[The evaluation of orthodontic treatments. Reflections on the Eismann procedure]

This study presents a broad overview of the fundamental questions involved in evaluating orthodontic treatment methods using a formalized index system. Eismann's numerical success evaluation, which he published 25 years ago and which is an example of this method, is examined in some detail. Both the dividends and limits of the Eismann method are discussed on the basis of our own studies and those of others and modifications to the method are suggested. Not withstanding the limitations inherent in any model based analysis, the Eismann approach is shown to be superior to many similar systems and it thus remains the method of choice for conducting scientific studies of the course of treatment over time. In addition possibilities of further developing and enhancing the method are presented.