Other

Hamilton Ortho Inc.

Augusta Developments Inc.

G Herbert Hanson

An orthodontic bracket or convertible buccal tube for use with arch wires has the usual mesial distal extending slot having one side open to receive the wire. The open side is closed by a shutter pivoting on a pivot pin, or coaxial pins, about a mesial distal axis, the shutter being latched in slot closed position to retain the arch wire in the slot. The device includes an attitude controlling spring member consisting of an integral extension of the part of the shutter member that closes the slot, the extension being thinner and therefore of greater flexibility than the relatively rigid shutter member. The extension can be progressively thinner that the shutter member from its junction therewith to a free end that engages the arch wire in the slot. In slot closed position a portion of the integral extension is positively engaged with a surface of the device body so as to preload the spring. Also in slot closed position the integral extension is engaged by lateral walls of the device body parallel to an occlusal, gingival, labial, lingual plane to protect it against mesial or distal directed stresses applied thereto.

Orthodontic devices for use with arch wires

An orthodontic bracket or convertible buccal tube for use with arch wires has the usual mesial distal extending slot having one side open to receive the wire. The open side is closed by a shutter pivoting on a pivot pin, or coaxial pins, about a mesial distal axis, the shutter being latched in slot closed position to retain the arch wire by a latch having one latch member on the pivot pin/s and a cooperating member on an annular part of the shutter surrounding the pin/s. Preferably the latch members are a mesial distal extending cam shaped recess in the pivot pin/s and a projection protruding from the annular shutter part, or vice versa. The part of the annular shutter part carrying the latch member is made flexible by a mesial distal extending through slot dividing it to form a movable segment of about 200&#xb0; to 270&#xb0; of the total circumference; a tool can be inserted into the slot to assist in disengaging the latch. The shutter member can have parts thereof that with the shutter in slot closed position are an interference fit against the device body providing an additional retaining force against opening movement. Preferably the device includes an attitude controlling spring member consisting of a thin sheet metal spring within the body having a free end extending into the arch wire slot to engage an arch wire therein, or alternatively consisting of a flexible extension of the part of the shutter member that closes the slot.

A new structure is provided for orthodontic devices comprising a bracket or a convertible buccal tube, both of which have a body with a mesial-distal extending arch wire receiving slot therein. Both have a slot closure member, also referred to as a jamming shutter, pivotally mounted by the body for movement between slot open and closed positions and consisting of a pivot portion including an arm portion with a mesially-distally extending slot closure portion at its end. The slot closure portion has a part that closes the slot and mesially-distally extending parts that in the slot closed position engage an adjacent body surface with an interference jamming fit sufficient to retain the slot closure member in slot closed position. Any movement of the slot closure member to and from the slot closed position involves flexing of these engaged parts away from the device body against the elasticity of the material, removing the need for latches or retaining springs. The body or the closure member has a recess into which an opening tool can be inserted and rotated to open the closure member. A bracket will usually be &ldquo;active&rdquo;, including a flat attitude controlling spring having a free end protruding into the slot to engage with an arch wire therein. A surface of the pivot portion can be a cam that in slot open position holds the spring out of the slot, so that the wire can be more easily inserted and removed. In brackets for incisors or canines the bracket body labial-lingual dimension decreases progressively from the lingual to the labial; with the slot closed the occlusal surface is unobstructed and forms a bite plane engaged by the cutting edge of the opposed tooth during biting action to oppose overbite. A convertible buccal tube employs the same basic structure and has the slot opening at an appropriate surface with the slot closure member, and an attitude controlling spring if provided, similarly mounted in the body.

Orthodontic brackets and convertible buccal tubes

An orthodontic bracket comprises a spring ligating member comprising a thin flat metal strip that embraces the bracket body and is moved thereon between slot closed and open positions. At least the free end part of the spring member labial arm portion that closes the slot is of smaller width in the mesial distal direction than the arch wire slot gingival surface which is provided with a recess of smaller mesial distal width so that it is closed at its mesial and distal ends. The free end part of the labial arm portion extends into the recess to protect the spring member against excessive movement in the labial direction, while the arch wire slot gingival surfaces at the closed mesial and distal ends of the recess are engagable by an arch wire in the slot for application of maximum torque moment from the arch wire to the bracket. The bracket also comprises a labial lingual extending passage in the spring member labial arm portion permitting insertion of a tool for moving the spring member from the slot closed to the slot open position. The bracket body is provided with a slot registering with the passage that enables the tool to engage the spring member occlusal portion thereby permitting the required movement without overstressing the spring member.

Self-ligating orthodontic brackets

An orthodontic bracket comprises a bracket body with a mesial distal extending arch wire slot and a ligating latch spring member having the form of a thin flat metal strip. The spring member comprises along its length, in the order stated, an anchor portion anchored in the bracket body, a flexing portion in which the majority of the flexing takes place, a ligating portion that closes the slot mouth and engages any arch wire therein, and a latching portion by which the spring member is latched to the bracket body. The spring member may comprise a biasing portion between the flexing and ligating portions at the slot occlusal surface, or between the ligating and latching portions at the slot gingival surface, this biasing portion being convex toward the slot lingual wall and protruding into the slot to press the arch wire into the respective slot wall junction for more precise control. The bracket body may be made as two mirror image parts which are laser welded together and between which the spring member is mounted. The latches between the spring member and the bracket body may comprise notches in the spring edges that are engaged by latch sears on the body, and two labially lingually spaced sears may be provided. Preferably the spring member is made of a nickel titanium shape memory alloy. The bracket body may have two pairs of tie wings for reception of an external ligature between which the spring member is disposed.

An orthodontic bracket comprises a bracket body with a mesial distal extending arch wire slot and a two-armed ligating latch spring member mounted thereon. The two arms comprise a ligating inner portion and a latching outer portion joined by a connecting portion and the spring member is movable between an unlatched slot open position and a latched slot closed position in which the slot is closed by the ligating portion and the spring member is latched to the bracket body by the latching portion. The bracket body may be made as two mirror image parts between which the spring member is mounted, the two body parts thereafter being fastened together. Each body part may carry a cylindrical mesial distal extending pivot post, the spring member being mounted on the posts for pivoting movement relative to the bracket body, the posts and spring member being frictionally engaged as it moves between slot open and closed positions for frictional damping of the pivoting movement. The latches between the spring member and the bracket body may comprise notches in the spring edges that are engaged by latch sears on the body, and preferably the latch sears have cam acting labial faces producing gingival movement until the latches are engaged. Preferably the spring member is made of a nickel titanium shape memory alloy. The bracket body may have one or two hook members for attachment of a traction spring member. It may instead have two pairs of tie wings for reception of an external ligature between which the spring member is disposed.

A self ligating orthodontic bracket comprising a U-shaped ligating spring member movable between slot open and closed positions on the bracket body is adapted for reception of an additional external ligating member, such as an elastomeric hoop or loop, by providing the spring member in its occlusal portion at least adjacent its junction with the lingual portion with a mesial distal extending spring slot in which the additional ligature is received and securely retained, the slot opening at least partly lingually and being convex in the labial gingival direction; preferably the slot opens both occlusally and lingually. Preferably also the gingival surface of the bracket body is provided with a mesial distal extending gingivally-opening body slot, convex in the occlusal direction, for reception and retention of an external additional ligating wire or elastomeric hoop engaged in the spring slot. Further, the mesial and distal surfaces of the bracket body are provided with respective grooves that cooperate with the slots for reception and retention of the additional ligating wire or hoop; the slots and grooves together may form a headed post for retention on the bracket of additional orthodontic elements such as a traction spring or a small hoop providing braking against sliding of the bracket along the wire.

Self-ligating orthodontic brackets comprise a spring ligating member of U-shape with converging arms movable on the bracket body between slot open and closed positions; in the latter position the spring retains an arch wire in the slot and urges the bracket and wire to their optimum relative positions. The ligating member is of a superelastic shape recovery metal alloy, preferably of thickness from 0.20 mm (0.008 in) to 0.25 mm (0.010 in), with rounded edges. At least the lingual portion of the member to be stiffer than the remainder; at least a part of the occlusal portion can also be stiffer. Alternatively, or in addition, the bracket body has a large mesial distal extending bore between and spaced from the bracket occlusal, lingual and labial surfaces and the arch wire slot occlusal surface. The large bore accepts attachment members used for attachment of a range of auxiliaries, such as hooks and traction springs. Alternatively, or in addition, the arch wire slot gingival wall comprises an additional spring; this can be of shape memory alloy and preset to become effective when heated above its transformation temperature. Alternatively, or in addition the arch wire slot has the lingual and gingival surfaces meeting at an angle from 120 to 150 degrees to provide a larger slot; the slot gingival surface may also be provided by an additional spring member.

A reinforced elastomeric non-hoop ligature comprises a thin flat body of the elastomeric material having incorporated therein a thin flat rigid insert of gingival-occlusal dimension greater than the corresponding dimension of the arch-wire receiving slot of the orthodontic bracket with which it is employed. The ligature body has holes or slots through which ligature retaining projections of the bracket body protrude, and when mounted on the bracket the rigid member straddles the bracket slot mouth. A reinforced hoop ligature comprises a torus of the elastomeric material with two diametrically opposed rigid inserts of gingival-occlusal dimension sufficient to straddle the bracket slot. The rigid insert or inserts increase the cooperative action between the arch wire and the ligature to facilitate the bracket and tooth movement, and when the arch wire is fully within the slot provides the possibility of controlling sliding friction between the arch wire and the bracket, including minimising when this is desirable. The mesial distal widths of the body and insert and the labial-lingual position of the insert can be varied in to provide the characteristics required.

Elastomeric orthodontic ligatures

An arch wire of T-shape cross section in the gingival occlusal transverse plane so as to have a labial lingual extending foot and a gingival occlusal extending crossbar is operative with a bracket having a mesial distal extending arch wire slot. The crossbar is urged against the bracket body by a ligature, usually an elastic ligation loop, until its lingual surfaces, which preferably are flat and coplanar, are in full butting engagement with the slot bordering portions of the bracket labial surface, which preferably are also flat and coplanar. At this time the foot is fully inserted in the slot and the optimum relative position and attitude of the bracket and the wire is determined for both tipping and rotation by this butting engagement. The function of the foot is primarily to guide the wire into this engagement and it can therefore fit with good clearance in the slot. The wire is usually used toward the end of the procedure after initial corrections and movements have been produced using round cross section wires. This replaces the prior art system of square or rectangular wires fitting in a rectangular slot. The labial slot surface is concave, usually semi-circular, so that it cooperates effectively with the round cross section wires used in the initial stages.

Orthodontic arch wires and brackets

An arch wire is provided with one or more sleeves, each of which is a close fit on the wire and in turn fits closely into the bracket slot in which it is inserted. The wire/sleeve combination and the bracket cooperate to produce the desired rotation and tipping of the tooth while, if required, the sleeve/bracket combination can slide freely along the wire. This permits the use of very light moving forces and the use of a wire of uniform cross-section along its length while permitting changes of the wire cross-section for each and any bracket to provide the desired orthodontic action. Preferably the wire and sleeve cross-sections cooperate to hold the sleeve against rotation about a mesial-distal axis. The ends of the sleeve may be splayed to limit its endwise movement in the bracket slot. A sleeve may extend over more than one bracket. The sleeve may be a continuous tube, or it may be slit mesially-distally along its lingual face that is within the slot.

Orthodontic arch wire sleeves for use with orthodontic arch wires and

A new multi-strand orthodontic arch wire comprises a plurality of wire strands of superelastic shape recovery metal alloy wrapped helically parallel to one another along the length of the wire, the ratio of the longitudinal pitch P of the wire to the external diameter D of the wire being between six and twelve. Such a wire is able to slide more freely in the bracket slots, and is less likely to breakage, than the short pitch wires previously used. A wire with a hollow central core, can also operate as a compression spring by frictionally engaging it with adjacent orthodontic elements, such as brackets, and arranging that its strands are spread radially apart from a neutral configuration, or it can operate as a traction spring by arranging that its strands are closed radially inward from a neutral configuration, the spring action being produced by the urge of the strands to return to the neutral configuration. Cored wires can act as a compression spring, but not as a traction spring. Partial cores strands can be provided to localize the spring action to specific parts of the wire. The wires can be provided with crimpable end members. The shape recovery metal alloy can be any one of nickel/titanium; nickel/titanium/copper; copper/zinc/aluminum; copper/zinc/aluminum/manganese; copper/aluminum/nickel; and copper/aluminum/nickel/manganese.

Multi-strand orthodontic arch wires and methods for use thereof

A new orthodontic bracket has a mesial-distal extending labially-open arch wire slot that in gingival-occlusal cross section is curved at its lingual face about a mesial distal axis and has its gingival and occlusial faces which usually are straight smoothly joining the lingual face and extending away from one another to form a slot opening of greater gingival-occlusial dimension. A spring retainer member embraces the gingival, occlusial and labial faces and is movable between a slot open position and a slot closed position, in the latter of which it opposes any protrusion of an arch wire out of the slot caused by misalignment between the slot and the arch wire The retainer is held in the slot closed position by latches which permit a small movement of the retainer away from the fully slot closed position, but which oppose such movement by spring and cam action. In a final stage of the orthodontic procedure the bracket is used with an arch wire of D-cross-section matched at its curved face to the curvature of the slot lingual face; the wire holds the teeth in the desired arch configuration while they are moved along it, anti-tipping forces of suitable low value being produced if the the wire tilts in the slot by spring reaction of the bracket retainer against the wire.

Orthodontic brackets and arch wires for use in combination therewith

An elastomeric traction ribbon spring for use in orthodontic procedures consists of a thin and narrow ribbon of substantially constant thickness and width along the length of its operative portion, which is provided with a centrally disposed row of relatively small relatively closely spaced holes extending through its thickness dimension. The tension applied between two anchor points is adjusted by choice of the holes engaged at these points. A specific example is 0.9 mm (0.035in) wide and 0.3 mm (0.012in) thick with holes of 0.2 mm (0.008in) diameter spaced 0.58 mm (0.023in) apart center to center. Each hole may have at the underface a funnel-shaped recess that facilitates mounting of the ribbon on its anchor point; a method of forming such holes is provided using an apertured die and a concentric pointed punch. The spring may be supplied in a long length from which the required amount is cut. Alternately they may be in separate lengths each with a finger-gripping part at one end; the distal end may be provided with a larger hole to facilitate attachment to the distal anchor point, while the mesial end may have a hole for temporary attachment of a tension meter. A particularly suitable anchor is a post with an enlarged head, the ribbon being forced over the head, which may be ball- or mushroom-shaped. A tool with a cup-shaped head is provided to facilitate forcing the ribbon over the enlarged head when it is inaccessible by hand.

Elastomeric orthodontic traction ribbon springs

New orthodontic traction devices that can be pre-assembled or custom assembled in the operatory using connector members consisting of cut lengths of metal spring material or wire rope material uses attachment members each of which has a recess into which the respective end of the spring or rope material is inserted. The attachment member is crimped radially inward to plastically deform the metal into the helical grooves in the connector member external surfaces and thus retain the end; alternatively the end can be secured by brazing or cementing. If spring material is used the attachment member has a central boss which protrudes into the spring. An eyelet attachment member is non-removable from an anchor hook, except by the orthodontist, by making the tongue with the eyelet hole too thick to pass through the hook mouth, while the tongue end-most border portion can pass through, so that the eyelet must be rotated to a required attitude before it can be placed on or removed from the hook. A hooked attachment member used with an enlarged-head anchor pin is non-removable by arranging that the attachment member body fouls the anchor body unless they are in required relative attitudes. Other forms of eyelet hole and hook and a ball and socket attachment system are also disclosed.

Growing community of inventors

Hamilton, Canada

G Herbert Hanson