Surgically Assisted Rapid Palatal Expansion Using a Patient-specific Prefabricated Transmucosally Fixed Appliance

Introduction: An increase in transverse maxillary width can be facilitated using tooth-borne, bone-borne or combined tooth-bone-borne appliances. The advantage of bone-supported expansion is the direct transfer of the expansion forces on to the bone, thus leading to a reduction in the negative side effects such as buccal tipping of the anchor teeth, root resorption and bone dehiscence associated with dental anchored expansion appliances. Ready-made skeletal anchored distractors are mostly fixed submucosally in the bone. However, this procedure is more invasive, patient comfort is reduced and the activation process complicated. Materials and Methods: A new patient-specific distraction device was developed using a standard Hyrax expansion screw made of titanium and standard titanium locking miniplates. After individual positioning and fixation of the locking plates and the Hyrax screw on the model of the patient's jaw, these components were laser welded. The appliance is fixed intraoperatively using standard-locking mini screws. Results: Treatment with this method was successfully completed in five cases. The activation of the screw by the patient seemed to be similar to standard removable appliances or dental anchored rapid maxillary extension appliances and was therefore very reliable. Removal of the devices is less invasive in comparison to the submucosally fixed appliances due to the epimucosal plate position. Conclusion: This newly described method combines the advantages of the hyrax appliances with skeletal anchored distractors. Patient compliance is increased, and the interdisciplinary treatment of these patients between maxillofacial surgeons and orthodontists is supported. Keywords: rapid palatal expansion, distraction osteogenesis