The Army first started using Contract Dentists in 1901 and this is when the first insignia of a Dentist came into being. But it was not until December 1917 that a single “D” on a caduceus came into being. Before that they used DS. BY WWII the size of the caduceus became much wider and either a gilt caduseus with a bronze D or an emamled D. They also started making the ones in all metal and some made them in sterling with a gold plate. This is a museum quality reproduction of the sterling insgnia for an officer with a gold plate. Sold in a set of two as would be needed for a uniform.