Although the National Association of Dental Plans insists that 90 percent of plans are true insurance, since there's a risk-transfer element and because enrollees could receive more in benefits than the premiums cost, many commentators quibble. A letter from Dr. Robert Helmholdt in the October 2004 issue of JADA claimed that "[D]ental insurance ... is an oxymoron. It defies the definition of insurance in that there is no catastrophic component. It is comparable to using insurance to pay monthly utility bills or for car tuneups." In an article in the June 2006 issue of JADA, Dr. Albert Guay, the ADA's chief policy adviser, argued that "Dental benefit plans are not insurance plans but are prepayment plans. The concept and the mind-set of insurance—a benefit to be used infrequently—must be abandoned in dental benefit plans." Elsewhere in the piece, he noted that "[u]nlike medical disease, oral disease is not an insurable risk." Whereas medical diseases have the necessary characteristics—they are "unpostponable, unpredictable, and unbudgetable"—oral diseases are not. Dr. Burton Edelstein offered this assessment of the two models: "The basic concept of medical insurance is shared risk. The basic concept of dental insurance is that we count on some people not utilizing it so that others get the benefit."