Investigating salivary matrix metalloproteinase‑2 and matrix metalloproteinase‑9 activity in fixed orthodontic‑induced gingival enlargement

Abstract

Background: Gingival enlargement (GE) is a common clinical observation among
orthodontic patients, yet its underlying causes remain unclear. This study aims to investigate
the potential involvement of salivary matrix metalloproteinase (MMP)‑2 and MMP‑9 activity in
orthodontic‑induced GE.
Materials and Methods: In this case–control study, we enrolled 50 subjects, including 25 individuals
with GE and 25 without. The participants, aged 10–35 years, were in the 4th or 5th month of their
orthodontic treatment. Comprehensive clinical assessments, encompassing plaque index, gingival
index, and GE score were performed, and saliva samples were subjected to gelatin zymography
to assess enzyme activity. Statistical analysis, including the Chi‑square test for age distribution,
independent samples t‑test for age comparison between study groups, Mann–Whitney U test for
MMP activity comparison, and Wilcoxon signed–rank test for comparison of data from the 4th to
5th months of treatment, was performed using SPSS version 23.0, with a significance level set at 0.05.
Results: MMP‑2 activity was undetectable in the zymograms. In the 4th month of treatment, MMP‑9
activity was more prominent in the case group, though this disparity did not reach statistical
significance in the 5th month. Furthermore, MMP‑9 activity did not exhibit a correlation with the
GE score.
Conclusion: The activity of MMP‑9 in the saliva of orthodontic patients with GE increases during
the 4th month of treatment, but no correlation exists with the degree of GE.
Key Words: Fixed orthodontic appliances, gingival overgrowth, matrix metalloproteinase‑2,
matrix metalloproteinase‑9

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 Shima Golmohammadi: Pubmed,Google Scholar