Eruption disturbances of permanent molars may become clinically and radiographically manifest as impaction, primary retention or secondary retention. This may result in clinical problems such as malocclusion and loss of neighboring teeth due to caries and periodontal disease. Which of these disorders will develop, depends primarily on the eruptive stage. Factors that may interfere with the eruptive stages (i.e. follicular growth, pre-emergent eruptive spurt, postemergent eruptive spurt, juvenile occlusal equilibrium, circumpubertal occlusal eruptive spurt, adult occlusal equilibrium) and the clinical consequences of that interference are reviewed. Treatment recommendations are given.