This is a unique publication – it is selected texts of Polish specialists', based on their own clinical cases and research! The articles are support in the diagnosis and planning of treatment and constitute source material for understanding the concepts of new methods and techniques of orthodontic therapy. The scientific editor of the issue is dr hab. n. med. Agnieszka Machorowska-Pieniążek. The experts have shared their knowledge, including: Krzysztof Dowgierd, Maciej Cićkiewicz, Joanna Antoszewska-Smith, Krzysztof Woźniak and Wojciech Bednarz.