This application claims the benefit of European Patent Application EP11382340.5 filed on 8 Nov. 2011, which is hereby incorporated in its entirety by reference.
The present invention relates to a base for an orthodontic appliance. It further relates to an orthodontic appliance comprising such a base.
Many different orthodontic appliances are known to correct malocclusions, such as e.g. crowns, bridges, brackets, distalizers and retainers. Some of these appliances may in use be attached to the surface of a tooth or various teeth in order to correct the orientation or position of one or more teeth. Depending on their function they may be attached on the lingual or labial surface of an incisor, canine, premolar or molar.
Examples of orthodontic appliances that may be attached to teeth include of course the well known brackets, but also e.g. distalizers such as known from e.g. US 2006/018833, and also e.g. buccal tubes, molar tubes, lingual buttons and others.
For their attachment to a tooth or various teeth, an orthodontic appliance may comprise one or more base surfaces which may be adapted to fit to a particular tooth or one of a plurality of teeth. This base surface may be substantially flat or may be concave to adapt to the specific tooth it needs to be attached to.
Before attachment, the surface of the tooth may be cleaned, possibly etched and subsequently dried. Then, an adhesive may be applied to the surface of the tooth. It is known to use an adhesive which may be activated using light. The orthodontic appliance, possibly also comprising an adhesive on its base surface may then be attached to the surface of the tooth. After activation of the adhesive using e.g. light, the orthodontic appliance may be firmly fixed to the tooth. Different types of adhesives may be used, such as e.g. composite resins or glass ionomer cement. This process is also referred to as “bonding”, or, depending on the adhesive used “cement bonding”.
The orthodontic appliance may stay bonded to a tooth by chemical bonding forces and/or mechanical retention forces. Depending on the base of the orthodontic appliance, specifically its shape and material, chemical bonding or mechanical retention may be dominant. For example, metallic appliances generally have limited chemical bonding. They rely mostly on mechanical retention. In this context, it is known to provide a base surface with a certain roughness or a plurality of protrusions that are adapted to retain the appliance on the tooth in a mesial-distal direction and a lingual-labial direction.
However, there still exists a need to provide an orthodontic appliance which in use is attached to a surface of a tooth that provides good mechanical retention in the lingual-labial direction, the mesial-distal direction, and the mandible-maxilla direction (up and down) and is easy to manufacture.
According to a first aspect, an orthodontic appliance is provided that comprises a base surface adapted to be attached to a tooth and a plurality of protrusions protruding from said base surface and extending in a first direction substantially from a first edge of the base surface to a second edge of the base surface. A second direction may be defined as perpendicular to said base surface, and a third direction may be defined as perpendicular to said first and said second direction. In this aspect, the distance (as measured along the third direction) between two of said protrusions in a plane substantially perpendicular to said first direction along at least a portion of said protrusions is smaller than the distance (as measured along the third direction) between said two protrusions at the base surface. Furthermore, the distance (as measured along the third direction) between two of said protrusions in any plane substantially perpendicular to said second direction at said first edge and said second edge is larger than the distance between said two protrusions in the same plane at a point between said first and said second edge.
In this aspect, an orthodontic appliance is provided that due to the shape of the protrusions provides mechanical retention once attached to the teeth in three directions. Firstly due to the arrangement of various protrusions extending in a first direction (e.g. up-down) next to each other, mechanical retention is provided in the mesial-distal direction. Due to the shape of the protrusions, mechanical retention may be provided both in the lingual-labial direction and the mandible-maxilla direction (i.e. up-down). Furthermore, due to the distance between the protrusions being at least as large at the edges than at a more central portion, the appliance may be easily manufactured using e.g. injection moulding or micro-injection moulding. However, it should be noted that embodiments of the present invention may also be manufactured using machining techniques such as e.g. milling.
As noted before, the base surface may be concave in e.g. the first and/or third direction. As such, the first direction and/or third direction may be curved. Thus, the vector representing the first, third and second direction may change from point to point on such a concave surface. Herein, the first, second and third direction are to be understood as the directions determined locally from a point on the base surface.
In some embodiments, all protrusions may be substantially identical. In other embodiments, the protrusions do not necessarily all need to be the same.
In some embodiments, one or more of the protrusions along its length has a linearly varying cross-section in planes substantially perpendicular to said first direction. In particular, the width may vary linearly along the length of the protrusion. These embodiments may be relatively easily manufactured. Alternatively, one or more of the protrusions along its length has a non-linearly varying cross-section in planes substantially perpendicular to said first direction.
In some embodiments, said protrusions have the widest cross-section in planes substantially perpendicular to said first direction substantially midway between said first and said second edge. In these cases, two negative moulds may be used for manufacturing. The split between these moulds may be substantially midway between the first and second edge. In alternative embodiments, the split between two negative moulds does not need to be midway between the first and second edge. If the distance between the protrusions is substantially larger at the edges than at a central portion, the moulds may be easily retracted after moulding.
In some embodiments, one or more of said protrusions have a dovetail cross-section in planes substantially perpendicular to said first direction. The dovetail cross-section is well known in the field, may be easily manufactured and provides good mechanical retention. In some other embodiments, one or more of said protrusions have a bulged cross-section in planes substantially perpendicular to said first direction. In yet other embodiments, the protrusions may comprise locally increased widths at one or more heights.
In some embodiments, the orthodontic appliance may be metallic. However, in other embodiments, polymers may be used. For example, the use of e.g. polysulfones is well known in the field. In yet further embodiments, ceramics may be used or fibre-reinforced composites. Regardless of the material used, the shape and arrangement of the protrusions may ensure sufficient bonding to the teeth.
In a further aspect, a bracket with a base such as substantially hereinbefore described is provided. The base may be manufactured integrally with the bracket, or may be manufactured separately and subsequently attached to a main body of a bracket.
In another aspect, a distalizer comprising a base such as substantially hereinbefore described is provided. In other implementations, other auxiliary orthodontic elements comprising such a base may be provided, such as e.g. buccal tubes, molar tubes and lingual buttons.
In yet another aspect, a base for an orthodontic appliance is provided that comprises a first flat surface for attachment to the main body of an orthodontic appliance and further comprising a base surface adapted to be attached to a tooth. A plurality of protrusions protrude from said base surface and extend substantially from a first edge of the base surface to a second edge of the base surface along a first direction. A second direction may be defined as perpendicular to said base surface, and a third direction may be defined as perpendicular to said first and said second direction. In accordance with this aspect, the distance (as measured along the third direction) between two of said protrusions in a plane substantially perpendicular to said first direction along at least a portion of said protrusions is smaller than the distance between said two protrusions at the base surface, and the distance between two of said protrusions in any plane substantially perpendicular to said second direction at said first edge and said second edge is larger than the distance between said two protrusions in the same plane at a point between said first and said second edge.
In yet a further aspect, an orthodontic appliance is provided that comprises a base surface with protrusions that are arranged and shaped such that three-dimensional mechanical retention is provided.
Additional objects, advantages and features of embodiments of the invention will become apparent to those skilled in the art upon examination of the description, or may be learned by practice of the invention.
Particular embodiments of the present invention will be described in the following by way of non-limiting examples, with reference to the appended drawings, in which:
Such a bracket may be firmly attached to a tooth using well known techniques employing adhesives. In order to increase the retention on the tooth, a certain roughness may be provided on the base surface. As the adhesive is spread in between the ridges and recesses of such a rough surface, the mechanical retention may be improved.
In the example shown, a large plurality of small bumps 12′ is provided in order to enhance the mechanical retention of the bracket on a tooth.
The protrusions extend in a first direction 1 (x-direction) from a first edge 13 to a second edge 14 of the base. The x-direction may correspond to the up-down direction when fitted on a tooth 40. A second direction 2 may be defined as perpendicular to the base surface. This direction corresponds to the z-direction shown in
The length of the protrusion may be defined as the dimension of the protrusion in the first direction. Its height may be defined as its dimension in the second direction, and its width may be defined as its dimension in the third direction.
In this case, the minimum distance between two neighbouring protrusions is reached at the top of the protrusion. It should be noted however that this does not necessarily need to be the case in order to provide mechanical retention in the second direction.
It may be seen in
In this example, between the point (or rather, plane) of minimum distance and the edge of maximum distance between protrusions, the width of the protrusions varies linearly.
The orthodontic appliance with such a base may be manufactured easily using e.g. injection moulding or micro-injection moulding. To this end, two negative moulds (or, two halves of a mould) 16 and 18 that meet each other substantially at a plane located midpoint between the first and second edge may be used. Since in this example, such a midpoint corresponds to the point at which the distance between two neighbouring protrusions is minimum, and the distance increases towards the edges, the two moulds may be retracted in the first direction.
Although in the example shown the first direction corresponds to the up-down direction, this first direction may be varied within the scope of the present disclosure. For example, the first direction could be the mesial-distal direction. The second direction in this case would be the lingual-labial direction and the third direction would be the up-down direction.
Since the distance between protrusions from a minimum increases towards the edges, the moulds that may be used for manufacturing may also be easily retracted towards the edges. Even though portions of substantially constant width (and constant distance between protrusions) are shown, in practice these portions may be very slightly angled to facilitate retraction of the moulds.
A further possible cross-section in a plane perpendicular to said first direction may be seen in
A further embodiment is shown in
It will be clear that further alternative cross-sections may be chosen for the protrusion in order to comply with the prerequisite of mechanical retention in the z-direction.
Although only a number of particular embodiments and examples of the invention have been disclosed herein, it will be understood by those skilled in the art that other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof are possible. Furthermore, the present invention covers all possible combinations of the particular embodiments described. Thus, the scope of the present invention should not be limited by particular embodiments, but should be determined only by a fair reading of the claims that follow.
Number | Date | Country | Kind |
---|---|---|---|
11382340 | Nov 2011 | EP | regional |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2012/072124 | 11/8/2012 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2013/068456 | 5/16/2013 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3975824 | Lee | Aug 1976 | A |
4604057 | Viglietti | Aug 1986 | A |
D290040 | Kelly | May 1987 | S |
4676746 | Klapper | Jun 1987 | A |
4936773 | Kawaguchi | Jun 1990 | A |
5071344 | Wong | Dec 1991 | A |
5095602 | Reher | Mar 1992 | A |
5267854 | Schmitt | Dec 1993 | A |
5295823 | Farzin-Nia | Mar 1994 | A |
5441408 | Moschik | Aug 1995 | A |
D373638 | Colbert | Sep 1996 | S |
5616026 | Cash | Apr 1997 | A |
5681165 | Feldman | Oct 1997 | A |
5711665 | Adam | Jan 1998 | A |
5820371 | Forster | Oct 1998 | A |
6190165 | Andreiko | Feb 2001 | B1 |
6444167 | Shimodaira | Sep 2002 | B1 |
6464494 | Young | Oct 2002 | B1 |
7845941 | Minium | Dec 2010 | B2 |
8251696 | Rodriguez | Aug 2012 | B2 |
20050069833 | Chikami | Mar 2005 | A1 |
20060263736 | Moon | Nov 2006 | A1 |
20070166658 | Voudouris | Jul 2007 | A1 |
20080138756 | Lim | Jun 2008 | A1 |
20080160474 | Wolf | Jul 2008 | A1 |
20090117512 | Minium | May 2009 | A1 |
20090325117 | Cervera Sabater | Dec 2009 | A1 |
20100285421 | Heiser | Nov 2010 | A1 |
20110086323 | Wessinger | Apr 2011 | A1 |
20110189623 | Moon | Aug 2011 | A1 |
20110195371 | Hirsch | Aug 2011 | A1 |
20120315593 | Ramos-de-la-Pena | Dec 2012 | A1 |
20130236847 | Shin | Sep 2013 | A1 |
20150037747 | Choi | Feb 2015 | A1 |
20160000530 | Hagelganz | Jan 2016 | A1 |
Number | Date | Country |
---|---|---|
44 34 209 | Mar 1996 | DE |
WO 2009094685 | Aug 2009 | WO |
Entry |
---|
International Search Report for PCT/EP2012/072124, mailed Feb. 27, 2013, 13 pgs. |
Number | Date | Country | |
---|---|---|---|
20140302450 A1 | Oct 2014 | US |