Correction of mandibular retrognathia and laterognathia by distraction osteogenesis 340 observe a significant increase in ramus length in patient 1 in whom the vertical component of the external distractor was activated. In our opinion, the activation did not translate exactly to the de- sired increase in ramus length due to angular al- terations performed during distraction. Patient 3 developed anterior open bite dur- ing distraction as a result of misplacement of the distractor and reduced vector control. Anterior open bite in this patient was corrected by mould- ing of the regenerate using intermaxillary elastics for 10 days following the removal of the distrac- tion cylinders from the distractors in the second week of the consolidation period. However, follow up records taken 5.3 years after the completion of treatment indicated relapse of the anterior open bite. Gateño et al suggested that computer as- sisted surgical planning and modeling could be helpful in determining the correct distraction vec- tor and in accurate placement of the distractors.36 In our opinion, the long term relapse observed in Patient 3 could have been avoided or its rate could have been decreased through the use of computer assisted surgical planning and modeling. The uni- lateral posterior open bite seen in patients 4 and 5 during distraction was corrected by orthodontic extrusion of the posterior teeth using elastic trac- tion. No anterior open bite was seen in patient 2 in whom an effort was made to place the distrac- tors parallel to the maxillary occlusal plane. We believe that gonial angle increase in patients 1,3 and 5 was caused by the downward relocation of menton point as a result of genioplasty. Although genioplasty was deemed indicated for the patients 2 and 4, it was not performed as the patients were satisfied with the treatment result. A possible advantage of distraction is its ef- fect on the inferior alveolar nerve. Makarov et al suggested that if acute nerve injury is avoided with surgery, then up to 10 mm of distraction of the mandible would appear to produce minimal effects on inferior alveolar nerve function.37 In all patients, paresthesia developed on the related side(s) following surgery and intensified during distraction period. However, it diminished gradu- ally after the treatment and was not observed in follow-up examinations. Marked changes occurred in the position and shape of the lower jaw and in the occlusion as a re- sult of mandibular distraction. Even though the ra- mus height remained unchanged in patients 2 and European Journal of Dentistry 3, significant amount of lengthening was achieved in mandibular corpus in patients 1,2 and 3. An in- crease in ramus height was observed in patients 4 and 5 on the affected side. Anterior movement of the lower jaw resulted in sagittal improvement of the prominence of the chin point. However in patients 1,3 and 5, genioplasty was deemed nec- essary as required chin prominence could not be achieved by distraction alone due to limitation im- posed by post-distraction dental occlusion. concLusIons It can be concluded that distraction of the de- formed mandible is a feasible and effective tech- nique for treating mandibular retrognathia and laterognathia and that long term relapse is within acceptable limits. However, it must be borne in mind that accurate placement of the distractors and determining the correct distraction vector are crucial factors that have an influence on long term clinical success. rEFErEncEs 1. Paley D, Catagni MA, Argnani F, Villa A, Benedetti GB, Cat- taneo R. Illizarov treatment of tibial nonunions with bone loss. Clin Orthop Relat Res 1989;241:146–165. 2. Samchukov ML, Ezaki M, Tucker WF, Ross JD. Restoration of apposition function in residual hand by Illizarov method: a case report. Bull Hosp Jt Dis Orthop Inst 1993;53:13–16. 3. Cope JB, Harper RH. Significant mandibular deficiency treated by osteodistraction: an alternative to traditional orthognathic surgery. World J Orthod 1999;5:25–34. 4. Bengi AO, Gürton AU, Okcu KM, Aydintug YS. Premaxillary distraction osteogenesis with an individual tooth-borne ap- pliance. Angle Orthod 2004;74:420–431. 5. Sayin S, Bengi AO, Gurton AU, Ortakoglu K. Rapid canine distalization using distraction of periodontal ligament: a preliminary clinical validation of the original technique. Angle Orthod 2004;74:304–315. 6. Stucki MC, Cormick SU. Reconstruction of the mandibular condyle using transport distraction osteogenesis. J Cranio- fac Surg 1997;8:48–52. 7. Snyder CC, Levine GA, Swanson HM, Browne EZ Jr. Man- dibular lengthening by gradual distraction: preliminary re- port. Plast Reconstr Surg 1973;51:506. 8. McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1–8.