A Three-dimensional Finite Element Analysis Of Maxillary Dentition Distalization Using Modified C-palatal Plates Combined With Different Palatal Arches

Objective To analyze the movement trend and the biomechanical mechanism of tooth in maxillary dentition distalization through modified C-palatal plate(MCPP)combined with continuous or discontinuous palatal arches under different force position using 3-dimensional finite element analysis.Methods Three-dimensional finite element model about maxillary dentition distalization through MCPP combined with continuous and discontinuous palatal arches was established using cone-beam CT scan data.The vertical position of MCPP notches are 2mm,5mm,8mm apical to the alveolar crest ridge and the palatal arch hooks height are 1mm,4mm,7mm.3N retraction forces were applied between the different notches and hooks in continuous and discontinuous palatal arches groups using 3-dimensional finite element analysis software to compare the tooth movement.Results 1.In continuous palatal arches group,the maxillary dentition showed different degrees of clockwise rotation at all 9 loading directions.The first molar crowns all had distalout rotation and distal and buccal movement with the width of the dental arch increasing.When the MCPP notches were 8 mm apical to the alveolar ridge with the 1 mm high hooks,the incisal edge of central incisors moved labially,which would retract under other loading directions.2.In discontinuous palatal arches group,when the MCPP notches were 2 mm apical to the alveolar ridge with the 4 mm and 7mm high hooks,the maxillary dentition showed a small amount of clockwise rotation.And it would have a counterclockwise rotation under other loading directions.The first molar crowns had distal-out rotation and distal movement.When the MCPP notches were 8 mm and 5mm apical to the alveolar ridge,The first molar crowns moved lingually with the width of the dental arch decreasing and the incisors moved labially.3.Compared with the continuous palatal arches group,the rotation,lateral movement and distal movement of the first and second molars in the discontinuous palatal arches group were more obvious.Conclusions MCPP combined with continuous palatal arch could effectively distal ize the maxillary dentition.The maxillary dentition had the trends to clockwise rotation and increasement in the width of the dental arch.When MCPP was combined with discontinuous palatal arch,the molars would distalize significantly,and the trend to the maxillary dentition counterclockwise rotation would be obvious.It is possible that the width of dental arch may decrease and the anterior teeth may move labially.The closer the MCPP notches position to the occlusal plane,the more obvious the trends to clockwise rotation of the occlusal plane and the distalization of the maxillary dentition.The higher the height of traction hooks,the more obvious the trends to increase in dental arch width.