The present invention relates to an orthopaedic device for protraction of the maxillary arc.

In particular, the present invention relates to a device adapted to apply a posteroanterior traction to the upper dental arc.

Currently, two devices suitable to perform this traction are known. A first one of these is known as Delaire mask and the second one is known as Petit mask.

The Delaire mask consists of a device that comprises two resting elements, a front one, shaped to act on the forehead of the patient, and the second chin one, shaped to act on the chin of the patient.

This device comprises two supports, each of which connects the front and chin resting elements so that when the mask is worn, if the patient is viewed from the front, the supports are arranged at the outer sides of the face of the patient.

A transverse element is fixed to the supports and connects them in a bridge-like fashion.

This transverse element is normally adjustable in its position along the supports.

The Delaire mask also comprises an anchorage element, which can be fixed to the dental arc to be treated, and elastic elements which can be fixed to the anchorage element in two symmetrical positions, which generally correspond to an intermediate position between the canine and the lateral incisor of the patient, and to the transverse element in two correspondingly symmetrical positions.

The elastic elements are chosen and sized so as to apply a predefined traction force to the dental arc, generally equal to 450 gf each, in two positions which are adjustable and not necessarily symmetrical.

The Petit mask differs from the Delaire mask in that it does not have two lateral supports but a single central support which, when the mask is in use, passes above the nose of the patient, connecting the chin support to the front support, which are each arranged at the center of the chin and of the forehead respectively.

In both of the described masks, the supports and the transverse element are rigid in order to allow to obtain the traction force described by means of the choice of elastic elements having adapted characteristics as a function of the contingent treatment requirements.

One drawback of these known devices is that the traction force applied by the elastic elements to the dental arc to be treated is balanced by a constraining reaction that is also applied by the chin support.

Said support, during use, therefore applies to the mandible of the patient an anteroposterior thrust which is discharged onto the temporomandibular joint, stressing it, and in cases with instability of the articular disc, as often occurs in subjects with high ligament laxity, causing disc-condyle miscoordination, with slippage of the mandibular condyle to a more rearward position.

In other words, the desired effect of deformation of the upper dental arc is partially thwarted by an unwanted and harmful retraction of the mandible, due to loss of the correct configuration of the temporomandibular joint.

Another type of traditional mask, which does not have a chin support, is the Baptiste mask, which discharges the reaction force onto the lower molars, subjecting them to an intense and potentially harmful thrust.

This mask has not become widespread because it limits the patient in speaking and in opening his mouth.

A further type of known mask is the Grummos mask, which is a variation of the Delaire mask in which the chin support is replaced by a zygomatic support. This structure is scarcely used, since it applies simultaneously two forces of opposite direction to the same bone: an anteroposterior force on the upper part of the maxillary bone, which in subjects in which this bone is underdeveloped has a concave profile at the level of the zygomatic-nasal region, whereas in the lower part of the maxillary bone it applies a posteroanterior force.

The problem underlying the present invention is therefore to avoid said harmful effects on the mandibular joint in case of treatment with orthodontic masks.

The aim of the present invention is to provide an orthopaedic device that solves this problem, solving the drawbacks of the orthopaedic device that were described above.

Within this aim, an object of the present invention is to propose an orthopaedic device for the protraction of the maxillary arc that allows to avoid stressing the mandible of the user.

Another object of the present invention is to provide an orthopaedic device for the protraction of the maxillary arc that is more compact and less bulky than the traditional masks described above, for an equal therapeutic action performed.

Another object of the invention is to propose an orthopaedic device for the protraction of the maxillary arc that allows to adjust the tension applied, during use, to the dental arc of the patient.

This aim, as well as these and other objects that will become better apparent hereinafter, are achieved by an orthopaedic device according to the accompanying claim 1 .

Detail characteristics of an orthopaedic device according to the invention are given in the corresponding dependent claims.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of an orthopaedic device according to the invention, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

Figure 1 is a schematic lateral elevation view of an orthopaedic device according to the present invention applied to the head of a patient;

Figure 2 is a schematic front view of the orthopaedic device of Figure l ;

Figure 3 is a perspective view of a variation of the orthopaedic device of Figures 1 and 2;

Figure 4 is a schematic view of the detail of the orthopaedic device of Figure 3;

Figure 5 is a perspective view of a variation of the orthopaedic device of Figure 3.

With particular reference to the cited figures, the reference numeral

10 generally designates an orthopaedic device for the protraction of the maxillary arc, comprising:

- an anchorage element 1 1 , which can be coupled to an upper dental arc of a patient to be treated;

- elastic elements 12a and 12b, which can be fixed to the anchorage element 1 1 in order to apply a traction thereto.

According to the present invention, the orthopaedic device 10 has a particularity in that it comprises:

- a cranial anchorage 13, which is configured to be fitted and fixed on the head 100 of the patient;

- traction means 14, which can be fixed to the elastic elements 12a and 12b and to the cranial anchorage 13 and comprising elastically resilient means 15.

The traction means 14 are configured so that when the orthopaedic device 10 is in use, the elastically resilient means 15 are deformed elastically, with respect to their inactive configuration, for example shown in broken lines in Figure 1 , in order to apply a traction force to the elastic elements 12a and 12b.

The cranial anchorage 13 is configured to be fixed to the head 100 of the user so as to maintain its own position thereon during use, balancing the force that the traction means 14 apply thereto as a reaction to said traction stress.

Preferably, the orthopaedic device 10 is configured so that when it is in use a traction force is applied to the dental arc to which the anchorage element 1 1 is coupled, wherein said traction force derives from the combined elastic deformation of the elastic elements 12a and 12b and of the elastically resilient means 15.

In this manner, the traction force is not obtained by virtue of the elastic means alone, as in the background art, but by the combined action thereof with the elastically resilient means 15.

In this manner modulation of the traction force is simpler and more effective.

The cranial anchorage 13 advantageously comprises a front portion 13a, which is adapted to rest, during use, on the forehead of the patient.

The traction means 14 advantageously have a part that is fixed to the front portion 13a of the cranial anchorage 13 so as to protrude from it frontally with respect to the face of the patient when the orthopaedic device 10 is in use, as shown for example in Figure 1 in broken lines.

The traction means 14 are preferably provided with a coupling portion 16 that is adapted to be engaged with the elastic elements 12a and 12b.

The elastically resilient means 15 are shaped so as to deform elastically so as to assume an active configuration in which, when the orthopaedic device 10 is in use, the coupling portion 16 is in a position that faces the mouth of the patient, in order to engage the elastic elements 12a and 12b with the coupling portion 16, as exemplified in Figure 1 in solid lines.

The traction means 14 comprise at least one wire-like element which is extended between the front portion 13a and the coupling portion 16 and has at least one intermediate part 14a, which is elastically flexible and forms the elastically resilient means 15.

In other words, with reference to the embodiment of Figures 1 and 2, the traction means are composed of a wire or a bundle or weave of wires, the intermediate part 14a of which defines the elastically resilient means 15.

In general, the wire-like element is preferably U-shaped, so as to have two lateral branches joined by a central portion.

The lateral branches are elastically flexible and the central portion is contoured so as to engage thereon the elastic elements 12a and 12b or is equipped with means for engaging thereon the elastic elements 12a and 12b.

The branches preferably have a free end which is fixed to a supporting element that can be fixed to the front portion 13a of the cranial anchorage 13.

As an alternative, the wire-like element can be shaped as in Figure 2, so as to pass over the nose of the user and not laterally to the eyes.

The wire-like element advantageously comprises a shape memory alloy wire preferably based on titanium and/or molybdenum.

Figures 3 and 4 are views of a variation of the embodiment described above, for which only the aspects of differentiation are described hereinafter.

In this embodiment, the traction means 1 14 advantageously are deformable along a substantially rectilinear active direction A between an inactive position and at least one active position, which is exemplified in Figure 4 in solid lines and in which the elastically resilient means 1 15 are deformed and apply, along the active direction A, a return force which tends to return the traction means 14 to the inactive position, shown in broken lines in Figure 4.

The traction means 14 advantageously comprise two telescopic elements 1 16, in which the elastically resilient means 1 15 act in order to extend them.

The telescopic elements 1 16 are advantageously arranged on opposite sides of the cranial anchorage 13, so that when the orthopaedic device 10 is in use the telescopic elements 1 16 are each arranged on one side of the head 100 of the user and protrude in front of the user's face with a front end 1 16a, having a rear end 1 16b that is fixed to the cranial anchorage 13.

A transverse element 1 17 is preferably connected to both of the front ends 1 16a of the telescopic elements 1 16 and to the elastic elements 12a and 12b.

When the orthopaedic device 10 is in use, the telescopic elements 1 16 are contracted in contrast with an elastic force that is applied by the elastically resilient means 15, which preferably comprise or consist of helical traction springs, and is transmitted by the elastic elements 12a and 12b to the dental arc of the patient, along a posteroanterior vector V with respect to the mandible of the user.

Clearly, the two embodiments described above can be combined easily for a person skilled in the art, who can for example provide the variation described above with the elastically resilient means 15 by connecting them for example to the supporting element or directly to the telescopic elements 1 16.

This combination is particularly preferable due to its solidity and precision in the direction of the traction action which, during use, the orthopaedic device applies to the upper dental arc of the patient.

In order to achieve good stability, the cranial anchorage preferably comprises a band to be fixed around the head and a ribbon-like portion to be passed under the chin or over the skullcap. Preferably, in the embodiment of Figures 1 and 2, the cranial anchorage comprises a structural band 13b that is arranged so that during use it is extended from the forehead to the nape of the patient, in order to give stability to the device.

With particular reference to Figure 5, a variation of the embodiment of Figure 3 is illustrated therein which differs from this one only due to the fact that it comprises structural elements 1 18 that connects the front ends 1 16a of the telescopic elements 1 16 to the cranial anchorage in order to direct precisely the posteroanterior stress applied by the elastic elements 12a and 12b.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the protective scope of the appended claims.

All the details may furthermore be replaced with other technically equivalent elements.

For example, the telescopic elements can be replaced with non- extensible elements of preset length.

In this manner, only the elastic elements are deformed elastically and said non-extensible elements will apply thereto, by means of the transverse element, a constraining reaction.

In this case it is also possible to provide the structural elements of the embodiment shown by way of example in Figure 5 in order to make the overall structure more stable.

In general, the cranial anchorage preferably comprises an under-chin band, i.e., a band which is extended so as to pass, during use, below the chin of the patient.

This allows in particular to control mandibular post-rotation.

A general advantage of a device according to the present invention is to reduce the mandibular post-rotation effect, which is not desirable in hyper-divergent subjects.

In practice, the materials used, as well as the contingent shapes and dimensions, may be changed according to the contingent requirements and the state of the art.

The disclosures in Italian Patent Application no. 102015000076771 (UB2015A005872), from which this application claims priority, are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.