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

OBJECTIVES: 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 x 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 x 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) RESULTS: 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). CONCLUSIONS: 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 x 0.022'' NiTi immediately after 0.016'' NiTi for alignment does not produce any damaging effect on the teeth.