OBJECTIVE: Relapse after rapid palatal expansion (RPE) is associated with insufficient bone formation in the midpalatal suture during retention. This study evaluated the effects of thymoquinone (TQ) and high-frequency vibration force (VF) on bone formation after RPE in a rat model. METHODS: 24 male Wistar rats were randomly divided into three groups (n = 8): control (RPE only), vibration (RPE + 111 Hz vibration) and TQ (RPE + TQ). RPE was performed for 5 days with a 50-g force followed by a 12-day retention period. VF was applied for 20 min/day during retention, while TQ was administered orogastrically at 10 mg/kg/day. Histomorphometric analysis included osteoblast, osteoclast, and capillary numbers, mineralized area, fibrous area, and osteocalcin immunoreactivity. Data were analysed using ANOVA or Kruskal-Wallis tests with Bonferroni correction (α = 0.05). RESULTS: Both VF and TQ groups showed significantly higher osteoblast counts than the control group (VF: 20.5 ± 3.56; TQ: 19.3 ± 2.80; control: 10.6 ± 2.16; p < 0.001). Capillary numbers were also higher in the VF (9.83 ± 2.78) and TQ groups (10.0 ± 2.82) than in the control group (3.50 ± 1.76) (p < 0.01). Mineralized area values were greater in the VF (41.06 ± 5.58) and TQ groups (38.35 ± 8.48) than in the control group (23.77 ± 3.37) (p < 0.001). Fibrous area values were lower in both experimental groups (p < 0.01). CONCLUSIONS: TQ and high-frequency vibration enhanced bone formation and angiogenesis during retention after RPE. These approaches may represent adjunctive strategies to improve post-expansion bone remodelling, although further clinical studies are required.
Zi̇nci̇r et al. (Wed,) studied this question.