth surfaces, the bristles 21 randomly assume po sitions in contact with and displaced from tooth surfaces. Since in the case of manual brushing, the bristle tips 85 rarely assume positions such that they extend deeply into the interproximal areas 126 the present brush is designed to approximate the curvature thereof.

In this manner the action between the sonic motion and ultrasonic motion is believed to result in a combination effect such that the beneficial features of each frequency is simultaneously obtained.

Accordingly, the removing of plaque of 128 on the tooth surface 124 and foreign deposits 130 are obtainable with the present invention. In FIG. 23 plaque 128 is illustrated as a layer of material that has adhered to the surfaces of the teeth 122. Plaque is a soft gelatinous substance produced in the mouth by the action of salivary and sub-gingival bacteria, hardens into calculus in a period of from two to twelve days, and is believed to be a significant factor in causing periodental diseases.

In use, the ultrasonic bristles clusters 15 are vibrated so as to introduce a micro-motion and a macro-motion to the teeth surfaces as by generating ultrasonic vibrations as illustrated by the double-headed arrow 60 in the bristle elements 21 at the working end of the hand held ultrasonic motor that is in turn coupled to the brush head 65. By amplitude modulating the ultrasonic vibrations at a sonic rate there is produced alternating periods of ultrasonic vibrating activities at the bristle elements and periods of rest or substantially zero ultrasonic vibrations. Then by engaging the bristle tips against the teeth surface 124 and maintaining a relative moving relationship there is generated sufficient action to remove the plaque 128 and interproximal deposits 130.

This action is generally obtained by providing a fluid film as illustrated by the particles 132 which may be in the form of a dentifrice having certain characteristics or simply that of saliva. The motion at the bristle tips 85 is of sufficient amplitude of vibrations to also produce a cavitational action in the fluid film 132 by the bristle elements 21.

Accordingly, FlGS. 23-26 inclusive are diagram- 7 matic views helpful in explaining how the interrelated phenomena are believed to simultaneously occur to obtain the improved cleaning results. The user applies the applicator means 10 in a manner so as it is longitudinally vibrated in the direction of two-headed arrow 60 with respect to microscopic action. Mechanical vibratory energy is transmitted to the free ends 85 of bristle clusters 15 and through a fluid or other medium 132, or directly by contact with teeth surface 124.

In use then, the applicator means 10 is inserted in the oral cavity of the user and may be maintained in fixed position relative to a number of teeth as, for example, illustrated in FIG. 23 such that the cavitational and other actions may occur as the bristle clusters 15 are maintained in relatively lightcontact with the teeth surface 124 as well as the gingival surfaces of the mouth. If the user desires, he may move the applicator means 10 across the surface of the teeth as well as the gingival surfaces to obtain the desired results. When movement occurs, the bristle clusters will assume various positions and, for example as seen in FIG. 26, two bristle clusters 15 are in contact with a single tooth 122 so that the plaque material 128 may be microscopically removed therefrom. The ultrasonic energy introduces the micromotion in the bristle clusters 15 which is responsible for certain cavitational effects that will be engendered between various clusters 15 depending upon the particular fluids 132 in use and the make-up thereof.

Accordingly, the inducement of the vibrations in the bristle elements are at an ultrasonic range of IOKHZ to SOOKHzto vibrate the bristle elements longitudinally and the vibration of the bristle elements at a low sonic frequency at the range-of 0.01 KHZ to l KI-Iz produces the cleaning. As' the brushing occurs there is maintained an amplitude of vibrations at the bristle elements 21 sufficient to obtain a cavitational action on the teeth surfaces 124.

The bristle elements 21 as seen particularly in FIG. 26 may have a contoured surface configuration that lend themselves to conform to the contour of teeth 122 such that the bristle elements form a surface consisting of a multiple number of pointed members interproximately of the teeth during the brushing thereof which produces peak accelerations in the bristle elements.

One aspect of the present invention is to provide insulating means that may surround'the toothbrush head 65 to improve efficiency in that the insulating means 115 may be of a material which prevents transmission of high frequency vibratory energy into liquid or teeth or gums.

This is readily accomplished, for example, with a closed cell rubber sheet. The closed cell material presents to the vibrating surface an acoustic impedance equivalent to that of an air film. The acoustic impedance of air is so mismatched (i.e., so much smaller) than the acoustic impedance of the brush head plastic 65 that all ultrasonic energy waves arriving at the brush head-closed cell firm interface will be almost totally re flected back into the plastic thereby making more energy available to the bristle clusters 15 to do their work.

For example, a very mild abrasive dentifrice could be used or, if desired, saliva or regular water may be used depending upon the condition of the users mouth at the time he starts using the present invention. The macro-motion provided by the low sonic frequency energy in a sense permits a flushing away aspect in that gross motion is simultaneously obtained with respect to the interaction between the various frequencies and thereby helps in the manual rushing concept. The low sonic rate also helps the user psychologically in knowing that the instrument is working, since the ultrasonic aspect is above the audible range of the user. Furthermore, a micro-massage of the gums of the user is also obtained. The utilization of the applicator means is such that it may be positioned against the various surfaces of the teeth as illustrated in FIGS. 24, 25, and 26 as would normally be the case with the positionment of a conventional cleaning operation.

The ultrasonic energy available at the bristle tips provide a number of beneficial results, which result in the plaque and other foreign deposits to be removed from the teeth. Accordingly, the brush of the present invention permits stimulation of the gingival tissue by macromassage and micromassage which has been found beneticial for dental health, and massage also results in more blood circulation than is obtained by conventional brushing techniques.

The angular positionment of the bristle clusters with respect to the applicator means 10 are substantially normal to the longitudinal mode of vibration, but these may be varied, as well as the fact that an oscillatory or radial mode of macromotion may also be applied to the applicator means 10 other than pure longitudinal motion. Furthermore, the length and stiffness of the various bristles may be varied within the confines of the present invention and the beneficial results may still be obtained.

Referring now to FIG. 27, applicants herein disclose the mothod of manufacture of the brush previously described and ideally suited for use with an instrument that drives it at an ultrasonic as well as sonic rate. Initially, the ultrasonic applicator or brush 10 is formed either by machining or injection molding such that the brush head portion has a plurality of the spaced apart apertures 98 contained therein and adapted to receive a plurality of individual bristles therein.

By conventional equipment well known in the art, the step of inserting and stapling the respective bristle clusters 15 in each respective aperture 98 is accomplished and may be carried on on an automatic process. It has been found that, if the stapling operation occurs when the brush head is at room temperature, that a certain degree of cracking or crazing will occur as thestaple is driven into the brush head or more particularly when the brush is ultrasonically vibrated. Accordingly, the brush head by heating is elevated to a temperature in the range of 100F to 250F, and for Lexan about 212F prior to stapling each bristle cluster 15 in place. The staple is of a conventional form and, for example,

may be of 0.024 inch diameter made of 302 stainless steel, 1/4 hard.

After this is accomplished, the temperature of the brush head for a brush made of Lexan material is raised to and stabilized at approximately 135F, and the entire brush or the brush head alone, is dipped in a liquid solvent such as methylene chloride, such that the applying of the solvent covers the entire brush and particularly seeps into the points between the aperture wall and the outer surface of the respective bristles of the clusters. After this occurs, the excess solvent may be removed by an air jet or other means. The next step in the operation is the drying of the brush such that the solvent is removed and this may occur by returning the brush to the oven which may be at a temperature of approximately l50F and retaining the brush in the oven at that temperature for approximately one half hour. As a result of the above steps, there occurs a flow of the plastic in the brush head portion into surrounding relationship of the bristles in each aperture therein such that the plastic solidifies in adhesive relationship to the bristles to transmit the ultrasonic vibratory energy from the brush head portion to the bristles. The fluidized plastic produces intermittent molecular contact to fill the interstices and provide an adhesion for acoustical transmission of energy. Accordingly, the brush of the present invention is manufactured and proper transmission of the vibratory energy is obtained as previously explained.

generally subsequent to the above, the next step is that of trimming or cutting of the bristle clusters to a desired shape as by shearing thereof such that the vibratory tips of the bristles may have the configuration desired.

The next step in the manufacture is the finishing of the bristle tips to a desired shape or contour and this may occur as by sort of a polishing or sand blasting process or, if desired, the tips 85 of the respective bristle elements 21 may be exposed to a heat source so, as seen in FIG. 16, a rounded edge occurs.

If the brush is designed in that the securing means are coupled to the brush as by threads, then prior to elevating the temperature of the brush for stapling, the solvent or wetting agent may be applied to the threaded portion 74 of the securing member 72 as well as to the thread 76 of the brush and then the parts may be screwed together tightly and the temperature of the entire brush elevated as discussed above prior to dipping of the entire brush in the solvent.

In addition, the step of applying the sleeving 88 to the brush is accomplished by using a shrink-type tubing that is axially slipped over the body and the securing means 70. Subsequent thereto, the temperature of the sleeving may be increased as by applying heat thereto and shrinking the tubing in place.

To acoustically insulate the head portion 65 of the brush 10 from its transmission of vibratory energy to the check of the user, an insulating material may be secured to the head portion as by an adhesive or other means.

CONCLUSION Accordingly, the toothbrush hereinabove illustrated is one embodiment that may be employed with a power handle so as to properly deliver the ultrasonic vibrational'energy to the bristle tips and besuitable for production on a mass basis. It will be appreciated by those skilled in the art that various modifications and devices may occur to the disclosure of the present invention, but the same are generally illustrated as being secured to the power source by securing means that may vary in shape or size and that the means may even be an integral part of the brush itself and be molded therewith to eliminate the necessity of another component part to be added to the brush.

While certain novel features of this invention have been disclosed herein and are pointed out in the claims, it will be understood that various ommissions, substitutions, and changes may be made by those skilled in the art, without departing from the teachings of the invention.

We claim:

1. A toothbrush adapted to be mounted on an automatic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising:

A. an elongated plastic brush portion adapted at one end to be removably mounted on the power handle and of a length greater than one wave length of a longitudinal elastic wave in the plastic brush portion medium at the operating ultrasonic frequency of said toothbrush;

B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster; and

C. a plurality of bristle clusters each including a plurality of bristle elements, disposed on the brush head within said apertures, said plastic brush head constituting a loaded longitudinal wave transmission line, wherein the bristle clusters coincide with the loaded parts of said loaded transmission line, and where such loaded locations are essentially at loops of longitudinal vibration.

2. A toothbrush as defined in claim I, wherein the loaded transmission line cross-section between bristle clusters, measured along the longitudinal axis of said brush head is A,,, and the equivalent cross-section, taking account of the bristle clusters in an adjacent loaded section of said line, is A,, larger than A and the lengths of each section are selected equal to each other and each length, 1 is selected so as to satisfy the equation:

where 1- is the wave length of a longitudinal elastic wave in the toothbrush plastic medium at the said operating ultrasonic frequency of said toothbrush.

3. A toothbrush as defined in claim 1, and furhter including means for transmitting the vibratory energy from said brush head to said bristle clusters within said apertures by substantially conforming the respective wall of the apertures to the surface configuration of the bristle elements comprising each cluster to form an adhesion therebetween.

4. A toothbrush as defined in claim 1, further comprising means for acoustically insulating the brush head of said toothbrush, wherein the vibratory motion remains isolated therein and is not transmitted to the oral cavity.

5. A toothbrush as defined in claim 1, wherein the means for conforming the wall of the apertures to the surface of the bristle elements is obtained byflowing matic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising:

A. an elongated plastic brush portion adapted at one end to be removeably mounted on the power handle;

. B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster;

C. a plurality of bristle clusters each including a plurality of bristle elements, disposed on the brush head within said apertures;

D. means for mechanically securing said bristle clusters to said brush head, and

E. means for transmitting the vibratory energy from said brush head to said bristle clusters within said apertures by substantially conforming the respective wall of the apertures to the surface configuration of the bristle elements comprising each cluster to form an adhesion therebetween.

9. A toothbrush as defined in claim 8, wherein the bristle clusters are'all of the same length.

10. A toothbrush as defined in claim 8, wherein the bristle clusters are arranged in rows on the brush head.

11. A toothbrush as defined in claim 8, wherein the means for mechanically securing each said bristle cluster includes a staple.

12. A toothbrush as defined in claim 8, wherein said elongated plastic brush portion has a length greater than one wave length of a longitudinal elastic wave in the plastic brush medium at the operating ultrasonic frequency of said toothbrush.

13. A toothbrush as defined in claim 8, wherein said plastic brush head constitutes a loaded longitudinal waver transmission line, whereby the .bristle clusters coincide with the loaded parts of said loaded transmission line, and where such loaded locations are essentially at loops of longitudinal vibration.

14. A toothbrush as defined in claim l3, wherein the loaded transmission line cross section between bristle clusters, measured along the longitudinal axis of said brush head is A and the equivalent cross-section, taking account of the bristle clusters in an adjacent loaded section of said line, is A,, larger than A,,, and the lengths of each section are selected equal to each other and each length, 1 is selected so as to satisfy the equation:

tan 2 11-1,, /1 VA /A =0:

17. A toothbrush as defined in claim 8, wherein the means for conforming the wall of the apertures to the surface of the bristle elements is obtained by flowing the plastic of the brush head into surrounding relation to the bristle elements. I

18. A toothbrush as defined in claim 8, wherein said bristle clusters are of a plastic material.

19. A toothbrush as defined in claim 8, further comprising means for acoustically insulating the brush head of said toothbrush, wherein the vibratory motion remains isolated therein and is not transmitted to the oral cavity.

20. A toothbrush as defined in claim 19, wherein said means for acoustically insulating the brush head of said toothbrush comprises a layer of vibration absorbent material which substantially covers the entire brush head.

21. A toothbrush as defined in claim 8, wherein said bristle clusters are disposed with respect to the direction of vibration in said brush head so that flexural vibrations are induced in said bristle clusters.

22. A toothbrush as defined in claim 21, wherein said bristle clusters are disposed in a plane substantially perpendicular to the direction of vibration.

23. A toothbrush as defined in claim 8, wherein said bristle clusters are comprised of a plurality of bristle elements.

24. A readily replaceable brush as in claim 23, wherein the bristle elements of the bristle cluster are of various lengths.

25. A toothbrush as defined in claim 23, wherein at the frequency of vibration the bristle elements are of a iength' and diameter to vibrate at a level sufficient to cavitate a fluid film on the tooth surfaces.

26. A toothbrush as defined in claim 23,

a. wherein said bristle elements extending from said brush head are of a length in the range of from substantially 0.30 inch to 0.60 inch; and

b. wherein said bristle elements are of a diameter in the range of substantially from 0.004 inch to 0.020 inch.

27. A toothbrush as defined in claim 8, wherein said means for removeably coupling said elongated brush portion to the power handle includes securing means including a threadably engageable portion adapted to mate with a complementary threadably engageable portion of the power handle.

28. A toothbrush as defined in claim 8, wherein the free end of the bristle elements are each rounded.

29. A toothbrush as defined in claim 8,

a. wherein said bristle elements are of a diameter in the range of 0.004 inch to 0.020 inch,

b. wherein a bristle cluster includes approximately eighty ends, at the nominal bristle element diameter of 0.008. and I 0. wherein each aperture is approximately 0.093 inch diameter and a depth of approximately 0.120 inch.

30. A toothbrush adapted to be mounted on an automatic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising:

A. an elongated plastic brush portion adapted at one end to be removeably mounted on the power handle and capable of supporting ultrasonic vibrations and adapted to be vibrated at said frequencies;

B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof and capable of supporting ultrasonic vibrations, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster;

C. a plurality of bristle clusters each comprised of plastic bristle elements and disposed on the brush head within said apertures;

D. means including a staple for mechanically securing said bristle clusters to said brush head; and

E. means for transmitting the vibratory energy from said brush head to said bristle clusters within said apertures, wherein the means for transmitting the vibratory energy waves from said brush head to said bristle clusters includes substantially conforming the respective wall of the apertures to the surface configuration of the bristle elements to form an adhesion therebetween,

F. said means for mounting said elongated brush portion to the power handle including securing means having a threadably engageable portion adapted to mate with a complementary threadably engageable portion of the power handle.

31. A toothbrush as defined in claim 30, further comprising means for acoustically insulating the brush head of said toothbrush whereby the vibratory motion remains isolated therein and is not transmitted to the oral cavity.

32. A toothbrush as defined in claim 31, wherein said means for acoustically insulating the brush head of said toothbrush comprises a layer of vibration absorbent material which substantially covers the entire brush head.

33. A toothbrush as defined in claim 31, wherein at the frequency of vibration the bristle elements are of a length and diameter calculated to vibrate at a level sufficient to cavitate a fluid film on the tooth surfaces.

34. A toothbrush as defined in claim 31,

a. wherein said bristle elements extending from said base are of a length in the range of from substantially 0.30 inch to 0.60 inch; and

b. wherein said bristle elements are of a diameter in the range of substantially from 0.004 inch to 0.020

inch.

Claims

1. A toothbrush adapted to be mounted on an automatic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising: A. an elongated plastic brush portion adapted at one end to be removably mounted on the power handle and of a length greater than one wave length of a longitudinal elastic wave in the plastic brush portion medium at the operating ultrasonic frequency of said toothbrush; B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster; and C. a plurality of bristle clusters each including a plurality of bristle elements, disposed on the brush head within said apertures, said plastic brush head constituting a loaded longitudinal wave transmission line, wherein the bristle clusters coincide with the loaded parts of said loaded transmission line, and where such loaded locations are essentially at loops of longitudinal vibration.

2. A toothbrush as defined in claim 1, wherein the loaded transmission line cross-section between bristle clusters, measured along the longitudinal axis of said brush head is Ao, and the equivalent cross-section, taking account of the bristle clusters in an adjacent loaded section of said line, is A1, larger than Ao, and the lengths of each section are selected equal to each other and each length, 11, is selected so as to satisfy the equation: tan (2 pi 1o/ Tau ) Square Root Ao/A1 Alpha where Tau is the wave length of a longitudinal elastic wave in the toothbrush plastic medium at the said operating ultrasonic frequency of said toothbrush.

5. A toothbrush as defined in claim 1, wherein the means for conforming the wall of the apertures to the surface of the bristle elements is obtained by flowing the plastic of the brush head into surrounding relation to the bristle elements.

6. A toothbrush as defined in claim 1, wherein said means for removably coupling said elongated brush portion to the power handle includes securing means including a threadably engageable portion adapted to mate with a complementary threadably engageable portion of the power handle.

7. A toothbrush as defined in claim 1, and further including means for mechanically securing said bristle clusters to said brush head.

8. A toothbrush adapted to be mounted on an automatic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising: A. an elongated plastic brush portion adapted at one end to be removeably mounted on the power handle; B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster; C. a plurality of bristle clusters each including a plurality of bristle elements, disposed on the brush head within said apertures; D. means for mechanically securing said bristle clusters to said brush head, and E. means for transmitting the vibratory energy from said brush head to said bristle clusters within said apertures by substantially conforming the respective wall of the apertures to the surface configuration of the bristle elements comprising each cluster to form an adhesion therebetween.

9. A toothbrush as defined in claim 8, wherein the bristle clusters are all of the same length.

13. A toothbrush as defined in claim 8, wherein said plastic brush head constitutes a loaded longitudinal waver transmission line, whereby the bristle clusters coincide with the loaded parts of said loaded transmission line, and where such loaded locations are essentially at loops of longitudinal vibration.

14. A toothbrush as defined in claim 13, wherein the loaded transmission line cross section between bristle clusters, measured along the longitudinal axis of said brush head is Ao, and the equivalent cross-section, taking account of the bristle clusters in an adjacent loaded section of said line, is A1, larger than Ao, and the lengths of each section are selected equal to each other and each length, 1o, is selected so as to satisfy the equation: tan ( 2 pi 1o / Tau ) Square Root Ao/A1 Alpha where Tau is the wave length of a longitudinal elastic wave in the toothbrush plastic medium at the said operating ultrasonic frequency of said toothbrush.

15. A toothbrush as defined in claim 8, wherein said bristles are crimped.

16. A toothbrush as defined in claim 8, wherein each said bristle cluster is mounted at substantially a loop of longitudinal motion along the axis of said brush head.

17. A toothbrush as defined in claim 8, wherein the means for conforming the wall of the apertures to the surface of the bristle elements is obtained by flowing the plastic of the brush head into surrounding relation to the briStle elements.

25. A toothbrush as defined in claim 23, wherein at the frequency of vibration the bristle elements are of a length and diameter to vibrate at a level sufficient to cavitate a fluid film on the tooth surfaces.

26. A toothbrush as defined in claim 23, a. wherein said bristle elements extending from said brush head are of a length in the range of from substantially 0.30 inch to 0.60 inch; and b. wherein said bristle elements are of a diameter in the range of substantially from 0.004 inch to 0.020 inch.

29. A toothbrush as defined in claim 8, a. wherein said bristle elements are of a diameter in the range of 0.004 inch to 0.020 inch, b. wherein a bristle cluster includes approximately eighty ends, at the nominal bristle element diameter of 0.008, and c. wherein each aperture is approximately 0.093 inch diameter and a depth of approximately 0.120 inch.

30. A toothbrush adapted to be mounted on an automatic toothbrush power handle having as a power source a source of vibratory energy in the ultrasonic range, the said toothbrush comprising: A. an elongated plastic brush portion adapted at one end to be removeably mounted on the power handle and capable of supporting ultrasonic vibrations and adapted to be vibrated at said frequencies; B. a plastic brush head formed integrally with the elongated brush portion at the opposite end thereof and capable of supporting ultrasonic vibrations, said brush head being provided with a series of apertures for respectively receiving an end of each bristle cluster; C. a plurality of bristle clusters each comprised of plastic bristle elements and disposed on the brush head within said apertures; D. means including a staple for mechanically securing said bristle clusters to said brush head; and E. means for transmitting the vibratory energy from said brush head to said bristle clusters within said apertures, wherein the means for transmitting the vibratory energy waves from said brush head to said bristle clusters includes substantially conforming the respective wall of the apertures to the surface configuration of the bristle elements to form an adhesion therebetween, F. said means for mounting said elongated brush portion to the power handle including securing means having a threadably engageable portion adapted to mate with a complementary threadably engageable pOrtion of the power handle.

34. A toothbrush as defined in claim 31, a. wherein said bristle elements extending from said base are of a length in the range of from substantially 0.30 inch to 0.60 inch; and b. wherein said bristle elements are of a diameter in the range of substantially from 0.004 inch to 0.020 inch.