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International Poster Journal of Dentistry and Oral Medicine



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Int Poster J Dent Oral Med 5 (2003), No. 1     15. Mar. 2003

Int Poster J Dent Oral Med 2003, Vol 5 No 01, Poster 169

PREPassist as digital assistance for dental education

Language: English

Authors: Berthold Jäger, Dr. Nikos Kournetas, Dr. Martin Groten, Dr. Stefan Lachmann, Prof. Dr. Heiner Weber, Prof. Dr. Jürgen Geis-Gerstorfer
Eberhard-Karls-University, University Hospital Tübingen
Clinic for Dental and Oral Medicine, Department of Prosthodontics

51. Jahrestagung der Deutschen Gesellschaft für zahnärztliche Prothetik und Werkstoffkunde
Dresden, Germany



The use of modern media in dental education is a useful supportive instrument [1,2,5-7,9]. Recent trends favor working in small groups matching the character of electronic teaching and studying media. [1,5,9]. Despite the different personal and technical equipment of the universities dental schools have one common problem: Compared to the number of students the number of instructors is low [1,3,4,6,8]. The demand to establish modern up-to-date teaching methods with success is difficult to comply with since the problem of staff for instructions and teaching cannot be solved with the use of technical equipment and modern media alone. The new media might only be used in a supportive manner. And this support has also to be developed and supported itself. The workgroup "Dental Preclinic Education (Zahnmedizinische Propädeutik)" of the DGZMK (Germany - www.dgzmk.de) promotes the integration of modern media in preclinical education [1]. On top of this the revised design of the approbational rules for dentists particulary allow for the use of interactive media in the preclinical as well as in the clinical education. Furthermore the workgroup "Didactic and Transfer of Knowledge (Didaktik und Wissensvermittlung)" and the workgroup "Informatics (Informatik)" of the DGZMK both support this development as well as similar projects at several locations [1]. But there are two essential questions remaining: Which concepts might be useful and appropriate to support dental education and how to implement them into daily practice?


Edcuation in Preparation today

Educational efforts in tooth preparation techniques have shown that the use of dental simulation units is an essential step towards clinical-like training conditions [1,3,4,8] (Figures 1-3).
Yet, the use of dental simulation units does not transfer knowledge to the trainee.
Merely by visualization, the student has to seek an optimal preparation. In this context, the application of modern media could provide a useful support. Feedback could be mediated by computerized visualization comparing the student's preparation with an ideal one (instructor-preparation). With the help of a digital preparation assistant "PREPassist" the students would be enabled to judge the quality of their preparations at a computer on their own based on the guidelines given by the instructor.

Figure 1: Education in dental preparation at the University of Tübingen

Figure 2: Dental simulation unit
Figure 3: Denture (simulated) Figure 4: PREPassist scanunit


PREPassist - parts, function principles

The system consists of a scanner for three dimensions and a computer-system that goes with it. A CCD camera is able to visualize different preparations of resin teeth and wax modelations (figures 4-6). The software consists of 4 windows (figure 7). The upper part shows the reference preparation (instructor), the lower is designated for the trainee. The results of the scanning process are shown as 3D-images while results from measurements of points, distances and angles are presented as cross-sectional slices along with associated numeric values. Individual criteria can be given by the instructor.

Figure 5: Camerasystem in scanner

Figure 6: Scanprocedure

Figure 7: Screendisplay of the PREPassist software



The evaluation of the performance of the PREPassist takes place in 2 phases by the departments of Prosthodontics of the dental schools of Tuebingen and Freiburg (Germany) respectively (figure 8).

Evaluation-phase I

First, the system will be screened on the reproducibility of acceptable measurement results (accuracy of measurements and reliability). At the same time, metric parameters for different types of preparations will be acquired. A preparation by choice out of multiple instructor preparations is the reference for the following examinations. Previously archived teeth will then be evaluated on their variance. Based on this empiric variance of teeth prepared by dental students, the previously developed criteria and parameters will be reevaluated and if needed redefined. In order to define the limits of a clinically acceptable preparation result a so called grading (- / 0 / +) will be implemented.

Evaluation-phase II

In phase II, the system will be integrated in the daily practice: students shall evaluate their preparations in free-training sessions. The participating students will be divided in a test and control group. The deviations of the preparations compared to the reference preparation will be assessed. The applied parameters and criteria will then be reevaluated. After a system feedback from the students with a questionnaire, the "PREPassist" will be integrated in student education step by step.

Identifiable advantages

  • objective evaluation
  • enlarged visualization in three dimensions
  • optical and numeric evaluation by use of cross-sectional slices
  • availability at different workstations

advantages to be proved

  • autonomous evaluation of own work which could lead to a more effective learning
  • preparation training "around the clock" in "Self-Learning-Center"
  • time saving for instructors and students


  • operating expense
  • question of accuracy of measurements
  • need of high computer power
  • high purchase costs
  • obsolescence of the computer system

Figure 8: Evaluation-flowchart



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  2. Devitt, P., Palmer, E.: Computer-aided learning: an overvalued educational resource? Med Educ 33, 136-139 (1999)
  3. DGZMK, BZÄK, VUD, VHZMK: Die Bedeutung der "Zahnmedizin" in der Medizin. Zahnärztl Mitt 92, 24-28 (2002)
  4. Lehmann, K.M., Stachniss, V.: Aspekte einer zukunftsorientierten propädeutischen Ausbildung in den restaurativen Fächern der Zahnheilkunde. Dtsch Zhnärztl Z 55, 515-517 (2000)
  5. Schittek, M., Mattheos, N., Lyon, H.C., Attstrom, R.: Computer assisted learning. A review. Eur J Dent Educ 5, 93-100 (2001)
  6. Stosch, C., Herzig, S., Kerschbaum, T., Lefering, R., Neugebauer, E., Koebke, J.: Medizinische Ausbildung 2000: Ziele-Qualität-Kosten. Med Ausbild 17, 120-139 (2000)
  7. Vichitvejpaisal, P., Sitthikongsak, S., Preechakoon, B., Kraiprasit, K., Parakkamodom, S., Manon, C, Petcharatana, S.: Does computer-assisted instruction really help to improve the learning process? Med Educ 35, 983-988 (2001)
  8. Weber, H.: Die neue Approbationsordnung - Forschung, Lehre, Praxis. 3. Assistentenkongress für Wissenschaftsmanagement in der Zahn- Mund- und Kieferheilkunde Berlin (2002)
  9. Yip, H.K, Smales, R.J, Chu, F.C, Newsome, P.R, Chow, T.W.: Computer-assisted learning (CAL) in undergraduate clinical dentistry: a review. SADJ 56, 476-80 (2001)


This Poster was submitted by Berthold Jäger.

Correspondence address:
Berthold Jäger
Zentrum für Zahn,- Mund- und Kieferheilkunde Tübingen
Poliklinik für Zahnärztliche Prothetik und Werkstoffkunde
Osianderstr. 2-8
D-72076 Tübingen