Establishment, FEM analysis and experimental validation of tooth movement prediction model of orthodontic archwire T-loop

Abstract

Background The T-loop has been used clinically to close gap between teeth. And it is a typical orthodontic archwire bending method. However, the design of the T-loop parameters for different patients is based on the clinical experience of the dentists. The variation in dentists' clinical experience is the main reason for inadequate orthodontic treatment, even high incidence of postoperative complications. Methods Firstly, the tooth movement prediction model is established based on the analysis of the T-loop structure and the waxy model dynamic resistance. As well as the reverse reconstruction of the complete maxillary 3D model based on the patient CBCT images, the oral biomechanical FEM analysis is completed. A maxillary waxy dental model is manufactured to realize the water-bath measurement experiment in vitro mimicking the oral bio-environment. Thus, the calculated, simulation and experimental data are obtained, as well as obtaining a cloud of total deformation from the simulation analysis. Results The growth trend of the 11 sets of simulation data is the same as that of the experimental data. And all of them show that the tooth displacement is positively correlated with the cross-sectional size of the archwire, and the clearance distance. As well as the higher Young's modulus of the archwire material, the greater the tooth displacement. And the effect of archwire parameters on tooth displacement derived from simulation and experimental data is consistent with the prediction model. The experimental and calculated data are also compared and analyzed, and the two kinds of data are basically consistent in terms of growth trends and fluctuations, with deviation rates ranging from 2.17 to 10.00%. Conclusions This study shows that the accuracy and reliability of the tooth movement prediction model can be verified through the comparative analysis and deviation calculation of the obtained calculated, simulation and experimental data, which can assist dentists to safely and efficiently perform orthodontic treatment on patients. And the FEM analysis can achieve predictability of orthodontic treatment results.

Reference values and reliability of occlusal force distribution and occlusal time measured by the T‐Scan system in adults with healthy dentition

“…Interestingly, one study that determined the multi‐bite OT with three consecutive closures to MIP reported mean values of 0.14−0.17 s in a general population with healthy dentitions or after the retention period of orthodontic treatment 19 . Studies assessing OT with a single bite have reported mean values of 0.21−0.70 s in a similar population 23,28,39,40 . Thus, current research data suggest that the OT is longer with single‐bite closure compared with multi‐bite or consecutive closures to MIP.…”

“…19 Studies assessing OT with a single bite have reported mean values of 0.21−0.70 s in a similar population. 23,28,39,40 Thus, current research data suggest that the OT is longer with single-bite closure compared with multi-bite or consecutive closures to MIP.…”

“…17,18 For individuals with natural occlusions, a range of 50 ± 3 or ±5 %R has been reported, [19][20][21][22] with 50 ± 10 %R considered to indicate marked asymmetry. 19 Second, the APOFD then describes the occlusal balance of the posterior and anterior teeth, expressed as the percentage of occlusal force on the posterior teeth (%P), 23 as the ratio between percentages in the posterior with respect to % in anterior teeth, 24 or as the area ratio between the anterior to posterior contact surfaces. 19 Interpreting APOFD data is difficult because reference values are lacking for healthy occlusions.…”