NL1040398C2

NL1040398C2 - Dental device.

Info

Publication number: NL1040398C2
Application number: NL1040398A
Authority: NL
Inventors: Masoud Ghavamikia
Original assignee: Masoud Ghavamikia
Priority date: 2013-09-19
Filing date: 2013-09-19
Publication date: 2015-03-23

Description

Dental device

Technical field

This invention relates to a dental device for holding a matrix band, the matrix band comprising, when hold, a central loop and overlapping mid sections adjacent to the loop, which device comprises a first wall enclosing a first passage configured to allow the matrix band to pass therethrough upon forming the loop, which first wall comprises a first main surface facing the loop when the matrix band is hold.

Background of the invention

Matrix bands are thin metallic or plastic strips that are flexible and are used by dental practitioners when filling a cavity in a tooth. They can be bent around the tooth being treated to retain the filling material until it is hardened. Devices for holding a matrix band are used to hold, and potentially tighten, a central loop, formed by the matrix band, around the tooth such that this loop follows the contour of the tooth as much as possible to allow the filling material to be hardened corresponding to the contour of the tooth. More specifically, the contact between the matrix band and the tooth area close to the gums should be sufficient to prevent filling material to escape through a gap between the matrix band and the tooth before it is hardened. In general matrix bands are positioned by first forming a cylindrical loop and second tightening the loop around the tooth. Because teeth are not cylindrical but rather trapezoidal often wedges are used in close proximity to the gums to fill the gap between the matrix band and the tooth. Positioning a matrix band using wedges is troublesome for the dental practitioner because he or she has to work with the fingers of both hands in the patient's mouth making it difficult to monitor the procedure and making the patient less comfortable.

To overcome the problems described above, several dental devices for holding a matrix band around a tooth have been described. These devices produce a central loop having a peripheral portion of the loop, situated at one side of the principal plane of the loop, having a larger diameter compared to the opposite peripheral portion.

In GB608107 such a dental device is described. In order to adjust the form of the loop to the inclined, trapezoidal, shape of tooth surfaces this device is provided with a clip which fits around, and holds together, overlapping mid sections of the matrix band adjacent to the loop. The clip can be tilted so as to cause the loop to adopt a generally conical shape. The clip can be tilted in opposite directions to accommodate usage of the clamp with the loop at the left side of the clamp body, or, when turned over, with the loop at the right side. Use of this device is inconvenient, because the clip has to be held manually in its tilted position.

In W02010061161 a device is described comprising a deflector member being movable transversely with respect to the device, such that it bears respectively against opposite peripheral portions of the mid sections of the matrix band adjacent to the loop. Due to these moving parts production of this device, more specifically assembly of the components, is relatively complicated and therefore expensive. Furthermore, additional moving parts increase the risk of malfunction.

An object of the present invention is to provide a dental device for holding a matrix band in a way that the central loop formed by the matrix band has one peripheral portion at one side of the principal plane of the loop having a larger diameter compared to the opposite peripheral portion, that overcomes the drawbacks described above.

Summary of the invention

The invention provides a dental device for holding a matrix band, the matrix band comprising, when hold, a central loop and overlapping mid sections adjacent to the loop, which device comprises a first wall enclosing a first passage configured to allow the matrix band to pass therethrough upon forming the loop, which first wall comprises a first main surface facing the loop when the matrix band is hold, where the device further comprises a guiding element configured to position the mid sections relative to the first main surface, such that a first angle, a1, between the principal plane of the loop, when the matrix band is hold, and the first main surface is 70-85 degrees.

Due to the fact that the first angle, a1, between the principal plane of the loop and the first main surface is 70-85 degrees, the loop formed is not cylindrical but has a lateral inclined portion, adjoining the first main surface. Using a dental device according to the invention, the matrix band can be hold around a tooth such that the narrowed side of the loop is able to clamp the tooth adjacent to the gingival line without having to plug the gingival margin with one or more wedges.

The term "tooth" as used herein, is referring to teeth of humans and of animals. In case of human teeth the term includes incisors, canines, premolars and molars. In practice a matrix band is predominantly used for human teeth and especially for premolars and molars.

The term "guiding element" as used herein, is referring to an element that contacts the matrix band, its mid sections or its end sections, in such a manner that the mid sections are positioned as described above.

When treating human molars or premolars it is preferred that the first angle is 78 degrees because of the anatomical form of the tooth.

To prevent the first main surface from contacting the tooth, it is preferred that the passage is a narrow slot. Preferably, the slot has a length somewhat greater than the matrix band width and a breadth that is sufficient to insert the end sections of the matrix band through the passage without difficulty, to allow forming of a loop.

This device allows forming of a loop having one peripheral portion at one side of the principal plane of the loop having a larger diameter compared to the opposite peripheral portion, without the requirement of additional moving parts. Only the orientation of the guiding element with respect to the first wall, more specifically the first main surface facing the loop, as described above, is sufficient and allows the production costs to be minimized and the devices to be produced for single use. On the other hand, because of its smooth design, the possibility of cleaning and/or sterilizing these dental devices is provided.

The guiding element is contacting the matrix band, for example at one of the outer surface portions of the overlapping mid sections or at one of the outer surface portions of the overlapping end sections of the matrix band, when the matrix band is hold by the device. The guiding element can be any component of the device having the effect that the mid sections are in the position as described above.

Preferably, the guiding element comprises a first guiding surface, where the plane of the guiding surface is tilted relative to the plane of the first wall at a second angle, a2, of 5-20 degrees. When treating human molars or premolars it is preferred that the second angle is 12 degrees as a consequence of the specific anatomical form of the tooth.

In one exemplary embodiment, the device further comprises holding means configured to engage overlapping end sections of the matrix band, and tensioning means configured to move the holding means relative to the first passage to tighten or loosen the matrix band around the tooth, where the holding means form the guiding element.

In this exemplary embodiment the dental device can be used to hold the matrix band as well as to tighten the loop around a tooth. The holding means function to hold the end sections of the matrix band and to position the mid sections as described above.

Examples of tensioning means are known from the art and usually comprise outer sections provided with inner screw thread and inner sections provided with corresponding outer screw thread, where rotating the outer sections will result in movement of the inner section according to the direction of the screw thread. Preferably, the end sections of the matrix band are provided with apertures and the holding means comprise engaging means, for example a protrusion, able to engage with the apertures. Also the apertures and holding means are known from the art.

Preferably, the holding means comprise a surface forming the guiding surface as described above.

When the loop is tightened around the tooth, first a substantial contact force between the loop area having a smaller diameter and the section of the tooth adjacent to the gums will occur and the contact force in this area will be higher compared to the contact force between the loop area having a larger diameter and the tooth area away from the gums.

Preferably, the device is made as a relatively inexpensive plastics moulding and the entire device, including the matrix band, is intended to be discarded and replaced after use.

Preferably, the device comprises an oblong body having a head section and an longitudinally extending body section and, and the first wall is located at a first lateral area of the head section, allowing the loop to be formed at a first lateral side of the head section.

An advantage of such embodiment is that the head section can be placed at one side of the tooth while the dental practitioner still has a sight on the tooth and on the loop tightened around the tooth. The dental practioner can hold the device between the tooth and either the vestibular (cheek) side, which is preferred, or the palatal or lingual (tongue) side, while tightening the loop around the tooth.

Preferably the holding means and tensioning means in this exemplary embodiment are situated in the longitudinally extending body section. Preferably, the tensioning means can be operated via one end of the longitudinally extending body section opposite to the head section, making it easier for the dental practioner to tighten the matrix band around the tooth or to loosen the matrix band. In other words, the dental practioner can execute the procedure using the matrix band having his or her hands mainly outside the patient's mouth. Also the patient will profit, because only a small device is inserted in his or her mouth.

In an exemplary embodiment, the head section comprises a second wall the second wall being a wall of a second lateral area of the head section opposing the first lateral area, where the second wall encloses a second passage, configured to allow the matrix band to pass therethrough upon forming the loop a second side of the head section, which second wall comprises a second main surface facing the loop when the matrix band is hold, where the guiding element is configured to position the mid sections relative to the second main surface, such that a third angle, a3 (not shown in the figures) between the principal plane of the loop, when the loop is formed at the second side of the head section, and the second main surface is 70-85 degrees.

When treating human molars or premolars it is preferred that the third angle is 78 degrees.

In this exemplary embodiment, the head section can approach every tooth in each quadrant of the mouth from the vestibular side.

Preferably, a cross section of the head section at the first passage and second passage is substantially symmetrical and wedgeshaped, and the guiding element is configured to position the main plane of the overlapping mid sections such that this is substantially coinciding with the symmetry plane of the cross section.

This allows a simple design of the head section, allowing a small sized cross section, and will therefore result in a greater degree of comfort to the patient.

Having such a symmetrical design, only one guiding element is needed to position the mid sections relative to the first main surface as well as relative to the second main surface, allowing a loop to be formed at either the first lateral side or the second lateral side. Preferably, only one surface of the guiding element, being the guiding surface as described above, is needed.

In another exemplary embodiment the first wall has a cross section that is tapered at a fourth angle, a4, of 5 - 20 degrees and a first wall portion, being opposite to a second wall portion comprising the first main surface, forms the guiding element Preferably, the first wall portion comprises a surface that forms the guiding surface as described above.

By having this tapered form the first wall itself can hold the mid sections in a tilted orientation with respect to the first main surface of the first wall, such that a first angle, a1, between the principal plane of the loop, when the matrix band is hold, and the first main surface is 70-85 degrees. The advantage of such tapered first wall is its simple design.

Brief description of the drawings

The invention will be exemplified in greater detail with reference to the accompanying figures, wherein

Figure 1 is a perspective view on a matrix band having the form as if hold by the dental device according to the invention;

Figure 2 is a perspective view on the head section of a first exemplary embodiment of a device according to the invention, and a loop of the matrix band hold by this device;

Figure 3 is a cross-sectional view taken along the lines of A-A of Fig. 2;

Figure 4 is a cross-sectional view taken along the lines of B-B of Fig. 2;

Figure 5 is a perspective view on a exemplary embodiment of a device according to the invention showing a large loop;

Figure 5 is a perspective view on a exemplary embodiment of a device according to the invention showing a smaller loop;

Figure 6 is a cross section of the head section having a tapered first wall and second wall.

Detailed description of the invention

In the following, three exemplary embodiments of the device according the present invention will be described in detail with reference to the attached drawings. It is to be noted that the embodiments described hereinafter are merely intended to illustrate the present invention and are not to be construed as limiting the scope thereof.

Fig. 1 shows the matrix band (2) having the form as if hold by the dental device according to the invention, showing the loop (3), the overlapping mid sections (4) and the overlapping end sections (11), which end sections (11) comprise apertures (18) to allow the holding means to engage these end sections (11).

The head section (15), shown in Fig. 2, comprises a first wall (5a) enclosing a first passage (6a). The ends of the head section are rounded on behalf of comfort to the patient, but the cross section of the head section at or near the passages (6a, 6b) is wedgeshaped, see also fig. 3 and fig. 4. As a result, the diameter of the upper part of the loop (3), in this drawing, has a larger diameter compared to the lower part, which is useful when tightening the loop (3) around a tooth. In the loop orientation shown here, a tooth present in a lower quadrant of the mouth can be treated. The first passage (6a) is a narrow slot having a length somewhat greater than the matrix band width and a breadth that is sufficient to insert the end sections of the matrix band through the passage without difficulty, to allow forming of a loop. Using each one of the exemplary embodiments illustrated by the drawings, the loop can be formed and the matrix band can be hold, using the steps of, manually folding a matrix band by arranging the end sections of one side of the matrix band against each other, inserting the end sections into one of the two passages (6a or 6b), and coupling the end sections to the holding means. Fig. 3 and 4 clearly show the lateral inclined portion of the loop (3), adjoining the first main surface (9a), where the first angle, a1, between the first main surface (9a) and the principal plane (19) of the loop (3), is 78 degrees. The specific feature of the first exemplary embodiment is the guiding element (8) which is formed by a clamping element of the holding means (not shown). Fig. 3 and 4 clearly show the symmetrical form of the head section (15), comprising a first passage (6a) and a second passage (6b) enclosed in a first wall (5a) and second wall (5b), respectively. The guiding element (8) is oriented such that, irrespective of the end section being inserted in the first passage (6a) or second passage (6b), a first angle, a1, between the principal plane (19) of the resulting loop (3) and the first main surface (9a) or second main surface (9b), respectively, at the first lateral side (17a) or second lateral side (17b), respectively, is 78 degrees.

The specific feature of the second exemplary embodiment, shown in Fig. 5 and 6, comprises holding means (10) that form the guiding element having a guiding surface (10), where the plane of the guiding surface (10) is tilted relative to the plane of the first wall (5a). These holding means comprise a protrusion (21) to allow engagement of the apertures in the end sections Except for these holding means this second exemplary embodiment is similar to the first exemplary embodiment. The dental device (1) comprises an oblong body (13) having a head section (15) and an longitudinally extending body section (14). Because of the symmetric form of the head section (15) the plane of the guiding surface (10) is tilted relative to the plane of the first wall (5a) and that of the second wall (5b), both at a second angle, a2, of 12 degrees. In Fig. 5 and 6, the function of the tensioning means (12) is illustrated schematically. In Fig. 5, the loop (3) has a large diameter. The loop (3) shown in Fig. 6 has a diameter that is smaller due to movement of the holding means, in a direction along the longitudinal axis of the oblong body (13), away from the passage (6a). This movement is driven by rotation of a rotation element (20).

Fig. 7 shows the third exemplary embodiment of a dental device according to the invention, of which the specific feature is that a first wall (5a) and a second wall (5b) have a cross section that is tapered at a fourth angle, a4, of 12 degrees. The first wall portion (22), being opposite to a second wall portion (23) comprising the first main surface (9a), forms the guiding element (8). Here, the surface being opposite to the first main surface (9a), forms the guiding surface (10). Except for this tapered walls, this dental can have the same features as described for the first and second exemplary embodiment.

Claims

A dental instrument (1) for holding a matrix band (2), wherein, when held, the matrix band (2) comprises a central loop (3) and intermediate portions (4) extending adjacent to the loop (3), which device comprises: - a first wall (5a) enclosing a first passage (6a) configured to allow the matrix band (2) to pass therethrough to form the loop (3), which first wall (5a) comprises a first main surface (9a) facing the loop (3) when the matrix band (2) is held, characterized in that the device further comprises - a guide element (8) configured to position the middle parts such that relative to the first major surface (9a) that a first angle, a1, between the major surface (19) of the loop when the matrix band is held, and the first major surface (9a) is 70-85 degrees.

Dental instrument (1) according to claim 1, characterized in that the guide element (8) comprises a guide surface (10), the surface of the guide surface (10) being inclined at a second angle, a2, of 5-20 degrees relative to the plane of the first wall (5a).

Dental instrument (1) according to claim 2, characterized in that the device further comprises holding means (7) which are configured for engaging the mutually extending end sections (11) of the matrix band (2), and tensioning means (12) which are configured to move the holding means (7) relative to the first passage for tightening or loosening the matrix band around the tooth or molar, the holding means (7) forming the guide element (8).

Dental instrument (1) according to one of claims 1-3, characterized in that it comprises an elongated body (13) with a longitudinally extending body part (14) and a main part (15), and the first wall ( 5a) is located at a first lateral region (16a) of the main part (15), thereby allowing the loop (3) to be formed at a first lateral side (17a) of the main part (15).

Dental instrument (1) according to claim 4, characterized in that the main part (15) comprises a second wall (5b), the second wall (5b) being a wall of a second wall remote from the first lateral region (16a) lateral region (15b) of the main part (15), where the second wall (5b) encloses a second passage (6b) that is configured to allow the matrix band (2) to pass through to form the loop (3) on a second side (17b) of the main part (15), which second wall (5b) comprises a second main surface (9b) facing the loop (3) when the matrix band (2) is held, wherein the guide element (8) is configured to position the center portions with respect to the second main surface (9b) such that a third angle, a3, between the main surface (19) of the loop when the loop (3) is at the second side of the main part (15) is formed, and the second main surface is 70-85 degrees.

Dental instrument (1) according to claim 5, characterized in that a cross-section of the main part (15) at the first passage (6a) and second passage (6b) is substantially symmetrical and wedge-shaped, and the guide element (8) is configured to position the main surface of the central parts (4) extending along each other such that it substantially coincides with the plane of symmetry of the cross-section.

Dental instrument (1) according to claim 2, characterized in that the first wall (5a) has a cross-section that tapers into a third angle, a3, of 5-20 degrees, and a first wall part (22), which is remote from a second wall part (23) comprising the first main surface (9a) forming the guide element (8).