A comparative study of initial changes in pulpal blood flow between conventional and self-ligating fixed orthodontic brackets during leveling and alignment stage



To evaluate and compare the initial changes in pulpal blood flow (PBF) between conventional and self-ligating fixed orthodontic brackets during leveling and alignment stage using 0.016 × 0.022 NiTi as alignment archwire.

Materials and methods

Twenty-two patients (16 females and 6 males) aged 19.00 ± 2.53 years who presented with mild lower arch crowding were selected to participate in the study. A split mouth study design was applied for each patient. The intervention (self-ligating brackets) was randomly allocated to the right or left side of the patient using the permuted random block size of 2 with 1:1 allocation ratio. Two different fixed appliance brackets were used in the lower arch (self-ligating brackets on one side and conventional brackets on the other side of the same patients. Two alignment archwires; 0.016″ NiTi and 0.016 × 0.022″ NiTi were used in this study. PBF was measured for the lower right and left sides using laser Doppler flowmetry at different time intervals (20 min, 24 h, 72 h, 1 week, and 1 month)


PBF started to decrease 20 min after insertion of both archwires using both types of brackets. Maximum decrease was reached after 72 h of archwire insertion. After 1 week of force application, PBF started to increase to restore its original values after 1 month. Differences between the 2 groups were not significant (P > 0.05).


In both treatment groups, PBF reduced within 48 h. PBF started to increase after 1 week until it reached its original values after 1 month. Changes in PBF at the measured time intervals in the two groups were similar.

Clinical relevance

The use of 0.016 × 0.022″ NiTi immediately after 0.016″ NiTi for alignment does not produce any damaging effect on the teeth.

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The study was supported by the deanship of research at Jordan University of Science and Technology, research grant number (236/2016).

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Corresponding author

Correspondence to Nessrin A. Taha.

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The authors declare that they have no conflict of interest.

Ethical approval

The study was approved by the institutional ethics and research committee at Jordan University of science and technology, and it is registered with clinicaltrials.gov registration number NCT NCT03780764

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A written informed consent was obtained from all participants before the treatment.

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Abu Alhaija, E.S., Taha, N.A. A comparative study of initial changes in pulpal blood flow between conventional and self-ligating fixed orthodontic brackets during leveling and alignment stage. Clin Oral Invest 25, 971–981 (2021). https://doi.org/10.1007/s00784-020-03386-2

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  • Pulpal blood flow
  • Self-ligating
  • Fixed orthodontics
  • Leveling and alignment stage