Apparatus and method for preventing tooth grinding in patients wearing braces

The present invention provides an apparatus and method for preventing grinding of the upper and lower teeth of a person wearing braces. The apparatus provides a bite guard adapted to prevent grinding of the teeth of a person wearing braces, the bite guard comprising a U-shaped base having a first surface, a second surface, a U-shaped inner side, and a U-shaped outer side, and a width at least as wide as the person's teeth, and a plurality of flexible hooks attached to the outer side and projecting at a first selected angle relative to a direction normal to the first surface. The method provides a way for preventing dental grinding of occlusal surfaces of a patient wearing braces, the method comprising positioning a bite guard between the occlusal surfaces of the patient's upper and lower teeth, and attaching the insert to the patient's braces on the upper or lower teeth.

FIELD OF THE INVENTION
 This invention relates to an apparatus and method for preventing teeth from
 grinding together, and in particular to an apparatus and method for
 preventing teeth from grinding together in patients wearing braces.
 BACKGROUND
 Grinding between a patient's upper and lower teeth can present a serious
 dental health problem. Often caused by stress, and usually occurring at
 night, grinding teeth result from tightly clenched jaw muscles, which
 force together the occlusal surfaces of the upper and lower teeth. In
 addition to the clenching action, the jaw muscles cause the upper and
 lower teeth to move relative to each other while they are being forced
 into contact, thus causing grinding. This grinding can cause serious
 damage to a person's teeth. In the short term, the constant grinding can
 wear enamel off tooth surfaces. Over a long period of time, the grinding
 can wear through the enamel and into the tooth pulp, causing more serious
 damage. Moreover, the clenched muscles that cause the grinding can, when
 chronic, lead to more serious conditions such as temporal mandibular joint
 (TMJ) disorder.
 Presently, the only method for preventing teeth from grinding together is
 to prevent the occlusal surfaces of the teeth from contacting one another.
 This is usually accomplished by inserting a "bite guard" between the
 occlusal surfaces of the upper and lower teeth. Bite guards are also known
 as night guards, occlusal splints, bruxism splints, TMJ/TMD splints, and
 gnathological splints. Bite guards are usually custom-fitted devices made
 by taking a mold of the person's upper or lower teeth and manufacturing a
 device which closely conforms to, and fits over, the teeth. Since they are
 tight-fitting, bite guards stay in place by snapping onto the contours of
 the teeth.
 Although they do a good job of addressing the problem of tooth grinding,
 presently available bite guards have an important limitation: they cannot
 be worn by persons who are wearing braces. Mostly, this is because the
 hardware associated with braces (brackets, bands and archwires) are
 cemented to the teeth, thus preventing the bite guard from conforming to,
 or attaching to, the contours of the teeth. Even if they could be used
 with braces, present bite guards are undesirable for use with braces
 because of their close fit, which would prevent the tooth movement the
 braces are designed to cause. Thus, persons wearing braces who are having
 problems with tooth grinding are left without recourse. For these reasons,
 there is a need in the art for a bite guard that is compatible with
 braces.
 SUMMARY OF THE INVENTION
 The present invention provides an apparatus and method for preventing
 grinding of the upper and lower teeth of a person wearing braces. The
 apparatus provides a bite guard adapted to prevent grinding of the teeth
 of a person wearing braces, the bite guard comprising a U-shaped base
 having a first surface, a second surface, a U-shaped inner side, and a
 U-shaped outer side, and a width at least as wide as the person's teeth,
 and a plurality of flexible hooks attached to the outer side and
 projecting at a first selected angle relative to a direction normal to the
 first surface. The method provides a way for preventing dental grinding of
 occlusal surfaces of a patient wearing braces, the method comprising
 positioning a bite guard between the occlusal surfaces of the patient's
 upper and lower teeth, and attaching the insert to the patient's braces on
 the upper or lower teeth.

DETAILED DESCRIPTION OF THE INVENTION
 Described below is an embodiment of the present invention. The embodiment
 illustrates ways in which the present invention can be implemented. In the
 description that follows, like numerals represent like elements in all
 figures. For example, where the numeral 10 is used to refer to a
 particular element in one figure, the numeral 10 appearing in any other
 figure refers to the same element.
 FIG. 1 illustrates an embodiment of the inventive bite guard. The bite
 guard 10 comprises a generally U-shaped base 12 and a plurality of hooks
 14 and 16 which are adapted to attach the bite guard 10 to the arch wires
 of the braces, thus securing the bite guard along the occlusal plane
 between the patient's upper and lower teeth. The bite guard 10 also
 includes a plurality of flanges 18 and 20 extending from the base 12;
 these flanges help prevent the bite guard 10 from becoming dislodged due
 to lateral or anterior-posterior grinding of the patient's teeth. The
 entire bite guard 10 may be made of any material softer than tooth enamel,
 but is preferably made of a soft rubber for flexibility and patient
 comfort. Both the hooks 14 and 16 and the flanges 18 and 20 are integrally
 molded into the base.
 The base 12 is typically contained in a single plane (i.e., flat) and has a
 first surface 22, a second surface 24, an inner (lingual) side 26 and an
 outer (labial) side 28. When the bite guard is attached to braces on the
 patient's lower teeth, the first surface 22 wi0 ll be a lower surface in
 contact with the occlusal surfaces of the lower teeth, and the second
 surface 24 will be an upper surface in contact with the occlusal surfaces
 of the upper teeth. When the bite guard is attached to braces on the
 patient's upper teeth, the reverse is true: the first surface 22 is an
 upper surface and the second surface 24 is a lower surface. The base need
 not be flat, though; it may have some contouring to adapt to the shape of
 the patient's teeth.
 FIG. 2 illustrates the shape of the base and the arrangement on the base of
 the plurality of hooks 14 and 16 and the plurality of flanges 18 and 20.
 The shape of the base 12 is designed so that the base will fit along the
 occlusal locus of the person's teeth. The occlusal locus is a generally
 U-shaped curve resulting from connecting the occlusal surfaces of the
 person's teeth, i.e., all points at which the upper teeth contact the
 lower teeth. The width of the base, which is the distance between the
 inner (lingual) side 26 and the outer (labial) side 28, is at least as
 wide as the person's teeth.
 The generally U-shaped base 12 comprises a vertex portion 30 and a couple
 of straight lateral portions 32. The hooks are attached to the base along
 the outer (labial) side 28. preferably, the hooks are arranged as shown,
 with a front hook 14 at the vertex of the base, and a pair of lateral
 hooks 16 located along the straight lateral portions of the base. The
 flanges comprise a front flange 18 and a pair of lateral flanges 20
 attached to the base along the inner (lingual) side 26 of the base.
 Preferably, the flanges are positioned on the inner (lingual) side
 directly opposite where the hooks are attached to the outer (labial) side,
 with the front flange 18 at the vertex 30 of the base and the lateral
 flanges along the straight lateral portions 32 of the base.
 FIG. 3 illustrates the positions of the hooks 14 and 16 and the flanges 18
 and 20. The hooks are attached to the base along the outer (labial) side
 28 and project from the base at a selected angle .beta. relative to a
 direction approximately normal to the base, i.e., relative to the normal
 vector N. The front hook 14 and lateral hooks 16 need not have the same
 angle .beta.; the front hook 14 may have a different value of .beta. than
 the lateral hooks 16, and each lateral hook 16 may have its own different
 value for .beta.. The angle .beta. is preferably about 27 degrees, but may
 range between about 0 degrees and about 45 degrees. It may be desirable to
 build the bite guard 10 such that the angle .beta. has a small positive
 value. That way, when the hook is bent inwardly to attach to the arch wire
 of the braces, a small reactive moment will be induced in the hook, which
 will secure the hooks 14 and 16 to the arch wires. The hooks 14 and 16
 have a height h measured from the first surface. The height h is slightly
 less than the distance between the occlusal surface of the tooth and the
 arch wire of the braces. Since the hooks 14 and 16 are made of a flexible
 material, they can be stretched until they attach to the braces. This
 stretching induces tensile loads in the hooks, which then help keep the
 bite guard firmly in place in the patient's mouth.
 The front flange 18 and lateral flanges 20 are similarly attached to the
 base along the inner (lingual) side 26 and project from the base at a
 selected angle .phi. relative to the normal vector N. The flanges 18 and
 20 need not have the same angle .phi.; the front flange 18 may have a
 different value of .phi. than the lateral flanges 20, and each lateral
 flange 20 may have its own different value for .phi.. The angle .phi. is
 preferably about 27 degrees but may vary between about 0 degrees and about
 45 degrees.
 FIG. 4 illustrates the use of the bite guard 10. The bite guard 10 is
 simply inserted between the patient's upper and lower teeth such that the
 occlusal surfaces of the teeth are in contact with the base, i.e., such
 that the bite guard rests on the occlusal plane. The bite guard 10 must be
 inserted in the desired orientation, with the hooks 14 and 16 positioned
 upward or downward, depending on whether they will be attached to braces
 on the upper or lower teeth. Once correctly positioned, the hooks are
 attached to the arch wires of the braces and the installation is complete.
 The bite guard 10 a single piece created by injection molding of the
 desired soft, rubber-like material. A mold is created having the desired
 shape and size, and the material is injected into the mold and allowed to
 set.
 An embodiment of the present invention has been described above. A person
 skilled in the art, however, will recognize that many other embodiments
 are possible within the scope of the invention. For this reason, the scope
 of the invention is not to be determined from the description of the
 embodiment, but must instead be determined solely from the following
 claims.