WO1998006347A1

WO1998006347A1 - Apparatus and method for lingual brackets placement

Info

Publication number: WO1998006347A1
Application number: PCT/IL1996/000080
Authority: WO
Inventors: Silvia Geron
Original assignee: Silvia Geron
Priority date: 1996-08-12
Filing date: 1996-08-12
Publication date: 1998-02-19
Also published as: AU6753296A

Abstract

This apparatus for lingual orthodontic bracket placement is used both clinically and in laboratory procedures to align a patient's displaced teeth. The apparatus includes a jig or fixture (5) for holding labial (3) and lingual brackets (4) at a fixed location and orientation with respect to each other and facing each other. When the labial bracket is positioned close to the labial surface of a tooth, the corresponding lingual bracket is close to the lingual surface of the same tooth. The apparatus is copying the exact position of the labial slot to the lingual slot. The orthodontist only has to place the labial bracket (3), an easy task, and the apparatus automatically places the lingual bracket (4), the more difficult task. A handle (52) attached to the jig (5) is pointing in the direction of the line of occlusion. The distance between the labial and the lingual bracket is adjustable. The method for lingual bracket placement includes the steps of removably attaching a lingual bracket to a jig in predetermined relationship to a labial bracket in the jig; positioning the labial bracket; adjustment of the labio-lingual distance; bonding the lingual bracket to the tooth; and disengaging the jig from the lingual bracket.

Description

Apparatus and method for lingual brackets placement

Background of the Invention

This invention relates to orthodontic devices, and more particularly to such devices used for placing lingual brackets, clinically and in laboratory procedure, to align patient's displaced teeth.

Heretofore, the orthodontic treatment of teeth alignment usually consisted of bonding brackets to the labial side of the teeth, and inserting a flexible wire through a slot (channel) in each bracket such that the wire exerts a continuous force on the displaced teeth to bring them to the desired location and orientation. The labial side of the teeth is the external side, or that side which is closer to the labia.

The other, alternative treatment is to bond the brackets to the lingual side of the teeth, that is the side closer to the lingua. Although this method has certain advantages, for example an aesthetic benefit, it is much less used because of the difficulty in bonding the brackets to the lingual side of the teeth.

The goal of the orthodontic treatment is to align the labial side of the teeth. The orthodent usually bonds brackets to the labial side of the teeth to a fixed location in each tooth (LA. point), such as to induce a stress in a rectangular wire inserted through the bracket; the wire tends to return to its normal state, and thus exerts the desired force on each tooth, to bring it to the desired position and orientation. The position and orientation of the labial slot is dictating the position and orientation of the tooth.

Thus, bonding brackets to the labial side of the teeth is relatively easy, since the labial surface is relatively consistent and the orthodent can put the bracket in its place, and be quite sure that the orientation of the slot will be correct, and will bring the tooth to its desired position. Bonding brackets to the lingual side of the teeth is much more difficult, since there is a wide variety of lingual anatomy, different slope, width and different surface shape on each tooth.

The labial and lingual sides are not parallel and have different shapes, thus it is difficult for the orthodent to define the required bracket position and orientation in the lingual side (or the position of the slot of the lingual bracket), that will bring the other (labial) side of the tooth to the desired position and orientation.

There are two methods of brackets bonding, the direct and indirect method, which consist in bonding the brackets to the teeth versus bonding the brackets to a model, respectively. In both methods, there exists the abovedetailed difficulty in bonding lingual brackets, that is brackets intended for the lingual side of the teeth.

The more accurate method is the indirect method, but it is time- consuming and is very expensive, as it requires a laboratory work. Because of the difficulties to position the lingual brackets, the usual way of bonding the lingual brackets is indirectly. There are only a few laboratories in the world, which have technicians specializing in this procedure. The orthodents which work in lingual orthodontics have to send the models to these laboratories abroad and wait 3 or 4 weeks to receive the indirect bonding tray for bonding the brackets in the patient's mouth. This procedure also gives them a very little control of the work of the technician. They cannot known whether the technician followed their instructions until the brackets are bonded in the mouth. If a bracket fails to bond then they have to send back the model to the laboratory, and to go again through the whole procedure.

The laboratory procedure today is done in two ways- TARG and CLASS. Both are very complicated and require special training and many steps. Each step is error-prone, thus mistakes can accumulate to a big mistake. Following is a detailed description of the TARG system. The TARG consists of a movable model support. The moloccluded model is placed on in. The tooth which is intended to receive the lingual bracket is positioned according to the desired position of its labial surface. The positioning of the tooth is by measuring its torque, angulation, height and labio-lingual distance of the lingual slot (width of the tooth). These measurements are performed using four different apparatus means which are combined together in the slot machine.

After the measurements of the labial surface are completed, the lingual bracket is positioned with a bracket holder, and then a conventional indirect bonding procedure is carried out.

Existing patents apparently do not address the abovementioned problems.

Thus, Diamond US Patent 4474555 details a dental instrument for positioning a lingual orthodontic bracket. The instrument comprises a housing on which is positioned an arm that includes means for holding the bracket.

Diamond US Patent 4455137 details a dental instrument and method for positioning a lingual orthodontic bracket, including two arms positioned on a housing, with means for measuring the angle of inclination of the arm.

Diamond US Patent 4422849 details a dental instrument and method for positioning a lingual orthodontic bracket, including an arm positioned on a housing and level indicating means.

Maijer US Patent 4478576 details an orthodontic attachment placement device, including a plate which engages the facial side of the tooth, and a member mounted on a pivotable bracket holder.

Maijer US Patent 4424029 details a lingual placement device for positioning orthodontic attachments, including a handle with a pivotable handle extension, to permit access to both sides of the tooth. Creekmore US Patent 4812118 details a placement apparatus for accurately placing orthodontic brackets on the lingual or labial surface of a model of a patient's maloccluded teeth.

It is an objective of the present invention to provide an apparatus and method for facilitating lingual brackets placement, directly and indirectly, and to make it possible for the orthodent himself/herself or one of their staff members to position the brackets easily, quickly and more accurately.

Summary of the Invention

According to the present invention, there is provided an apparatus and method for facilitating lingual brackets placement either on a model (indirectly) or in the mouth (directly).

According to one aspect of the present invention, the apparatus for lingual brackets placement includes fixture or jig means for holding a labial and a lingual bracket at a fixed location and orientation with respect to each other and facing each other , and such that, when the labial bracket is positioned close to the labial surface of a tooth, the corresponding lingual bracket is close to the lingual surface of the same tooth. The apparatus is copying the exact position of the labial slot to the lingual slot. Thus, the orthodent only has to place the labial bracket (an easy task), with the apparatus automatically placing the lingual bracket (the difficult task).

According to a second aspect of the present invention, the apparatus for lingual brackets placement further includes a handle or pointer means attached to the jig and pointing in a direction generally parallel to the line of occlusion, to assist the orthodent in evaluating the orientation of the bracket to be bonded. According to a third aspect of the present invention, the apparatus for lingual brackets placement includes means for adjusting the distance between the labial and the lingual bracket, according to the characteristics of the teeth.

According to a fourth aspect of the present invention, the apparatus for lingual brackets placement includes two arms, an external and an internal arm, with these arms each including an end segment which is generally parallel to the other end segment, and shaped such as to allow its insertion into the slot in the corresponding bracket.

According to a fifth aspect of the present invention, the apparatus for lingual brackets placement further includes means for holding each bracket to one of its two arms, while allowing at least the lingual bracket to be disengaged from its holding arm.

According to a sixth aspect of the present invention, the method for lingual brackets placement includes the steps of removably attaching a lingual bracket to a jig means, at a fixed location and orientation with respect to a labial bracket attached to the jig, with the brackets facing each other; alignment of the labial bracket into the desired location and orientation relative to the labial surface of the tooth; adjustment of the labio-lingual distance according to the tooth characteristics; bonding the lingual bracket which is automatically placed in the desired location and orientation to the tooth lingual surface; and disengaging the jig from the lingual bracket thus bonded.

Further objects, advantages and other features of the present invention will become obvious to those skilled in the art upon reading the disclosure set forth hereinafter. Brief Description of the Drawings

Fig. 1 illustrates the structure of the apparatus for facilitating lingual brackets placement, with labial and lingual brackets being applied to a tooth.

Fig. 2 illustrates the lingual brackets being bonded to the teeth, with the flexible wire attached to the brackets.

Fig. 3 details the structure of the apparatus for facilitating lingual brackets placement.

Description of the Preferred Embodiment

A preferred embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings.

Referring to Fig. 1 , an example of an apparatus for facilitating lingual brackets placement according to the present invention, the apparatus includes a set of jigs for accurately placing orthodontic brackets 4 on the lingual surface 83 of patient's teeth 8 or on a model of patient's teeth 8. The lingual brackets 4 are easily placed, without any measurement, by the orthodent or its staff.

The apparatus includes external arm means 1 and internal arm means 2. Each of arm means 1 , 2 includes means for holding a labial bracket 3 and a lingual bracket 4, respectively. In the example as illustrated, these holding means include labial bracket 3 having a slot 32 for inserting a flexible wire (not shown) therethrough, and arm 1 having an end segment 12 having a corresponding shape and dimensions, such as to enable to insert segment 12 into slot 32 to hold it mechanically. Similarly, holding means for bracket 4, include lingual bracket 4 having a slot 42 for inserting a flexible wire (not shown) therethrough, and arm 2 having an end segment 22 having a corresponding shape and dimensions, such as to enable to insert segment 22 into slot 42 to hold it mechanically. Additionally, arm 2 includes flexible holding means 23, for example metallic spring means, for holding bracket 4 while pressing it against arm 2 (Fig. 1 illustrates bracket 4 separated from arm 2, for the sake of clarity). Spring 23 allows bracket 4 to be attached to arm 2 before bonding to tooth 8, and for arm 2 to be removed after bracket 4 bonding. The tip 232 of spring 23 holds bracket 4 against arm 2.

Similar spring means (not shown) may be used to hold bracket 3 attached to arm 1 , or bracket 3 may be fixedly soldered to arm 1. Bracket 3 is not being bonded to tooth 8, but only serves to align caliper means 5 with its line of occlusion 51 in the desired orientation.

Thus, the apparatus for lingual brackets placement includes fixture or jig means including caliper means 5 and arms 1 , 2 for holding a labial bracket 3 and a lingual bracket 4 at a fixed location and orientation with respect to each other and generally facing each other, and such that, when the labial bracket 3 is positioned close to the labial surface 82 of a tooth 8, the corresponding lingual bracket 4 is close to the lingual surface 83 of the same tooth 8. The actual distance between the surfaces 82, 83 is approximately the width of a tooth.

The width is adjustable and is set using the caliper means 5 and the scale 54, as detailed below.

The brackets facing each other is intended to mean that the bonding surfaces 33, 43 generally face each other, with the slots 32, 42 of each bracket generally pointing out and away from the second bracket. The apparatus is copying the exact position of the labial slot 32 to the lingual slot 42.

The millimetric scale 54 enables to put all the brackets in the same labio-lingual distance, in spite of differences in the width of the teeth. The space between a small or thin tooth and its corresponding bracket is filled with the bonding material. The apparatus for lingual brackets placement automatically places the lingual bracket 4 in the desired location and orientation, while the orthodent places the labial bracket 3 in the corresponding location and orientation relative to the labial surface 82 of tooth 8, for the planned treatment.

Thus, the orthodent only has to place the labial bracket 3 relative to labial tooth surface 82 (an easy task) , with the apparatus automatically placing the lingual bracket 4 relative to the lingual bracket 83 (the difficult task). This is implemented by means for holding the labial bracket 3 and lingual bracket 4 at a fixed distance and orientation with respect to each other, in the present example using arms 1 and 2 with end segments 12, 22 and brackets 3, 4 having slots 32, 42 respectively. The apparatus is copying, or transferring, the exact position of the labial slot 32 to the lingual slot 42, while allowing the orthodent to manipulate the two brackets together.

This enables the orthodent to set the labial bracket 3 in the desired location and orientation, and to bond the lingual bracket 4, which is automatically placed in the corresponding location and orientation, to lingual surface 83.

The apparatus further includes a handle or pointer means 52 generally parallel to the line of occlusion 51 , to assist the orthodent in evaluating the orientation of the bracket 4 to be bonded.

The apparatus for lingual brackets 4 placement also includes caliper means 5 for adjusting the distance between the external arm 1 and the internal arm 2, according to the characteristics of the tooth 8. The distance between arms 1 , 2 can be manually adjusted, for example using sliding handle means 53 connected to caliper 5, with millimetric scale 54 indicating the set distance.

The linear sliding movement performed by caliper means 5 allows for adjusting the distance between external arm 1 ( first jig means) and internal arm 2 (second jig means) while preserving the relative angle and orientation between lingual bracket 4 and labial bracket 3. The external arm 1 and the internal arm 2 includes each an end segment 12. 22 respectively, with segments 12, 22 being generally parallel to each other and to the line of occlusion 51.

Each of the end segments 12, 22 is shaped such as to allow its insertion into the slot 32, 42 in the corresponding bracket 3, 4 respectively. This allows for holding each bracket 3, 4 to one of the two arms 1 , 2, while allowing at least the lingual bracket 4 to be disengaged from its holding arm 2 after bracket 4 is bonded to tooth 8.

Bracket 3 may be either fixedly or removably attached to arm 1 .

In the first case, bracket 3 is fixedly attached to arm 1 , so the invention consists of a set of these devices, each device adapted for one labial bracket, or for each tooth.

In the latter case, to achieve an apparatus capable of holding various prescription types of brackets, bracket 3 is removably attached to arm 1 , as illustrated above. For each prescription bracket type a bracket pair

3, 4 is attached to arms 1 , 2, with their corresponding bonding surfaces

33, 43 being kept at a fixed location relative to each other.

The method for lingual brackets placement according to the present invention includes the following steps:

1. Removably attach a lingual bracket 4 to a jig means, at a fixed location and orientation with respect to a labial bracket 3 attached to the jig, with the brackets facing each other and such that, when the labial bracket is positioned close to the labial surface of a tooth, the corresponding lingual bracket is close to the lingual surface of the same tooth.

2. Align the labial bracket 3 into the desired location and orientation relative to the labial surface of the tooth, according to the planned orthodontic treatment. 3. Adjust the labio-lingual distance, for example by sliding caliper means included in the jig, according to the distance between the labial and lingual surfaces of the tooth, in the planned bonding location.

4. Bond the lingual bracket 4 which is automatically placed in the desired location and orientation to the tooth lingual surface 83.

5. Disengage the apparatus (jig) from the lingual bracket 4 bonded to tooth 8.

Fig. 2 illustrates the lingual brackets 4 being bonded to the teeth 8. with the flexible wire 6 attached to the brackets 4. Preferably, wire 6 has a rectangular cross-section (not shown) corresponding to a similarly shaped slot in each of brackets 4, to allow changing both the location and the orientation of each bracket.

The six anterior teeth have to be in a straight line at the end of the treatment.

Fig. 3 details the structure of the apparatus for facilitating lingual brackets placement. Arm segments 12, 22 of arms 1 , 2 are used to hold the labial and lingual brackets (not shown) respectively at the same slot position. Caliper means 5 with sliding handle 53 enable to change the distance between arms 1 , 2. Using a rectangular handle 53 assists the orthodent in setting the desired angle of orientation of caliper means 5.

Preferably, arm segment 12 is located higher up the tooth than segment 22, the preferred height difference being about 2 - 3 mm.

Optional mirror 7 allows to visually check the lingual bracket placement and bonding, while using the apparatus for direct bonding in the mouth.

Various embodiments of the present invention may be implemented. For example, the scale 54 in Fig. 1 may be in inches, instead of a millimetric scale.

Sliding handle means 53 may include means (not shown) for stopping the sliding movement after the device is set to the desired distance. Handle means 53 may include rotating means to actuate screw means (not shown) inside caliper means 5 to precisely bring the distance between arms 1. 2 to the desired value.

Caliper means 5 and arms 1 , 2 may be made of a durable material like stainless steel, for repeated use. Another embodiment uses low cost, disposable caliper 5 and arms 1 , 2, made of low cost plastics. A low cost, rigid plastic material should be used, as known in the art.

Whereas Fig. 1 illustrates a lingual bracket 4 having a horizontal slot 42, another embodiment (not shown) may use a lingual bracket 4 having a vertical slot; in the present invention, either a vertical or horizontal (rectangular) slot and corresponding wire can be used. A round section wire can also be used, but it results in inferior performance.

The bracket holding means in a presently preferred embodiment include spring means 232, which are used to attach bracket 4 to the jig before bonding. Other means may be used, for example (not shown) a weak glue or a spring attached to the end segment 22 which is forcibly attached to bracket.

Arm 2 may include two parts (not shown), one fixedly attached to caliper means 5 to be set at desired distance from arm 1 , and the second being capable of being attached to the first; the second part is disposable, being made with a lingual bracket attached thereon.

Another embodiment may include a fixture (not shown) with a handle and first arm holding a labial bracket or an imitation thereof, and means for holding a second arm which can be attached at various distances from the first arm. Using a caliper or micrometer, the second arm is attached to the fixture at the desired distance from the first arm. This embodiment lends itself for use as a disposable device, because of its simple structure.

Labial bracket 3 is attached to caliper means 5 to allow setting the distance between the brackets, and to facilitate bracket positioning and orientation by the orthodent. In another embodiment, a low cost part (not shown) which is shaped as a labial bracket may be used instead of bracket 3. Since bracket 3 is used only for aligning the device with respect to tooth 8, there is no need to attach an actual, expensive bracket to the jig; a plastic, low cost replica of a labial bracket will suffice.

It will be recognized that the foregoing is but one example or embodiment of an apparatus and method within the scope of the present invention and that various modifications will occur to those skilled in the art upon reading the disclosure set forth hereinbefore.

Claims

ClaimsWhat is claimed is:

1. Apparatus for lingual brackets placement comprising:

(A) first jig means for holding a labial bracket or a device shaped like a labial bracket at a fixed location relative to said apparatus;

(B) second jig means for holding a lingual bracket:

(1 ) at a fixed location and orientation with respect to said labial bracket; and generally facing each other and such that, when said labial bracket is positioned close to the labial surface of a tooth, then said lingual bracket is close to the lingual surface of said tooth; and

(2) with said labial and lingual brackets generally facing each other; and

(3) at such a distance between said brackets that, when said labial bracket is positioned close to the labial surface of a tooth, then said lingual bracket is close to the lingual surface of said tooth; and

(C) means for adjusting the distance between said first jig means and said second jig means while preserving the relative angle between said lingual bracket and said labial bracket.

2. Apparatus for lingual brackets placement according to claim 1 , further including handle or pointer means attached to either said first or second jig means and pointing in a direction generally parallel to the line of occlusion.

3. Apparatus for lingual brackets placement according to claim 1 , further including means for adjusting the distance between said first jig means and said second jig means.

4. Apparatus for lingual brackets placement according to claim 1 , wherein said first jig means and said second jig means each includes an arm with an end segment which is shaped such as to allow its insertion into the slot in its said corresponding bracket and with said end segments being generally parallel to each other.

5. Apparatus for lingual brackets placement according to claim 1 , wherein said second jig means further includes means for allowing said lingual bracket to be disengaged therefrom.

6. Apparatus for lingual brackets placement according to claim 1 , wherein said first jig means and said second jig means and said means for adjusting the distance between said first and second jig means are made of a durable material, like stainless steel.

7. Apparatus for lingual brackets placement according to claim 1 , wherein all or part of said first jig means and said second jig means and said means for adjusting the distance between said first and second jig means are made of a low cost rigid plastic material to make a disposable device.

8. Method for lingual brackets placement including the steps of:

(A) Removably attaching a lingual bracket to a jig means, at a fixed location and orientation with respect to a labial bracket attached to said jig, with said brackets facing each other;

(B) alignment of said labial bracket into the desired location and orientation relative to the labial surface of said tooth;

(C) adjustment of the labio-lingual distance according to said tooth characteristics;

(D) bonding said lingual bracket, which is automatically placed in the desired location and orientation, to the lingual surface of said tooth;

(E) disengaging said jig from said lingual bracket.