Background and Aim: Among various retraction methods for first premolar extraction space closure, the palatal approach is preferred to labial appliances in cases having high esthetic demand. A FEM and clinical randomized prospective trial was undertaken to find out the possibility of en-mass retraction of maxillary anteriors using palatal TAD’s and a clear aligner like appliance in patients undergoing extraction of maxillary 1st premolars and to study the effects of the above using 3D scanned models & lateral cephalograms.
Methodology: A Finite Element Model of maxillary dentition along with alveolar bone, acrylic splint on anterior six teeth ,palatal implants and short E-chain was developed with defined material properties. The model was analysed to calculate the displacement when force was applied from different levels. Thereafter, the finite element analysis findings were applied to the 10 patients requiring fixed orthodontic treatment with first premolar extraction and fulfilling the inclusion criteria. Impressions were made and the rate of retraction evaluated at 4-week intervals by superimposition of scanned models.
Result: En-mass bodily retraction was seen when both canine hook and palatal TAD was placed at 10mm distance from respective gingival margin. Clinically subjects showed significant retraction at that level and statistically significant results in some cases.
Conclusion: Translational tooth movement was observed when line of force application was at level of centre of resistance.