Patent Description:
Dental calculus develops mostly in mouth areas that are difficult to access, in particular during home care treatments like a toothbrush or a water spray treatment. These areas are also difficult to access during a professional care treatment, especially during scaling, and calculi formed are hard and strongly attached to the teeth.

Ultrasonic scaling instruments are well known to efficiently remove hard calculus due to their power of ultrasonic vibrations and a low impact on teeth. A removal capacity of the ultrasonic scaling instrument is achieved by their ultrasonic vibrational power, which can be approximated to be proportional to an amplitude, i.e. a vibration amplitude, for a given stiffness of the tip element. Thereby, the amplitude needs to be optimized when determining a geometry of the tip element to ensure its efficiency, in a limit of an instrument resistance.

A low invasiveness of the tip element is ensured by a controlled ultrasonic vibration in one-dimensional or translation direction. The calculus is kicked, not cut, due to a force of the ultrasonic motion, having a low amplitude, but a high speed and a high acceleration due to a high frequency of the ultrasonic motion. This ensures a low contact force between teeth and instrument.

For kicking the calculus with low or no impact on teeth, a characteristic planar flexural motion of the tip element must be perfectly tangential to a teeth surface. For areas, which are difficult to access, particularly for mesial and distal access of molar and premolar teeth, it gets harder to guarantee the tangential positioning of the tip element with traditional straight tip elements.

To properly remove calculus in these areas, it turned out that the tip element has to be tilted to a certain angle, preferably to <NUM>°. However, these instruments are known for having a low efficiency and it further turned out that the vibrational motion could not be properly controlled. For example, the actual amplitude is less than <NUM> at full motion, and a planar flexural motion could not be ensured. Especially due to its specific geometry, no ultrasonic vibration could be sent to the dental calculus to remove it.

Other solutions, including for example a different angle for the planar motion, could not ensure proper rerouting of the vibration motion. Solutions that ensure a proper rerouting of the vibration motion, in turn, could not guarantee a proper alignment of the tip element relative to the teeth, increasing the risk of teeth damages.

Further, <CIT> concerns a motion transformation that transforms a first linear vibration to another second linear vibration being perpendicular to the previous one. It uses a radial mode of vibration, which re-orientates the vibration without any amplification. Thereby, the system of <CIT> is not intended for scaling, but for instruments having a low amplitude and a low efficiency. Further, the element realizing the motion transformation is arranged between the hand piece and the tip element being reversibly attachable.

<CIT> discloses an ultrasonic tip for ultrasonic instruments, and further provides a method of dental treatment of peri-implantitis using an ultrasonic tip operable to cooperate with an ultrasonic instrument to transmit ultrasonic vibrations to a surface of a dental implant to be treated, said implant and said ultrasonic tip being made of titanium.

<CIT> discloses a tip having a ball-like end section.

<CIT> concerns a lighted dental instruments and, more particularly, powered dental scalers incorporating both an integral light source and a fluid passageway that directs fluid adjacent to tooth surfaces with which the scalers are in contact.

<CIT> discloses a disposable dental tip incorporated in an ultrasonic scaler and a dental working distal end piece used for the dental tip.

<CIT> concerns a moulded gauge used for both manual and automated inspection of the length of at least one ultrasonic scaler tip.

It is an object of the present invention to provide an improved tip element, which performs an ultrasonic vibration during its utilization, in particular with respect to its efficiency, its control of the motion along a tilted direction and its low invasiveness.

This object is achieved by the tip element according to claim <NUM>, and a dental treatment device according to claims <NUM>.

Preferred embodiments are incorporated in the dependent claims, the description and the figures.

According to the invention a tip element for a dental treatment device, in particular a scaler, is provided, wherein the tip element performs an ultrasonic vibration during its utilization, comprising.

wherein, for transforming an ultrasonic vibration having a first vibration direction to an ultrasonic vibration having a second vibration direction, the motion transformation section has a first bended subsection and a second bended subsection.

The first end section forms a proximal end and the second end section forms a distal end of the tip element.

The tip element according to the invention includes a motion transformation section having a first bended subsection and a second bended subsection for transforming an ultrasonic vibration, having a second vibration direction, i. the tip element is at least double bended in the motion transformation section. Due to the motion transformation section it is advantageously possible to block at least a part of a forward and backward movement of the tip element, i. an ultrasonic vibration having a first direction, in particular at its first end section, and to transform this forward and backward movement at least partially to an up-and-down movement, i. an ultrasonic vibration having a second direction, at the end of the motion transformation section. For example, the forward and backward movement is performed parallel to a longitudinal direction and the up- and down-movement is directed perpendicularly to the forward and backward movement.

Furthermore, it is advantageously possible to fine tune an amplitude of the ultrasonic vibration, in particular at the end of the motion transformation section. This allows adapting the efficiency for properly removing calculus. It further turned out that the control of the motion transformation by the motion transformation section can be applied to different forms of the second end section, in particular to those that are designed for removing calculus in areas, being hard to access. Thereby, a controlled motion of the second end section, in particular in one certain plane, can be advantageously used to avoid hammering against the tooth during its utilization.

In particular, it is provided that the tip element is free of titanium. According to the invention, the tip element comprises a titanium amount of less than <NUM> weight-%, preferably less than <NUM> weight-% and most preferably less than <NUM> weight-%. Thereby, it is conceivable that the tip element includes a section being made of titanium. For example, a front end of the tip element is made of titanium. It is also thinkable that only a core section or a sleeve section is made of titanium. For example, the tip element is only coated with a titanium layer. Preferably, free of titanium means that the amount of titanium is less than <NUM> weight-%, preferably less than <NUM> weight-% and more preferably less than <NUM> weight-%.

Furthermore, it is preferably provided that the tip element does not extend only in one plane. In other words: the extension of the first end section, the second section and the motion transformation section define a volume, since they are not located or arranged in a common plane, in which the first end section, the second section and the motion transformation section can extend. In other words: The first end section, the second section and the motion transformation section define a set of three independent vectors.

Furthermore, the tip element is ball free, in the region of the pointed tip, i. the tip elements only tapers to its front end, without having an ball like front end.

Preferably, it is provided that the tip element is reversibly attachable to a hand piece including an activator unit that induces the ultrasonic vibration to the tip element, in particular to the first end section of the tip element. For example, the activator unit comprises a piezo transducer. Furthermore, in order to ensure continuity of the ultrasonic vibration between the hand piece (which includes the piezo-transducer) and the tip element, the hand piece and the tip element have an interface, preferably at a front side of the hand piece and the first (proximal) end section, for inserting the tip element to a corresponding recess of the hand piece. For example, the first end section of the tip element can be screwed to the hand piece or the hand piece and the first end section are configured to form a key lock principle mechanism. Preferably, the first end section of the tip element is screwed to the hand piece.

Especially, the activation unit induces an ultrasonic vibration having the first vibration direction in the first end section, wherein the first vibration direction is parallel to a longitudinal direction of the hand piece, usually initiated by piezo transducer which is stacked longitudinally inside the actuator of the hand piece. The second end section particularly tapers to a pointed end that is in contact with the tooth during its utilization. To avoid damages at the tooth, it is preferably provided that the tip element, in particular the second (distal) end section of the tip element, has smooth edges. Preferably, the cross section of the tip element in the first end section is bigger than a cross section of the tip element in the second end section.

In particular, the tip element is a single piece, i. the tip element is constructed integrally. Especially, the first end section merges into the motion transformation section and/or the motion transformation section merges into the second end section. Further, it is provided that the second end section is configured to perform a planar flexural motion, in particular at its pointed end. "Planar" means that the movement is performed in a single plane, i.e. a two dimensional plane, without having a movement component perpendicular to that plane.

According to the invention, it is provided that a course of the tip element is bended.

Preferably, it is provided that the first angle and/or the second angle are between <NUM>° and <NUM>°, more preferably between <NUM>° and <NUM>° and most probably between <NUM>° and <NUM>° or even mainly <NUM>°. By choosing the first angle as close as possible to <NUM>°, it is advantageously possible to almost block the whole ultrasonic vibration having the first vibration direction and transfer an energy mainly completely to the vibration having the second vibration direction at the ending of the motion transformation section.

Particularly, it is provided that a first radius of curvature Rα1, satisfying <MAT> is assigned to the first bended subsection, wherein D<NUM> is in the range between <NUM> and <NUM>. The second radius of curvature Rα2, assigned to the second bended subsection, is determined by the lengths L1 and L2 and by the angle α1.

In particular, it is provided that the motion transformation section has a first length and the course of the tip element in the motion transformation section causes a lateral shift having a second length, wherein the first length is longer than the second length. By choosing the first length longer than the second length, it is advantageously possible to amplify the amplitude of the ultrasonic vibration, in particular of the ultrasonic vibration at the pointed end of the second end section. Preferably, the first and the second length are dimensioned to form an elliptic resonator, wherein the first length forms a large axis and the second length forms a short axis of the elliptic resonator.

Preferably, the first length and/or the second length is/are in a range between <NUM> to <NUM>. Thus, the first length and second length are dimensioned for transferring the ultrasonic vibration, having the first vibration direction, to the ultrasonic vibration, having the second vibration direction. Simultaneously, the first length and the second length are small enough for a simple handling of the tip element being attached to the hand piece.

Furthermore, it is particularly provided that the first length is equal to or longer than the second length and/or the first cross-section area is equal to or larger than the second cross-section area. Thus, it is possible to tune the amplitude, for example by modifying the ratio of the first and the second length and/or the first cross-section and the second cross-section area correspondingly.

Furthermore, it is particularly provided that the tip element has a core region and a cover region, wherein the cover region surrounds the core region, wherein along the course of the tip element the cover region modifies its extension in a direction perpendicular to the course of the tip element, in particular in the motion transformation section. Thus, another possibility for adapting the amplitude at the pointed end of the tip element is provided by adapting the size of the cover region. Preferably, the core region and the cover region are concentric to each other. Preferably, the modification of the size of the cover region is realized within the motion transfer section. The core region is preferably cylindrical and forms a channel for transporting a liquid stream, preferably water.

Preferably, it is provided that in the motion transformation section the cover region has a first cross-section area in a first cross section perpendicular to the course of the tip element, in particular measured at a beginning of the motion transformation section, and/or a second cross-section area in a second cross section perpendicular to the course of the tip element in the motion transformation section, in particular measured at an ending of the motion transformation section, wherein the first cross-section area is bigger than the second cross-section area. The size of the core region remains constant. Especially for the first cross-section area being bigger than the second cross-section area it is advantageously possible to amplify the amplitude of the ultrasonic vibration at the pointed end of the second end section. Actually, it turned out that an amplitude of <NUM> at full power (when water is passing through the core region,) could be reached, in particular if the size modification has been combined with the elliptic resonator formed with the first length being bigger than the second length. For comparison, the same type of tip element without motion transformation section, having a first bended subsection and a second bended subsection, provides an amplitude of <NUM> under the same condition. Consequently, it is possible to amplify the amplitude by at least a factor of <NUM> by adapting the motion transformation section correspondingly.

Preferably, the cover region has a conical, stepped and/or exponential shape along the course of the tip element, in particular in the motion transformation section. Advantageously, it is possible to adapt the amplitude of the ultrasonic vibration at the pointed end of the tip element by adapting the shape of the cover region along the course of the tip element.

According to the invention, it is provided that, preferably in the second end section, the course of the tip element is bended in a tilted direction about a third angle relative to a main plane including the first bended subsection and the second bended subsection, wherein the third angle is between -<NUM>° and +<NUM>°, preferable between -<NUM>° and <NUM>°. Especially, a third angle and/or a third radius of curvature is adapted depending on its planned application. For example, for a straight tip element the third angle is <NUM>°. For curved instruments, preferred for mesial and distal treatment of molar or premolar teeth, the third angle is adapted to an area to be treated. For example, the range of the third angle is between -<NUM>° and <NUM>° depending on the mouth quadrant. For -<NUM>° and <NUM>° as third angle, access to areas otherwise hard to access for a tip element is simplified.

In one embodiment, it is provided that in the second end section the course of the tip element is bended about a fourth angle in a plane including a part of the second end section, extending in the tilted direction. This is particularly useful for dental applications. In particular, the second end section is bended such that the second end section defines a plane, in particular tilted about the third angle. During its utilization, the pointed end performs its ultrasonic vibration in said plane to remove the calculus from the teeth. Thereby, the second end section, in particular its pointed end, performs a planar flexural motion, for example a motion tangential to the tooth surface. Advantageously, the geometry of the motion transformation section ensures that the pointed tip performs no additional movement out of said plane that would otherwise hammer the tooth and might cause damages.

Another aspect of the present description is a motion transformation section for the tip element. All features and benefits described above for the tip element can be applied to the motion transformation section analogously and vice versa. It is even considerable that the first end section, the second end section and/or the transformation section can be put together to form the desired tip element. For example, the transformation section and the second end section provides an interface to reversibly attach the second end section to the motion transformation section. Thus, it is possible to interchange the second end region and for example change the third angle and/or the fourth angle by using another differently bended second end section.

Furthermore, the present invention concerns a dental treatment device having a tip element according to the present invention. All features and benefits described in the context of the tip element apply analogously to the dental treatment device and vice versa. Preferably, the dental treatment device comprises an activator unit for inducing a linear ultrasonic vibration to the tip element, especially to a tip element being reversibly attachable to the activator unit. In particular, the tip element is screwed to the dental treatment device at its front side.

Preferably, the dental treatment device is configured to establish a linear vibration of the tip element having a frequency of less than <NUM>, preferably a frequency between <NUM> and <NUM>.

Another aspect of the present description concerns a tip card device for checking a status of a tip element according to the present invention, comprising a holding element for arranging the tip element in a fixed orientation relative to a projection area. Thus, it is advantageously possible to check whether the transformation section and/or the second end section has been deformed during its utilization and the user is informed whether he needs to replace the tip element. Thereby, the holding element is configured such that the tip element can be checked from different perspectives, for example by transferring the tip element into a certain orientation that allows checking the geometry of the tip element on the same projection area. It is also thinkable that the projection area forms a box, in particular an open box or a transparent box, which allows to check the geometry of the tip element from different perspectives. All features and benefits described in the context of the tip element apply analogously to the tip card device and vice versa.

In the <FIG> and <FIG> a tip element <NUM> according to a preferred embodiment of the present invention is shown. For example, the tip element <NUM> is a scaling tip, i. tip element <NUM> that is used to clean teeth by scaling. Preferably, during its utilization the tip element <NUM> is reversibly attached to a hand piece (not shown) and, in particular, in the mounted state the hand piece and the tip element <NUM> form a medical instrument, preferably a dental instrument. In particular, the tip element <NUM> and the hand piece are connected to each other via corresponding interfaces being respectively assigned to the hand piece and the tip element <NUM>.

For removing tartar, calculus and/or plaque from the teeth the hand piece having the tip element <NUM> is led to the teeth such that the tip element <NUM> comes into contact with the surface of the teeth. Preferably, the hand piece comprises an activator unit for activating a movement, in particular an ultrasonic movement, of the tip element <NUM> connected to the hand piece. This ultrasonic movement supports removing spots, plaque and/or dentine tartar. The tip element <NUM> might be used in subgingival or supragingival treatments.

In particular, the tip element <NUM> comprises a first end section <NUM> and a second end section <NUM> being opposite to the first end section <NUM> along a course of the tip element <NUM>. The first proximal end section <NUM> is configured for being attached to the hand piece, for example by plugging in the tip element <NUM> into a corresponding recess of the hand piece. In its utilization the activator unit transfers or induces an ultrasonic vibration to the first end section <NUM> causing an ultrasonic vibration along a first vibration direction V1. For example, the activator unit comprises a piezo transducer for realizing such an ultrasonic movement. The hand piece might further comprise a cooling unit, such a cooling circuit including a water inlet and/or outlet, for cooling the hand piece during its operation.

The second distal end section <NUM> forms a tool that is preferably in contact with the teeth during utilization of the tip element <NUM>. In the present embodiment of <FIG>, it is provided that the second end section <NUM> tapers along the course or the tip element <NUM> for forming a pointed tip <NUM> at its front side being faced to the teeth during its utilization.

To modify an amplitude of the ultrasonic vibration, in particular at the pointed end <NUM> of the tip element <NUM> in the second end section <NUM>, a geometry of the tip element <NUM> is adapted correspondingly. In particular, a motion transformation section <NUM> is provided between the first end section <NUM> and the second end section <NUM>. The motion transformation section <NUM> preferably is S-shaped and includes a first bended subsection <NUM> and a second bended subsection <NUM>. Preferably, the second bended subsection <NUM> directly follows the first bended subsection <NUM> along the course of the tip element <NUM>. In particular, the tip element <NUM> is bended in the first subsection <NUM> about a first angle α1 and in the second bended subsection <NUM> about a second angle α2, wherein a difference between the first angle α1 and the second angle α2 is smaller than <NUM>°, more preferably smaller than <NUM>° and most preferably smaller than <NUM>°. Especially, the first bended subsection <NUM> and the second bended subsection <NUM> are bended in opposite direction for forming an S-like geometry.

Furthermore, the first angle α1 and/or the second angle α2 is/are between <NUM>° and <NUM>°, more preferably between <NUM>° and <NUM>° and most probably between <NUM>° and <NUM>° or is even mainly <NUM>°. In particular, the course of the tip element <NUM> in the first bended subsection <NUM> mainly changes its direction about <NUM>°. As a consequence, it is possible to block the ultrasonic vibration having the first vibration direction V1 and to transfer the ultrasonic vibration having a first vibration direction V1 in the first end section <NUM> of the tip element <NUM> into an ultrasonic vibration having a second vibration direction V2 at the end of the motion transformation section <NUM>, wherein the second vibration direction V2 mainly extends perpendicularly to the first vibration direction V1. Thus, a motion transformation can be realized. In particular, an ultrasonic vibration parallel to the course of the tip element <NUM>, i. a backward - forward movement, is transferred to an ultrasonic vibration perpendicular to the course of the tip element <NUM>, i. to an up-and -down movement of the tip element <NUM> at the end of the motion transformation section <NUM>.

Actually, a first radius of curvature Rα1 can be assigned to the first bended subsection <NUM>, wherein the radius of curvature Rα1 satisfies <MAT> wherein D1 is in the range between <NUM> and <NUM> and corresponds to the length of the cover and core region of the tip element in a first cross section. The same applies to a second radius of curvature Rα2 that can be assigned to the second bended subsection <NUM>.

Moreover, it is preferably provided that the motion transformation section <NUM> extends about a first length L1 measured in a direction parallel to the first vibration direction V1. Due to the form of the first bended subsection <NUM> and second bended subsection <NUM>, the course of the tip element <NUM> behind the second bended subsection <NUM> is laterally or radially shifted to the course of the tip element <NUM> in front of the first bended subsection <NUM> (seen in a direction from the first end section <NUM> to the second end section <NUM>). Preferably, a second length L2 is assigned to the radial shift caused by the motion transformation sector <NUM>.

By choosing a certain ratio between the first length L1 and the second length L2 it is advantageously possible to modify the amplitude of the ultrasonic vibration. For example, the amplitude is amplified, if the second length L2 is smaller than the first length L1, and the amplitude is reduced, if the second length L2 is bigger than the first length L1. Especially, the first length L1 and the second length L2 form axes of an elliptic resonator. The amplitude mainly remains constant, if the second length L2 is equal to the first length L1. In this case, the first length L1 and the second length L2 represent a radius of a circle.

Furthermore, the tip element <NUM> has a core region D and a cover region S, wherein in a first cross section I-I perpendicular to the course of the tip element <NUM> the core region D is surrounded by the cover region S, preferably completely surrounded in the first cross section I-I. Preferably the core region is cylindrical and forms a channel for transporting a liquid stream, preferably water. By modifying a dimension of the cover region S along its course in the motion transformation section <NUM>, it is advantageously possible to adapt the amplitude of the ultrasonic vibration. This can be done in addition to the modification of the amplitude by the ratio of the first length L1 and the second length L2. In particular, the cover region S has a first cross-section area S1 in the first cross section I-I perpendicular to the course of the tip element <NUM> and a second cross-section area S2 in a second cross section H-H perpendicular to the course of the tip element <NUM>. Preferably, the first cross-section area S1 is assigned to a beginning of the motion transformation section <NUM> and the second cross-section area S2 to an ending of the motion transformation section <NUM>. Thereby, the beginning of the motion transformation section <NUM> is preferably defined by the last cross section (seen in a direction from the first end section <NUM> to the second end section <NUM>) of the tip element <NUM> perpendicular to the course of the tip element <NUM> that is perpendicular to the first vibration direction V1. The ending of the motion transformation section <NUM> is preferably defined by the cross section perpendicular to the course of the tip element <NUM>, wherein said cross section (seen in a direction from the first end section <NUM> to the second end section <NUM>).

Furthermore, a first length D1 is assigned to the cover S and core region D in the first cross section I-I and a second length D2 is assigned to the cover S and core region D in the second cross section H-H. When the cover region S and the core region D are cylindrical, both D1 and D2 represent the diameter of the core region plus the cover region. The diameter of the core region is preferably constant along the tip element.

By choosing the second cross-section area S2 of the cover region S smaller than the first cross-section area S1, it is advantageously possible to amplify the amplitude of the ultrasonic vibration. Alternatively, it is possible to maintain the amplitude by choosing the second cross-section area S2 equal to the first cross-section area S1 or to decrease the amplitude by choosing the second cross-section area S2 bigger than the first cross-section area S1.

Preferably, the cover section S has a conical, exponential and/or stepped shape along the course of the tip element <NUM> in the motion transformation section <NUM>.

<FIG> shows the tip element <NUM> in a perspective view parallel to a main plane M including the first bended subsection <NUM> and the second bended subsection <NUM>. As a consequence of this perspective, the double bended structure of the motion transformation section <NUM> cannot be observed in this illustration. In the embodiment shown in <FIG> the second end section <NUM> of the tip element <NUM> is bended into a tilted direction T relative to the main plane M, including the first bended subsection <NUM> and the second subsection <NUM>, about a third angle α3, wherein the third angle α3 is <NUM>° in the shown embodiment. Due to the bending about the third angle α3, at least a part of the second end section <NUM> extends along the tilted direction T for performing a planar flexural motion during utilization of the tip element <NUM>. The third angle α3 or a corresponding third radius of curvature Rα3 depends on a planned application of the tip element <NUM>, in particular a region of the mouth the tip element <NUM> is intended for.

<FIG> shows the second end section <NUM> of the tip element <NUM> illustrated in the <FIG> and <FIG>. Especially, the part of the second end section <NUM>, extending along the tilted direction T, is bended about a fourth angle α4 and forms a plane including the tilted direction T. The fourth angle α4 or a corresponding fourth radius of curvature Rα4 is adapted depending on surfaces to access and preferably ranges between <NUM>° and <NUM>°, more preferably ranges between <NUM>° and <NUM>° and most preferably is mainly <NUM>°. Preferably, a bend of the course of the second end section <NUM> about the third angle α3 is perpendicular to a bend of the course of the second end section <NUM> about a fourth angle α4.

In addition to the motion transformation section <NUM>, the geometry of the application part of the tip element (section <NUM>) has a significant influence on the direction of the vibration. To ensure the correct orientation, an anti-axisymmetric structure is retained to limit hammering motions that may be introduced by parasitic motions when the ultrasonic vibration is not controlled. The anti-axisymmetric structure gives a preferential direction to the vibration by filtering parasitic motions thanks to a specific quadratic moment, i.e. selective stiffness, and select only the vibration on the rerouted direction.

Claim 1:
A tip element (<NUM>) preferably for a dental treatment device, in particular a scaler, wherein the tip element (<NUM>) performs an ultrasonic vibration during its utilization, comprising
- a first end section (<NUM>) for reversibly attaching the tip element (<NUM>) to a hand piece,
- a second end section (<NUM>), forming a dental tool, and
- a motion transformation section (<NUM>) arranged between the first end section (<NUM>) and the second end section (<NUM>),
wherein, for transforming an ultrasonic vibration having a first vibration direction (V1) to an ultrasonic vibration having a second vibration direction (V2), the motion transformation section (<NUM>) has a first bended subsection (<NUM>) and a second bended subsection (<NUM>), wherein the tip element (<NUM>) has a pointed tip and wherein a course of the tip element (<NUM>) is bended
- about a first angle (α1) in the first bended subsection (<NUM>) and
- about a second angle (α2) in the second bended subsection (<NUM>) wherein in the second end section (<NUM>) the course of the tip element (<NUM>) is bended in a tilted direction (T) about a third angle (α3) relative to a main plane (M) including the first bended subsection (<NUM>) and the second bended subsection (<NUM>), wherein the third angle (α3) is between -<NUM>° and +<NUM>°, preferable between -<NUM>° and <NUM>°,characterized in that the tip element (<NUM>) comprises a titanium amount of less than <NUM> weight - %.