Biomechanics
Prerna Pahuja; Divya Yadav; Harshita Gupta; Gurkeerat Singh; Monika Dahiya; Arisha Izhar; Akanksha Shukla; Deepali Bisht
Abstract
Aim: Among various retraction methods for space closure in first premolar extraction, the palatal approach is preferred to labial appliances in cases having high aesthetic demand. A finite element model and clinical randomized prospective trial was undertaken to determine the possibility of en-masse ...
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Aim: Among various retraction methods for space closure in first premolar extraction, the palatal approach is preferred to labial appliances in cases having high aesthetic demand. A finite element model and clinical randomized prospective trial was undertaken to determine the possibility of en-masse retraction of maxillary anterior teeth using palatal TAD and a clear aligner-like appliance in patients undergoing extraction of maxillary first premolars and to study the effects of the above using three-dimensional scanned models and lateral cephalograms.Methods: A finite element model of maxillary dentition with alveolar bone, an acrylic splint on six anterior teeth, palatal implants, and short e-chain were produced to measure shifting when force was applied from three various levels. Thereafter, the finite element analysis findings were applied to 10 patients requiring fixed orthodontic treatment with first premolar extraction and fulfilling the inclusion criteria. Impressions were made and the rate of retraction was evaluated at 4-week intervals by superimposition of scanned models.Results: En-masse bodily retraction was seen when both canine hooks and palatal TAD was placed at 10 mm distance from the respective gingival margin. Clinically, subjects showed significant retraction at that level and statistically significant results in some cases. The maximum rate of retraction was seen in the first three months (average: 5.310 mm) with p-value <0.0001.Conclusion: Translational tooth movement was observed when line of force was at the level of the center of resistance.
Arisha Izhar; Gurkeerat Singh; Varun Goyal; Rajkumar Singh; Nishant Gupta; Prerna Pahuja
Abstract
Objectives: The objective of this clinical study was to assess the predicted treatment outcome and actual treatment outcome and compare the models of both the groups so as to evaluate the efficacy of tooth movement with clear aligner.
Methods: The sample size included 10 cases with mild anterior crowding ...
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Objectives: The objective of this clinical study was to assess the predicted treatment outcome and actual treatment outcome and compare the models of both the groups so as to evaluate the efficacy of tooth movement with clear aligner.
Methods: The sample size included 10 cases with mild anterior crowding treated with aligner therapy. The predicted software models were superimposed on the Clinical STL models at various stages by using MeshLab software (Developed at the Visual Computing Lab at ISTI-CNR with the support of the 3D-co-form project).The predicted software models showing orthodontic tooth movement was compared with the actual movement achieved clinically. Results: The results of this study have shown that when a comparison was made on the basis of irregularity scores in both the groups, it was seen that the irregularity score was more in Clinical STL group at each stage such as 2.55 at T4, 1.65 at T6 and 1.0 at T8 whereas 2.0 at T4. 0.90 at T6 and 0.25 at T8 in the Software model group. Also, on comparing mean accuracy these three stages, the analysis of data showed the mean accuracy at T4 is 62.5%, mean accuracy at T6 is 68.8% and the mean accuracy at T8 is 78.1%.
Conclusions: The predicted software models do not accurately reflect the patient’s tooth position .There is an overestimation by predicted software as compared to the actual achieved tooth position. There is a need of overcorrection to be built in the treatment planning stage itself and execution of the anticipated end result.