This document discusses dental materials. It begins by defining dental materials as those used for prevention and treatment in dentistry. It notes that studying dental materials is important for providing better patient care. The document then categorizes dental materials as preventive/therapeutic, restorative, or auxiliary. It explains that restorative materials can be primary to slow disease or secondary to restore structure. The document outlines why dental materials are studied, including understanding their behavior, proper handling, evaluating problems and treatments, and educating patients. It provides examples of how different materials behave and should be used. The document concludes with a brief history of dental materials from ancient times to the present.