Therapeutic pet toy

Disclosed is a dental hygienic pet toy for dental prophylaxis on the teeth of a dog or other carnivore as the toy is chewed by the carnivore. The toy includes an elastomeric body having an outer surface and at least one groove which opens onto the outer surface. The groove is sized and configured so that a functional prophylaxis lip will scrape plaque and other debris from a tooth and gingiva of a carnivore which is repeatedly inserted into and at least partially withdrawn from the groove as the toy is chewed by the carnivore. An oral hygiene substance may be provided along the lip to enhance the benefit to the teeth and gingiva.

TECHNICAL FIELD 
The invention relates generally to a toy for pets, and, more particularly, 
to a pet toy which additionally is of value as a dental hygienic aid for 
pets. 
BACKGROUND ART 
Play toys for use by pets, particularly dogs, have been commercially 
available for years. Those particularly designed for dogs are generally 
shaped like a dog bone. However, dog toys having ring-like and ball shapes 
are also sometimes seen in the marketplace. Most dog toys are also made 
from a rubber-like material so that the toy will bounce when played with 
by the dog. Researchers studying dog behavior discovered years ago that 
dogs prefer toys having bouncing characteristics. 
U.S. Pat. No. Des. 256,958 which issued on Sept. 16, 1980 to Markham, a 
coinventor of the present invention, discloses a pet toy, preferably made 
from rubber, which provides pets, primarily dogs, with masticatory 
exercise when they chew the toy. The toy has two circumferentially 
extending shallow grooves which facilitate a dog's chewing of the toy. 
U.S. Pat. Nos. Des. 234,789 and Des. 234,790 to Rosenberg disclose sounding 
toys having spiraling members which define chambers for housing objects 
secured therein. The objects rattle when a pet plays with the toy. The toy 
is not disclosed as having any utility as a chewing toy for pets, nor does 
the design lend itself to such utility. While the toys are possibly 
resilient in a direction parallel to the toy's longitudinal axis, the 
spiraling members would not appear to provide the toy with much give or 
elasticity in a direction perpendicular to the longitudinal axis. 
Accordingly, it is unlikely that a dog would chew these toys. 
U.S. Pat. No. 2,194,736 to De Bruler discloses a tether pet toy which 
includes a dog bone shaped member which is attached to an elastic 
string-like member. The string-like member is attached to the dog bone 
member by wrapping and tying it about two lips provided on the dog bone. 
The lips prevent the string-like member from slipping off the dog bone. 
U.S. Pat. No. 3,198,173 to Fisher discloses a pet toy made from a strip of 
rawhide wound and rolled into a loosely coiled configuration. 
U.S. Pat. No. 2,185,547 to Fowler discloses a pet toy having a core which 
is covered by two pieces of rawhide sewn together. 
U.S. Pat. Nos. 4,513,014 and 4,557,219 to Edwards disclose a dog bone 
shaped tough molded elastomeric chewable polyurethane toy for an animal. 
The toy has a longitudinal groove extending along a substantial portion of 
its midsection. The groove facilitates flexing of the dog bone at opposite 
sides of the groove to provide a satisfying crunching effect to the 
chewer. 
The aforementioned patents demonstrate that very few pet toys have been 
specifically designed with features that are directed to improving a dog's 
dental health. Some of the more resilient or rubber-like toys described 
above inherently provide some massaging of a dog's gums as the dog chews 
the toy, but few are specifically designed for such purpose. Moreover, 
none of the toys discussed above were developed for the purpose of 
scraping or scaling plaque and other debris from a dog's teeth. 
DISCLOSURE OF THE INVENTION 
The present invention addresses the aforementioned dental hygiene concerns 
of carnivores, such as dogs, by providing a pet toy which not only 
provides masticatory exercise for a dog or other carnivore, but also 
performs dental prophylaxis as the dog chews the toy. The toy is also 
capable of massaging portions of the dog's gingiva or gums which lie 
adjacent to the dog's teeth. 
The toy includes an elastomeric body having an outer surface and at least 
one groove which opens onto the outer surface. The groove is sized and 
configured to scrape plaque and other debris from the tooth and gingiva of 
a carnivore which is being repeatedly inserted into the groove and at 
least partially withdrawn from the groove as the carnivore chews the toy. 
In a preferred embodiment, the elastomeric body of the toy is also provided 
with an inner surface which defines an inner hollow core. The hollow core 
enhances tooth and gingival scraping when a dog chews the toy by providing 
the body with the capability of resiliently bowing into the hollow core. 
The bowing action causes the groove having a dog's tooth inserted therein 
to resiliently elongate which thereby causes the sides of the groove to 
move inwardly towards each other. This inward movement of the groove sides 
results in clamping or engagement of the tooth located in the groove. 
which thereby results in scraping of the tooth's side and neck and the 
dog's gingiva surrounding the neck of the tooth. The elastomeric material 
of the toy body preferably has a hardness which facilities bowing of the 
body into the hollow core and elongation of the grooves as the animal 
chews the toy. The resilient nature of the elastomeric material also 
provides the toy with the ability to bounce as a dog plays with the toy. 
This keeps the dog's interest and thus insures that the dog will chew the 
toy for a while, thereby cleaning teeth and gingiva, as desired. 
In addition, the toy preferably has a functional prophylaxis lip located 
between each groove side and the toy's adjacent outer side. The lips 
partially project over the opening of the groove and are sized and 
configured to scrape a tooth as it is inserted into and withdrawn from the 
groove.

BEST MODE FOR CARRYING OUT THE INVENTION 
FIG. 1 discloses a ring-shaped dog toy 10 distributed by Pet Land of 
Chillicothe, Ohio 45601. The toy is apparently made by a molding process 
since it is entirely one-piece and made from a resilient vinyl material. 
Toy 10 includes a ring-shaped central core 12 having a round solid cross 
section. Core 12 has a plurality of integral, radially extending discs or 
fins 14 which are spaced uniformly from each other. Fins 14 define a 
plurality of gaps 16 between the fins. Toy 10 will provide masticatory 
exercise for a dog chewing the toy. However, it will not perform much, if 
any, tooth scaling since the fins 14 and gaps 16 are not specifically 
sized and configured to provide such. 
FIGS. 2 through 7 illustrate toy 20 of the present invention which is 
specifically designed to provide the dog with dental prophylaxis and 
masticatory exercise. The unique design accomplishes this by scraping the 
dog's teeth and gingiva or gums as the dog chews the toy. 
Toy 20 has a body 22 which is preferably made from natural rubber by an 
injection molding process at conventional pressures and temperatures of 
about 300 tons and at 300.degree. F., respectively. Conventional additives 
should preferably be added to the rubber to provide it with a hardness 
between about 30 and 70 durometers, ideally about 45 durometers. 
As illustrated, the toy's body is somewhat elongate and bounded by four 
general surfaces, an inner surface 24, and outer surface 26, groove sides 
28 and lip surfaces 30 and 32. 
Inner surface 24 defines a hollow core 34 which extends completely through 
body 22 about an axis X as illustrated in FIG. 4. Core 34 is generally 
cylindrical. However, as illustrated in FIGS. 4 and 6 its midsection is 
tapered or frustoconically shaped in a fashion which generally follows the 
toy's elongated contour. Tapering is important for purposes of providing 
the toy's body 22 with a relatively uniform thickness in certain areas, 
the importance of which will be discussed in detail below. 
Groove sides 28 and lip surfaces 30 and 32 of FIG. 5 define a generally 
V-shaped groove 36a having a root 38. The V-shape of the groove preferably 
has an included angle between about 60.degree. and 100.degree.. 80.degree. 
is illustrated. However, root 38 of the groove is not preferably sharp. 
Preferably, root 38 is rounded. A sharp root 38 is to be avoided, if 
possible, since it could provide a point from which cracks could 
propagate. 
Body 22 is also provided with four other grooves which are labeled, 
respectively, as grooves 36b through 36e. Each groove extends 
circumferentially around outer surface 26 of body 22 in a fashion whereby 
all the grooves are axially aligned along axis X. 
Grooves 36a and 36c are spaced a preselected distance apart from each other 
to accommodate, respectively, the left and right upper fourth premolars of 
most dogs engaging one side of the toy, and the left and right lower first 
molars of most dogs engaging the other side of the toy. Appropriately 
sized toys are designed to accommodate the different lengths and widths of 
mandible and maxilla seen in the various breeds of dogs. Grooves 36a and 
36c are also preferably sized and configured to scrape plaque and other 
debris from the aforementioned teeth and gingiva of dogs. The dimensions 
for medium size dogs are those shown in FIG. 4 which are drawn very close 
to scale. 
Grooves 36b and 36d as illustrated in FIG. 4 are similar to 36a and 36c. 
However, 36b and 36d are specifically sized and configured and spaced from 
one another to provide dental prophylaxis for most dogs left and right 
molars, whether they be upper or lower molars. 
Groove 36e is specifically designed to provide dental prophylaxis for the 
long canine teeth of most dogs. The canine tooth's length requires, as 
illustrated, that at least one groove side 28 of groove 36e be long enough 
to provide dental prophylaxis. FIG. 4 which is drawn to scale, illustrates 
preferred groove sizes and configuration for medium size dogs, i.e., dogs 
in the 20 to 45 pound range. 
Returning to FIG. 5, it can be seen that surface 30 is beveled at either an 
upper or downward 45.degree. angle with respect to axis X, the upper or 
downward direction of the angle depending on which side of the groove the 
surface is located. Surface 32 which adjoins surface 30 runs perpendicular 
to axis X and has a length of 0.032 of an inch as mentioned along axis X. 
Surface 30 has a vertical length of 0.050 of an inch as measured along 
axis X. Surfaces 30, 32 and adjacent outer surface 26 define a functional 
prophylaxis lip 40. One lip 40 is preferably located on each side of 
grooves 36 at the entrance or top of each groove 36 between each groove 
side 28 and the toy's adjacent outer surface 26 as such is illustrated in 
FIG. 4. 
Functional prophylaxis lips 40 significantly enhances plaque removal by toy 
20 by providing a pair of surfaces which scrape the dog's teeth and 
gingiva as they are inserted into and withdrawn from a groove. The lips 
provide dental prophylaxis since they remain in contact with the tooth 
surface as the tooth is being lowered into and withdrawn from the groove 
(See FIGS. 6 and 7). Moreover, by bending downwardly as depicted in FIG. 
7, lips 40 permit the tooth to be fully inserted into each groove 36. This 
enables the lips to provide dental prophylaxis to the side and neck of the 
tooth, but also enables the lips to provide dental prophylaxis to the 
dog's gingiva or gums which surround the tooth's neck. 
Enhanced dental prophylaxis and gum massaging is also provided by making 
the toy's body 22 out of an elastomeric material such as natural rubber 
having a hardness ideally around 45 durometers as previously mentioned. 
The resilience of natural rubber having such a hardness provides the toy 
with the ability to bounce, thereby attracting the dog's interest and 
insuring that the dog will play with the toy to receive the desired 
masticatory exercise and dental cleaning. In addition, such elasticity (or 
hardness) enables stretching or elongation of a groove 36 when a dog bites 
down upon the groove with a tooth located in the groove. This stretching 
of the groove causes the groove's sides and lips to move inwardly toward 
each other. This inward action causes lips 40 to in effect, engage or 
clamp the dog's tooth and surrounding gingiva thereby scraping the tooth 
and gingiva as the dog chews. 
To facilitate such stretching of the grooves, it is also important that the 
body's thickness between each groove root 38 and the inner surface 24 
defining the core be thin enough to allow this portion of the body to bow 
inwardly into the core as such, as illustrated in FIG. 7. This bowing 
action facilitates full insertion of the tooth into the groove which, in 
turn, facilitates stretching or elongation of the groove. In the 
embodiment illustrated having a body made of a material having a hardness 
of about 45 durometers, the body's thickness between each groove root 38 
and inner surface 24 defining core 34 should preferably be between about 
1/4 and 3/8 of an inch. Anything less than 1/4 of an inch will probably be 
too weak and will probably tear after the toy has been chewed by a dog for 
a while. Anything thicker than 3/8 of an inch and having a hardness of 
about 45 durometers will probably be too thick to permit the 
aforementioned bowing and groove stretching. 
Flavoring additives may also be added to the material from which the toy's 
body is to be made during the injection molding process. Such additives 
will enhance the toy's appeal to a dog, thereby making it more likely that 
the dog will play with the toy and benefit from the dental cleaning and 
masticatory exercies provided by the toy. Also, oral hygiene substances 
can be added along the functional prophylaxis lip to enhance the benefit 
of the toy to the dog's teeth and gingiva. 
Based on the foregoing description, those skilled in veterinary medicine, 
particularly those interested in the dental aspects of veterinary 
medicine, will readily appreciate that the present invention provides a 
pet toy which not only provides masticatory exercise for a dog, but also 
provides dental prophylaxis for the dog's teeth and gingiva as the dog 
chews the toy. Moreover, the unique design of the toy provides massaging 
of the dog's gingiva which surrounds the neck of a tooth being scraped by 
the toy. 
The invention has been described in detail with particular references to a 
preferred embodiment thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.