In the past it was usual for dentists to use the explorer to determine the presence of tooth decay on tooth enamel. Some dental professionals have questioned this practice in the first decade of the twenty-first century.[1][2] Since enamel is demineralized in the early stages of tooth decay, the use of an explorer opens a cavity in the enamel where none existed previously.[citation needed] Instead, they argue that fluoride and oral hygiene should be used to remineralize the enamel and prevent it from decaying further. This debate still continues because sometimes decay can be difficult to diagnose without tactile verification. Additionally, radiographs and other products designed to identify decay (such as measuring fluorescence from a laser) help the dental professional make a final diagnosis of tooth decay.