Nowadays dental cavity is the most common disease. According to statistics, it is found in more than 93% of people. Despite the prevalence of such problem, a method of diagnosing an early stage of cavity hasn’t been invented until now. At the stage of a deep lesion the diagnosis is not a problem. Dental cavity is rather unpleasant thing, and the sooner a doctor identifies the problem the better. Without forehanded treatment, cavity can progress to more severe diseases, such as pulpitis or periodontitis, lead to tooth loss and even to serious life-threatening complications. It is very important to inspect the initial stage of dental cavity.