Having previously reported on George Washington's dentures, I have no idea whether the following is true (emphasis added):
By 1789 [George Washington] was using false teeth, and he lost his last tooth in 1795. At first these substitutes were very badly fitted, and when Stuart painted his famous picture he tried to remedy the malformation they gave the mouth by padding under the lips with cotton. The result was to make bad worse, and to give, in that otherwise fine portrait, a feature at once poor and unlike Washington, and for this reason alone the Sharpless miniature, which in all else approximates so closely to Stuart's masterpiece, is preferable. In 1796 Washington was furnished with two sets of "sea-horse" (i.e., hippopotamus) ivory teeth, and they were so much better fitted that the distortion of the mouth ceased to be noticeable.