Stress analysis of maxillary first molar and its periodontium in lingual orthodontics

Objective To observe the stress distribution of maxillary first molar and its periodontium in lingual orthodontics.Methods The finite element model was built by using the advanced 3-dimensional laser scanning,comprising a maxillary first molar,periodontal ligament,alveolar bone,and a lingual tube.Different kinds of loads were applied at a point of the lingual tube.The stresses of root,periodontal ligament(PDL)and alveolar bone were analyzed.Results The order of stress of maxillary first molar and its periodontium was mostly rootPDLalveolar bone.The stress of bodily movement was smaller than that of tipping and rotation.The order of stress in different sections was:cervial region or furcation levelupper of root 1/3 level midst of root 1/3 level below of root 1/3 level.Conclusion The stress of the maxillary first molar and its periodontium was the biggest in cervial region or furcation level.So the changes of their regions should be observed carefully.When the tooth obtained bodily movement,the stresses of PDL and alveolar bone were uniform and low.So the bodily movement was more beneficial to the health of tooth and peridontal tissue.