Fig. 28 should not be extracted until at least half of the succeda-neous tooth roots have developed (Fig. 26). 2 Fig. 29 and utilizing timely serial guidance principles allow for efficient treatment (reducing the chances for impacted and ectopic teeth) and excellent clinical outcomes. When to Perform Serial Guidance In my opinion, serial guidance should not be performed until there is adequate space for the succes-sor teeth to erupt. The arch should be under control before performing serial guidance with space main-taining (Fig. 3) or space gaining (Fig. 27) appliances to allow the teeth to erupt properly. In the case shown in figures 20, 28 and 29, a maxil-lary NPE and mandibular lip bumper were used to develop the arches. An .018 NUA was used to align the mandibular incisors (Fig. 20). The red lines showing the axial inclinations of the cuspids and bicuspids demon-strate over time the uprighting (redirection of eruption) of these teeth as the arches were developed (Figs. 28 and 29). The remaining primary cuspids and first molars were extracted (serial guidance) to allow for the eruption of the succedaneous teeth as they now have adequate space to erupt (Fig. 29). References 1. Buschang PH.: Maxillomandibular expansion: Short-term relapse potential and long-term stability. Am J Orthod Dentofacial Orthop 2006 Apr; 129(4Suppl): S75-9. 2. Carapezza, Leonard J., DMD. Six Keys to Early Mixed Dentition Class II Correction: A Quantified Approach to Diagnosis and Treatment. Journal of American Orthodon-tic Society; Spring 2014. 3. Gerety, Robert G. Gerety Orthodontic Seminars. Palatal Expansion with the Nitanium Palatal Expander 2 (NPE). Straight Wire Concepts: Diagnosisi and Technique. Produced by Kay C. Gerety, CDA. 4. Greenfield, Raphael L. DDS, MSCD. Non Ex Factors. 98.5% Nonextraction Therapy using Coordinated Arch Development. DaehancNarae Publishing, Inc. Seoul, South Korea; 2010. 5. http://www.orthonj.com/leeway.html 6. http://www.columbia.edu/itc/hs/dental/d7710/ client_edit/syllabus/spacerelationships.html 7. Korn, Marcel, DMD. Redirecting Eruption. Orthodontic Products; Sept. 1, 2005. http://www.orthodonticproduct-sonline.com/2005/09/redirecting-eruption-2005-09-05/ 8. Newby, Randy K., DDS. Exploring the First Two Keys of Class II Correction:Maxillary Arch Development and Maxillary Molar Position. Journal of the American Orthodontic Society; Fall 2014. 9. Ortho Organizers. 1822 Aston Avenue. Carlsbad, CA 92008. 1-800-547-2000. www.orthoorganizers.com Conclusion Leeway space may be lost, preserved or enhanced. In non-extraction crowded cases gaining arch length through arch development is imperative. Orthopedic appliances such as the NPE and lip bumper allow the practitioner to accomplish this. Buschang attributes the long term stability of lip bumper therapy to leeway space maintenance and transverse development of the mandible. 1 In other words, leeway space is enhanced and there are perma-nent positive orthopedic changes in the mandible to help resolve crowding. In mixed dentition cases, the practitioner needs to be aware of the eruption patterns of unerupted perma-nent teeth. Redirecting faulty eruption paths of teeth 24 Summer 2016 JAOS
Journal of the American Orthodontic Society Summer 2016 / Buyer's Guide: Page 24
