Human beings have two dentitions, which require at least fifteen years for consolidation. During this process, the genetic information that determines shape and growth are expressed and the occlusion consolidates; however, during this period, environ- mental factors can generate changes in the form and function of the individual. Crowding is one of the most prevalent malocclusions and the treatment approach depends on the facial, skeletal and occlusal features of each patient. This article discusses the eruption guide procedure as an interceptive treatment for crowding based on the concepts of growth and occlusion development. It addresses the importance of developing preventive methods based on adequate knowledge of normal growth, dentition development and the factors that modify it. This review highlights the importance of serial extraction to anticipate space changes that will occur unless the teeth are removed with strategic intervals to relieve the severity of malocclusion.

Most patients with skeletal Class II malocclusion present a retruded position of the mandible. Functional appliances are fixed or removable appliances designed to alter the sagittal and vertical mandibular position, resulting in orthodontic and orthopedic skele- tal changes. Despite their long history, functional appliances remain controversial in their use, effectiveness and mode of action. This review will reveal the different treatment options for skeletal Class II malocclusion caused by mandibular retrusion, such as: Bionator, Twin block, Herbst, Jasper jumper, Forsus, mara and Advansync; it will also explain the mode of action, skeletal and dental effects and optimum treatment time for stability.