Pain assessment using prostaglandin E₂ levels in passive self-ligating and conventional fixed appliances :...

To evaluate pain differences using prostaglandin (PGE₂) levels and visual analog scale (VAS) scores with passive self-ligating appliances (PSLA) and conventional fixed appliances (CFA).

Twenty-two eligible patients were randomized 1:1 to PSLA or CFA groups. Both arches were bonded with 0.022-inch appliances. A 0.014-inch Damon CuNiTi archwire was used in the PSLA group, while a 0.014-inch CuNiTi ovoid archwire was used in the CFA group. Gingival crevicular fluid from the distal gingival sulcus of the maxillary right canine and VAS scores were recorded at five time points: 1 h before archwire insertion (T0), and 24 (T1), 48 (T2), 72 (T3), and 168 h (T4) after insertion. Longitudinal changes were analyzed using generalized estimating equation (GEE) models with group, time, and group × time interaction effects. Data were expressed as median and interquartile range (IQR).

PGE₂ levels increased after archwire placement, peaked at 48 h, and subsequently declined in both groups. VAS scores peaked at 24 h before declining. Time had a significant effect on PGE₂ levels (Wald χ² = 55.69, p < 0.001) and VAS scores (Wald χ² = 742.30, p < 0.001). Despite significant group × time interactions for PGE₂ (p < 0.001) and VAS (p = 0.035), overall group effects were not significant.

Both PSLA and CFA demonstrated similar temporal patterns in PGE₂ levels and VAS pain responses during the early phase of orthodontic treatment, indicating that the appliance type alone may not substantially influence initial pain.