US 3651576 A
A waterproof dental probe is mounted at one end of a slender handle. The probe includes an ultrasonic transducer for vibrating the surface of the probe. Thus, ultrasonic vibrations may be transferred to the gums and teeth by applying the vibratile probe to the surface thereof.
Description (OCR text may contain errors)
United States Patent Massa Mar. 28, 197 2 54] ELECTROACOUSTIC MASSAGER FOR 3,427,480 2/1969 Robinson ..32/58 THE GUMS 2,920,617 1/1960 Borarsky ..l28/24 A  Inventor: Frank Massa, Cohasset, Mass. 2 I I  Assignee: Massa Division Dynamics Corporation of Primary Examiner-Rben Peshock America, Hingham, Mass. 2 74twmey -Louis B  Filed: May 18, 1970 21 App]. No.: 37,953 I ABSTRACT A waterproof dental robe is mounted at one end of a slender iii E581.111::13::11::31'"'"""'"'"":11iiiiiiffffffiffliiofi 3335653385551591E330??-iiiifiiilsgifiiiiiiii  Field of Search ..l28/62 A, 24 A; 32/58 $23; g ffigig i f gi fif zg teem by apply'ng  References Cited 20 Claims, 11 Drawing Figures UNITED STATES PATENTS 2,917,042 12/1959 Brown et al ..l28/24 A Patented March 28, 1972 //v VENTOR.
FRANK MA SSA ELECTROACOUSTIC MASSAGER FOR THE GUMS This invention relates to a prophylactic aid for the gums and teeth, and more specifically to hand held probes which include ultrasonic transducer means for transmitting ultrasonic vibrations to the outer surface of the probe for vibrating the gums and the teeth.
Regular massaging of the gums improves the circulation of the blood in the gums and assists in maintaining a healthy mouth, tooth, and gum structure. Also, an important preventative of tooth decay requires a removal of plaque, which forms on the surface of the teeth. If it is not removed, bacteria grows in the plaque environment and leads to difficulties.
A commonly used aid for gum massage is a pointed rubber tipped end on the handle of a tooth brush. Usually, this tip is rubbed into the space between the teeth and between the teeth and gums, thereby manually cleaning the regions where plaque forms and simultaneously providing a massage of the gums. While the manual rubbing action of the rubber tip improves the health of the gums, there is a great improvement when a mechanical aid rubs the gum at the proper frequency and with the proper vigor.
Therefore, an object of this invention is to provide a dental probe with an electroacoustic transducer for generating high frequency vibrations which may be transferred to the gums and teeth.
Another object of this invention is to provide a low-cost, hand held probe for general use as a dental prophylactic aid. Here an object is to provide an inexpensive, but efficient, ultrasonic transducer which may drive such a probe.
An additional object of this invention is to provide a double ended probe having a generally flat area on one side and a generally pointed tip on the opposite side. In this connection, an object is to drive both sides of the probe with ultrasonic energy from a common electroacoustic transducer.
A still further object of this invention is to provide a very simple and inexpensive hand held prophylactic device which includes an ultrasonically activated probe which may be conveniently used for greatly improved dental hygiene in the,
home. This device is used in much the same manner as a conventional tooth brush is now used.
In keeping with an aspect of the invention, a preferred embodiment includes a waterproof dental probe mounted'at one end of a slender handle. An ultrasonic transducer vibrates the surface of the probe. Thus, these ultrasonic vibrations may be transferred to the gums and teeth by applying the vibratile probe surface to the region of the gums or teeth.
The novel features which are characteristic of the invention are set forth with particularity in the appended claims. However, the invention itself, both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description of several embodiments thereof when read in conjunction with the accompanying drawings in which:
FIG. 1 is a perspective view of an ultrasonically driven dental probe incorporating the features of the invention;
FIG. 2 is a cross-sectional view of the probe handle and ultrasonic transducer, taken along line 2-2 of FIG. 1;
FIG. 3 is a longitudinal cross-sectional view, taken along line 3-3 ofFlGS. 1 and 2;
FIG. 4 is a bottom plan view looking at the handle end of the structure along line 44 in FIG. 2;
F IG. 5 is a top plan view of the probe assembly, taken along line 55 ofFlG. 3;
FIG. 6 is an enlarged cross-sectional view of the probe end;
FIG. 7 is a schematic illustration of a reduced voltage variation of the piezoelectric transducer element assembly;
FIG. 8 illustrates another form of the transducer element which results in a flexurally vibrating transducer element;
FIG. 9 illustrates a positive flexural vibration amplitude which is produced by the transducer element of FIG. 7 when a positive voltage is applied to one of the electrical conductors;
FIG. 10 illustrates a negative flexural vibration amplitude which is produced when the phase of the electrical signal is reversed; and
FIG. 11 illustrates a reduced operating voltage variation of the piezoelectric plate.
In the various figures, the reference character 21 identifies a rigid tubular handle with an axial hole 22 extending throughout its length. At the bottom end, the handle is provided with an enlarged cavity in which an insulated terminal board 23 is sealed. This board carries the pin terminals 24 and 25 for making a connection with an electrical cable 26. This cable has socket terminals which mate with the pin terminals 24 and 25. The electrical cable 26 furnishes any suitable electrical power from a source, not shown, to drive the electroacoustic transducer assembly.
In any suitable manner, a rigid tubular member 28 is attached within a counterboard hole in the upper end of the handle 21. While this member 28 is here shown as a separate part,'it could be an integral extension portion of the handle 21. This tube is of a small diameter so that it will not be bulky or hard to manipulate when held against the gums.
A probe transducer housing 30 is attached to the upper end of the tubular member 28. For example, the tube 28 may pass through a hole in and be attached to the housing 30, as by cementing or soldering. The housing 30 is an annular shell which surrounds a pair of piezoelectric ceramic plates 31 and 32. The common polarities, marked of the plates are electrically connected together by means of a conducting cement. These ceramic plates 31, 32 and the housing structure 30 are shown in greater detail in the enlarged view of the probe tip illustrated in FIG. 6.
The transducer drive assembly (FIG. 6) includes a thin annular layer of low acoustic impedance material 35, such as Corprene. Preferably, this layer is wrapped around the periphery of the ceramic plates 31, 32 for isolating the radial vibrations of the plates from the annular housing 30.
An insulated conductor 36 passes through the hollow handle 21 and establishes an electrical connection from the common polarity of the ceramic plates 31, 32 to the terminal pin 24. The outside or opposite electrode surfaces of the ceramic plates3l and 32 are marked These two surfaces are connected together by another electrical conductor schematically shown at 36A in FIGS. 7, 8 and 11. This conductor also passes through the handle 21 and connects to the terminal pin 25.
To complete the probe assembly, a tapered adapter member 40 is bonded at its base to one of the plane vibratile surfaces of the ceramic plate assembly. While this bond may be made by epoxy, for example, the member 40 may be attached to the surface of the ceramic plate 32 by any other suitable cement.
Finally, a layer of waterproof sound transmitting material 42 is applied over the transducer housing 30, tube 28, and perhaps over the entire handle 21 also. The waterproof covering 42 is here shown as being formed with a skirt-like portion 43 bonded to an undercut tip of the handle 21 to achieve a completely waterproof assembly for the structure. This layer 42 may be molded rubber or any other suitable resilient material. Preferably, it is bonded in intimate contact to the tapered tip 40 and also to the opposite exposed plane face of the ceramic plate 31. Thus, the probe is sealed against mouth moisture, both at the probe and the handle. Nevertheless, there is an acoustic coupling from both sides of the ceramic transducer plate assembly to the outer opposite surfaces of the probe tip. Thus, the vibratory energy from the ceramic plates is transferred to the teeth or gums.
Since the instrument described herein is to be used in the mouth area, as a prophylactic aid for massaging the gums and the teeth, it is desirable to keep the operating voltage as low as possible. There should not be any danger of electrical shock in connection with the use of the instrument.
To reduce the level of operating voltage, the ceramic plate assembly may be subdivided into thinner sections, which may be connected as illustrated schematically in FIG. 7. In greater detail, the multi-plate assembly of FIG. 7 uses four plates with the electrode polarities connected as illustrated; that is, similar polarities on each plate are placed in face-to-face relationship (i.e., to and to This assembly may be substituted directly for the two-plate assembly of FIG. 6. If the over-all dimensions of the ceramic assembly are not changed, the operating voltage for the transducer assembly of FIG. 7 is reduced by one-half, as compared with the voltage requirements for the assembly of FIG. 6. Further subdivision of the plates into still thinner sections further decreases the operating voltage to any value required.
FIG. 8 illustrates an alternative type of transducer construction. More particularly, the open annular housing 30 of FIG. 6 is replaced by an annular housing 44 which contains a central web portion 45. For this construction, the piezoelectric ceramic plates 46 and 47 are rigidly bonded to the web section 45, as by means of conducting epoxy, for example. The piezoelectric plates 46, 47 are connected with opposite polarities together and on opposite sides of the housing web section. This connection is shown and indicated by the and polarity markings of the electrode surfaces in FIGS. 8-l0. The electrical conductor 36 is electrically connected to the conducting web member 45 and the two outer surfaces of the piezoelectric ceramic plates are connected to the electrical conductor 36A.
In operation, the transducer structure shown in FIG. 8 causes flexural vibrations when alternating current is supplied to the terminals 36, 36A. The piezoelectric excursion causes displacement to the right, as illustrated in FIG. 9, when a positive potential is applied to one of the electrical terminals ofthe assembly. When the polarity of the applied signal is reversed, the displacement of the piezoelectric excursion is also reversed, as illustrated in FIG. 100 This flexural vibration is most efficiently established when the frequency of the alternating current corresponds to the natural flexural resonant frequency of the assembly. These resonant frequencies range from about 25 kHz. to about 100 kHz. They can be achieved in a practical low-cost design of a flexural vibrating transducer element assembly which is small enough to fit into the end ofa dental probe of convenient size.
For the transducer construction illustrated in FIG. 6, efficient operation occurs at either the planar resonant frequency mode of the assembly or at the thickness resonant mode of the assembly. For either of these modes and for practical probe sizes, the resonant frequency will generally be' greater than 100 kHz. Small size probes, specifically designed for childrens use, may operate at frequencies as high as 500 kHz.
FIG. 11 schematically illustrates how the ceramic plates in FIG. 8 may be further subdivided to reduce the operating voltage required for the flexural transducer design. Each plate in FIG. 8 is replaced in FIG. 11 by a pair of plates 52, 52A and 53, 53A. Each of the plates 52, 53 has one-half the thickness of the corresponding plates 46, 47. These plates 52, 52A and 53, 53A are connected with their electrode polarities as indicated in FIG. 11, by the and signs. The operating voltage for the subdivided plate arrangements 52, 53 of FIG. 11 is about one-half the operating voltage required by the arrangement ofFIG. 8.
While several specific embodiments have been shown, it should be understood that various modifications and alternate constructions may be made without departing from the true spirit and scope of the invention. Therefore, the appended claims are intended to cover all equivalent constructions falling within their true spirit and scope.
I. An electroacoustic appliance having a shape and dimension suitable for the application of acoustic energy to local areas of the human gums while being held in the hand of the person using said appliance, said appliance comprising an elongated slender handle with a probe tip frame structure attached thereto and shaped to fit in the region surrounding said gums, means comprising an electroacoustic transducer having at least one exposed vibratile surface mounted on said tip frame structure, means for transferring vibrations from said vibratile surface to the exterior of said probe tip, electrical means coupled to said transducer means for driving said transducer means, and waterproof acoustic coupling means bonded to said vibratile surface and to said probe tip frame structure for transferring the vibratory energy to localized areas of the gums, said waterproof coupling means comprising a unitary hood surrounding said transducer and probe tip frame shaped and dimensioned to fit into the region surrounding said gums.
2. The appliance of claim 1 wherein said frame includes an annular housing and said electroacoustic transducer means comprises a plurality of piezoelectric plates mounted inside said annulus.
3. The appliance of claim 1 and an annular housing surrounding said piezoelectric plates, and further characterized in that the surfaces of said plates are located approximately perpendicular to the axis of the annular housing and parallel to the axis of said elongated housing.
4. The appliance of claim 3 further characterized in that said acoustic coupling means includes a tapered member attached to said vibratile surface whereby the tip portion of said tapered member transfers the acoustic energy from the vibratile surface to the gums.
5. The appliance of claim 1 further characterized in that said acoustic coupling means includes a tapered member attached to said vibratile surface whereby the tip portion of said tapered member transfers the acoustic energy from the vibratile surface to the gums.
6. The appliance of claim 1 and an annular housing surrounding said transducer, further characterized in that said transducer presents a vibratile surface on each of the opposite sides of the opening through said annular housing, and still further characterized in that the waterproof acoustic coupling means are bonded to each of said oppositely exposed vibratile surfaces, and still further characterized in that a tapered member is perpendicularly attached to one of said vibratile surfaces whereby the tip portion of said tapered member transfers the acoustic energy to the gums from the vibratile surface to which it is attached.
7. The appliance of claim 6 further characterized in that the other of said vibratile surfaces is acoustically coupled to a surface layer of acoustically transparent waterproof material.
8. The appliance of claim 7 further characterized in that the external surface of said layer of acoustically transparent material is convex.
9. The appliance of claim 7 further characterized in that said layer of acoustically transparent material is resilient.
10. The appliance of claim 1 further characterized in that said electroacoustic transducer means operates in the ultrasonic frequency region.
11. The appliance of claim 10 further characterized in that said ultrasonic frequency region is greater than 25 kHz.
12. The appliance of claim 10 further characterized in that the frequency region lies between and 500 kHz.
13. A prophylactic device for the treatment of gums comprising a handle with a probe for fitting into a persons mouth attached to one end thereof, electroacoustic transducer means contained within said probe, acoustic coupling means attached to said electroacoustic transducer means and sealed to. said probe, and means for electrically driving said electroacoustic transducer means to vibrate at a characteristic frequency.
14. The device of claim 13 characterized in that said electroacoustic transducer means includes a piezoelectric transducer element.
15. The device of claim 14 further characterized in that said transducer element operates in the ultrasonic frequency region.
16. The device of claim 15 further characterized in that said frequency region is higher than 25 kHz.
17. The device of claim 15 further characterized in that the frequency region is in the range between 100 and 500 kHz.
18. The device of claim 14 further characterized in that said transducer element includes at least one piezoelectric plate having a surface parallel to said handle, and still further characterized in that said acoustic coupling means includes a tapered member perpendicularly attached to said surface of bonded to each of said separate vibratile surfaces and said acoustic coupling means is sealed to the surface of said probe.
20. The device of claim 19 further characterized in that said coupling means includes a tapered member perpendicularly attached to one of said vibratile surfaces whereby the tip portion of said tapered member transfers the acoustic energy from the vibratile surface to which it is attached to the gum.