While impaired eruption of permanent molars is a rare phenomenon, its prevalence appears to be increasing. Among these disorders, a distinction can be made between impactions, in which a tooth is blocked along its eruption path by a physical obstacle, and primary retention, in which eruption ceases in the absence of such a barrier. Within primary retention, primary failure of eruption (PFE) is a genetically determined condition that can severely affect one or more teeth and impact adjacent teeth. The clinical management of PFE is complex and multidisciplinary, and orthodontic traction is not recommended, as it often results in progressive ankylosis. Early identification of PFE is therefore essential to guide the therapeutic strategy.