The Evaluation of Vertical Tooth Movement During Mandibular Molar Distalization Using 3-D Printed Retromolar plate

Abstract

Evaluation of the amount of mandibular molars movement is challenging in the field of orthodontics. Intrustion of teeth during distalization was not thoroughly investigated in previous studies. The present study CBCT and intra-oral scans were used for assessment of occlusogingival movement of mandibular molars after distalization. Eight participants were recruited in this study who required mandibular distalization, all candidates were treated by unilateral mandibular distalization. Molar Bands were selected for the first and second molars and an impression was taken for the fabrication of the intra-oral appliance. The intra-oral appliance was fabricated using a rigid stainless steel wire 1 mm thickness soldered from buccal and lingual site to connect the two molar bands and soldered to the connector wire form labial and buccal side a rigid power arm extending vestibular till the level of the molar bifurcation. 3-D printed titanium plate was designed using solid works software after importing the STL file converted from the CBCT DICOM file. The plate was designed so that it fits the retro-molar area giving enough space for mandibular distalization and to be secured in place using standard surgical fixation screw. The plate was designed to have two arms extending vestibular buccally and lingually to the level of the power arms. The occlusogingival movement of each cusp in reference to horizontal plane on axial plane was assessed to evaluate the amount of intrusion. The results revealed that the amount of intrusion of lower first molar and lower second molar were considered to be clinically acceptable.