Patent Description:
Dentists typically use a dental apparatus, which may be referred to as a dental matrix clamp, when performing restorative procedures such as, for example, filling a tooth cavity. Known clamps comprise a body which is held in the hand by the dentist and a head from which a looped section of a band projects. The band may be referred to as a matrix band. The band typically comprises a strap formed from a thin sheet of metal having a looped section (formed from a central portion of the strap) which projects from the head of the clamp and a flat section (formed from two opposed end portions of the strap) which is held by the body of the clamp. The looped section of the band is placed around a tooth that is to be treated and an actuator, which is typically provided on the body, is used to alter an extent of the looped section of the band and thereby tighten or loosen the looped section of the band around the tooth. A restorative material such as a dental amalgam or composite may then be introduced between the tooth and a portion of the looped section of the band in order to fill the cavity and restore the tooth.

Some known clamps are reusable and are typically made of metal. These known reusable clamps must be cleaned (e.g. autoclaved) between uses to reduce the risk of contamination and infection. However, contamination and infection are still known to occur through, for example, sharps injuries (i.e. penetration of the skin by a medical instrument) which may be suffered by the dentist when replacing the band of the clamp. The looped section of the band of these known reusable clamps projects from the clamp at a fixed angle resulting in an inflexible device and making it difficult for the dentist to position the looped section of the band around some teeth. Other known clamps are disposable and typically comprise a body formed from plastic and a metal loop. The disposable nature of these known clamps reduces the risk of contamination and infection compared to the known reusable clamps. Some known disposable clamps comprise a rotatable head that can rotate relative to a main portion of the body. Such an arrangement provides some control over an angle at which the
looped section of the band projects from the main portion of the body, which may improve the ease with which the dentist can position the looped section of the band around teeth.

Generally, even once the extent of the looped section of the band has been adjusted to tighten the looped section of the band around a tooth, additional finer adjustments to the shape of the looped section of the band may be desirable to improve a fit of the looped section of the band around the tooth. The shapes, sizes, positions and orientations of teeth differ greatly between different patients. It is desirable to provide a clamp for a tooth that obviates or mitigates one or more problems of the prior art whether identified herein or elsewhere.

<CIT> discloses a matrix band holder including contour surfaces on the clamp head corresponding to a pre-contoured matrix band so that the concave shape of the band is maintained as it is tightened against the tooth. The clamp further includes a tethered outward-tension horseshoe-shaped spring with downward-facing perpendicular ends that force the band into contact with adjacent teeth, thus facilitating tight proximal contact of dental restorations.

<CIT> discloses a dental matrix device which may include a body and a clamp retainer. The body may include a clamp cavity, an aperture, and a ramp immediately adjacent to the aperture. The clamp retainer may be at least partially positioned in the clamp cavity. The clamp retainer may be at least partially positioned in the clamp cavity and may include a clamp portion at a first end that may include a levered portion that is rotatably connected to a base. Translation of the clamp retainer in a first direction may draw the clamp retainer into the clamp cavity such that a lower surface of the levered portion rotates towards an upper surface of the base. Translation of the clamp retainer in a second direction may push the levered portion up the ramp to separate the lower surface of the levered portion from the upper surface of the base.

<CIT> discloses a dental matrix retainer package including a plastic matrix retainer clamp which permits a matrix band to be unlocked from its tightened position over a tooth without releasing the matrix band from the clamp entirely, permits a matrix band to be swivelled to accommodate different mouth quadrants with removal for reorientation, permits rapid retraction of a matrix band from a tooth, and permits careful tightening of a matrix band over a tooth in order to avoid the possibility of overtightening. The package is designed so that it must be entirely disposed of after use on a patient, thereby providing maximum assurance against cross contamination.

According to a first aspect of the invention, there is provided a clamp for a tooth comprising a body for adjustably supporting a band such that a looped section of the band projects from the clamp, and a removable implement configured to adjust a shape of the looped section of the band once the removable implement has been removed from the clamp, wherein the removable implement is a dental wedge.

Currently, separate implements, which may be referred to as wedges, are used during many restorative dental procedures to adapt the shape of the looped section of the band to a patient's tooth. The invention of claim <NUM> advantageously provides a single product having all implements that may be required by a dentist during such procedures, said implements being quickly and easily accessible. The removable implement may be quickly and easily removed from the clamp and used to improve a fit of the looped section of the band around the tooth, which would not be possible using known clamps.

The clamp may be known in the art as a dental matrix clamp or dental matrix retainer. The band may be known in the art as a dental matrix band. The clamp may be disposable and/or reusable.

The removable implement may taper at one end for insertion of the removable implement between a tooth and the looped section of the band.

According to the invention, the removable implement is a dental wedge. Wedges are the preferred implement used by dentist for procedures involving a dental matrix clamp. The tapered removable implement advantageously assists the dentist with adapting the looped section of the band around the patient's tooth so a desired fit can be achieved.

The removable implement may have a length of between about <NUM> and about <NUM>.

This range of lengths of removable implement advantageously provides the greatest flexibility to the dentist when using the clamp whilst also ensuring that the clamp does not become too large or bulky thereby potentially hindering the actions of the dentist during use. The term "length" may be understood to mean the greatest of the three dimensions of the removable implement.

The clamp may further comprise an actuator configured to alter an extent of the looped section of the band. The removable implement may form part of the actuator.

The removable implement may be an integral part of the actuator. The actuator may comprise a handle connected to a screw. Rotation of the screw in a first rotational direction may increase an extent of the looped section of the band (i.e. increase a perimeter of the looped section of the band), thereby allowing the looped section of the band to fit around larger teeth. Rotation of the screw in an opposite rotational direction may reduce an extent of the looped section of the band (i.e. decrease a perimeter of the looped section of the band), thereby allowing the looped section of the band to fit around smaller teeth. The actuator may house the removable implement within an internal space of the actuator. Available internal space of the body of the clamp may be limited due to the body of the clamp already housing other components, e.g. the band and the screw of the actuator. The actuator may have a larger amount of available internal space to accommodate the removable implement without reducing the structural robustness of the clamp.

The removable implement may be connected to the clamp by a breakable connector.

The breakable connector advantageously provides a simple and quick way of detaching the removable implement from the clamp for use during a dental procedure. The simplicity of the breakable connector advantageously increases an ease with which the clamp may be manufactured.

The clamp may further comprise a head that is rotationally connected to the body by an interference fit, the head comprising a slot through which the looped section of the band projects, wherein the interference fit is arranged to maintain the head at any one of: a centred position in which the looped section of the band projects from the slot in a direction that is substantially parallel to a length of the body; and a plurality of angular positions in which the looped section of the band projects from the slot in a direction that is not substantially parallel to the length of the body, wherein the interference fit is arranged such that the head may be maintained in at least two different angular positions on at least one side of the centred position.

The shape, size, position and orientation of teeth vary greatly between different patients. The interference fit advantageously provides greater flexibility of use of the clamp by offering a greater number of rotational positions of the head. The interference fit increases a dentist's ability to adapt the looped section of the band to different patients' teeth and thereby improves the ease with which the clamp may be used compared to known clamps.

The interference fit may comprise a faceted pin, wherein different facets on the faceted pin correspond to different angular positions of the head.

The faceted pin may be a prism with a cross-section that is a polygon such as a pentagon, a hexagon, a heptagon, an octagon, etc. In general, a greater number of facets on the pin corresponds to a greater number of available angular positions of the head, thereby improving the adaptability and ease of use of the clamp.

The interference fit may comprise a substantially circular pin which allows the head to rotate across and remain at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body.

The circular pin arrangement advantageously provides the greatest degree of adaptability and ease of use of the clamp.

The interference fit may be formed by components that comprise polypropylene.

Polypropylene has been found to be particularly effective in providing a suitable interference fit between the body and the head. That is, polypropylene provides enough friction such that the head will remain in any rotational position it is placed in by a user but not too much friction such that the head may be moved between different angular positions by a user.

According to a second aspect of the invention, there is provided a clamp for a tooth comprising a body for adjustably supporting a band such that a looped section of the band projects from the clamp, and a head that is rotationally connected to the body by an interference fit, the head comprising a slot through which the looped section of the band projects, wherein the interference fit is arranged to maintain the head at any one of: a centred position in which the looped section of the band projects from the slot in a direction that is substantially parallel to a length of the body; and a plurality of angular positions in which the looped section of the band projects from the slot in a direction that is not substantially parallel to the length of the body, wherein the interference fit is arranged such that the head may be maintained in at least two different angular positions on at least one side of the centred position.

Known clamps either comprise a head that is fixed relative to the body or a rotatable head that is only able to move between three discrete locked positions relative to the body: a centred position, a clockwise position and an anti-clockwise position. The rotational freedom of the head of the known disposable clamps may be limited to no rotation or these three discrete locked positions, thereby restricting freedom of use of the clamp by the dentist. The interference fit advantageously provides greater flexibility of use of the clamp by offering a greater number of rotational positions of the head compared to known clamps. The interference fit increases the dentist's ability to align the looped section of the band to different patients' teeth and thereby improves the ease with which the clamp may be used compared to known clamps.

The body may be an elongate body, which may define an axis. The length may be a dimension of the body parallel to the axis.

The clamp may further comprise a removable implement configured to adjust a shape of the looped section of the band once the removable implement has been removed from the clamp.

According to a third aspect of the invention, there is provided a kit of parts comprising a clamp according to the first or second aspects of the invention and a band configured to be attached to the clamp.

According to a fourth aspect of the invention, there is provided a method of manufacturing a clamp for a tooth, the clamp comprising a body for adjustably supporting a band such that a looped section of the band projects from the clamp, the method comprising forming a removable implement as part of the clamp, the removable implement being configured to adjust a shape of the looped section of the band once the removable implement has been removed from the clamp.

The method may further comprise tapering the removable implement at one end for insertion of the removable implement between a tooth and the looped section of the band.

The method may further comprise injection moulding the clamp and the removable implement.

The method may further comprise forming a breakable connector between the removable implement and the clamp.

The method may further comprise forming a head that is rotationally connected to the body by an interference fit, the head comprising a slot through which the looped section of the band projects, wherein the interference fit is arranged to maintain the head at any one of: a centred position in which the looped section of the band projects from the slot in a direction that is substantially parallel to a length of the body; and a plurality of angular positions in which the looped section of the band projects from the slot in a direction that is not substantially parallel to the length of the body, wherein the interference fit is arranged such that the head may be maintained in at least two different angular positions on at least one side of the centred position.

Using an interference fit may comprise providing a substantially circular pin which allows the head to rotate across and remain at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body.

The method may further comprise using components that comprise polypropylene to form the interference fit.

According to a fifth aspect of the invention, there is provided a method of manufacturing a clamp for a tooth, the clamp comprising a body for adjustably supporting a band such that a looped section of the band projects from the clamp, the method comprising forming a head that is rotationally connected to the body by an interference fit, the head comprising a slot through which the looped section of the band projects, wherein the interference fit is arranged to maintain the head at any one of: a centred position in which the looped section of the band projects from the slot in a direction that is substantially parallel to a length of the body; and a plurality of angular positions in which the looped section of the band projects from the slot in a direction that is not substantially parallel to the length of the body, wherein the interference fit is arranged such that the head may be maintained in at least two different angular positions on at least one side of the centred position.

The method may further comprise using components comprising polypropylene to form the interference fit.

The method may further comprise forming a removable implement as part of the clamp, the removable implement being configured to adjust a shape of the looped section of the band once the removable implement has been removed from the clamp.

<FIG> schematically depicts a perspective view of a clamp <NUM> for a tooth according to an embodiment of the invention. The clamp <NUM> comprises a body <NUM> for adjustably supporting a band <NUM> such that a looped section <NUM> of the band <NUM> projects from the clamp <NUM>. In use, a dentist places the looped section <NUM> of the band <NUM> around a tooth that is to be treated. The body <NUM> is elongate and defines an axis <NUM> along which the body <NUM> generally extends. The body <NUM> is generally cylindrical and comprises first and second opposing flat portions <NUM>, <NUM> which may be gripped by a dentist when the clamp <NUM> is being used. The clamp <NUM> further comprises a head <NUM> that is rotationally connected to the body <NUM> about an interference fit <NUM>. A portion of the head <NUM> forms an interference fit <NUM> with a portion of the body <NUM> as described below. In the following discussion we will refer to this arrangement as the interference fit <NUM>. The interference fit <NUM> is shown and discussed in greater detail with respect to <FIG> and <FIG>. The head <NUM> comprises a slot <NUM> (not visible in <FIG>, see <FIG>) through which the looped section <NUM> of the band <NUM> projects. In the example of <FIG>, the head <NUM> is in a centred position in which the looped section <NUM> of the band <NUM> projects from the slot <NUM> in a direction <NUM> that is substantially parallel to the axis <NUM> of the body <NUM>. The head <NUM> may be rotated about the interference fit <NUM> into other positions which are herein referred to as angular positions (not shown in <FIG>). Angular positions are positions in which the looped section <NUM> of the band <NUM> projects from the slot <NUM> in a direction that is not substantially parallel to the axis <NUM> of the body <NUM>. The interference fit <NUM> is configured to allow the head <NUM> to be disposed in at least two different discrete angular positions on at least one side of the centred position. Angular positions of the head <NUM> with respect to the body <NUM> are shown and discussed in greater detail with respect to <FIG>.

The body <NUM> tapers towards the head <NUM> and includes third and fourth opposing flat portions <NUM>, <NUM>. The third and fourth opposing flat portions <NUM>, <NUM> house a flat section <NUM> (not visible in <FIG>, see <FIG>) of the band <NUM>. The clamp <NUM> further comprises an actuator <NUM>. The actuator <NUM> may be formed from a plastics material such as, for example, polypropylene. The actuator <NUM> is configured to alter an extent of the looped section <NUM> of the band <NUM>. In the example of <FIG>, the actuator <NUM> comprises a screw <NUM> (not visible in <FIG>, see <FIG>) and a handle <NUM> which forms a tail at an end of the body <NUM> of the clamp <NUM>. The screw <NUM> may alternatively be referred to as a screw portion or a threaded portion (which may have an external thread). The handle <NUM> of the actuator <NUM> may comprise fifth and sixth opposing flat portions <NUM>, <NUM> which may be gripped by the dentist when rotating the handle <NUM> to use the actuator <NUM> (relative to the body <NUM>). The screw <NUM> is held by a screw thread <NUM>, <NUM> (not visible in <FIG>, see <FIG>) formed within the body <NUM>. The screw thread is shown and discussed in greater detail with respect to <FIG>.

One end of the screw <NUM> (in particular an end of the screw distal from the handle <NUM>) is attached to the flat section <NUM> of the band <NUM> within the body <NUM>. As described further below with reference to <FIG>, this attachment of an end of the screw <NUM> to the flat section <NUM> of the band <NUM> is achieved using a fastener <NUM>. In use, a dentist may hold the body <NUM> in one hand and rotate the handle <NUM> of the actuator <NUM> (about the axis <NUM> relative to the body <NUM>) with the other hand. Rotation of the actuator <NUM> in a first rotational direction <NUM> (e.g. clockwise) about axis <NUM> may cause the screw <NUM> to move along the inner screw thread <NUM>, <NUM> and push the band <NUM> (along the axis <NUM>) further out of the clamp <NUM> thereby increasing an extent of the looped section <NUM> of the band <NUM> that projects from the clamp <NUM>. This allows the looped section <NUM> of the band <NUM> to receive, and fit around, larger teeth. Rotation of the actuator <NUM> in an opposite rotational direction <NUM> (e.g. anti-clockwise) about axis <NUM> may cause the screw <NUM> to move along the inner screw thread <NUM>, <NUM> in the opposite direction (along axis <NUM>) and pull the band <NUM> into the body <NUM> of the clamp <NUM> thereby reducing an extent of the looped section <NUM> of the band <NUM>. This allows the looped section <NUM> of the band <NUM> to tighten around a tooth received within the looped section <NUM>.

Once the looped section <NUM> of the band <NUM> has been adjusted to a desired extent, the dentist may then position the clamp <NUM> such that the looped section <NUM> of the band <NUM> fits around a tooth that is to be treated. The dentist may then introduce an amalgam between the tooth and a portion of the looped section <NUM> of the band <NUM> so as to fill a cavity in the tooth. Once the amalgam has set, it may be referred to as a filling. The looped section <NUM> of the band <NUM> may be held in place by the dentist while the amalgam sets. In the majority of cases, a dentist will also use an implement, which may be referred to as a wedge or an interproximal wedge, to adjust a shape of the looped section <NUM> of the band <NUM> around the tooth while holding the clamp <NUM> in place. Such adjustment of the shape of the looped section <NUM> of the band <NUM> may improve a shape of the filling formed in the cavity by maintaining pressure at a desired area of the looped section <NUM> of the band <NUM> and may at least partially account for the finite thickness of the band <NUM> when forming the filling. The clamp <NUM> of <FIG> advantageously comprises a removable implement <NUM> configured to adjust a shape of the looped section <NUM> of the band <NUM> once the removable implement <NUM> has been removed from the clamp <NUM>. In the example of <FIG>, the removable implement <NUM> forms part of the handle <NUM> of the actuator <NUM>. In particular, the removable implement <NUM> is provided in an internal space of the handle <NUM> of the actuator <NUM>. The removable implement <NUM> is shown and discussed in greater detail with respect to <FIG>.

<FIG> schematically depicts an exploded view of the clamp <NUM> shown in <FIG>. The body <NUM> of the clamp <NUM> comprises a casing having two halves <NUM>, <NUM>. The casing may be formed from a plastic such as, for example, polypropylene. At one end of the casing (in particular at an end proximate the head <NUM> of the clamp <NUM>) the two halves <NUM>, <NUM> of the casing comprise opposing rings <NUM>, <NUM>. The head <NUM> comprises two pins <NUM>, <NUM> configured to be inserted into the two rings <NUM>, <NUM> of the casing. For this reason, the shape of the pins <NUM>, <NUM> and the shape of the rings <NUM>, <NUM> are complimentary. The head <NUM> may, for example, be formed from a plastic such as polypropylene. Once the pins <NUM>, <NUM> of the head <NUM> have been inserted into the rings <NUM>, <NUM> of the casing, the body and the head <NUM> can be considered to be rotationally connected to each other, in that the pins <NUM>, <NUM> and rings <NUM>, <NUM> arrangement allows rotation of the head <NUM> with respect to the body <NUM>. It will be appreciated that this rotation of the head <NUM> with respect to the body <NUM> is about an axis that is perpendicular to the axis of the body <NUM>. The pins <NUM>, <NUM> and the rings <NUM>, <NUM> form an interference fit with one another. The interference fit allows for the head <NUM> to be rotated (relative to the body <NUM>) between and held stationary in different angular positions with respect to the body <NUM>. In the example of <FIG>, the pins <NUM>, <NUM> on the head <NUM> are substantially circular pins <NUM>, <NUM> about which the head <NUM> can rotate across and remain at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body <NUM>. Multiple forms of interference fit are shown and discussed in greater detail below with reference to <FIG>.

At the opposite end of the casing (i.e. at an end of the casing proximate the actuator <NUM> of the clamp <NUM>) the two halves <NUM>, <NUM> of the casing comprise corresponding halves <NUM>, <NUM> of an inner screw thread. The inner screw thread is configured to receive at least a portion of the screw <NUM> of the actuator <NUM>. The two halves <NUM>, <NUM> of the inner screw thread form an opening <NUM> at the end of the casing through which the actuator <NUM> projects. A first half <NUM> of the casing comprises protrusions <NUM>-<NUM> along its edge and a second half <NUM> of the casing comprises complimentary recesses (not shown) along its edge for receipt of the protrusions <NUM>-<NUM> of the first half <NUM>. The two halves <NUM>, <NUM> of the casing may fasten together in a snap-fit configuration. Alternatively and/or additionally the two halves <NUM>, <NUM> of the casing may be welded together using, for example, sonic welding.

<FIG>, consisting of <FIG>, schematically depicts perspective views of some of the components of the clamp <NUM> at different stages of construction (but with the body <NUM> not shown). <FIG> schematically depicts the band <NUM>, the head <NUM>, a fastener <NUM> and the actuator <NUM> detached from one another. The band <NUM> comprises a thin strip of metal such as, for example, stainless steel. The strip of metal may alternatively be referred to as a strap of metal. The strip may come in a variety of lengths, each of which may be useful for a different range of sizes of a patient's teeth. The strip may have a length of more than about <NUM>. The strip may have a length of less than about <NUM>. The strip may have a length of about <NUM>. The strip may have a thickness of between about <NUM> and about <NUM>, e.g. about <NUM>. The strip is folded in half to form the band <NUM>. The band <NUM> comprises a flat section <NUM> in which two ends of the strip are pressed together and a looped section <NUM> in which the two folded halves of the strip separate from one another to form a loop which projects from the head <NUM> of the clamp <NUM>. During use of the clamp <NUM>, the looped section <NUM> is to be fitted around a tooth that is to be treated using the clamp <NUM>. The strip of metal comprises a plurality of holes <NUM>-<NUM> at opposing ends of the strip. In the example of <FIG>, the strip comprises four holes <NUM>-<NUM>. The holes <NUM>-<NUM> are arranged on both ends of the strip such that when the strip is folded in half to form the band <NUM>, a first hole <NUM> on a first end of the strip aligns with a second hole <NUM> on the other end of the strip and a third hole <NUM> on the first end of the strip aligns with a fourth hole <NUM> on the other end of the strip.

The head <NUM> of the clamp <NUM> comprises a slot <NUM> through which the looped section <NUM> of the band <NUM> projects. The head <NUM> has a generally hemicylindrical shape which may help allow the head <NUM> to rotate about the body of the clamp <NUM>. The slot <NUM> is formed in a curved section of the hemicylindrical head <NUM>. The two pins <NUM>, <NUM> of the head <NUM> are formed on different opposed flat sections of the hemicylinder.

The fastener <NUM> is configured to fasten the band <NUM> at a first end whilst connecting to the actuator <NUM> at the opposing end. The fastener <NUM> may be formed from a plastic such as, for example, polypropylene. The fastener <NUM> comprises first and second plates <NUM>, <NUM> which are connected together by a hinge <NUM>. The plates <NUM>, <NUM> may be formed from the same material and the hinge <NUM> may be a living hinge formed from a portion of the same material that connects the plates <NUM>, <NUM> together. The first plate <NUM> includes a plurality of protrusions <NUM>, <NUM> (visible in <FIG>). The second plate <NUM> includes an equal number of apertures <NUM>, <NUM>. In the example of <FIG>, the first plate <NUM> includes two protrusions <NUM>, <NUM> and the second plate <NUM> includes two apertures <NUM>, <NUM> for receipt of the protrusions <NUM>, <NUM>. The protrusions <NUM>, <NUM> of the first plate <NUM> are aligned with the apertures <NUM>, <NUM> of the second plate <NUM> such that, when the second plate <NUM> is folded over the hinge <NUM> towards the first plate <NUM>, the protrusions <NUM>, <NUM> of the first plate <NUM> pass through the apertures <NUM>, <NUM> of the second plate <NUM>. The protrusions <NUM>, <NUM> of the first plate <NUM> and the apertures <NUM>, <NUM> of the second plate <NUM> may be sized and shaped so as to act as a snap-fit when they are brought together in order to fasten the first and second plates <NUM>, <NUM> together. In this regard, the protrusions <NUM>, <NUM> of the first plate <NUM> and the apertures <NUM>, <NUM> of the second plate <NUM> may be thought of, and referred to, as snap-fit buttons.

During assembly, the flat section <NUM> of the band <NUM> may be passed through the slot <NUM> in the head <NUM> and the apertures <NUM>-<NUM> at both ends of the strip may be aligned with one another and the protrusions <NUM>, <NUM> of the first plate <NUM> (this arrangement is shown in <FIG>). The protrusions <NUM>, <NUM> of the first plate <NUM> may be passed through the apertures <NUM>-<NUM> of the flat section <NUM> of the band <NUM>. In particular, the first hole <NUM> and the second hole <NUM> are aligned with and receive one protrusion <NUM> and the third hole <NUM> and the fourth hole <NUM> are aligned with and receive the other protrusion <NUM>. The second plate <NUM> may then be folded over the hinge <NUM> towards the first plate <NUM> and the protrusions <NUM>, <NUM> of the first plate <NUM> may pass through the apertures <NUM>, <NUM> of the second plate <NUM> so as to clamp the band <NUM> in place between the first and second plates <NUM>, <NUM> of the fastener <NUM>.

The second end of the fastener <NUM> comprises a socket <NUM>. The actuator <NUM> comprises a generally cylindrical plug <NUM>. The socket <NUM> of the fastener <NUM> is configured to receive and hold the plug <NUM> of the actuator <NUM> so as to connect the actuator <NUM> to the fastener <NUM> (as is shown in <FIG>). Inner dimensions of the socket <NUM> are such that the plug <NUM> can, in use, rotate about axis <NUM> within the socket <NUM> and such that the plug <NUM> cannot move significantly relative to the socket along the axis <NUM>. The two halves of the casing (not shown in <FIG>) may be brought together to enclose the flat section <NUM> of the band <NUM>, the fastener <NUM> and at least a portion of the screw <NUM> of the actuator <NUM> (as shown in <FIG>).

<FIG>, consisting of <FIG>, schematically depicts different views of the actuator <NUM> comprising the removable implement <NUM> according to an embodiment of the invention. <FIG> schematically depicts a view from the side of the actuator <NUM>. <FIG> schematically depicts a cross-sectional view of the actuator <NUM> through the line X-X shown in <FIG>. The removable implement <NUM> forms part of the handle <NUM> of the actuator <NUM>. The removable implement <NUM> is provided in an internal space <NUM> of the handle <NUM> of the actuator <NUM>. The removable implement <NUM> tapers to a point at one end <NUM> for insertion of the removable implement <NUM> between a tooth and a portion of the looped section <NUM> of the band <NUM> when the clamp <NUM> is being used. The removable implement <NUM> includes a base portion <NUM> at an opposite end of to the end <NUM> at which the removable implement <NUM> tapers to a point. The base portion <NUM> may be referred to as a stud <NUM>. The base portion <NUM> projects out of internal space <NUM> of the handle <NUM> of the actuator <NUM>.

<FIG> schematically depicts a magnified view of an end portion of the handle <NUM> of the actuator <NUM> shown in <FIG> but in a plane that is orthogonal to the plane of <FIG> (such that the internal space <NUM> of the handle <NUM> is not visible in <FIG>). The removable implement <NUM> is connected to the handle <NUM> of the actuator <NUM> by a breakable connector <NUM>. The breakable connector <NUM> may be formed from a plastic such as, for example, polypropylene. In the example of <FIG>, the stud <NUM> of the removable implement <NUM> is connected to the handle <NUM> of the actuator by the breakable connector <NUM>. It will be appreciated that the removable implement <NUM> and the handle <NUM> of the actuator <NUM> may be integrally formed as a single member from the same material (the breakable connector <NUM> comprising a relatively thin portion of said single member). The breakable connector <NUM> comprises material that becomes thinner at a breaking location <NUM> thereby forming a structural weakness at the breaking location <NUM>. A user may remove the removable implement <NUM> from the handle <NUM> of the actuator <NUM> by applying force to the stud <NUM> of the removable implement <NUM> such that the breakable connector <NUM> breaks at the breaking location <NUM> thereby separating the removable implement <NUM> from the clamp <NUM>.

<FIG>, consisting of <FIG>, schematically depicts different views of the actuator <NUM> of <FIG> after the removable implement <NUM> has been removed from the handle <NUM> of the actuator <NUM>. The removable implement <NUM> may have a length <NUM> of about <NUM> or more. The removable implement <NUM> may have a length <NUM> of about <NUM> or less. The removable implement <NUM> may have a length <NUM> of about <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>. A body of the removable implement may have a greatest width <NUM> of more than about <NUM>. The body of the removable implement may have a greatest width <NUM> of less than about <NUM>. The width of the body of the removable implement may reduce in size (i.e. taper) from the greatest width <NUM> to an end point <NUM> of the removable implement <NUM> at which the width of the removable implement <NUM> is substantially zero (e.g. about <NUM>). The body of the removable implement <NUM> may have a greatest height <NUM> of more than about <NUM>. The body of the removable implement <NUM> may have a greatest height <NUM> of less than about <NUM>. The body of the removable implement <NUM> may have a greatest height <NUM> of about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>, or about <NUM>. The height of the body of the removable implement <NUM> may reduce in size (i.e. taper) from the greatest height <NUM> to an end point <NUM> of the removable implement <NUM> at which the height of the removable implement <NUM> is substantially zero (e.g. about <NUM>).

A base <NUM> of the removable implement <NUM> may curve towards the end point <NUM> of the removable implement <NUM>. The removable implement <NUM> may be described as having a shape similar to that of a straightened claw. The removable implement <NUM> may be referred to as a dental wedge, an anatomical wedge or an interproximal wedge. Such wedges are used by dentists during many restorative dental procedures such as, for example, plastic restorations. For example, the wedge may be used to adapt the shape of the looped section of the band to a proximal part of a tooth cavity such that, once the cavity is filled with amalgam, the solidified amalgam has a desired shape with respect to the rest of the tooth and the surrounding teeth and gums. This may be achieved by inserting the end <NUM> of the removable implement <NUM> between the looped section <NUM> of the band <NUM> and an adjacent tooth.

The clamp <NUM> advantageously provides a single product having all implements that may be required by a dentist during such procedures, said implements being quickly and easily accessible. The removable implement <NUM> may be quickly and easily removed from the clamp <NUM> and used to improve a fit of the looped section <NUM> of the band <NUM> around the tooth, which would not be possible using known clamps.

<FIG>, consisting of <FIG>, schematically depicts magnified views from the side of different forms of interference fit <NUM> between the head <NUM> and the body <NUM> of the clamp <NUM> according to embodiments of the invention. As previously discussed, a portion of the head <NUM> forms an interference fit <NUM> with a portion of the body <NUM>. The arrangement of the portion of the head <NUM> (i.e. the pin <NUM>) and the portion of the body <NUM> (i.e. the ring <NUM>) is herein referred to as the interference fit <NUM>. The interference fit <NUM> comprises flexible and resilient material such that the head <NUM> can rotate relative to the body <NUM> about the interference fit <NUM>. The interference fit <NUM> may be formed by components (e.g. the pins <NUM>, <NUM> and the rings <NUM>, <NUM>) that comprise polypropylene which has been found to have a good degree of flexibility and resilience for providing the interference fit <NUM>.

In the example of <FIG>, the interference fit <NUM> is formed between a substantially circular pin <NUM> about which the head <NUM> can rotate across and remain at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body <NUM> of the clamp. That is, the interference fit <NUM> provides a suitable amount of friction between the pin <NUM> of the head <NUM> and the rings <NUM> of the body <NUM> such that a user may rotate the head <NUM> and thereby position the head <NUM> at any desired angular position relative to the body <NUM> within a semicircle of travel and, when the user releases the head <NUM>, the interference fit <NUM> ensures that the head <NUM> remains at the desired angular position. In practice, the range of travel of the head <NUM> may be slightly less than a semicircle due to the presence of the band <NUM>. For example, the range of travel of the head <NUM> relative to the body <NUM> may be about ± <NUM>°, ±<NUM>°, ±<NUM>°, etc. The range of movement of the head <NUM> relative to the body <NUM> is shown in <FIG>.

In the examples of <FIG>, the interference fit <NUM> is formed between a faceted pin <NUM> on the head <NUM> of the clamp and complimentarily faceted rings <NUM> on the body <NUM> of the clamp. The gap between the pin <NUM> of the head <NUM> and the ring <NUM> of the body <NUM> has been exaggerated in <FIG> for clarity and ease of understanding. The faceted arrangement shown in <FIG> may also be referred to as a ribbed pin <NUM> and ribbed rings <NUM>. The faceted pin <NUM> may be rotated relative to the faceted ring <NUM>. Different facets (i.e. faces or sides) on the pin <NUM> correspond to different angular positions of the head <NUM>. That is, each time the pin <NUM> is rotated such that the facets of the pin <NUM> align with the facets of the ring <NUM>, the head <NUM> may remain in that angular position until the head <NUM> is rotated again by a user. In general, the greater the number of facets or ribs there are on the pin <NUM> and rings <NUM>, the greater the number of available angular positions of the head <NUM> there are relative to the body <NUM>. In general, the smaller the distance between neighbouring facets or ribs on the pin <NUM> and rings <NUM>, the greater the precision with which the angular position of the head <NUM> may be changed. The faceted structure of the pin <NUM> and ring <NUM> arrangement may take a variety of forms. In cross section, the pin <NUM> and ring <NUM> have shapes that may generally be referred to as polygons having a desired number and/or size of facets or ribs to achieve a desired number of angular positions and angular positioning precision of the head <NUM> relative to the body <NUM>. For example, the pin <NUM> and the rings <NUM> may be faceted such that, in cross section, they are generally pentagonal (as shown in <FIG>), generally hexagonal (as shown in <FIG>), generally heptagonal (as shown in <FIG>), generally octagonal (as shown in <FIG>), etc..

<FIG> depicts a pin <NUM> comprising a plurality of ribs <NUM> forming an interference fit <NUM> with a ring <NUM> comprising a plurality of ribs <NUM>. The ribs <NUM> of the pin <NUM> and the ribs <NUM> of the ring <NUM> interdigitate with one another in each angular position of the head <NUM>. The pin <NUM> may be rotated within the ring <NUM> such that the ribs <NUM> of the pin <NUM> and the ribs <NUM> of the ring <NUM> deform as they move past one another until the ribs <NUM>, <NUM> interdigitate with one another again such that the head <NUM> is in a different angular position.

<FIG>, consisting of <FIG>, schematically depicts views from the side of a clamp <NUM> according to an embodiment of the invention with the head <NUM> located in different rotational positions relative to the body <NUM>. As previously discussed, the head <NUM> is rotationally connected to the body <NUM> by an interference fit <NUM>, and the head <NUM> comprises a slot through which a looped section <NUM> of the band <NUM> projects from the clamp <NUM> for fitting around a tooth. <FIG> schematically depicts the head <NUM> in a centred position relative to the body <NUM> in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in a direction <NUM> that is substantially parallel to the axis <NUM> of the body <NUM>. When we discuss a direction in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM>, we are referring to the direction in which the slot <NUM> of the head <NUM> is facing. A length <NUM> of the body <NUM> may be considered to be the greatest of the three dimensions of the body <NUM>, and generally defines the axis <NUM> along the body <NUM>.

<FIG> show the head <NUM> in different angular positions in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in directions <NUM>-<NUM> that are not substantially parallel to the axis <NUM> of the body <NUM>. In the example of <FIG>, the head <NUM> has been rotated to a first angular position in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in a direction <NUM> that is about <NUM>° anti-clockwise from the centred position shown in <FIG>. The interference fit <NUM> between the head <NUM> and the body <NUM> ensures that the head <NUM> stays in the first angular position once the user has stopped applying a rotational force to the head <NUM>. In the example of <FIG>, the head <NUM> has been further rotated to a second angular position in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in a direction <NUM> that is about <NUM>° anti-clockwise from the centred position shown in <FIG>. The interference fit <NUM> between the head <NUM> and the body <NUM> ensures that the head <NUM> stays in the second angular position once the user has stopped applying a rotational force to the head <NUM>. In the example of <FIG>, the head <NUM> has been rotated in the opposite rotational direction to a third angular position in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in a direction <NUM> that is about <NUM>° clockwise from the centred position shown in <FIG>. The interference fit <NUM> between the head <NUM> and the body <NUM> ensures that the head <NUM> stays in the third angular position once the user has stopped applying a rotational force to the head <NUM>. In the example of <FIG>, the head <NUM> has been further rotated to a fourth angular position in which the looped section <NUM> of the band <NUM> projects from the clamp <NUM> in a direction <NUM> that is about <NUM>° clockwise from the centred position shown in <FIG>. The interference fit <NUM> between the head <NUM> and the body <NUM> ensures that the head <NUM> stays in the fourth angular position once the user has stopped applying a rotational force to the head <NUM>.

Although <FIG> only shows five examples of different rotational positons of the head <NUM> relative to the body <NUM> of the clamp <NUM>, it will be understood that the head <NUM> of the clamp <NUM> of <FIG> may be positioned at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body <NUM> of the clamp <NUM>.

The interference fit <NUM> between the head <NUM> and the body <NUM> of the clamp <NUM> provides for at least two different angular positions of the head <NUM> on at least one side of the centred position shown in <FIG>. For example, <FIG> show the head <NUM> at two different angular positions on the left-hand side (i.e. in an anti-clockwise rotational direction) of the centred position shown in <FIG>. As a further example, <FIG> show the head <NUM> at two different angular positions on the right-hand side (i.e. in a clockwise rotational direction) of the centred position shown in <FIG>.

Known clamps comprising a rotatable head may only be able to move between three discrete locked positions relative to the body: a centred position, a clockwise position and an anti-clockwise position. The rotational freedom of the head of the known disposable clamps may be to these three discrete locked positions, thereby restricting freedom of use of the clamp by the dentist. The interference fit <NUM> advantageously provides greater flexibility of use of the clamp <NUM> by offering a greater number of rotational positions of the head <NUM> compared to known clamps. The interference fit <NUM> increases the dentist's ability to adapt the looped section <NUM> of the band <NUM> to different patients' teeth and thereby improves the ease with which the clamp <NUM> may be used compared to known clamps.

<FIG>, consisting of <FIG>, schematically depicts the pins <NUM>, <NUM> of the head <NUM> of the clamp <NUM> and a ring <NUM> of the body <NUM> of the clamp <NUM> according to an embodiment of the invention. <FIG> schematically depicts a view from the side of the head <NUM> of the clamp <NUM>. <FIG> schematically depicts a cross-sectional view from the side of a portion of one half <NUM> of the casing of the body <NUM> of the clamp <NUM>. One of the pins <NUM> shown in <FIG> is configured to be received in the ring <NUM> shown in <FIG> to thereby form the interference fit between the head <NUM> and the body <NUM> of the clamp <NUM>. The pins <NUM>, <NUM> of the head <NUM> taper along their axes such that the diameter of the pins <NUM>, <NUM> increases when travelling towards a central portion of the head <NUM>. The taper may assist in assembly of the clamp <NUM>. That is, the taper of the pins <NUM>, <NUM> may make it easier to insert the pins <NUM>, <NUM> in the rings <NUM>, <NUM> when forming the interference fit between the head <NUM> and the body <NUM>.

The head <NUM>, along with other components of the clamp <NUM> such as the casing <NUM>, <NUM>, the actuator <NUM> comprising the removable implement <NUM> and the fastener <NUM>, may be formed by injection moulding plastics material, such as polypropylene, into a mould made of, for example, metal. The mould may be an inverse or negative image of the component (e.g. the head <NUM>) such that when the mould is filled with the plastics material and the plastics material is allowed to set, the component (e.g. the head <NUM>) is formed within the mould. When the mould is first formed, the portion of the mould that corresponds to the pins <NUM>, <NUM> may be substantially the same size as the portion of the mould that corresponds to the rings <NUM>, <NUM>. The portion of the mould that corresponds to the pins <NUM>, <NUM> may be further machined to remove some material and thereby slightly increase a size of the pins <NUM>, <NUM> and/or to create the taper of the pins <NUM>, <NUM> that result from the injection moulding process. This in turn may assist in forming a suitable interference fit between the pins <NUM>, <NUM> and the rings <NUM>, <NUM>. This technique of removing some of the mould material may be referred to as a tool-safe mould change.

The pins <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM> or more. The pins <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM> or less. The pins <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM>. The pins <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM> or more. The pins <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM> or less. The pins <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM>.

The rings <NUM>, <NUM> of the head <NUM> taper along their axes such that the diameter of the rings <NUM>, <NUM> increases when travelling towards a region which receives the head <NUM>. The taper may assist in assembly of the clamp <NUM>. That is, the taper of the rings <NUM>, <NUM> may make it easier to insert the pins <NUM>, <NUM> in the rings <NUM>, <NUM> when forming the interference fit between the head <NUM> and the body <NUM>.

The rings <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM> or more. The rings <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM> or less. The rings <NUM>, <NUM> may, for example, have a smallest diameter <NUM> of about <NUM>. The rings <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM> or more. The rings <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM> or less. The rings <NUM>, <NUM> may, for example, have a greatest diameter <NUM> of about <NUM>.

The tapered diameters of the pins <NUM>, <NUM> may be slightly smaller than the tapered diameters of the rings <NUM>, <NUM> whilst still providing an interference fit. For example, the tapered diameters of the pins <NUM>, <NUM> may be up to about <NUM> less than the tapered diameters of the rings <NUM>, <NUM>. Alternatively, the tapered diameters of the pins <NUM>, <NUM> and the tapered diameters of the rings <NUM>, <NUM> may be substantially the same. Alternatively, the tapered diameters of the pins <NUM>, <NUM> may be slightly greater than the tapered diameters of the rings <NUM>, <NUM>. For example, the tapered diameters of the pins <NUM>, <NUM> may be up to about <NUM> greater than the tapered diameters of the rings <NUM>, <NUM>. In any case, the tapered diameters of the pins <NUM>, <NUM> and the tapered diameters of the rings <NUM>, <NUM> are similar enough such that, when they are assembled, an interference fit forms between the pins <NUM>, <NUM> and the rings <NUM>, <NUM> which allows a user to rotate the head <NUM> about the body <NUM> and allows the head <NUM> to remain at a desired angular position relative to the body <NUM> once the user has released the head <NUM>.

A method of manufacturing the clamp <NUM> discussed and depicted herein may comprise forming the removable implement as part of the clamp <NUM>. For example, part of the clamp <NUM> (for example the actuator <NUM>) and the removable implement <NUM> may be formed by injection moulding. For example, when the removable implement <NUM> forms part of the handle <NUM> of the actuator <NUM>, the actuator <NUM>, the removable implement <NUM> and the breakable connector <NUM> in-between may all be formed by injection moulding using a single cast. The method of manufacture may further comprise tapering the removable implement <NUM> at one end for insertion of the removable implement <NUM> between a tooth and the looped section <NUM> of the band <NUM>.

The method of manufacture of the clamp <NUM> may additionally or alternatively comprise forming a head <NUM> comprising a slot <NUM> through which a looped section <NUM> of the band <NUM> projects and rotationally connecting the head <NUM> to the body <NUM> using an interference fit <NUM> which provides for at least two different angular positions on at least one side of a centred position of the head <NUM>. Using an interference fit <NUM> may comprise providing a substantially circular pin <NUM> about which the head <NUM> can rotate across and remain at any one of a substantially continuous range of angles between about -<NUM>° and about +<NUM>° relative to the body <NUM>. The components used to form the interference fit <NUM> may comprise polypropylene.

Claim 1:
A clamp (<NUM>) for a tooth comprising:
a body (<NUM>) for adjustably supporting a band (<NUM>) such that a looped section (<NUM>) of the band (<NUM>) projects from the clamp (<NUM>); and,
a removable implement (<NUM>) configured to adjust a shape of the looped section (<NUM>) of the band (<NUM>) once the removable implement (<NUM>) has been removed from the clamp (<NUM>),
characterised in that
the removable implement (<NUM>) is a dental wedge.