Matrix metalloproteinase 9 levels in gingival crevicular fluid in patients after periodontal microsurgery for orthodontic induced gingival hypertrophy.

INTRODUCTION: In this study, we aim to compare the levels of matrix metalloproteinase 9 (MMP9) in the gingival crevicular fluid (GCF), as indicators for healing, in two groups of patients - operated with a classic periodontal surgical technique and the same technique but using a dental microscope. MATERIALS: We included 14 patients with ages between 12 and 26 years, average 14±6.2 years. Eight patients were women and six men. All patients presented gingival hypertrophy because of the orthodontic treatment on the mandibular arch. We performed gingivectomy on one-half of the mandibular arch by classic periodontal surgery and on the other half of the mandibular arch by a microscope-assisted gingivectomy. METHODS: In the hypertrophied gingiva, the expression of MMP9 was identified using immunohistochemical-staining techniques. For immunological determination of MMP9 in GCF we performed Elisa tests. RESULTS: We found different levels in different moments of the healing process for the two hemiarcades. CONCLUSIONS: We consider that faster healing in case of microscope-assisted gingivectomy may be related to the expression of MMP-9 in the GCF.