OTC denture cushion classification as low-risk devices sought by Mentholatum.

OTC DENTURE CUSHION SAFETY CONCERNS "NOT APPLICABLE" if the products are used as a temporary fix until a dentist can be seen, Mentholatum argued in a July 26 petition requesting that FDA reclassify the over-the-counter devices from Class III (high risk) to Class I (lowest risk). The petition was submitted in response to FDA's July 11 proposal calling for premarket approval applications for OTC denture cushions or pads and repair kits ("The Tan Sheet" July 17, p. 20).

Mentholatum's comments are specific to soft plastic denture cushions. The proposed rule covers all denture cushions/pads except those made of wax-impregnated cotton cloth and intended for one-day use, which are in lowest-risk Class I.

Noting that the cushions are intended only for temporary use, Mentholatum argued that FDA's concerns "only arise if denture cushions are used over a long period of time." Under the FD&C Act, the company maintained, FDA must evaluate safety and efficacy based on conditions of use suggested in the labeling of the device.

"FDA should only require sufficient information to support the conditions of use that appear on product labeling," the company asserted. Because Mentholatum's Snug soft plastic denture cushions "are clearly labeled for temporary use...FDA should not classify such cushions in Class III due to the concern that consumers may misuse the cushions." The company added that "FDA has no factual or legal support for its apparent assumption that consumers will misuse soft plastic denture cushions."

Mentholatum maintained that soft plastic denture cushions are the same "generic type of device" as wax-impregnated cotton cloth denture cushions and, therefore, should be similarly regulated. "FDA concluded that wax-impregnated cotton cloth denture cushions should be placed into Class I `because a single layer of material is used to make the cushion, the disposable cushion is discarded after one day's use, and the device is intended for short-term use,'" the petition states, adding that "soft plastic cushions, such as Snug, share these same characteristics."

Mentholatum said it is willing to add to labeling a recommendation that Snug be discarded after one day's use as well as the statement: "For temporary use only, see your dentist within 24 hours to obtain professional reconstruction of the denture."

In the proposal, FDA cited several safety issues identified by the agency's Dental Devices Classification panel in 1980. One of the panel's concerns was that the cushions might cause a change in the vertical dimension of a denture, which could "result in increased occlusal (biting) forces and lead to bone loss through resorption" or cause long-term irritation of oral tissue that might lead to carcinoma.

Included with the petition are two studies not previously submitted to FDA that Mentholatum said establish the safety and efficacy of Snug cushions.

One study, a six-week evaluation of 40 patients completed in 1981, was conducted by Richard Stallard and Ralph Heiser, then at the University of Minnesota School of Dentistry. Stallard, who concluded that the soft plastic cushion is safe and effective, also conducted a similar study on wax-impregnated cotton cushions, which, according to Mentholatum, was "primarily responsible" for the panel's recommendation that the wax-impregnated cushions be placed in Class I. "Consequently, the similar conclusions reached by Dr. Stallard with regard to Snug denture cushions (that the cushions are safe and effective) support the reclassification of soft plastic denture cushions into Class I," Mentholatum reasoned.

The second study, conducted at the Veterans Administration Medical Center in Buffalo, evaluated the use of Snug cushions for three weeks in 25 patients with ill-fitting dentures. In the 1984 study, Snug cushions "were evaluated favorably with regard to: the clinical impression of fit and stability; the appearance of oral mucosa; the professional evaluation of cushion utility and safety; patient impression of comfort and stability; and patient impression of the ability to eat," the firm reported. The study "found no adverse effects on soft tissue," and the 2.29 mm increase seen in vertical dimension "is minimal and should pose no concern," the petition says.

The new Snug studies "are more persuasive, or as persuasive, as the studies relied upon by FDA to reclassify EZO [wax-impregnated] denture cushions into Class I," Mentholatum claimed. The company also cited its marketing history with the product, noting that Snug has been sold since 1939 with sales totaling over $30 mil. Approximately 160 complaints have been received by the company in the last seven years, most related to product packaging, and some related to price concerns. "Only one of the 160 complaints claimed that the cushion caused soreness or irritation within the mouth," the petition says.

Based on the data and the fact that FDA's safety concerns are based on long-term use, Mentholatum argued that the devices should be placed in Class I "so that they [would be] regulated identically to wax-impregnated cotton cloth denture cushions" and, therefore, would be exempt from PMAs.

Brimms Laboratories also filed a reclassification petition with the agency. The manufacturer of Denturite flow-fit denture cushions is seeking Class I status for flow-formed temporary denture surfaces.

The petition includes clinical and toxicological studies of Denturite that the company said "clearly demonstrate that flow-formed temporary surfaces do not present the risks that the agency asserts are characteristic of most other types of denture cushions or pads." Brimms noted the studies have "never been addressed by FDA or the Dental Devices panel, despite repeated submissions by Brimms." The firm presented its studies to the panel in 1980 and to FDA in 1981 following the agency's proposed rule to place OTC denture cushions and pads in Class III. The company submitted the studies again in 1994 in response to a document that listed OTC denture cushions and pads among high priority devices for which PMAs might be appropriate.