The Oral Radiology Department of the School of Dentistry of California University (UCLA) offers the general practitioner the possibility of getting a differential diagnosis via a questionnaire online. In this case it concerns 130 radiographic lesions manifested in the maxilla and mandible. A computer software application, which is an example of an expert system for the dental practice, makes this possible. On this website one can also see many radiographs which show examples of numerous dental lesions. By means of interactive assignments the general practitioner can also practice in judging radiographs.