PIO – Progress in Orthodontics is a fully open access, international journal owned by the Italian Society of Orthodontics and published under the brand SpringerOpen. The Society is currently covering all publication costs so there are no article processing charges for authors. It is a premier journal of international scope that fosters orthodontic research, including both basic research and development of innovative clinical techniques. Progress in Orthodontics considers for publication only meritorious and original contributions. These may be: original articles reporting the findings of clinical trials, clinically relevant basic scientific investigations, or novel therapeutic or diagnostic systems, review articles on current topics,articles on novel techniques and clinical tools, articles of contemporary interest.