A mouthguard comprises a member formed of a resilient material and having an approximately U-shape corresponding generally to the shape of the arch of the upper jaw. The member includes a bottom wall designed to engage the lower teeth and spaced side walls or flanges extending upwardly therefrom and forming a cavity for receiving the upper teeth. Laterally the bottom wall comprises an approximately planar surface of sufficient width to extend laterally the full width of the lower teeth and engage both the buccal and the lingual cusps of the lower teeth. The bottom wall is formed to include a portion of greater thickness in the molar-bicuspid region, and a portion of maximum thickness in the region engaging the lower first molar. As the jaw closes, the jaw tends to pivot about the lower first molar, causing a slightly increased separation between the condyle of the mandible and the temporal bone and minimizing any damage caused by force transmitted in the temporomandibular joint area.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to mouthguards and particularly to mouthguards 
adapted for minimizing shock to the teeth and head area. 
2. Description of the Prior Art 
There are a number of different types of mouthguards presently available on 
the market but they have deficiencies which prevent their giving optimum 
protection to the wearer against serious injuries to the teeth and 
particularly to the head and neck area. 
For example, many mouthguards consist simply of U-shaped trough-like 
members of resilient material, such as rubber or suitable plastic, shaped 
to fit over the upper or lower teeth or both. In the case of many such 
mouthguards, a blow to the lower jaw may result in one or more teeth 
penetrating through the mouthguard structure and, more importantly, such 
mouthguards provide little, if any, protection against head and neck 
injuries. 
One prior art mouthguard is formed to provide a bottom wall which increases 
in thickness from the posterior to the anterior area, this increase in 
thickness being such as to conform to the normal angle of approach of the 
upper and lower jaws in the act of closing the mouth and thereby to ensure 
engagement of the mouthguard by the incisors of the lower jaw 
simultaneously with the molars thereof. Because of the construction and 
hinging of the lower jaw, the movement of the forward portion thereof 
relative to the rear portion during opening and closing of the mouth is 
approximately a three-to-one ratio. This prior art structure is apparently 
intended to have a gradually increasing thickness toward the forward 
portion so as to correspond generally to this ratio and to thereby provide 
an even distribution of contact over all the teeth. As will be explained 
later in describing the invention of the present application, this even 
distribution of contact cannot accomplish the beneficial results of the 
applicant's invention. 
Another prior art structure involves a mouthpiece with a triangular-shaped 
ridge depending from the lower wall thereof in the molar-bicuspid area. In 
this structure, the depending ridge has a relatively sharp edge which is 
intended to engage the lower teeth in the central area between the buccal 
and lingual cusps, that is, in the fossa of the lower teeth. In the case 
of this structure, as the triangular ridge is compressed as a result of a 
blow to the lower jaw, it spreads somewhat against the sides of the cusps, 
creating an undesirable lateral force. Moreover, in the case of many 
individuals, the teeth are not in direct line and the straight edge of the 
ridge in that case would engage not the fossa but the inner or outer 
inclined walls of the cusps, depending on the direction of misalignment of 
each individual tooth, again creating undesirable lateral force and 
defeating the purpose of the mouthguard. 
Normally, the head of the condyle of the mandible articulates with a 
cartilagenous disk or movable cartilagenous pad in the temporomandibular 
joint, and it is this pad which glides between the condylar head of the 
mandible and the articular surface of the glenoid fossa of the temporal 
bone. In wearing conventional mouthguards, the athlete is not only subject 
to potential damage to the teeth but, more importantly, to damage 
resulting from direct transmittal of force through the mandible, the thin 
layer of cartilage, and into the temporal bone and the cranial cavity. 
Substantial increases in intracranial pressure and cranial bone 
deformation have been shown to occur when a football player, for example, 
receives a blow on the chin or on the faceguard of the protective helmet. 
This results in a measurable deformation of the skull. Similar damage 
occurs in other contact sports, such as, boxing, hockey, soccer, lacrosse, 
etc. Because of the use of protective helmets with faceguards for 
intercepting horizontal blows, the principal injuries to football players 
in the head area result from upward blows to the lower jaw, especially the 
chin area, and upward blows to the faceguard which transmit force to the 
jaw through the chin strap. 
By the present invention these limitations and deficiencies of the prior 
art mouthguards have been overcome and not only is protection provided 
against damage to the teeth, but the mouthguard is constructed so as to 
provide an increased separation between the mandible and the glenoid fossa 
and to slightly increase this separation in the case of a blow to the chin 
or faceguard and thereby to avoid transmission of damaging force from the 
condyle of the mandible to the temporal bone and the cranium. 
Accordingly, it is a primary object of the present invention to provide a 
protective mouthguard designed to provide an orthopedic placement of the 
mandible relative to the cranium and, more specifically, relative to the 
glenoid fossa of the temporal bone with which it articulates. 
It is a further object of this invention to provide not only a cushioning 
against upward forces but also to provide a pivoting action about a 
fulcrum point in the molar area to cause a slight rocking shock absorption 
motion. 
It is a further object of this invention to minimize stresses to the 
incisor teeth and to provide for easier breathing and speaking while 
wearing the mouthguard. 
It is still another object of this invention to provide a mouthguard which 
functions effectively despite irregularities in the upper dental arch and 
in the plane of occlusion between the upper and lower jaws and teeth. 
It is still a further object of this invention to provide a mouthguard in a 
limited number of sizes which are suitable for fitting substantially all 
mouth sizes and teeth characteristics and which may be fitted by the 
athlete without the necessity of custom-fitting by a dentist. 
It is another object of this invention to provide a mouthguard which may be 
standardized in a limited number of sizes for commercial production and 
economically produced. 
It is a further object of this invention to provide a mouthguard which will 
protect the temporomandibular joint against trauma. 
SUMMARY OF THE INVENTION 
In carrying out this invention, in one form thereof, the mouthguard 
comprises a member formed of a resilient material and having an 
approximately U-shape corresponding generally to the shape of the arch of 
the upper jaw. The member includes a bottom wall designed to engage the 
lower teeth and spaced side walls or flanges extending upwardly therefrom 
and forming a cavity for receiving the upper teeth. Laterally the bottom 
wall comprises an approximately planar surface of sufficient width to 
extend laterally the full width of the lower teeth and engage both the 
buccal and the lingual cusps of the lower teeth. The bottom wall is formed 
to include a portion of greater thickness in the molar-bicuspid region, 
and more particularly in the region generally extending from the second 
molar through the first bicuspid. The lower surface of this thicker 
portion is shaped to follow approximately the normal dental Curve of Spee 
found between the upper and lower dental arches. Not only is a greater 
thickness of cushioning material present between opposing sets of teeth in 
the molar-bicuspid region to give a better cushioning effect, but the 
mouthguard of this invention is constructed with a portion of maximum 
thickness in the region which engages the lower first molar so that the 
mouthguard initially engages the lower teeth in this region. Thus, as the 
jaw closes further, the jaw tends to pivot about this fulcrum point, 
thereby causing a slightly increased separation between the condyle of the 
mandible and the temporal bone and minimizing any damage caused by force 
transmitted in the temporomandibular joint area. Further, because of this 
portion of increased thickness and the location of the pivot point, a blow 
on the chin tends to increase the separation at the temporomandibular 
joint, thereby further minimizing transmission of force to this joint and 
to the cranial area. 
The anterior portion of the mouthguard is recessed or offset superiorly to 
minimize stresses to the incisor teeth (which, being single-rooted, are 
more prone to fracture), to allow freer pivotal action and to provide for 
easier breathing and speaking when the mouthguard is being worn. The 
anterior portion of the mouthguard may include a depending element adapted 
to engage the lower incisor teeth when the mouthguard is being fitted to 
the teeth, this depending element being thereafter snipped off. 
The mouthguard is intended to be provided in two forms. In one form it 
would be custom-fitted to the wearer by a dentist. In the other form, 
which is designed to be fitted by the user, a somewhat softer material 
would be provided in the cavity of the mouthguard and the user could 
install the mouthguard over the upper teeth so as to cause the upper teeth 
to be impressed into this softer material.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIG. 1, there is shown a representation of a human head 
10 with a conventional football helmet 12 thereon. The helmet includes a 
protective cage or faceguard 14 for protecting the facial area and a chin 
strap 16 for holding the helmet in place. Despite the protective aspects 
of the conventional helmet, a blow to the chin or to the chin strap area 
or an upward blow to the faceguard is still capable of causing significant 
damage, not only to the teeth, but to the cranial area indicated generally 
at 18. 
The nature of the potential damage associated with such blows to the chin 
or faceguard area can be better appreciated by reference to FIG. 2. This 
figure illustrates the temporomandibular joint 19 formed between the 
condyle 20 of the mandible or lower jaw 22 and the temporal bone 24, the 
movement at the lower jaw being controlled by muscles shown generally at 
25. A cartilagenous disk or pad 26 is disposed between the condyle and the 
glenoid fossa 28 of the temporal bone. The head of the condyle 20 
articulates with the cartilagenous disk or pad 26 in the temporomandibular 
joint and the cartilagenous disk or pad 26 glides between the condylar 
head of the mandible and the articular surface of the glenoid fossa of the 
temporal bone. With conventional mouthguards, the components of the 
temporomandibular joint are positioned as shown in FIG. 2. Under these 
circumstances a blow to the chin or upward blow to the faceguard causes a 
transmission of force in the direction of the arrow 30 into the 
temporomandibular joint and through the temporal bone into the cranial 
area, as generally indicated by the arrows 31. This not only causes 
potential damage to the joint itself but the force is transmitted to the 
cranium resulting in potential deformation in the cranial area indicated 
at 18 and damage to the brain, for example, concussion. 
The mouthguard of this invention, as described in detail below, tends to 
cause a separation of the condyle 20 of the mandible relative to the 
temporal bone 24 as illustrated in FIG. 3. When a blow is received to the 
chin or faceguard with the mouthguard of this invention in place, any 
force in the direction of the arrow 30 has a significantly less damaging 
effect on the temporomandibular joint 19. Moreover, the separation of the 
bony parts of the temporomandibular joint, namely the condyle of the 
mandible and the temporal bone, prevents a damaging shock wave from being 
transmitted through the temporomandibular joint 19 to the brain and other 
underlying structures in the cranial area. Further, as will be explained 
in detail below, because of the construction of the mouthguard of this 
invention, such a blow tends to cause a greater rather than lesser 
separation at the temporomandibular joint 19 and thereby further reduces 
the potential damage. 
Referring now to FIG. 4, there is shown an illustration of a portion of a 
human head 10 with sections broken away to illustrate the teeth and 
temporomandibular joint area. The dashed line 32 shown in FIG. 4 indicates 
the Curve of Spee which is a line generally extending between the upper 
and lower dental arches. The relationship of the components of the 
temporomandibular joint 19 shown in FIG. 4 correspond to those shown in 
enlarged form in FIG. 2. 
Turning now to FIG. 5, there is shown a view similar to FIG. 4 but with the 
mouthguard 34 of this invention shown superimposed on the upper teeth. The 
mouthguard 34 has a bottom wall of increased thickness in the region 
indicated at 36. Specifically, this greater thickness is in the region 
extending from the second molar 38 through the first bicuspid 40 and 
including the first molar 42 and the second bicuspid 44, that is, the 
portion of greater thickness extends in an anterior-posterior direction. 
Viewed laterally, the thickness is constant, that is, whatever the 
thickness is in a given tooth area, it is the same from the buccal side of 
the mouthguard to the lingual side. The lower surface 45 of the thicker 
portion 36 of the bottom wall 48 is shaped to follow approximately the 
Curve of Spee, but the bottom wall has its maximum thickness in the area 
positioned to contact the lower first molar. As shown in FIG. 5, as the 
jaw closes to the position there illustrated, the mouthguard initially 
contacts the lower teeth generally in the area of the lower first molar, 
as indicated by the numeral 46, and the lower jaw tends to pivot about 
this area 46 as the mouth is closed. It can be seen by reference to FIG. 5 
that with this mouthguard construction, when the lower jaw has almost 
reached its closed position, the aforementioned pivoting effect has 
resulted in a slight separation in the area of the temporomandibular joint 
19. This separation is shown in greater detail in the enlarged view of 
FIG. 3. 
The mouthguard 34 of this invention is shown in greater detail in FIGS. 6, 
7 and 8. Referring now to these figures, the mouthguard 34 is formed in an 
approximately U-shape corresponding generally to the shape of the dental 
arch of the upper jaw. The mouthguard 34 has a substantially U-shaped 
cross section and includes a bottom wall 48, an inner or lingual flange 50 
extending upwardly from the bottom wall, and an outer or buccal flange 52 
also extending upwardly from the bottom wall. The inner and outer flanges 
50 and 52, respectively, are intended to conform generally to the lingual 
and buccal areas, respectively, of the upper teeth and gums, and each of 
the flanges end in a rounded edge 53 approximating the gingival tissues. 
The flanges 50 and 52 are connected at their posterior ends by transverse 
flanges 54. The buccal flange 52 is notched downwardly, as indicated at 
55, to provide space for the superior labial frenum. The bottom wall 48 is 
generally flat in a lateral direction and is of greater width than the 
width of the lower teeth so as to extend fully across the surface of the 
lower teeth and slightly beyond these teeth on both the lingual side and 
the buccal side. This insures that the bottom wall engages both the 
lingual and buccal cusps of the molars and bicuspids. Moreover, the bottom 
wall is of such width as to contact the lower teeth across both the 
lingual and buccal sides even where there is variation in the width of the 
dental arch, or misalignment, as is often the case, of these lower teeth. 
This can be visualized from FIG. 7. Although this figure shows the 
impressions 56 of the upper teeth in the mouthguard rather than showing 
the lower teeth, the lower teeth are slightly inward of the upper teeth 
(the lingual cusps of the upper molars, for example, normally engage the 
fossa of the lower molars), and it can be visualized from FIG. 7 that the 
lower teeth would fall within the area of the bottom wall 48 of the 
mouthguard. 
The side view of the mouthguard 34 shown in FIG. 8 further illustrates the 
construction of the mouthguard of this invention. As there shown, 
particularly by reference to the dashed line 57 which indicates the inner 
bottom surface of the cavity of the mouthguard, the bottom wall 48 has a 
portion of greater thickness in the region 36 which, as explained in 
connection with FIG. 5, extends from the second molar 38 through the first 
bicuspid 40. Forward of the region 36, the bottom of the mouthguard is 
recessed or offset upwardly, as indicated at 58, so as to provide a space 
59 between the anterior portion of the mouthguard and the lower incisors 
60. As indicated by the dashed line 57, the bottom wall of the mouthguard 
is of reduced thickness in the region 58. This recessed portion 
accomplished several functions. First, it allows a pivoting of the lower 
jaw about the fulcrum area indicated at 46 in FIG. 5 so as to provide a 
slight separation in the temporomandibular joint area. Secondly, it 
minimizes the possibility of damage to the upper incisors 61 and the lower 
incisors 60 in the event of a blow to the chin. Finally, it provides an 
assured breathing area when the mouthguard is in place, making the 
mouthguard more comfortable to wear, and also making it easier to speak 
clearly with the mouthguard in place. 
In order to facilitate correct positioning of the mouthguard, particularly 
where this is done by the user rather than by a dentist or orthodontist, 
the mouthguard includes a positioning tab 62 formed to depend from the 
bottom wall of the mouthguard in the anterior region and positioned to 
engage the lower incisors 60. In order to ensure engagement with the lower 
incisors, the positioning tab is preferably formed in a T-shaped cross 
section as shown. After the mouthguard is properly fitted to the upper 
teeth, the positioning tab 62 is simply snipped off. 
The effectiveness of the mouthguard in minimizing injury will be more clear 
by observing its operation when positioned properly in the mouth about the 
upper teeth, referring primarily to FIGS. 2, 3, 4 and 5. As indicated 
previously the lower surface 45 of the thicker portion 36 of the 
mouthguard is shaped to follow approximately the Curve of Spee, that is, a 
line generally following the line of occlusion between the upper and lower 
teeth, but the bottom wall 48 has its maximum thickness in the area 46 
positioned to contact the lower first molar. When the lower jaw is closed, 
the lower teeth engage the thicker portion 36 of the mouthguard 
approximately at the first molar, as indicated by the numeral 46 in FIG. 
5. Thereafter, as the lower jaw completes its closure, it tends to pivot 
about the fulcrum provided at the area 46, thereby effecting a slight 
separation in the temporomandibular joint, as can best be seen by 
comparing FIGS. 4 and 5 or, on a larger scale, comparing FIGS. 2 and 3. 
Because the bottom wall 48 of the mouthguard is, as described previously, 
relatively flat laterally and of a width sufficient to extend laterally 
beyond the lower teeth both buccally and lingually, the force between the 
mouthguard and the lower teeth is distributed relatively evenly laterally 
over the molars and over the bicuspids and not concentrated on any limited 
area of each of these teeth. In accordance with this invention, however, 
the force is initially not evenly distributed anteriorly and posteriorly 
because of the initial contact at the fulcrum area 46 and the pivoting 
movement about this fulcrum. 
Unlike prior art mouthguards, when an upward blow in the general direction 
of the arrows 63 in FIG. 2 is received on the chin or faceguard of an 
individual using the mouthguard of this invention, because of the 
aforementioned separation in the temporomandibular joint, the force of the 
blow does not result in the transmission of shock waves through the 
temporomandibular joint to the brain and cranial area 18. Because of the 
separation in the temporomandibular joint area, possible damage to the 
temporomandibular joint itself from such a blow is minimized. Moreover, 
because of the pivoting about the area 46, as previously described, a blow 
to the chin also tends to slightly increase the separation in the 
temporomandibular joint, further reducing the transmission of force to and 
through this joint. The thicker material in the region 36 acts as a 
cushion and helps absorb force transmitted in a vertical direction, that 
is, along the long axis of the ramus and condyle of the mandible. Even 
though under a strong upward blow the entire jaw may move upwardly as the 
lower teeth are pressed into and cushioned by the mouthguard, unlike prior 
art structures this upward movement does not result in the transmission of 
damaging force to and through the temporomandibular joint, because the 
aforementioned pivoting action counteracts this upward movement at the 
temporomandibular joint, and the separation between the condyle and the 
temporal bone is slightly increased rather than reduced under the impact 
of the blow. 
It is contemplated that the mouthguard of this invention will be provided 
in two forms. In one form, the mouthguard would be custom-fitted by a 
dentist or orthodontist, utilizing impressions of the upper and lower 
dental arches. In this form the mouthguard would be of unitary 
construction and made of a suitable material compatible with the oral 
tissues, for example a latex rubber or a synthetic plastic material of 
sufficient durability and density to maintain its form and function and 
having sufficient resiliency to provide the necessary cushioning effect. 
This form of the mouthguard would be made to conform to the upper dental 
arch of the prospective user and would include impressions of the upper 
teeth in the inside bottom wall of the mouthguard, as indicated in FIG. 7. 
The mouthguard could subsequently be installed in the correct position by 
the user with the upper teeth fitting in the previously-formed 
depressions. 
The second form of the mouthguard is contemplated to be of the 
"do-it-yourself" variety. In this case, it is contemplated that the 
mouthguard would be made available commercially in three sizes, small, 
medium and large, which should be sufficient to fit, with adequate 
accuracy, essentially all mouths. The selected sizes are based on 
comprehensive studies by the dental profession of jaw and dental arch 
shapes and sizes occurring in a substantial number of individuals 
adequately representative of the population as a whole. In this form of 
the invention, the mouthguard may be made of unitary construction, as in 
the case of the first form just discussed or it may be of double-layered 
construction, including an outer shell of a material having the same 
characteristics as that of the unitary construction and an inner layer 
within the mouthguard made of moldable synthetic plastic material which 
the user would mold to the hard and soft structures of the upper dental 
arch. For example, the outer shell could be preformed of a suitable 
material and an inner layer could be made of a material which can be 
softened adequately by immersing in water at boiling temperature. In this 
case the outer shell is preferably made of a material which retains its 
shape when subjected to water at boiling temperature. The user, having 
selected the mouthguard of the proper size, would soften the inner layer 
by immersing the mouthguard in boiling water for a suitable length of 
time. The user would then fit the mouthguard, with the softened inner 
layer over the upper teeth in the position shown in the drawings and mold 
it against the upper teeth and gums so that these teeth are impressed into 
the softer layer of material forming the inside bottom wall 48. The 
material of the inner layer would then be allowed to cool and set in its 
final form. If desired, the shell could also be formed of a similar 
material which would soften to some degree when subject to boiling water, 
but still retain its shape, so that impressions of the lower teeth could 
also be formed therein during fitting by the user. Thereafter, the 
mouthguard can be installed in the mouth for regular use with the upper 
teeth being received in the formed impressions and with the lower teeth 
received in formed impressions if these are formed during fitting. 
Alternatively, the mouthguard or the inner layer thereof could be formed of 
a material which is in a softened condition and which is caused to set 
after the impression is made by treating it within a proper temperature 
range. Also the inner layer could be made of a material which is soft 
enough to receive a proper impression but which then is caused to harden 
with the impression formed therein, by exposing it to air for a period of 
time. 
When sold in the "do-it-yourself" form, it is contemplated that the 
mouthguard would include the positioning tab 62 to aid the user in 
properly fitting the mouthguard. This tab 62 helps the athlete in properly 
centering the mouthguard during fitting. It also aids the athlete in 
determining how far to close the mouth during fitting, thereby maintaining 
the proper spacing. Thereafter, the tab 62 would be snipped off to leave a 
smooth bottom surface in the anterior area of the mouthguard. The 
positioning tab 62 may also be included in the mouthguard which is 
professionally installed. The material of which the mouthguard is made can 
be cut by scissors, so that any portion which uncomfortably contacts the 
gum or cheek area can easily be cut off by the user. Similarly, any excess 
material of the inner layer can be easily trimmed. 
In one specific embodiment of the mouthguard of this invention, the 
thickness of the bottom wall 48 is approximately 5 millimeters at the 
region 46 which is positioned to be engaged by the lower first molar. The 
portion of the mouthguard bottom wall extending posteriorly from the 
region 46 is approximately 4 millimeters thick and the portion extending 
anteriorly to and including the area of the lower first bicuspid is also 
approximately 4 millimeters thick. The recessed portion at 58 is 
approximately 2 millimeters thick. 
It can be appreciated from the above description of the construction and 
operation of the mouthguard of this invention that it possesses a number 
of particular advantages. It provides a pivoting action in the molar area 
to allow a rocking shock absorption motion of the mandible. It provides a 
thicker pad of soft protective shock-absorbing material in the 
molar-bicuspid area. It provides a construction which automatically 
assures a slight separation in the temporomandibular joint and which 
minimizes both damage to this joint and the transmission of shock waves 
through the joint to the brain area. The upward offset of the mouthguard 
in the anterior area minimizes stresses to the upper and lower incisor 
teeth, allows a freer pivotal action, thereby further minimizing potential 
damage, and provides for easy breathing and speaking. Finally, the 
mouthguard readily adapts itself to irregularities in the occlusion 
between the upper and lower jaws and the upper and lower teeth and to 
asymmetries of the dental arch. 
In addition to the above advantages, experimental results have indicated 
that wearing of the mouthguard of this invention appears to result in an 
increase in strength. Several individuals have found that they can press 
an additional amount of weight and have more endurance when wearing the 
mouthguard of this invention. The applicant has been told by athletes who 
have used the mouthguard of this invention that when they resumed use of 
conventional mouthguards, their front teeth hurt from the pressure, 
presumably because of the absence of the recess of the applicant's 
structure at the anterior portion. 
While a specific form of the mouthguard of this invention has been 
illustrated and described, modifications may be made in the details of the 
structure without departing from the substance of the invention. For 
example, while specific dimensional relationships of a preferred 
embodiment have been set forth, these specific dimensions may be varied to 
some extent so long as a portion of greater thickness is provided in the 
molar-bicuspid area. Also while the portion of greater thickness has been 
disclosed as extending from the first bicuspid to the second molar, a 
somewhat shorter portion of greater thickness could be employed, for 
example not extending over the first bicuspid or over the second molar, so 
long as the thicker portion is provided in the molar-bicuspid region. 
Further, while the mouthguard is primarily intended for use on the upper 
teeth, and it is expected that it would be so used in essentially all 
cases, it could be adapted for use on the lower teeth if that should be 
necessary for a particular prospective user. It is intended, therefore, by 
the appended claims to cover all such modifications as come within the 
spirit and scope of this invention.