Contact dermatitis can affect dentists, orthodontists, technicians, nurses and the patients. The increase of dental patients in recent years caused an increase in reports of dermatitis and other allergies in patients and in dentists too. With changes in dental materials through years, allergy and contact reactions in persons in contact with new allergens had been increased. So dentists and dermatologists should be aware of new allergens and try to avoid contact with these materials as possible. This review is performed to increase the knowledge of medical personnel about this issue with description of each allergen.