Accuracy of maxillary digital setup predictions of patients treated with maxillary first premolar extractions: A retrospective study.

Introduction: This study aimed to assess the predictability and accuracy of treatment virtual simulation when compared with the final outcome in patients treated with the extraction of maxillary first premolars according to the type of anchorage.

Methods: A total of 62 patients were selected, based on the extraction of at least the maxillary first premolar in patients with Angle Class I or II malocclusion. Notably, 40 were treated with the maximal anchorage technique, whereas the 22 others were treated with the reciprocal anchorage technique for space closure. The study models were scanned with a 3Shape D500 desktop scanner. Digital setups were constructed according to their respective treatment plans. Digital measurements of the intercanine, interpremolar, and intermolar width on scans 1, 2, and 3 and the variation on each superimposition in the sagittal, transversal, and vertical plane of the following teeth: maxillary first right molar (16), maxillary first left molar (26), maxillary right canine (13), and maxillary left canine (23).

Results: For the virtual setup compared with the final outcome scan, it was found to be reliable for simulations of intercanine, interpremolar, and intermolar width using the reciprocal anchorage technique (P = 0.889, P = 0.212, and P = 0.059, respectively) but not for the maximal anchorage (P = 0.003, for the intercanine width and P <0.001 for the interpremolar and intermolar width). Regarding the reliability of the virtual setup scan in the 3 directions, the virtual scan was found to be reliable for predicting the following movements: (1) sagittal movements of the 4 selected teeth using reciprocal anchorage, (2) vertical movements of 13 and 23 using both anchorage techniques, and (3) transversal movement of the 4 selected teeth using both anchorage techniques. The differences between the final outcome scan and virtual setup scan were not significantly different from 0, with P >0.05.

Conclusions: This study supported the use of virtual setups for the purpose of guiding treatment and visualizing potential outcomes of patients treated with maxillary first premolar extraction with the reciprocal anchorage technique.