Product Lines

A ‘product line’ is two or more products manufactured or marketed by one company that incorporate the same plaque and/or tartar (calculus) retardant formulation, ingredients or technology.

VOHC recognizes that the VOHC two-trial protocol requirement may not be necessary for every product in a product line. The primary considerations for VOHC are whether the products in the product line:

  • Have different dental effectiveness, and if so, whether each product meets the
    minimum VOHC standard.
  • Are marketed for different ‘body-size classes’ of dogs. (Not applicable to cats).

Although it is not possible to state a definitive policy that will apply to all product lines because of the range of possible product lines, a general policy is described below. Contact VOHC to determine how this general policy may apply to a specific product line.


Minor Difference Between Products
in a Product Line

Difference in Flavorings or Colorants, With No Other Differences Between Products:

Example: A treat product is marketed in one size, but in two or more different flavors. VOHC would permit the Seal to be used on the product with the un-tested flavors if one flavor was tested as per the VOHC protocol, and the company offered an explanation satisfactory to VOHC as to why the difference in the flavorings would not affect the dental effectiveness of the product. No trials for the product coated with the other flavors would be required if VOHC accepts that there is no difference in dental effectiveness.

Major Differences Between Products
in a Product Line

Different Sizes of the Product Marketed for Dogs of Different Body Weight Ranges.

VOHC will award the VOHC Accepted Seal to a product that is marketed in two or more sizes for dogs of different body weight ranges if two trials conducted with one size of the product in dogs limited to the body weight range shown on the product label for that product size meet or exceed the VOHC minimum efficacy criteria, and one additional trial is conducted using a different size of the product, again in dogs limited to the body weight range shown on the package for that size of the product, and the third trial data meet or exceed the VOHC minimum efficacy criteria. Other sizes of product will be permitted to use the Seal without further testing.
VOHC is aware that recruiting dogs for dental trials of a specific body weight range can be a frustrating exercise. VOHC is willing to offer some flexibility in this requirement – contact VOHC by email to to explore possibilities.

If a product is marketed in two or more sizes with no indication of a specific body-weight range for each size, VOHC would not review these products as a single product line, because a significant difference in size of a chewed product will affect chewing time and thus dental effectiveness. Each size would require a separate VOHC submission, and VOHC would also require justification from the sponsor that the larger size will not risk injury when given to a small dog, or when the small size is given to a larger dog.

Differences in Shape of Product

Some dog and cat treat product lines consist of products with the same manufacturing formulation and ingredients, 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 differences in chewing patterns or chewing time that affect the mechanical action on the teeth. This could be a frustrating situation for VOHC and industry, because testing of each different shape for a separate VOHC submission may be prohibitively expensive.

All products of a similar ‘type’ (e.g. ingested treats made with same ingredients and manufacturing process, but made in different shapes and sizes) marketed by a company under a single product name will be considered by VOHC if there is an initial trial (conducted under VOHC protocols) of all of the product shapes, plus a negative control; this trial would be subject to a requirement that if particular shapes are offered in different sizes, the trial must be conducted in dogs in the body weight range assigned to the product sub-set that includes more than one size. This would be a multi-arm parallel group trial or a multi-leg cross-over trial. The result would allow the dental effectiveness of the whole set of products marketed under that name to be ranked in effectiveness, and would be followed by a single additional trial of the product that is least dentally effective but whose dental efficacy meets or exceeds the VOHC standard (to meet the VOHC ‘two trials’ requirement).

All of the products tested in the first trial that are ‘at least as good as’ the double-tested product would be permitted to use the Seal if the second trial also meets or exceeds the VOHC standard.
If the first multi-product trial identified particular shapes that did not meet the minimum VOHC standard, the company could choose to continue to market those products, but they would not be permitted to carry the VOHC Seal. The company would be required to ensure that the VOHC Seal is not associated with the insufficiently effective products – VOHC reviews all marketing materials to ensure that the Seal is being used appropriately.

VOHC strongly recommends preliminary discussion between the company and VOHC about product lines that include products with different shapes – send an email message to

Differences in Ingredients

When a line of products incorporating the same dental formulation or technology (such that the general physical characteristics of the diet such as kibble size and processing are the same) is marketed in a number of different nutritional profiles (e.g. for different life-stages, or for obesity control and as a maintenance formula) that have differences in ingredients, VOHC will consider a submission to award the Seal to all of the products in that product line based on:

    1. The company provides appropriate information about the differences in the formulations, and justification acceptable to VOHC for assuming that the differences in ingredients will not affect the dental effectiveness of the products. If the explanation is not satisfactory to VOHC, see item 5, below.
    2. A two-trial study as per the VOHC protocol (link to Product-details page) using one of the products (“primary product”) meets the VOHC standard.
    3. A single trial of each of the other products in the same product line for which the Seal is requested is conducted. If the results of the single trial of each additional product demonstrate that each is statistically “at least as good as” the product subjected to the standard two-trial protocol, the VOHC Accepted Seal will be awarded to the additional products.
    4. 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, meet or exceed the VOHC criteria for an original submission. One practical way of approaching this would be to proceed as for the product comparison trial described in the ‘different shapes’ section.
    5. If VOHC does not accept that the differences in ingredients will not affect the dental effectiveness of the product, separate two-trial submissions would be required for each additional diet.
      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.
        1. 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).
        2. The obesity diet may have a higher fiber content than the maintenance diet, as well as lower carbohydrate/fat/protein content, with possible effects on oral bacterial growth.

Preliminary consultation with VOHC is recommended, to discuss issues such as whether the trial of the e.g. weight-control dental diet would need to be conducted in obese dogs – send an email message to