Simulations are important educational tools in the development of health care competence. This study describes a virtual learning environment (VLE) for diagnosis and treatment planning in oral health care. The VLE is a web-based, database application where the learner uses free text communication on the screen to interact with patient data. The VLE contains forms for history taking, clinical images, clinical data and X-rays. After reviewing the patient information, the student proposes therapy and makes prognostic evaluations of the case in free text. A usability test of the application was performed with seven dental students. The usability test showed that the software responded with correct answers to the majority of the free text questions. The application is generic in its basic functions and can be adapted to other dental or medical subject areas. A randomised controlled trial was carried out with 39 students who attended instruction in history taking with problem-based learning cases, lectures and seminars. In addition, 16 of the 39 students were randomly chosen to practise history taking using the virtual patient prior to their first patient encounter. The performance of each student was recorded on video during the patient sessions. The type and order of the questions asked by the student and the degree of empathy displayed towards the patient were analysed systematically on the videos. The data indicate that students who also undertook history taking with a virtual patient asked more relevant questions, spent more time on patient issues, and performed a more complete history interview compared with students who had only undergone standard teaching. The students who had worked with the virtual patient also seemed to have more empathy for the patients than the students who had not. The practising of history taking with a virtual patient appears to improve the capability of dental students to take a relevant oral health history.