Differences in Size of Product
and in Body Size Classes of Dogs
A significant difference in size of a chewed product (and thus likely chewing
time) would be reason for VOHC not permitting use of the Seal on more than
one size of the product even when a product of one size has satisfactorily
completed the VOHC review system. Conducting the two required trials using
one size of product in one trial and another size in the second trial would
not be accepted, because VOHC’s basic statistical hurdle includes conducting
two trials of the same product, in both of which the product performs significantly
better than in the control group.
Differences in size of product are compounded
by the fact that products of different sizes are often marketed
for use in dogs of specific body-sizes (e.g. the ‘Jumbo’ product
package may state ‘For Giant-sized Dogs’).
Based on epidemiological evidence (references
2,3), toy and small-breed dogs are prone to develop more severe
periodontal disease than are larger dogs; with increasing body
weight, there was a significant decrease in gingival index,
mobility index, attachment loss and presence of a complete
furcation defect (3). The decrease was most obvious when comparing
small dogs to medium-large sized dogs, as opposed to comparing
medium-sized dogs with large-sized dogs (3). In addition to
having smaller jaws in absolute terms, small dogs have teeth
that are proportionately larger relative to jaw size than those
of larger dogs (1).
Based
on this evidence of increased severity of disease and anatomical
pre-disposition in small dogs,
VOHC requires separate submissions for products marketed
for small dogs and for products marketed for medium-sized and
larger dogs. Given that there are
insufficient data on which to define body-weight groups, VOHC
is willing to review body-weight grouping prior to commencing
the trials, and will take into consideration the availability
of dogs of different body sizes for clinical trials. Use of laboratory-housed
beagles for trials of products marketed for small-medium dogs
and laboratory-housed mixed breed pointer-retriever sized dogs
for trials of products marketed for large dogs is acceptable.
Use of client-owned dogs is acceptable provided that randomization,
blindedness of the scorer and compliance with the instructions
for the assigned group can be assured.
When two sizes of a product are marketed:
Testing the small-sized product in small dogs using the VOHC
two-trial criterion, and testing the large-sized product in
large dogs in one VOHC trial (or vice-versa) will be acceptable.
If results in all three trials exceed the VOHC statistical
criteria, the VOHC Seal will be awarded for use on both
products.
When more than two sizes of a product are marketed:
Testing the small-sized product in small dogs using the VOHC
two-trial criterion, and testing the large-sized product in
large dogs in one VOHC trial (or vice-versa) is recommended.
If results
in all three trials exceed the VOHC statistical criteria, other
sizes of product will be permitted to use the Seal without
further testing.
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Differences in Shape of Product
Many dog and cat treat product lines are marketed in a variety of shapes.
These different shapes may have widely different abilities to retard
plaque and calculus deposition, based on the interest of the dog or
cat in chewing the product and on the mechanical effect the treat has
on the teeth. In the absence of results of testing for each shape,
this is a frustrating situation for VOHC and industry. Testing of each
different shape may be prohibitively expensive. The general policy
outlined above may be applicable. Assuming that there is prior agreement
with VOHC on what constitutes the "ends of the range of shapes" and
what constitutes "intermediate shapes", testing products
at either end of a spectrum of shapes (using VOHC criteria and with
results that meet VOHC standards) will permit use of the Seal on those
two products and on any intermediate shapes. VOHC strongly recommends
pre-trial discussion between the company and VOHC about what constitutes
the "ends of the range of shapes" and what constitutes "intermediate
shapes". The body-size(s) of the dogs for which the products are
marketed are to be taken into consideration.
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Other Differences, e.g. Nutritional
Formulation
When a line of products incorporating the same dental formulation or technology
is marketed in a number of different nutritional profiles (e.g. for
different life-stages, or for obesity control and as a maintenance
formula), and general physical characteristics of the diet such as
kibble size are very similar in each product, VOHC will consider a
submission to award the Seal to all of the products in that line based
on: A two-trial study as per VOHC protocol using one of the products
(“primary product”), and a single trial of each of the other products
in the same product line for which the Seal is requested, provided
that the single trial of each additional product demonstrated that
each additional product is statistically “at least as good as” the
product subjected to the standard two-trial protocol, and that the
company provides appropriate information about the differences in the
formulations. If one of the additional products was not statistically
“at least as good as” the primary product, this additional product
may still be eligible for the VOHC Seal if results of a second trial
of that specific product, in combination with the first trial of that
specific product, met the VOHC criteria for an original submission.
This policy is subject to the provision
regarding body size noted above, and possibly additional considerations.
For example, consider a dental diet line that includes a diet
marketed for diabetic dogs and another for non-diabetic obese
dogs, both of which incorporate the same dental technology as
the maintenance diet that has been awarded the VOHC Seal. The
diabetic diet may have a higher fiber content than the maintenance
diet as part of its diabetic control mechanism (and thus may
have potentially higher dental abrasive action), and the glucose
content of saliva may be higher in the diabetic dogs (which may
have a stimulatory effect on oral bacterial growth). The obesity
diet may have a higher fiber content than the maintenance diet,
as well as lower carbohydrate/fat/protein content. Separate two-trial
submissions would be required for each additional diet in the
absence of explanations satisfactory to VOHC that the differences
in dental effectiveness of the products are not significant.
1. Gioso MA et al: Mandible and mandibular first
molar tooth measurements in dogs: relationship of radiographic
height to body weight. J Vet Dent 18; 65-68, 2001
2. Hamp SE
et al: Macroscopic and radiologic investigation of dental diseases
of the dog. Vet Radiol; 25, 86-92, 1984.
3. Harvey
CE et al: Association of age and body weight with periodontal
disease in North American dogs. J Vet Dent 11; 94-105, 1994.
