Finite Element Analysis Of The Influence Of Canine Offset Opposite Position On The Trend Of Canine Movement In Tip-Edge Technique

When close the extraction spaces in Tip-Edge technique,the canine crown inclines tolingual side. Patients lead to premature contact and obstacle of lateral movement. Regulateintermaxillay is difficult to the one whose intermaxillay is disharmony. To this clinicalphenomenon we simulate the process of anterior teeth moved by Tip-Edge technique. Howto affect the trend of canine movement, we analysis different positions of closed force anddifferent widths of canine offset. These provide a theoretical basis for orthodontic treatment.Objectives:Analysis of the influence of canine offset opposite position on the trend of caninemovement in Tip-Edge technique by three dimensional finite element.Methods:The model for this study comes from a young female. This experiment employedhelicon-CT to scan the maxilla and maxillary dentition, establish the maxilla bone and teeth,divide grid and finished assembly by software of Mimics and Ansys13.0.Thus，we get thethree dimensional model for mechanic analysis. Simulate the process of anterior teeth movedby Tip-Edge technique, we design0mm,1mm,2mm different widths offset in mesial ofcanine bracket, then execute the size of the force load and change the force in the mesial anddistal of canine offset. Finally, finite element is calculated and analysised.Results:Simulate the process of anterior teeth moved by Tip-Edge technique.The afterburner point in the mesial or disal of the canine offset.The trend of caninecrown displacement is distal and lingual side. The stress of root concentrates at the mesiallabial side,and that of periodontal ligament concentrates at root and cervical margin. Whenafterburner point is located in the distal side of offset, the trend of crown displacement andthe equivalent stress of root increases with the width of offset and closed force increasing.The trend of the lingual tipping movement of the canine crown reducing whenafterburner point is located in the mesial side of offset. With the width of canine offsetincreasing, the trend of lingual displacement decreases obviously in the process. Conclusion：1. When close the extraction spaces in Tip-Edge technique, besides the distalmovement，canine crown has the trend of lingual movement.2. The trend of the lingual displacement of the canine crown is not the same whenafterburner point is located in the mesial or distal side of offset.3. At the same situation of closed force, the trend of canine crown lingual displacementincreases with the width of offset increasing,when the afterburner point is located in thedistal side of offset.4. At the same situation of closed force, with the width of canine offset increasing, thetrend of lingual displacement decreases in the process, when the afterburner point is locatedin the mesial side of offset.