Guided tissue regeneration may modulate gene expression in periodontal intrabony defects:: a human study

Background and Objective: Guided tissue regeneration has been shown to lead to periodontal regeneration; however, the mechanisms involved remain to be clarified. The present study was carried out to assess the expression of genes involved in the healing process of periodontal tissues in membrane-protected vs. nonprotected intrabony defects in humans. Material and Methods: Thirty patients with deep intrabony defects (>= 5 mm, two or three walls) around teeth that were scheduled for extraction were selected and randomly assigned to receive one of the following treatments: flap surgery alone (control group) or flap surgery plus guided tissue regeneration (expanded polytetrafluorethylene (e-PTFE) membrane) (test group). Twenty-one days later, the newly formed tissue was harvested and quantitatively assessed using the polymerase chain reaction assay for the expression of the following genes: alkaline phosphatase, receptor activator of nuclear factor-kappa B ligand, osteoprotegerin, osteopontin, osteocalcin, bone sialoprotein, basic fibroblast growth factor, interleukin-1, interleukin4, interleukin-6, matrix metalloproteinase2 and matrix metalloproteinase9. Results: Data analysis demonstrated that mRNA levels for alkaline phosphatase, receptor activator of nuclear factor-kappa B ligand, osteoprotegerin, osteopontin, bone sialoprotein, basic fibroblast growth factor, interleukin-1, interleukin-6, matrix metalloproteinase-2 and matrix metalloproteinase -9 were higher in the sites where guided tissue regeneration was applied compared with the control sites (p < 0.05), whereas osteocalcin mRNA levels were lower (p < 0.05). No difference was observed in interleukin-4 mRNA levels between control and test groups. Conclusion: Within the limits of this study, it can be concluded that genes are differentially expressed in membrane barrier-led periodontal healing when compared with flap surgery alone, and this may account for the clinical outcome achieved by guided tissue regeneration.