Can I use foam or polystyrene plastic cups? Stephanie November 27, 2018 21:36 Updated Follow Avoid using foam cups because polystyrene plastics will not hold up to the menthol in this product. Related articles Should I continue to floss when using OraMD? Does OraMD whiten the teeth? Are there any side effects from using OraMD? Can I use a Water Pik with OraMD? Is it safe to swallow OraMD? Comments 0 comments Please sign in to leave a comment.