Medical Devices: Evidence and Research (Mar 2020)
A New Methodology for the Digital Planning of Micro-Implant-Supported Maxillary Skeletal Expansion
Abstract
Daniele Cantarella,1 Gianpaolo Savio,2 Luca Grigolato,2 Paolo Zanata,3 Chiara Berveglieri,4 Antonino Lo Giudice,5,6 Gaetano Isola,5 Massimo Del Fabbro,1 Won Moon7 1Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy; 2Department of Civil, Environmental and Architectural Engineering ICEA, University of Padova, Padova, Italy; 3Private Practice, Castelfranco Veneto, Italy; 4Private Practice of Orthodontics, Bondeno, Italy; 5Department of General Surgery and Surgical-Medical Specialties, Section of Orthodontics, School of Dentistry, University of Catania, Catania, Italy; 6Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Section of Orthodontics, University of Messina, Messina, Italy; 7Division of Growth and Development, Section of Orthodontics, School of Dentistry, Center for Health Science, University of California, Los Angeles, Los Angeles, CA, USACorrespondence: Daniele CantarellaDepartment of Biomedical, Surgical and Dental Sciences, University of Milan, Via Commenda 10, Milan, ItalyEmail [email protected]: Miniscrew-assisted rapid palatal expansion (MARPE) appliances utilize the skeletal anchorage to expand the maxilla. One type of MARPE device is the Maxillary Skeletal Expander (MSE), which presents four micro-implants with bicortical engagement of the palatal vault and nasal floor. MSE positioning is traditionally planned using dental stone models and 2D headfilms. This approach presents some critical issues, such as the inability to identify the MSE position relative to skeletal structures, and the potential risk of damaging anatomical structures.Methods: A novel methodology has been developed to plan MSE position using the digital model of dental arches and cone-beam computed tomography (CBCT). A virtual model of MSE appliance with the four micro-implants was created. After virtual planning, a positioning guide is virtually designed, 3D printed, and utilized to model and weld the MSE supporting arms to the molar bands. The expansion device is then cemented in the patient oral cavity and micro-implants inserted. A clinical case of a 12.9-year-old female patient presenting a Class III malocclusion with transverse and sagittal maxillary deficiency is reported.Results: The midpalatal suture was opened with a split of 3.06 mm and 2.8 mm at the anterior and posterior nasal spine, respectively. After facemask therapy, the sagittal skeletal relationship was improved, as shown by the increase in ANB, A-Na perpendicular and Wits cephalometric parameters, and the mandibular plane rotated 1.6° clockwise.Conclusion: The proposed digital methodology represents an advancement in the planning of MSE positioning, compared to the traditional approach. By evaluating the bone morphology of the palate and midface on patient CBCT, the placement of MSE is improved regarding the biomechanics of maxillary expansion and the bone thickness at micro-implants insertion sites. In the present case report, the digital planning was associated with a positive outcome of maxillary expansion and protraction in safety conditions.Keywords: miniscrew-assisted rapid palatal expansion, MARPE, CBCT, MSE, virtual planning, cephalometrics-based digital planning, CBDP, workflow, TAD
