Orthodontic treatment represents an important fraction in dental interventions. According to other medical methods the question for scientific evidence for the effectiveness of these treatments arises.
The question of the effectiveness is connected with the question what is understood as an effect. In principle, the effect of the intervention is understood on the basis of the occlusion or dental health, what disregards further functions of oral health. The generalization to oral health is therefore a necessary consideration in science now.
If one appreciates this further development, then there is no one single randomised study available which examines the long-term effect of the orthodontic intervention or for the effects on the oral health.
The question, whether the application of a fixed appliance in an orthodontic treatment causes a long-term improvement in oral health, cannot be answered at the present time. The scientific status is the definition of oral health at present. Also the question, whether in the long run the dental health can be improved by fixed appliances cannot be answered with a quality usually achieved by evidence-based medicine.
Whether correction of a dental malposition is an effective prerequisite for the preservation of the natural teeth, cannot be answered. There is no generalizing study with sufficient scientific background for Europe or Germany to this topic.
The risk for caries cannot be quantified. Caries is identified as a central topic in general but due to numerous factors influencing the risk it is not quantified.
The question of the indications is completely open from the scientific literature. For the question of the therapy need or therapy priority some indexes were developed, which lead to a quantification. These indices however are fundamentally criticised by recent research in their meaning and the empirical relevance.
There is an impression that there exists a big gap between the practical application and the scientific investigation of this effectiveness of fixed appliances or orthodontic treatment in general. There is much research in the area of diagnostics or further development of appliances or techniques done, however extremely few in the area of need for intervention, analysis of the sustainability; influence factors on the success, like caries or quantification of side effects e. g. root resorption.
This research to evaluate the indications is completely lacking, also the required evaluation parameters (e. g. means long-term dental maintenance).
This gap is in this respect dubious since a link of determining the demand (inducing demand) and supply in Central European health systems is economically given. This enables to create a possibility for a so-called supply induced demand.
To get rid of discussions that the professional work of orthodontics can be near to induced demand or unnecessary indications, research of this topic is quite essential. This requires much stronger information for indications. This can improve confidence for patients and insurance companies. Existing indices like the Index of Treatment Need (IOTN) seem to be of academic interest without practice importance for daily work.
The question which indications can be regarded as scientifically proven for the intervention must be given big attention immediately. The individual and subjective assessment of the orthodontist (whose experience is not doubted) has to be considered as not sufficient. The scientific background is absolutely necessary due to ethic reasons for the patient, economic reasons for the social insurance system or financiers and also for the orthodontists to evaluative and legitimates the treatment.
Well coordinated research with the goal of collecting specific data is urgently required for individual therapeutic processes with appropriate design. The study quality is also an essential topic. It is unacceptable at the beginning of the 21st century with the background of the evidence based medicine, that studies are published with enormous methodological errors. Orthodontics deserves a well discussed scientific position to prove the enormous individual success and to demonstrate the effectiveness of the developed treatments.