Tissue Perfusion and Biomarkers Assessment Following Root Coverage Procedures.

Abstract

Aim: To assess tissue perfusion changes and wound healing biomarker levels after root coverage procedures with coronally advanced flap in combination with the cross-linked xenogeneic collagen matrix (CCMX), loaded either with a placebo or recombinant human platelet-derived growth factor-BB (rhPDGF).

Methods: This study was designed as a secondary analysis from a previously published clinical trial, and it assessed the tissue perfusion changes over 6 months around multiple gingival recession defects, treated with either with CCMX alone (control) or with CCMX + rhPDGF (test). High frequency Doppler ultrasonography (HFUS) scans were obtained at sites of interest at baseline, 2 weeks, 3 months, and 6 months after surgery. Dynamic tissue perfusion measurements (DTPMs) were performed at the midfacial, interproximal, and transverse aspects of the teeth by an operator, blinded to treatment allocation, using a software package. The expression of different wound healing biomarkers from the gingival crevicular fluid was also assessed.

Results: The regression analyses showed similar tissue perfusion changes between the two groups throughout the majority of the 6 months. DTPMs at 2 weeks showed the test group to have significantly higher perfusion relief intensity (pRI, p < 0.001), mean perfused area (pA, p < 0.001), mean blood flow intensity (FI_mean, p = 0.021), and total blood flow intensity (FI_tot, p = 0.021) at the graft region of interest (ROI) compared to control sites. The test sites also exhibited significantly greater pA (p = 0.033) and blood flow intensity "blue" (FI_blue, meaning flow away from the transducer, p = 0.035) at the level of the flap compared to the control sites. At 2 weeks, FI_blue of the graft was directly correlated with the final mean root coverage (p = 0.008) and complete root coverage (p = 0.003). FI_mean and FI_tot of the graft exhibited a direct correlation with volume gain at 6 months (p = 0.031 for both parameters). The final GT gain was correlated to the early DTPMs (pA and FI_blue) of the graft and the flap. The two groups exhibited different expressions of IL-1β, PDFG-BB, and VEGF over 3 months, with the 1-week levels of PDGF-BB that were associated with time to recovery.

Conclusions: HFUS allowed exquisite assessment of tissue perfusion occurring at the entire surgical reconstructive regions and also within the flap and the graft. Sites treated with CCMX + rhPDGF exhibited higher DTPMs, primarily within the graft and flap ROIs at the 2-week timepoint compared to sites augmented with CCMX + saline. Early DTPMs at the graft and flap ROIs showed associations with PROMs and the final clinical outcomes.

Trial registration: ClinicalTrials.gov: NCT04462237.