A comparative study of initial changes in pulpal blood flow between clear aligners and fixed orthodontic appliances

Introduction: The objective of this study is to evaluate and compare the initial changes of pulpal blood flow (PBF) using clear aligner and fixed orthodontic treatment. Methods: A total of 45 subjects were subdivided into 2 groups: group 1; 25 subjects treated with preadjusted edgewise fixed appliance with 0.014 '' nickel titanium as the alignment archwire and group 2; 20 subjects treated using clear aligner. In both groups, PBF was measured for the maxillary right and mandibular left teeth using Laser Doppler flowmetry at different time intervals (20 minutes, 48 hours, 72 hours, and 1 month) after the fitting of the nickel titanium archwire in group 1 and after the delivery of the second aligner in group 2. A repeated-measures analysis of variance and a Bonferroni post-hoc comparison test were applied to determine differences at the various time intervals. Results: The PBF decreased in both types of appliances after force application. The maximum reduction in PBF was reached after 72 hours. It returned to its normal values within 1 month. The differences in PBF between the 2 groups did not reach any statistical significance. Conclusions: PBF in orthodontically treated teeth decreased 20 minutes after orthodontic force application in both fixed and clear aligner appliances. In both treatment groups, most changes occurred within 48 hours of force application. PBF returned to its normal values within 1 month. Changes in PBF in both treatment groups were comparable.