Distraction Osteogenesis of the Midface George K.B. Sa ´ndor, MD, DDS, PhD, Dr Habil, FRCDC, FRCSC, FACS a,b,c,d,e,f, T , Leena P. Ylikontiola, DDS, PhD e,f,g , Willy Serlo, MD, PhD g,h , Robert P. Carmichael, DMD, MSc, FRCDC a,b,c,d , Iain A. Nish, DDS, MSc, FRCDC a,b,i , John Daskalogiannakis, DDS, MSc, FRCDC a,b,c a University of Toronto, Toronto, Ontario, Canada b The Hospital for Sick Children S-525, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8 c Bloorview MacMillan Children’s Centre, 170 Kilgour Road, Toronto, Ontario, Canada M4G 1R8 d Department of Oral and Maxillofacial Surgery, Mount Sinai Hospital, Toronto, Ontario, Canada e Department of Oral and Maxillofacial Surgery, University of Oulu, Oulu, Finland f Institute of Dentistry, University of Oulu, Box 5281 FIN-90014, Finland g Oulu University Hospital, Box 23, FIN-90029 Oulu, Finland h Department of Pediatric Surgery, University of Turku, Turku, Finland i Lakeridge Medical Centre, Oshawa, Ontario, Canada The field of pediatric oral and maxillofacial sur- gery is continuing to evolve and is in a dynamic phase as our understanding of growth and develop- ment of the craniomaxillofacial complex expands. Bone regeneration and tissue engineering technolo- gies have been developed to treat skeletal defects with reduced morbidity [1]. Distraction osteogene- sis recently emerged as a technique that by its very nature allows changes to the vectors of growth and results in the genesis of new tissues [2]. It is a rapidly developing area with applications in the area of pediatric oral and maxillofacial surgery. Distraction osteogenesis is a biologic process that promotes bone formation between cut osseous surfaces that are gradually separated by incremental traction [3]. This process is initiated when forces are applied to separate the segments and continues as long as the tissues of the callus that forms between the segments are stretched. Bone formation occurs parallel to the direction or vector of distraction. This process also initiates histiogenesis of the tissues surrounding the distracted bone: cartilage, liga- ments, muscle, blood vessels, gingiva, and nerve tis- sue [2,4,5]. History of midfacial distraction osteogenesis Distraction osteogenesis as it applies to the mid- face is not a new concept. Dentists have used tech- niques that involve the application of tensile and compressive forces to the bones of the craniomax- illofacial skeleton for almost 300 years. According to Balaji [6], Fauchard described the use of an expan- sion arch as early as 1728, a custom-made metallic arch applied to the crowded maxillary dentition, to widen the arches to a more physiologic form. Wescott attempted to correct a crossbite by placing two double clasps on the maxillary bicuspid teeth and a tele- scopic bar to apply transverse force [6]. Similarly, Angell [7] expanded a maxillary arch by using a transverse jackscrew and clasps on the bicuspid teeth. 1042-3699/05/$ – see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.coms.2005.06.005 oralmaxsurgery.theclinics.com T Corresponding author. The Hospital for Sick Children S-525, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. E-mail address: george.sandor@utoronto.ca (G.K.B. Sa ´ndor). Oral Maxillofacial Surg Clin N Am 17 (2005) 485 – 501