Received: 3 July 2018
Accepted: 18 September 2018
First Online: 24 September 2018
Ethics approval and consent to participate
: This retrospective study received full approval from the ethics commission of Hannover Medical School (MHH; # 7727_BO_K_2018) prior to the commencement of data collection.
: All patients signed a written consent form.
: DW is the inventor of the completely customized lingual appliance WIN and owner of the DW LingualSystems, Bad Essen, Germany. All other authors don’t have any competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.