The Effect of Tractive Force Using a Temporary Anchorage Device (Screw Type) on the Alveolar Bone-Stress Analysis Using the Three-Dimensional Finite Element Method
Temporary anchorage devices (TAD) have been used for tooth intrusion and distal movement in recent years, and their clinical usefulness has been recognized. One of the advantages of using TAD in orthodontic treatment is shortening of the treatment period. A three-dimensional model of the maxilla was constructed to evaluate the utility of TAD, and stress change affecting the alveolar bone after the extraction of the first premolar was investigated using a three-dimensional finite element method.
Materials and methods
An outline of the model was fabricated from CT image data with extracted contours using the stress analysis software MECHANICAL FINDER version 6.2, followed by the construction of a three-dimensional maxillary model and fabrication of an extracted maxillary first premolar model. Four chronological models, immediately after tooth extraction, and after 1, 3, and 6 months, were fabricated by changing the CT values of the extracted area based on this model. A TAD was constructed in the mesial area of the upper first molar using SolidWorks (Solid Works Corporation.).
Method of data analysis
The upper first molar was constrained, and the upper canine was pulled in a distal direction towards a constructed anchor at 1 N to analyze stress change affecting the alveolar bone of the extracted area.
Results
Stress affecting the alveolar bone of the extracted area peaked immediately after tooth extraction, gradually decreased from 1 to 6 months, and reached a minimum at 6 months. Similarly, the amount of tooth displacement peaked immediately after tooth extraction, and gradually decreased from 1 to 6 months, and reached a minimum at 6 months.
Conclusions
The results suggest that it is more beneficial to apply tractive force in an early stage after tooth extraction for distal tooth movement using TAD.
two references
1,Ozaki K, Nakajima M, Kakudo K. Biomechanical analysis of corcicotomy. Jpn JournalofOsakaDentalUniversity2013;47-1
2,Motohashi T, Nakajima M, Kakudo K. Three-demensional finite element stress analysis on compression osteogenesis. Jpn J Jaw Deform 2007; 17: 1-8.