Aim: Facial orthopedics must be applied with individualized patient needs and goals in mind. This article describes some effective appliances for mandibular arch development and space gain in nonextraction therapy. Methods: Determine the appliance(s) and the most effective approach for individualized therapeutic requirements. Removable and fixed appliances are often used in tandem. Results: Mandibular arch space gains of 4 to 8 mm are consistently achieved, depending on individual facial type and arch discrepancies. The mandibular arch form and width are optimized as transverse decompensation (buccal uprighting) is achieved. Class II malocclusions have a transverse deficiency component. Expansion therapy and lateral arch development increase available space, help to unlock mandibular posture, and optimize anteroposterior development. Conclusion: Nonextraction treatment is more possible with early orthopedic and mixed dentition intervention. Transverse dimension is a treatment priority that is accomplished by reshaping the arch form and uprighting the buccal segments. Greater posterior arch width and alveolar remodeling changes can be achieved when treatment occurs before the permanent canines and premolars have erupted. The mandibular posterior transverse dimension dictates the extent of maxillary expansion that will coordinate the arches and allow optimal interdigitation. Facial harmony and balance are optimized with transverse structural and dentoalveolar space gains, resulting in improved occlusal and smile features. World J Orthod 2001;2:177-189