Abstract: In a dental handpiece with an elastically arranged reception part (8) for a tool, compressed air from angled exit nozzles (9) can be applied to a sleeve (7) allocated to the reception part (8) with radial play. The circulating movement of the sleeve (7) is converted into a vibration of the reception part (8). The plane of vibration lies essentially perpendicular to the longitudinal axis of the reception part (8).

Abstract: An electric toothbrush is provided which includes an elongate body having an interior cavity, a power source mounted within the cavity, an elongate drive shaft driven rotatably by the power source, a camwheel mounted on the drive shaft, a yoke with projecting arms which confine travel of the camwheel, a crankshaft section driven by the drive shaft, an output shaft axially aligned to the drive shaft, and a collar with a guide track eccentrically coupling the crankshaft section to the output shaft thereby imparting both lateral and rotary reciprocating motion to the output shaft. A brushhead mounted on the front end of the elongate body accepts the motion from the output shaft. The mechanical drive system is fully enclosed within the housing of the elongate body. Brushheads are replaceably mountable outside the cavity on the front end.

Abstract: An interproximal flossing device including a link member that isolates lateral from vertical rotational movement to transfer only translatory arcuate movement. This is done by the combination of a hinge and pivot structure. A tip attachment structure is also included for secure placement of the tip on the link member, and allows easy removal and replacement. A tip member removal structure is also included to allow for easy removal of the tip member from the link member.

Abstract: The invention relates to a handpiece (3) for medical purposes, having a tool holder (5) arranged in the forward end region of the handpiece (3), a retaining coupling (16) for releasably fixing a tool (6) in the tool holder (5), and a drive connection (8), for a rotary and/or stroke drive of the tool holder (5), extending longitudinally through the handpiece (3), there being provided an arrangement for limiting the maximum torque value which can be transmitted to the tool holder (5) to a lesser torque value. For the purpose of broadening the range of application of the handpiece (3), the arrangement can be selectively deactivated and again activated, by means of a setting device (14).

Abstract: An air-driven dental instrument (10) includes a replaceable vibrator module (16) detachably accommodated in an axial lodgment defined by an elongated outer casing (14) comprised of a frontal cap (22A) and a main body (26A) coupled with each other. When the cap (22A) is coupled, the module (16) is axially positioned against the cap (22A) by a positioning sleeve (90A) and is rotationally locked against the sleeve (90A) by a hexagonal formation (128) engaging into cutouts (136) formed on a housing (134). When the cap (22A) is disconnected from the main body (26A), the module (16) is retained by the housing (134) but is partly exposed therefrom. This permits a user to grip the module to thereby facilitate replacement of the module (16).

Abstract: A flossing device having two times. An advancing mechanism advances an end of a piece of floss from the end of one tine to the end of the other tine so that a segment of the floss spans the inter-tine space. In use, an inter-dental space is placed in the inter-tine space and a segment of floss is advanced from one tine through the inter-dental space to the second tine. The end of the floss segment is locked to the second tine; and the floss is vibrated so as to floss the inter-dental space.

Abstract: A handle housing that is modular and easily assembled and disassembled for maintenance and cleaning. The handle housing has an integrally-formed orientation shape (e.g. S-shape) to keep it from tipping onto the flossing tip. The handle housing also includes the rocker arm, cam drive (together the drive train), motor, power supply and bobbin for full functionality, with linear, reciprocating motion created by the drive train for effective cleaning.

Abstract: A transmission for changing rotary motion into angularly reciprocating motion and adapted to be mounted on the output end of a dental power unit of the type having a rotary drive output and used to drive a dental tool. The transmission is comprised of a support member, a driving resinous member supported by the support member for rotary motion, and a driven resinous member supported by the support member for reciprocating angular movement by the support member. The transmission subassembly is formed by the driving resinous member, driven resinous member and support member and adapted to be mounted on the output end of the dental power unit with a rotary drive output mechanically coupled to the driving resinous member. A driving cam surface is disposed on a portion of the driving resinous member. A driven cam surface is disposed on a portion of the driven resinous member.

Abstract: In a dental handpiece with an elastically arranged reception part (8) for a tool, compressed air from angled exit nozzles (9) can be applied to a sleeve (7) allocated to the reception part (8) with radial play. The circulating movement of the sleeve (7) is converted into a vibration of the reception part (8), the plane of vibration lying essentially perpendicular to the longitudinal axis of the reception part (8).

Abstract: A contra-angle dental handpiece is capable of rotating a cutting tool in the forward direction when the cutting tool is in the most advanced position in a root canal of a tooth and preventing the reverse rotation of the cutting tool when the cutting tool is retracted therefrom. The contra-angle dental handpiece includes a rotation shaft for rotating a dental cutting tool about a rotation axis, a drive shaft for rotating the rotation shaft, and a drive mechanism for driving the dental cutting tool in a backward and forward direction of the rotation axis and for intermittently rotating the dental cutting tool only in the forward rotational direction about the rotation axis when the cutting tool is at around a most advanced position in a root canal of a tooth.

Abstract: A flossing tip for a power dental flossing device. The tip is elongated and includes a base portion, a central portion having a generally rectangular cross-section, and an enlarged end portion including a disk shape. The tip is compressible. The base portion supports the tip when the tip is coupled to the dental flossing device. The central portion couples the base portion to the end portion. The end portion is inserted between a pair of adjacent teeth of a user, and helps guide and orient the tip between the adjacent teeth. When in use, the rectangular cross-section of the tip provides multiple points of contact against a tooth for cleaning, and also helps maintain the tip in proper orientation with respect to the teeth. The enlarged end portion assists in positioning the tip, provides additional cleaning edges, and helps prevent trauma to the gums.

Abstract: A handle housing that is modular and easily assembled and disassembled for maintenance and cleaning. The handle housing has an integrally-formed orientation shape (e.g. S-shape) to keep it from tipping onto the flossing tip. The handle housing also includes the rocker arm, cam drive (together the drive train), motor, power supply and bobbin for full functionality, with linear, reciprocating motion created by the drive train for effective cleaning.

Abstract: The invention is an endodontic handpiece, its control system and method of use for rotating an endodontic file to clean a root canal. The invention control system provides for rotating a file clockwise or counterclockwise through a desired first arc of rotation and, next, sequentially rotating the instrument in the opposite direction of the first arc of rotation through a second arc of rotation, wherein the first arc of rotation exceeds the second arc of rotation such that sequentially occurring rotations cause debris material removed in cleaning the canal to be ejected upwardly from the clean surfaces as such file is advanced in cleaning the canal.

Abstract: The invention is directed to an electrically powered dental cleansing device (1) to which a cleansing implement (32) is fitted. In this manner, the cleansing implement (32) can be rotated about its longitudinal axis. The cleansing implement (32) is configured as an integrally formed part comprising a thin and elongate cleansing shaft (125). The cleansing shaft has at least one longitudinal edge and is provided with a plurality of serrations.

Abstract: A transmission for changing rotary motion into angularly reciprocating motion and adapted to be mounted on the output end of a dental power unit of the type having a rotary drive output and used to drive a dental tool. The transmission is comprised of a support member, a driving resinous member supported by the support member for rotary motion, and a driven resinous member supported by the support member for reciprocating angular movement by the support member. The transmission subassembly is formed by the driving resinous member, driven resinous member and support member and adapted to be mounted on the output end of the dental power unit with a rotary drive output mechanically coupled to the driving resinous member. A driving cam surface is disposed on a portion of the driving resinous member. A driven cam surface is disposed on a portion of the driven resinous member.

Abstract: In a medical or dental treatment instrument (1) for chip-removing treatment of body tissue or a substitute material with an abrasive tool (7), consisting of a handpiece (2) with an oblong gripping sleeve (41), in the front end area of which a vibration part (4) is supported, which can be set vibrating by a vibration generator (5), the handpiece (2) being connected or connectable at its rear end area to a flexible supply line (18), which extends from a supply device, the output of the vibration generator (5) is variable, and a control device (72) is provided with which the output can be increased or reduced.

Abstract: In a dental hand-piece, a sleeve connected to a dental tool reciprocates in a head. A fixed protrusion from the head engages a groove on the moving sleeve. The groove has portions that are transverse to the axis of reciprocation causing the sleeve to oscillate about the axis during reciprocation.

Abstract: A sonic delivery system for dentistry. The sonic delivery system includes a hand piece housing an exciting energy source connected to a driver rod which is further releasably engaged with an energy transfer tip. The driver rod linearly extends and contracts in response to the exciting energy source producing a reciprocating linear movement of the driver and energy transfer tip. In one embodiment, a rotary coupler is connected to the driver to convert the reciprocating linear movement of the driver into rotary movement of the energy transfer tip. Preferably the exciting energy source is alternating current and the driver is a rod constructed of terfnol material.

Abstract: The invention is directed to an electrically powered dental cleansing device (1) to which a cleansing implement (32) is fitted. In this manner, the cleansing implement (32) can be rotated about its longitudinal axis. The cleansing implement (32) is configured as an integrally formed part comprising a thin and elongate cleansing shaft (125). The cleansing shaft has at least one longitudinal edge and is provided with a plurality of serrations.

Abstract: A dental hand instrument consisting of a body (1) destined to be coupled at one end with a cover (14) and at the other end with an electrical and hydraulic connector (4); inside said body (1) is positioned a transducer (2) destined to vibrate a workpiece (10) which effects removal of tartar and plaque from the tooth surface, wherein within the body of the handpiece a light source is disposed that emits blue light, able to detect tartar and plaque in the areas in which to operate, treated beforehand with a contrast agent.

Abstract: An ultrasonic dental scaler insert includes a tool coupled to a connecting body which is mechanically coupled to a transducer. When the insert is placed within an ultrasonic dental scaler device handpiece, the transducer produces ultrasonic vibrations which are transmitted to the tool via the connecting body. In order to reduce the noise generated by the operating scaler insert, the connecting body includes an elastomeric material which surrounds a portion of the connecting body. Additionally, a sleeve is provided which surrounds a portion of the connecting body providing a place to grasp the scaler insert during operation. The sleeve includes a bellows section which provides vibrational damping for the insert. Furthermore, the connecting body includes a vibration dampening bushing at an end adjacent the working tool.

Abstract: In the case of a medical or dental handpiece with a tool for the processing of body tissue or of a substitute material by machining, wherein the tool comprises an, in particular, elongated processing section extending from a base part connected to the handpiece by a detachable connecting device, the processing section having at least one abrasive working face extending in its longitudinal direction and/or transverse thereto, the handpiece has an oscillating drive for the tool, in particular for a frequency in the ultrasonic range, an articulation is assigned to the connecting device, and the axis of the articulation extends approximately in the longitudinal direction of the longitudinal axis of the processing section, approximately at a right angle thereto or in an angular range lying in between.

Abstract: An electrically powered dental cleansing apparatus in which a cleansing implement is coupled to a drive sleeve and adapted to be rotated about a longitudinal axis. The coupling is effected by a resilient member, in particular a spring which includes a slip coupling and/or a buffer zone. Under normal conditions, the slip coupling provides a non-rotative connection between the drive sleeve and the cleansing implement. However, in the event of the cleansing implement seizing in an interproximal space, for example, the slip coupling will slip, thus avoiding potential damage. The buffer zone acts to prevent displacement of the cleansing implement--although intended by the user--in cases where, for example, the cleansing implement is positioned against a tooth surface rather than against an interproximal space.

Abstract: A dental hand instrument consisting of a body (1) destined to be coupled at one end with a cover (14) and at the other end with an electrical and hydraulic connector (4); inside said body is positioned a transducer (2) destined to vibrate a workpiece (10) that effects removal of tartar and plaque from the tooth surface, wherein the power supply of the light source of the hand instrument is taken from the power supply of the transducer (2).

Abstract: In a tool (1) for the preparation, with the removal of material, of a lateral cavity (K) in a tooth (Z), which tool has a tool shaft (2) of which one end is connected or can be connected with a dental handpiece (4) and of which the other end is connected or can be connected with a working body (14), the longitudinal middle axis (11b) of which working body extends approximately co-axially or axis parallel to the longitudinal middle axis (11a) of the tool shaft (2), and which working body has to both sides of a longitudinal middle plane (7) extending into its longitudinal middle axis (11b), lateral working surfaces (6) which each include an acute angle with the longitudinal middle plane (7), whereby the working surfaces (6) diverge in the direction towards the tool shaft (2), the working surfaces (6) have, at least in their longitudinal region (L3) towards the tool shaft (2), or over their entire length (L), a progressive divergence (18) relative to the middle axis (11b) of the working body (14).

Abstract: An electromechanical dental flossing device is disclosed for flossing the area between a portion of the tooth and the gum tissue. The device comprises an elongated member coupled to a motor source to effect oscillation of the elongated member. The elongated member includes an intermediate portion and a tip which are capable of being received between the tooth and the gum tissue.

Abstract: A dental tool assembly having a driving mechanism with interengaging camming surfaces shaped for continuous contact during use. The mechanism includes a drive shaft having a drive surface and a driven shaft having a driven surface. The cam surfaces are shaped and the shafts are transversely juxtaposed with respect to each other such that the drive surface and driven surface are in continuous contact during rotation of the drive shaft to impart oscillatory rotation to the drive shaft. Specifically, the drive surface is conical and preferably has a cone axis that is at an approximately 45.degree. angle with respect to the rotation axis of the drive shaft. The driven surface has alternating hills and valleys that are shaped for continuous engagement with the drive surface as the drive shaft rotates. Preferably a pair of juxtaposed valleys are provided with juxtaposed hills formed therebetween.

Abstract: A dental flosser has a bushing with a lateral pin that engages in a spiral groove in a sleeve that surrounds the bushing. The bushing is driven backwards and forwards by a shaft and this causes a flosser element base anchor to be rotated clockwise and counterclockwise, and moved backwards and forwards at the same time during use.

Abstract: The invention is directed to a dental cleansing implement (101) having a thin, elongate shaft (102) comprising a free end portion (105) suitable in particular for insertion in the interproximal spaces and connected with a mounting portion (6) or the like. The mounting portion (6) is adapted to be coupled to an electric motor drive means of a handle member, and the cleansing implement is adapted to be rotated or oscillated about a shaft longitudinal center line (135). The free end portion (105) of the shaft (102) is made of a flexible material bent in the shape of a crescent (130), approximately.

Abstract: In the case of a handpiece (3) for medical purposes, preferably for a cutting treatment of a dental root canal, with a tool holder (5) arranged in the front end region of the handpiece (3), with a retaining coupling (16) for detachable fastening of the tool (6) in the tool holder (5) and with a drive connection (8) extending lengthwise through the handpiece (3) for a rotary and/or reciprocating drive of the tool holder (5), an overload coupling (14) that limits the transmittable torque to a maximum torque value is arranged in the drive connection (8).

Abstract: The invention relates to a dental device, and a method for exchanging a working tool at a dental device having an exchangeable vibrating of rotating working tool. The working tool (1,3,33) is corrected to a protective housing (2) to be mounted around a movement generating or transmitting device (5,5A). The working tool is exchangeable by aid of a turning operation of said housing (2) in relation of the movement generating or transmitting device.

Abstract: There is provided a substantially disposable dental tip incorporated in an ultrasonic scaler and a dental working distal end piece used for the dental tip.The dental tip in accordance with the present invention includes a transmission medium whose proximal end portion is connected to an ultrasonic vibration source to transmit ultrasonic vibrations generated from the ultrasonic vibration source and the dental working distal end piece of the present invention which is mounted on a distal tip end of the transmission medium and consists of a tip end member having a shape suitable for dental treatment etc. and a connecting portion connected integrally to a proximal end portion of the tip end member.

Abstract: The invention is directed to an apparatus for treating the teeth and/or gums. This apparatus includes a treatment tool (1) for removing plaque in particular from the gum margin and/or for stimulating the gingival tissue. The treatment tool (1) is adapted to be set in vibration. For example, it is possible to generate the vibration by an unbalance structure (12) on a drive shaft (7) of the apparatus. The vibration results in a substantial improvement of the tooth cleaning and/or gum stimulating action.

Abstract: A air-powered dental tool (20) for animals such as the equine species includes a dental rasp (34) which reciprocates at at least 3,000 oscillations per minute, and has a stroke of approximately 10 millimeters. In a preferred embodiment, dental tool (20) further includes a noise abatement system which routes the exhaust compressed air to a remote location away from the animal and using veterinarian.

Abstract: A method and device for enabling oscillating drive of at least one tooth cleaning element in a tooth cleaning device which includes a drive unit and motion transmitters acting between the drive unit and the at least one tooth cleaning element. A rotary motion, derived from the rotary motion of the drive unit, is converted and one of the motion transmitters in a vicinity of at least one tooth cleaning element into a cyclic linear motion directed at an angle to an axis of the rotary motion of the drive unit and transmitted to the cleaning element.

Abstract: An apparatus and methods of its use in the treatment of oral tissue are disclosed. The apparatus of the present invention includes a vibrator that is adapted to allow at least one shaft to be mounted thereon, at least one shaft defining a first end and a second end wherein the first end is adapted to be mounted to the vibrator such that vibrational motion is transferred to said shaft, and a tip mounted on the second end of the shaft. The size and conformation of the tip can be altered to the specific treatment. The apparatus uses a vibrational massage to treat and enhance treatment of oral tissue. The apparatus is particularly effective in providing an enhanced treatment used for the application of medicaments to oral tissue, the placement of filling materials in prepared cavities, the treatment of dry sockets, burnishing in desensitizers, placement and cementation of inlays and onlays and treatment of temporomandibular joint disease.

Abstract: Improved methods and apparatus for the removal of plaque from interproximal areas of the dental anatomy and from periodontal pockets. An reciprocal or orbital vibratory motion about the longitudinal axis of the bristles is utilized to impart frictional forces from a multitude of bristles positioned within the interproximal area of two adjacent teeth and in the periodontal pockets of the gum. An advanced embodiment utilizes ultrasonically enhanced bristle tufts to transmit ultrasonic vibrations into the gingival fluids in the periodontal pockets, producing standing ultrasonic waves within the gingival fluids which augments and enhances the plaque removal capability of the reciprocally or orbitally vibrating nylon bristles.

Abstract: An electro-mechanical dental flossing device is disclosed for flossing the area between a portion of the tooth and the gum tissue. The device comprises an elongated member coupled to a motor source to effect oscillation of the elongated member. The elongated member includes an intermediate portion and a tip which are capable of being received between the tooth and the gum tissue.

Abstract: Improved methods and apparatus for the removal of plaque from interproximal areas of the dental anatomy and from periodontal pockets. An orbital vibratory motion about the longitudinal axis of the bristles is utilized to impart frictional forces from a multitude of bristles positioned within the interproximal area of two adjacent teeth and in the periodontal pockets of the gum. An advanced embodiment utilizes ultrasonically enhanced bristle tufts to transmit ultrasonic vibrations into the gingival fluids in the periodontal pockets, producing standing ultrasonic waves within the gingival fluids which augments and enhances the plaque removal capability of the orbitally vibrating nylon bristles.

Abstract: A dental cleansing implement having a thin, elongate shaft. The shaft includes a free end portion suitable in particular for insertion in the interproximal spaces and connected with a mounting portion or the like. The mounting portion is adapted to be coupled to an electric motor drive means of a handle member, and the cleansing implement is adapted to be rotated or oscillated about a shaft longitudinal center line. The free end portion of the shaft is made of a flexible material bent in the shape of a crescent, approximately.

Abstract: In a tooth cleaning instrument (1) with an elongate handpiece, which carries a tooth cleaning tool (3) on its forward end, which can be set into vibration by a motor driven vibration generator (7) which is associated with the tooth cleaning instrument (1), whereby the tooth cleaning instrument (1) is connected or is detachably connectable at its rear end to a supply hose (6) having energy and/or media supply lines, the tooth contact element (17) is areal or quasi-areal and has a surface structure which is suitable for the abrasion of the tooth coating.

Abstract: An electric device which removes supragingival and subgingival plaque and undesirable debris from the interproximal surfaces between teeth is described. This device utilizes a combination of sonic energy and dental floss which is secured between two tines, the tines being part of a flexible fork which is removable from a powered handle which contains batteries and an electric motor. The electric motor, which is coupled to an eccentrically mounted disc on an output shaft, revolves at sonic frequencies which in turn generates sonic energy that is transmitted to the flexible fork which holds the floss. The sonic energy is synchronized and in tune with the natural resonance frequencies of the fork thereby stimulating the resonance action of oscillating vertical and/or elliptical movement of the fork which in turn imparts cleaning energy to and enhances the cleaning properties of the floss.

Abstract: A dental treatment device for forming a screw hole for embedment of an implant material by a tool attached to the dental treatment device contains a speed-reducing unit for decelerating rotation of an external electric motor and raising torque for transmitting rotation to the tool, and a clutch unit provided between the speed-reducing unit and the tool. The clutch unit contains a driving side clutch having a first indented surface on its forward side, a tool side clutch having a second indented surface on its rear side, and a spring for thrusting the driving side clutch towards the tool side clutch for axially mating the first indented surface and the second indented surface with each other.

Abstract: The invention is directed to a brush for cleaning the teeth, the brush being suitable for use in a toothbrush having a handle member and a brush member and comprising a bristle supporting structure and bristles fixedly secured thereto. The bristle supporting structure is configured as a rod-shaped stem having a first and a second end portion and carrying no bristles in the region of the second end portion. The bristles extend radially relative to the stem in the region of the first end portion and are arranged in a circumferentially distributed pattern. The length of the bristles decreases starting from the first end portion of the stem in the direction of the second end portion of the stem. This brush allows effective and gentle cleaning of the teeth, in particular the interproximal spaces thereof.

Abstract: Dental apparatus includes a handpiece graspable at one end by a user, and a head at the opposite end of the handpiece including a single nozzle, or a pair of nozzles, connectible to a source of a liquid, a gas, and/or powder. An electrical oscillating drive within the handpiece oscillates the head; and a manual fluid selector device manually selects the liquid, gas, and/or powder for conduction to the single nozzle or to the pair of nozzles.

Abstract: An electrically driven dental flossing device which is used for flossing teeth. A flossing assembly is adapted to be mounted to the electrically driven dental flossing device. The dental flossing assembly includes a disposable floss holder which comprises a bow with a stem which in turn is replaceably mounted to a unitary driving shaft adaptor which in turn is mounted to the upper end of the electrically driven dental flossing device. The dental flossing device is gripped in the hand and the thumb is placed over the normally open spring urged thumb switch means. The flossing device works such that the dental floss material on the floss bow moves reciprocally between the teeth when the switch means is activated to energize a motor means within the handle to operate a gearing means which in turn moves the driving shaft adaptor in a reciprocating straight line in a back and forth motion to move the floss bow relative to the interproximal surfaces of the teeth.

Abstract: An electro-mechanical dental flossing device is disclosed for flossing the area between a portion of the tooth and the gum tissue. The device comprises an elongated member coupled to a motor source to effect oscillation of the elongated member. The elongated member includes an intermediate portion and a tip which are capable of being received between the tooth and the gum tissue.

Abstract: A dental tool driving device comprising a facility within a housing for driving a driven mechanism. A component within the housing is for selectively placing the driven mechanism in a rotating mode and in an oscillating mode. An element is for coupling a rotatable tool implement to the housing in a removable manner. When the selectively placing component is put in the rotating mode, the driving facility will operate the driven mechanism and cause the rotatable tool implement to turn about an axis. Another element is for coupling the oscillating tool implement to the housing in a removable manner. When the selectively placing component is put in the oscillating mode, the driving facility will operate the driven mechanism and cause the oscillating tool implement to swing back and forth.

Abstract: An electric device which removes supragingival and subgingival plaque and undesirable debris from the interproximal surfaces between teeth is described. This device utilizes a combination of sonic energy and dental floss which is secured between two tines, the tines being part of a flexible fork which is removable from a powered handle which contains batteries and an electric motor. The electric motor, which is coupled to an eccentrically mounted disc on an output shaft, revolves at sonic frequencies which in turn generates sonic energy that is transmitted to the flexible fork which holds the floss. The sonic energy is synchronized and in tune with the natural resonance frequencies of the fork thereby stimulating the resonance action of oscillating vertical and/or elliptical movement of the fork which in turn imparts cleaning energy to and enhances the cleaning properties of the floss.

Abstract: An electric device which removes supragingival and sub-gingival plaque and undesirable debris from the interproximal surfaces between teeth is described. This device utilizes a combination of sonic energy and dental floss which is secured between two tines, the tines being part of a flexible fork which is removable from a powered handle which contains batteries and an electric motor. The electric motor, which is coupled to an eccentrically mounted disc on an output shaft, revolves at sonic frequencies which in turn generates sonic energy that is transmitted to the flexible fork which holds the floss. The sonic energy is synchronized and in tune with the natural resonance frequencies of the fork thereby stimulating the resonance action of oscillating vertical and/or elliptical movement of the fork which in turn imparts cleaning energy to and enhances the cleaning properties of the floss.