فهرست نشریات علمی دسترسی آزاد ایران

AimThis study aimed to compare changes in gingival crevicular fluid (GCF) matrix metalloproteinase‑9 (MMP‑9) levels and radiographically assessed orthodontically induced root resorption (OIRR) in patients undergoing maxillary anterior retraction with or without mini‑implant–assisted intrusion.MethodsIn this clinical trial, 14 participants were allocated into two groups (n = 7 each). Group 1 underwent anterior retraction following first premolar extraction, whereas Group 2 received simultaneous intrusion and retraction using a midline mini‑implant. GCF samples were collected at three time points: T0 (baseline), T1 (initiation of retraction), and T2 (three months after retraction). MMP‑9 concentrations were quantified using an ELISA assay. Radiographic evaluation of OIRR via standardized RadioVisioGraphy (RVG) was performed at T0 and T2 using the Modified Malmgren Criteria. Statistical analyses using Fisher Exact, independent and paired t‑tests. P-value<0.05 was considered as significant.ResultsBaseline MMP‑9 concentrations were comparable between the two groups (Group 1: 0.99 ± 0.37 ng/mL; Group 2: 0.96 ± 0.10 ng/mL; P > 0.05). Both groups showed a significant increase in GCF MMP‑9 levels from T0 to T1 and from T1 to T2. At T2, mean MMP‑9 levels were significantly higher in Group 2 (2.82 ± 0.62 ng/mL) compared with Group 1 (2.12 ± 0.49 ng/mL) (P = 0.03), corresponding to percentage increases of 193.7% and 114.1%, respectively.Radiographic assessment revealed no evidence of root resorption at baseline in either group. At T2, both groups demonstrated a statistically significant increase in root resorption scores compared with baseline (P = 0.0001). The Pearson correlation test for Group 1 showed a moderate negative correlation between T2 MMP-9 values and T2 root resorption grade (r = -0.46, p = 0.299). In Group 2 , the Pearson correlation test showed a strong negative correlation between T2 MMP-9 values and T2 root resorption grade (r = -0.89, p = 0.007).Conclusion Both orthodontic retraction alone and retraction combined with mini‑implant–assisted intrusion were associated with increases in GCF MMP‑9 levels and mild radiographic root resorption over the three‑month period. Although the intrusion group showed higher MMP‑9 levels, this did not lead to clear radiographic differences between the groups. This study showed a strong and statistically significant negative correlation between T2 MMP‑9 levels and root resorption grade , but the overall clinical relevance of this pattern remains uncertain.