In patients with premature loss of baby teeth and insufficient retention of spaces, the Leeway space can be reduced due to undesired neighbouring tooth migration and space could become insufficient for the eruption of all permanent teeth. Various orthodontic treatment options may be used to reopen spaces and avoid potential extractions in the permanent dentition. One option is treatment with the Invisalign Teen System, which allows an almost invisible and comfortable way of treating patients, with fewer potential side effects than with conventional fixed appliances. Several examples will be presented in this article to show how Invisalign treatment procedures in early years can avoid potential extraction treatments. Schlagwörter: aligner orthodontics, case reports, ClinCheck Software, extractions, interceptive treatment, Invisalign, lack of space, mixed dentition, teen treatment