A mandibular protrusion splint includes a maxillary splint part and a mandibular splint part, each of which have a laterally attached joint pin, and joint rods which couple the splint parts together in a movable manner. Each joint pin comprises a shoulder facing the splint part, a head facing away from the splint part, and a neck arranged between the shoulder and the head. The shoulder and head cross sections are larger than a neck cross section. Each joint pin holds a joint rod. The joint rods have a collar at each end. Each collar surrounds the neck in a mounted state. The collar(s) and/or the head(s) have a flexibility which, upon an excessive application of a laterally directed force exerted via a joint rod, allows a yielding movement of the joint rod and then allows the collar to slip over the head of the joint pin without being destroyed.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2018/053924, filed on Feb. 16, 2018 and which claims benefit to German Patent Application No. 10 2017 103 722.5, filed on Feb. 23, 2017. The International Application was published in German on Aug. 30, 2018 as WO 2018/153789 A1 under PCT Article 21(2).

FIELD

The present invention relates to a mandibular protrusion splint for positioning the mandible relative to the maxilla of a patient, having a maxillary splint part and a mandibular splint part, wherein two joint rods attached to the sides of the splint parts couple the two splint parts together in a movable manner. For holding the joint rods, the two splint parts have laterally, or temporarily, attached joint pins, which have a shoulder facing the splint part, a head facing away from the splint part, and a neck located between the shoulder and head, having a smaller diameter. The joint rods each have at their ends a collar which surrounds the neck of a joint pin in the mounted state, wherein the joint rod is held, via the collar, between the shoulder and the head, which each have a larger cross section than the neck.

BACKGROUND

Such mandibular protrusion splints are used for the therapy of obstructive sleep apnea (OSA). By appropriate positioning of the mandible, they prevent a pathological limitation, caused by OSA, of the respiratory function during sleep. Such two-part mandibular protrusion splints having a settable therapy position—or protrusion—have been known for some time. The mechanical coupling between the maxillary splint part and the mandibular splint part is in this case implemented differently while maintaining the desired therapy position.

The two splint parts are connected together via connecting elements, which are in the form of joint rods, wherein the geometry and the mounting of the joint rods determine the degree of protrusion and have a decisive influence on the range of the possible movements of the mandible. Known mandibular protrusion splints also allow a certain range of movement for the lateral movement of the mandible, but this only corresponds to a part of the anatomically possible range of movement of the mandible. Since the actual range of movement of the mandible is greater than the range of movement allowed by the mandibular protrusion splint, high mechanical loads on the splint parts and on the patient can arise at the limits of the range of movement defined by the protrusion splint. These loads can damage the splint and in the worst case injure the patient.

SUMMARY

An aspect of the present invention is to provide a mandibular protrusion splint which, while having a simple structure and high wearing comfort, affords a great deal of breakage resistance and therefore considerably reduces the risk of injuries.

In an embodiment, the present invention provides a mandibular protrusion splint for positioning a mandible relative to a maxilla of a patient. The mandibular protrusion splint includes a maxillary splint part comprising a joint pin which is laterally attached to the maxillary splint part, a mandibular splint part comprising a joint pin which is laterally attached to the mandibular splint part, and joint rods configured to couple the maxillary splint part and the mandibular splint part together in a movable manner. The joint pin of the mandibular protrusion splint comprises a shoulder facing the maxillary splint part, a head facing away from the maxillary splint part, and a neck arranged between the shoulder and head, a cross section of each of the shoulder and the head being larger than a cross section of the neck. The joint pin of the mandibular protrusion splint comprises a shoulder facing the mandibular splint part, a head facing away from the mandibular splint part, and a neck arranged between the shoulder and head, a cross section of each of the shoulder and the head being larger than a cross section of the neck. Each joint pin is configured to hold one of the joint rods. The joint rods each comprise a collar arranged at each of their respective ends. Each collar is configured to surround the neck of one of the joint pins in a mounted state. Each of the joint rods are thereby held between the shoulder and the head. At least one of the collars of the joint rods and the head of the joint pins comprise a designed-in flexibility which, upon an excessive application of a laterally directed force exerted via one of the joint rods, initially allows a yielding movement of the joint rod and then allows the collar to slip over the head of the joint pin without being destroyed.

DETAILED DESCRIPTION

A key aspect of the present invention resides in a designed-in flexibility in the collar of the joint rod and/or designed-in flexibility in the head of the joint pin, which, upon excessive lateral force application, results in one of the components yielding so that, in an extreme case, the joint rod can disengage with its collar passing over the head of the joint pin without being destroyed. This function is in particular supported by a special shaping of the head of the joint pin and/or by the choice of the material thereof. Excessive lateral force application is in particular understood as meaning those forces which would cause conventional protrusion splints to be destroyed and which are caused by movements, which, as overstretched movements, lie at the limits of what is anatomically possible.

The present invention provides for a quasi two-stage yielding to be realized, wherein the joint rod is guided over the joint pin so that, in the event of lateral force application, it first of all escapes from the path of movement of the other splint part in a reversible yielding movement. Upon the application of further force beyond the end of the reversible yielding movement, the joint rod disengages over the head of the joint pin without being destroyed via the collar widening somewhat and slipping over the head of the joint pin and/or in that a part of the head yields, in particular in the region of the rear head, on account of its material or shape.

The stages are also dependent on the individual adaptation of the protrusion splint to the patient's anatomy. The splint parts thereby ideally move on a horizontal surface that is defined via the contact faces of the splint parts. Depending on the anatomy, the splint parts can tilt out of the plane in the event of extreme movements. When such a tilting occurs, the overload can ultimately no longer be prevented by a yielding movement of the joint rod since the latter, in spite of the yielding movement, is still in the range of movement of the other splint part. The overload in such extreme cases is relieved by the disengagement of the joint rod, thereby avoiding the destruction of the protrusion splint.

In an embodiment of the mandibular protrusion splint according to the present invention, the mechanical coupling can, for example, be implemented via two joint rods that act as connecting elements, one on each side. Each joint rod is assigned a receiving element in the form of an in particular integrally formed joint pin on the maxillary and the mandibular splint part.

The joint pins keep the joint rods movably in position. They are subdivided into three parts, namely, the head, the neck, and the shoulder. The shoulder and the neck can, for example, be configured in a rotationally symmetric manner with respect to the axis of the joint pin, wherein the shoulder forms the transition from the neck to the splint part. The neck is the central part of the joint pin, which forms the actual receptacle for the joint rod, wherein the mounted joint rod encloses the neck with a collar formed at its end. The neck of the joint pin is followed toward the outside by the head, which, upon normal use of the protrusion splint, prevents the joint rod from slipping off the joint pin. The joint rod has, at each end, a collar in the form of a cutout therefor, through which the joint pin projects in the mounted state. The collar advantageously forms a clearance in the form of a slot. The diameter of the cutout in the collar is dimensioned so that, in the starting state, it is less than the diameter of the head of the joint pin, thereby preventing any disengagement without expansion of the collar of the joint rod.

The flexibility according to the present invention advantageously results from the material, or material pairing, from which the parts of the protrusion splint are manufactured. The flexibility is supported by the shaping of the joint pin inasmuch as sliding and bearing faces are created that initially cause the joint rod to tilt and then the collar to slowly expand. In an embodiment of the present invention, the two splint parts with the joint pins integrally formed thereon can in this case be manufactured, for example, from a material that is harder than that of the joint rod, in particular from plastic, for example, from PMMA. The splint parts are ideally manufactured in a manner personalized to the patient and rest immovably on the teeth of the jaw. The two joint rods attached laterally by the joint pins can, for example, be manufactured from a less hard material than the splint parts, advantageously also from a plastic, for example, a polyamide. The claimed flexibility thus resides in the joint rod, the collar of which widens to a certain degree upon excessive loading so that the joint pin can disengage. The shape of the joint pin additionally provides that the joint rod can carry out the yielding movement along the joint pin in that the rounded shape at the transition from neck to head guides the joint rod and does not block it.

Excessive loading arises when a jaw movement of the patient in particular exceeds the lateral limits of the range of movement defined by the mandibular protrusion splint. While either the joint pin or the joint rod would break in such a situation in known protrusion splints, such overloading for the protrusion splint according to the present invention merely results in a yielding movement of the joint rod out of the range of movement or in reversible decoupling of the joint pin and joint rod.

The configuration according to the present invention or as a result of the specific geometry of the splint parts with their joint pins and the connecting elements in the form of joint rods, with which the two splint parts are connected, results in overloading being reversibly dampened, and the protective mechanism according to the present invention protects the protrusion splint from being destroyed, and thus the patient from being injured, in the event of an overload.

In an embodiment of the present invention, the head of the joint pin is, for example, not formed in a rotationally symmetric manner. The asymmetric head of the joint pin ideally has a raised front head and a flat rear head so that a sort of hook shape is produced. The flat rear head in this case faces the respectively other splint part. The advantages of the geometry of the joint pin according to the present invention reside in the resultant behavior of the entire connecting mechanism of the protrusion splint upon lateral loading caused by a sideways movement of the mandible executed by the patient. According to the present invention, the loading to the patient anatomy, which results, for example, in tooth loosening or damage to the mandibular joints and/or to the chewing muscles, can be avoided. A defect in the protrusion splint caused by a collision between the splint parts and the connecting element as a result of a yielding movement of the connecting element can also be reduced and thus overloading prevented.

The mandibular protrusion splint according to the present invention is described in greater detail below under reference toFIGS. 1-6.

FIG. 1shows a mandibular protrusion splint, which is worn between the toothed maxilla1and the toothed mandible4of a patient. Both the maxillary splint part2and the mandibular splint part3are molded in a manner personalized to the patient's teeth. The maxillary splint part2is connected to the mandibular splint part3in a movable manner only via two laterally attached joint rods5and6(only the ends of which are shown forFIG. 6). The length of the joint rods5and6is used to set the protrusion of the mandible inasmuch as the mandible is prevented from moving backward by the joint rods5and6. In order to hold the joint rods5and6, the two splint parts have laterally, or temporarily, integrally formed joint pins7, which pass into the collars8, provided in the joint rods5, in the form of slots. As a result of the slots, the two splint parts2and3are in particular able to move in a sagittal direction.

FIG. 2shows an individual joint rod5having a solid central part and having collars8that are provided at the ends which are formed as slots. The joint rod5is molded in one piece from a polyamide and dimensioned so that the collars8have a degree of flexibility in the direction of the arrows A. The opening of the slot can accordingly widen reversibly when the collar slips over the flat rear head of the joint pin.

FIG. 3shows a section through a joint pin7, which is integrally formed on the splint part (not illustrated) via a shoulder10. Facing away from the splint part, the joint pin7has a head11so that a neck12is formed between the shoulder10and head11, the neck12having a smaller diameter than the shoulder10and head11with respect to an axis13. As is apparent, the head11of the joint pin7is asymmetric and forms a protruding front head14and a flat rear head15. As can be seen fromFIGS. 4-6, the flat rear head15faces the respectively other splint part—in this case the maxillary splint part2. As is likewise apparent fromFIGS. 3-6, the contacting faces of the joint pin7and of the collar8of the joint rod5are formed as edge-free sliding faces.

In the mounted state, the collar8surrounds the neck12of a joint pin, wherein the joint rod5is held between the shoulder10and the head11, which each have a larger cross section than the neck12.

The manner in which the joint rod is mounted according to the present invention on the joint pin can be described as follows with reference toFIGS. 4-6.

Since the mandibular protrusion splint has a design that is personalized to the patient, the position of the joint pins7on the corresponding splint parts differs from patient to patient. Depending on the situation, it may become necessary to position the joint pin7at different heights on the outer edge of the splint parts.

FIG. 4shows the situation in which the patient moves their toothed maxilla1excessively to the side in the direction of the arrow B and the opposite maxillary splint part2passes into the trajectory of the joint rod5so that the maxillary splint part2collides with the joint rod5at the point16.

If the toothed maxilla1continues to move in this direction (arrow B), as inFIG. 5, in spite of the collision, the particular design of the transition from the shoulder10to the asymmetric head11via the neck12causes the joint rod5to tilt and one side of the collar8at first to bear against the shoulder10on the side of the projecting front head14, while the other side of the collar8butts against the flat rear head15. The joint rod5thus moves out of the direction of movement of the other splint part, thereby avoiding an overload. If the other splint part moves back again (counter to arrow B), the joint rod5straightens up; the function of the protrusion splint is not further impaired.

In this case, the inclination movement is realized by the asymmetrically designed head11, in particular by the flat portion of the transition from neck12to head11, wherein the flat portion, and thus the flat rear head15, of the joint pins is located in each case on the side facing the opposite splint. Compared to the center of the neck12, the flat rear head15is, however, elevated so that the distance of the outer edge of the flat rear head15from the axis of the opposite splint part is greater than the size of the radius of the neck12. This elevation consequently has a larger cross section than the collar8, and so, in the event of a continued inclination movement of the joint rod5, a reversible mechanical expansion of the collar8occurs, which results in a damping effect on the force exerted by the opposite jaw.

If the loading by the opposite splint part, caused, for example, by tilting out of the horizontal plane of the protrusion plane, exceeds the mechanical deformation, as inFIG. 6, so that it is greater than the force brought about by the plastic deformation of the joint rod5, at the highest point of the flat rear head15, the joint rod5moves over the head11of the joint pin7, thereby preventing damage to the splint part or injury to the patient. The maxillary splint part2is thereby decoupled from the mandibular splint part3, at least on this side.

The two aspects, namely, the possible yielding movement of the joint rod equipped with a flexible collar out of the trajectory of the opposite splint including the undamaged return movement of the joint rod into the original orientation and the lifting of the joint rod off the joint pin in the event of an overload without damaging the protrusion splint or injuring the patient, distinguish the solution of the present invention from previously described mandibular protrusion splints.