WO2016185018A1 - Bone anchor for an orthodontic apparatus and method for producing a jaw model - Google Patents

Abstract

The invention relates to a bone anchor (5, 9) for anchoring an orthodontic apparatus, comprising a shaft (7, 10) having at least two bores (8, 11) for screwing to a jaw bone, and having a head part (6, 12) for securing the apparatus, wherein the head part (6, 12) has a section (24), the cross-section of which is substantially evenly tapered in a pull-off direction (17). The pull-off direction is substantially parallel to the shaft (7, 10) and faces away from the shaft (7, 10), and has at least one opening (21, 22) having an internal thread (23) extending substantially transversely to the pull-off direction (17). The invention further relates to a method for producing a jaw model and for adapting an orthodontic apparatus, wherein a head part (27) of a model anchor (26) is positioned relative to the jaw model and is connected to the jaw model in accordance with the position of a head part (6, 12) of a bone anchor (5, 9) that was implanted in the modeled jaw (2, 3) beforehand.

Description

 Bone anchor for an orthodontic appliance and method for making a jaw model

The invention relates to a bone anchor for anchoring an orthodontic appliance, with a shaft having at least two holes for screwing to a jawbone and a head part for fastening the apparatus, a model anchor and a method for producing a jaw model for adapting an orthodontic appliance using such Bone anchor and model anchor.

In an orthodontic treatment for the regulation of one or more teeth and / or for jaw regulation, it is known to use an orthodontic appliance by means of a

Bone anchor anchored to the jawbone. Such a

Bone anchor is known for example from EP 2 227 169 B1. In such bone anchors, the problem is that the

Orientation of the implanted bone anchor can not be defined by exact specifications. Accordingly, a must

Orthodontic apparatus on implanted bone anchor to be adapted to its exact positioning. Such

Adjustment is made on the patient, which can be a tedious procedure due to the often difficult accessibility and the necessary precision and thus both for the

Patients as well as the doctor is uncomfortable and exhausting.

It is therefore desirable to reduce the time of treatment on the patient and thus reduce the inconvenience to the patient and the physician as compared to the conventional approach.

The invention is based on the finding that the adaptation of the orthodontic appliance to a model can be carried out if the model accurately reproduces at least the part of the jaw and the teeth relevant to the treatment and at least one head part of the implanted bone anchor provided for fastening the appliance , The invention therefore relates - as stated above - on the one hand

Method for producing such a model and on the other hand correspondingly adapted material, ie a bone anchor and a model anchor, which are particularly suitable for use in the method. As will be seen below, the individual parts are in direct relationship with each other, particularly with regard to the particular shape, which is of decisive importance for the suitability in the stated method.

The production of jaw models in the form of jaw impressions is known per se and is used, for example, for diagnosis and control at the beginning and end of an orthodontic

Treatment performed. Accordingly, such models serve the documentation of the jaw and tooth situation and can not adapt to an orthodontic apparatus to the

Position of a bone anchor can be used because they do not have a suitable image of the bone anchor.

In addition, DE 20 2005 017 462 Ul describes a

Method in which a retaining element is snapped onto an implanted fastening screw by means of transfer feet. Subsequently, the jaw is molded together with the holding element, with special outer, provided as a retention surface for the impression foot for a connection of the

Make holding element with the impression material. After the impression has been taken on the imprint

Transmission aids in the form of holding elements

 Fixing screws or analogs clicked, which are then included in the created positive model. Furthermore, DE 20 2005 017 462 U1 shows a plate-shaped armature with the screw head, which has a chamfer at the upper end.

Other bone anchors are described in WO 2014/163154 AI and

EP 2 666 436 AI, wherein in each case a star-shaped

conical elevation is provided on the headboard. In each case one is arranged parallel to the axis of the conical elevation

Opening provided.

In addition, US 2009/220916 AI shows a method for

Production of three-dimensional jaw models and

Implants, wherein on a previously introduced implant in the form of a bone screw a Abformstecker is plugged before an impression material is used to produce a jaw impression, with the impression jig remaining in the jaw impression. Subsequently, on the impressed in the impression Abformstecker

Model implants or analogs attached before the model is cast from the impression.

It is an object of the invention to achieve an accurate reproduction of the relevant section of the head part in the negative mold and to facilitate the removal of the negative form from the bone anchor and to allow a certain play in impressions with more than one bone anchor.

To solve this problem, the invention provides a bone anchor of the initially mentioned kind, wherein the head part a

Section having in a stripping direction substantially uniformly tapering cross-section, wherein the

Extracting direction substantially parallel to the shaft and from

Shank points away, and at least one opening with an in

Has substantially transverse to the withdrawal direction extending internal thread. The withdrawal direction is the direction in which the negative form of the jaw and thus also of the bone anchor should be removed. That it is substantially parallel to the longitudinal axis of the teeth adjacent the bone anchor at the intended position. The cross section thus corresponds to one

Cut in the plane normal to the removal direction. These

Arrangement of the bone anchor relative to the jaw or to the

Teeth simplifies both the removal process and the

Imprint process. With the opening having a substantially transverse to the withdrawal direction internal thread is achieved in this arrangement of the bone anchor horizontal Verschraubbarkeit the apparatus on the bone anchor, i. transverse to the longitudinal axis of the anchor. This can be counteracted sliding of a mounted on the tapered head portion apparatus and at the same time a to be arranged in the opening of the bone anchor fixing screw when mounted in the mouth of a patient is relatively easily accessible. In addition, the

Arrangement transverse to the removal direction and the penetration of

Impression material in the opening when making an impression compared to an arrangement parallel to the peeling

reduce. The diameter of the opening can be, for example between 0.1 and 1 mm, preferably about 0.5 mm

(equals 0.02 inches). With such diameters, hardly any molding compound can be used in the production of the

Penetrate negative mold in the headboard, so that the negative mold can still be easily pulled off.

Furthermore, the object is achieved with a model anchor according to the invention for placement on a jaw model comprising a head part, wherein the shape of the head part corresponds to that of the head part of the bone anchor described above. The model anchor is intended for use outside the human body; i.e. The model anchor does not have to be suitable as an implant and in particular does not have to fulfill the medical requirements of an implant. He can

For example, made of aluminum or other suitable, inexpensive material (compared to that for implants

commonly used titanium). Of the

Model anchor thus differs from the bone anchor thus usually by the material used. Apart from the head part, the shape of the model anchor may differ from that of the bone anchor, but this is not a mandatory requirement. As a model anchor, for example, an exact replica of the bone anchor made of a less expensive material could be used. In the method according to the invention, a head part of a model anchor corresponding to the position of a head part of a previously implanted in the modeled jaw bone anchor for anchoring an orthodontic relative to the jaw model

positioned and connected to the jaw model, wherein the implanted bone anchor has a shaft with at least two

Holes for screwing to a jawbone and the

Having head part for fixing the apparatus, wherein the

Head portion of the bone anchor a section with in a stripping direction substantially uniformly tapered

Cross-section, wherein the withdrawal direction substantially parallel to the shaft of the bone anchor and away from the shaft, wherein the shape of the head part of the model anchor that of the

Head portion of the bone anchor corresponds.

There is therefore a model anchor, i. a model of

implanted bone anchor, used, whose head part the Position of the head portion of the implanted bone anchor and is therefore suitable for fitting an orthodontic appliance. Thus, the adaptation to the

made jaw model (with the model anchor) are made and the patient can be fitted after the adaptation of the already exactly adapted apparatus, which significantly reduces the necessary treatment time. The model anchor used in the process is generally no

complete copy of the bone anchor; only the

Head part of the model anchor is at least geometrically substantially coincident with the head part of the bone anchor in order to reproduce this part and its as accurate as possible

Position to achieve.

For example, the present method may include the steps of

 a negative form of a jaw and a bone anchor previously implanted in the jaw is produced,

 a head portion of a model anchor is positioned corresponding to the position of a head portion of the implanted bone anchor relative to the female mold and

 - The jaw model is molded from the negative mold and connected to the positioned model anchor.

In this procedure are - apart from the model anchor used - no special equipment, especially none

Scanners or tomographs, required, so that the procedure without significant additional effort in the conventional

Treatment procedure can be used.

To connect the model anchor with the jaw model, it has been found to be advantageous if the jaw model is molded by pouring the negative mold, wherein a shaft of the model anchor is at least partially poured into the jaw model. The shaft of the model anchor is connected to the head part and for attachment in or on the jaw model

arranged so that the head part is fixed over the shaft relative to the jaw model. The partial pouring of the stem can easily create a stable connection

be prepared without the position of the model anchor or the Head part to influence.

Furthermore, it is advantageous if, before making the

Negativform a Abformkappe is fixed to the head part of the bone anchor, the Abformkappe in the manufacture of

Negative mold is connected to the negative mold of the jaw and the head part of the model anchor before the impression of the

Jaw model is positioned by fixation on the impression cap. The impression cap forms in this context

Cap-shaped cover or recording of the head part of the

Bone anchor and is almost a counterpart to the headboard. The Abformkappe can thus the headboard and any openings or recesses in the headboard from contamination in the

Protect the production of the negative mold. At the same time, the

Abformkappe form a prefabricated exact imprint of the head part, which in the manufacture of the negative mold in the

Negativform is integrated and thus an even more accurate

Imaging of the implanted bone anchor is possible. at

Use of such an impression cap can also

Bone anchors are used for a direct impression rather unsuitable forms in the context of the method according to the invention.

Conveniently, the negative mold can be produced from an impression compound, in particular alginate or silicone. Such impression compounds are also used for conventional jaw impressions

used. They are suitable for accurate impressions of the jaw and teeth relative to the imaged head portion of the

Bone anchor.

In addition, it is advantageous if the jaw model is molded in the form of a plaster cast. Plaster allows a stable and rigid connection with the model anchor and is therefore suitable for the present method.

As an alternative to the production of a negative mold, in the context of the present method the jaw model can also be obtained by digital impression, in particular with an intraoral and / or

extraoral scanner and / or a digital volume tomograph, as a digital jaw model (ie as a digital model of the teeth and the jaw), using a prepared digital model of the bone anchor, ie a digital

Model anchor in which digital jaw model is integrated. However, this procedure requires the appropriate equipment. While in intraoral and extraoral scanners

Tooth-bearing extension and soft tissues (such as mucous membranes) are mapped, in a digital volume tomography soft tissues are only insufficiently or approximately represented. For extraoral scanners, plaster models are scanned. For intraoral scanners, the jaw is scanned directly. to

Accuracy of these procedures are related to

Bone anchors no examination, as there is no moldable

Bone anchor gives. These techniques are possible variants of the impression - with all its advantages and disadvantages.

It is related to the digital jaw model

advantageous when the digital jaw model is printed together with the digital model of the bone anchor. According to a less preferred alternative, the jaw model may also be initially printed without a model anchor, with a

prefabricated model anchor later with the printed

Jaw model is connected. Based on the printed model, an orthodontic appliance to be adapted can be tested and tested immediately, which significantly speeds up the process of adaptation. Alternatively, the apparatus could

For example, be tested by digital modeling or digital recording of the adapted apparatus purely virtual on the digital jaw model. Examples of such virtual tests are finite element studies.

In connection with the jaw model produced according to the above method, in the context of the invention for adapting an orthodontic appliance following the production of the jaw model, a fixing cap of an apparatus to be adapted can be connected to the head part of the model anchor and the apparatus can be adapted to the jaw model. The use of a mounting cap has the advantage that this on

simple, rapid and reproducible way of the head part of the model anchor can be separated and connected to the head part of the bone anchor. This allows the treatment time on Patients continue to be shortened. In connection with the bone anchor, it has proven to be particularly advantageous

pointed out when at least two mutually approaching outer edges in the relevant portion of the head part in

Longitudinal section parallel to the stripping an angle of less than 45 °, preferably between 5 ° and 25 °, in particular between 10 ° and 20 °, include. The so defined

included angle defines the degree of taper, i. how strongly the cross section of the head part tapers.

With regard to the positioning and orientation of the

Apparatus, it is advantageous if the head part at least partially has a non-radially symmetrical (or single radiärsymmetrischen) cross-section. In this case, the position of the entire bone anchor, i. including shaft, clearly defined by the impression of the head part and taken into account in the manufacture of the jaw model.

For example, can thus with a longer shaft

Model anchor with a correspondingly aligned shaft

be used so that the course of the shaft in the

Adjustment of the apparatus can be considered.

Furthermore, a Abformkappe with a recess for in

Substantially positive receiving a head portion of the bone anchor described above and provided with a connection device for connection to a negative form of a jaw. The advantages of using such an impression cap have already been explained above in connection with the method according to the invention, so that reference is made to the above statements to avoid repetition.

Finally, a mounting cap for the top

described bone anchor, with a recess for in

Essentially positive reception of a head portion of the

Bone anchor and with a fastening device for

Attachment of an orthodontic apparatus provided. The fastening device is designed for attachment of the remaining parts of the orthodontic appliance, eg by means of a wire. Alternatively, the mounting cap can already be permanently connected in advance with other parts of the apparatus, eg welded, be. Optionally, the mounting cap may be adapted for positive engagement with an opening in the head portion of the bone anchor.

The invention will be described below with reference to preferred

Embodiments, to which, however, it should not be limited, and further explained with reference to the drawings. In detail in the drawings:

 Figure 1 schematically shows a skull bone with the upper and lower jaws respectively arranged bone anchors.

 Fig. 2 shows schematically an implanted bone anchor with the passages through the gum;

 3a, 3b and 3c is a front view, side view and top view of a first embodiment of the

present bone anchor;

 4a, 4b and 4c is a front view, side view and top view of a second embodiment of the

present bone anchor;

 5a, 5b and 5c show a front view, side view and top view of an existing model anchor;

6a, 6b and 6c a front view, side view and top view of a present impression cap; and

 Fig. 7a, 7b and 7c is a front view, side view and top view of an existing mounting cap.

In Fig. 1 is a skull bone 1 with an upper jaw 2 and a lower jaw 3, each with teeth 4, shown. At the

Upper jaw 2, a first bone anchor 5 is arranged. The first bone anchor 5 comprises a head part 6 and a shaft 7 with three holes 8. The bone anchor 5 is provided with bone screws (not shown), which pass through the holes 8 on

Upper jaw 2 attached. At the lower jaw 3 is a second

Bone anchor 9 arranged. The shaft 10 of the second

Bone anchor 9 on the lower jaw 3 has two holes 11. The head part 12 of the second bone anchor 9 is aligned substantially parallel to the lower incisors 13. In both bone anchors 5, 9, the cross sections of the head parts 6, 12 taper in a withdrawal direction essentially parallel to the respective shaft 7, 10 and into one away from the shaft 7, 10 pointing direction of the head part 6, 12th

FIG. 2 shows the second bone anchor 9 according to FIG. 1 in an enlarged view. The bone anchor 9 was replaced by two

Sections 14, 15 implanted in the attached gum 16. A small part of the shaft 10 with the head part 12 passes through a transverse to the shaft 10 section 15 in the region of the attached gum 16 through the gums outward into the oral cavity. The remaining part of the shaft 10 is below the gum. The bone anchor 9 on the lower jaw 3

fixing screws (not shown) passing through the

Run holes 11, were mounted by a parallel to the shaft 10 extending section 14 in the solid gums. The withdrawal direction 17 of the head part 12 is arranged parallel to the longitudinal axis of the lower incisors 13 or substantially normal to a bite plane.

In FIGS. 3 a to 3 c, the first bone anchor 5 according to FIG. 1 is shown in detail. The bone anchor 5 comprises an elongate shaft 7, at the upper end of a head part 6 is arranged. The head part 6 and the shaft 7 are integral, e.g. made of titanium. The shaft 7 points directly below the

Head part 6 a in the side view (Fig. 3b) obliquely

extending portion 18, with the bone anchor 5 passes through the soft gums to the outside. Below the sloping portion 18, the shaft 7 has a narrow neck 19, which is then to a

Widened attachment portion 20 with the holes 8. The neck 19 and the attachment portion 20 are in the

Side view (Fig. 3b) swung outward according to the contour of the jaw. The head part 6 has two openings 21, 22, which are each provided with an internal thread 23. The internal thread 23 in this case runs essentially transversely to a withdrawal direction 17 of the head part 6. The withdrawal direction 17 is defined by the section 24 of the head part 6, which tapers in cross-section (see plan view FIG. The

Outer edges 24a and 24b and 24c and 24d of the tapered portion 24 approach each other in the peeling direction 17 and enclose an angle of about 33 ° (outer edges 24a and 24b) and about 16 ° (outer edges 24c and 24d). The openings 21, 22 are arranged in the region of the tapering section 24, just above the middle. The head part 6 is wider in the front view (FIG. 3 a), ie, as seen through the bores 8, than in the side view (FIG. 3 b), in particular the upper end of the head part 6 having a circular shape

deviating plan 25 has (see Fig. 3c). The

Dashed lines indicate optional additional auxiliary slots 40. A worm screw for attaching a mounting cap may alternatively fix an orthodontic wire in one of the auxiliary slots 40 here.

In FIGS. 4a to 4c, the second bone anchor 9 according to FIG. 1 is shown in detail. The structure corresponds largely to that of the first bone anchor 5, so that the same reference numerals as in Fig. 3a were used to 3c and to the related

Figure description is referenced. In contrast to the first bone anchor 5, the second bone anchor 9 in

Attachment section 20 only two holes 11.

FIGS. 5a to 5c show an existing model anchor 26. The head part 27, the upper part of the shaft 28 with the oblique section 18 and the upper part of the neck 29 substantially corresponds to the structure of the bone anchors 5 and 9, so that

in this regard, reference is made to the above statements. In the lower part of the shaft 28 connects to the narrow neck 29 of the model anchor 26, a substantially cylindrical Eingussteil 30, which has annular recesses 31 for anchoring in a jaw model. The recesses 31 are formed when pouring the model anchor 26 e.g. filled with plaster, so that the model anchor 26 is connected after curing form-fitting with the jaw model. Due to the openings 21, 22 and the internal thread 23 and in general the detail

reproduced form of the head portion of the bone anchor 5, 9, an orthodontic appliance (not shown) can be fixed to the model anchor 26 exactly as on a bone anchor 5, 9 and thus adjusted in advance on the jaw model exactly. The model anchor 26 may for example be made in one piece from aluminum.

In FIGS. 6a to 6c, a present impression cap 32 is shown

shown. The impression cap 32 has on its underside a Recess 33. The shape of the recess 33 corresponds to the shape of an upper portion of the head part 6, 12, 27 of the

Bone anchor 5, 9 and the model anchor 26. Accordingly, the recess 33 has a tapered portion 34 which defines a withdrawal direction 17. On a recess 33 opposite the top of the substantially parallelepiped Abformkappe 32 with rounded edges outer circumferential Abformrippen 35 are arranged, which serve the anchorage in an impression material and thus a

 Form connection device. In order to avoid the teeth of the patient in this area during the production of the negative mold, the impression ribs 35 in an inner area (see Fig. 6b, right side) are inwardly to the center of the impression cap 32nd

offset.

FIGS. 7a to 7c show a present fastening cap 36. The fastening cap 36 is designed for attachment to a bone anchor 5, 9 and the model anchor 26. It has - as the impression cap 32 (see Fig. 6a to 6c) - on its underside a recess 37 for receiving a head portion 6, 12, 27. The inner contour of the recess 37 corresponds to the outer contour of the head part 6, 12, 27, so that a positive connection and thus an exact positioning and alignment of the

Attachment cap 36 on the bone anchor 5, 9 (on the patient) or the model anchor 26 (on the jaw model, for the adjustment) is achieved. In addition, from the mounting cap 36, two screws 38, 39 substantially horizontally inwardly, which engage in the internal threads 23 of the openings 21, 22 and thus the mounting cap 36 on the head part 6, 12, 27th

fix. The screws 38, 39 can be guided and tightened from the outside through the mounting cap 36, so that they can also serve as fastening means for attaching an orthodontic appliance to the mounting cap.

Claims

claims 1. bone anchor (5, 9) for anchoring a Orthodontic apparatus, with a shaft (7, 10) with at least two holes (8, 11) for screwing to a Jawbone and with a head part (6, 12) for fastening the apparatus, characterized in that the head part (6, 12) has a section (24) with a substantially uniformly tapered cross-section in a stripping direction (17), wherein the stripping direction substantially has parallel to the shaft (7, 10) and away from the shaft (7, 10), and at least one opening (21, 22) with an essentially transversely to the stripping (17) extending internal thread (23). 2. Bone anchor (5, 9) according to claim 1, characterized in that at least two mutually approaching outer edges (24a-d) in the section (24) in longitudinal section parallel to Stripping direction (17) an angle of less than 45 °, preferably between 5 ° and 25 °, in particular between 10 ° and 20 °. 3. bone anchor (5, 9) according to claim 1 or 2, characterized characterized in that the head part (6, 12) at least Sectionally has a non-radial symmetry cross-section. 4. model anchor (26) for placement on a jaw model, comprising a head part (27), characterized in that the shape of the head part (27) that of the head part (6, 12) of a Bone anchor (5, 9) according to one of claims 1 to 3 corresponds. 5. A method for producing a jaw model, characterized in that a head part (27) of a model anchor (26) corresponding to the position of a head part (6, 12) of a previously implanted in the modeled jaw (2, 3) bone anchor (5, 9) for anchoring an orthodontic appliance relative to the jaw model and connected to the jaw model, wherein the implanted bone anchor a shaft (7, 10) with at least two holes (8, 11) for screwing on a jaw bone and the head part (6, 12) for fastening the apparatus, wherein the head part (6, 12) of the bone anchor has a section (24) in a Abziehhrichtung (17) substantially uniformly tapering cross section, wherein the removal direction in Substantially parallel to the shaft (7, 10) of the bone anchor and away from the shaft (7, 10), the shape of the head portion (27) of the model anchor (26) being that of the head portion (6, 12) of the bone anchor (5, 9) equivalent. 6. The method of claim 5, wherein  a negative form of a jaw (2, 3) and of the bone anchor (5, 9) previously implanted in the jaw (2, 3) is produced,  - A head portion (27) of the model anchor (26) corresponding to the position of a head portion (6, 12) of the implanted bone anchor (5, 9) is positioned relative to the female mold and  - The jaw model is molded from the negative mold and connected to the positioned model anchor (26). 7. The method according to claim 6, characterized in that the jaw model is molded by pouring the negative mold, wherein a shaft (28) of the model anchor (26) is at least partially poured into the jaw model. 8. The method according to claim 6 or 7, characterized in that prior to the preparation of the negative mold, a Abformkappe (32) on the head part (6, 12) of the bone anchor (5, 9) is fixed, that the Abformkappe (32) in the manufacture of the Negative form is connected to the negative shape of the jaw (2, 3) and that the Head part (27) of the model anchor (26) before the impression of the Jaw model by fixation on the impression cap (32) is positioned. 9. The method according to any one of claims 6 to 8, characterized in that the negative mold is produced from an impression compound, in particular alginate or silicone. 10. The method according to any one of claims 6 to 9, characterized characterized in that the jaw model is molded in the form of a plaster cast. 11. The method according to claim 5, characterized in that the jaw model by digital impression, in particular with an intraoral and / or extraoral scanner and / or a digital volume tomographs, as a digital jaw model with a prepared digital model of the bone anchor integrated into the digital jaw model. 12. The method according to claim 11, characterized in that the digital jaw model is printed together with the digital model of the bone anchor. 13. Method of adjusting an orthodontic Apparatus, whereby first a Kiefermodell after one of the Claims 5 to 12 is produced, characterized in that then a mounting cap (36) of a to be adapted apparatus with the head part (27) of the model anchor (26) is connected and the apparatus is adapted to the jaw model.