Topical Oxygenation Improves Microvascularity in a Human Ex Vivo Palatal Tissue Model: A Histological Analysis

<b>Background:</b> Several therapies involving the use of oxygen have been developed; however, the literature to date has poorly addressed the effects of Topical Oxygen Therapy (TOT) on oral tissues. The aim of the present pilot study was to histologically evaluate the response to TOT in epithelial-connective samples harvested from the palate. <b>Methods:</b> In eight patients selected for a free gingival graft (FGG) procedure, the lateral portions of the graft were randomly assigned to receive TOT (test) or no treatment (control). Both the portions were stained with hematoxylin-eosin for the evaluation of histomorphological changes and with Picrosirius for the study of collagen. Immunohistochemical staining was performed with antibodies for the characterization of the inflammatory infiltrate and neoangiogenesis. <b>Results:</b> The analysis failed to show morphological variations in both groups, demonstrating that there was no tissue damage due to TOT. The prevalence of type I collagen in both samples supported this finding. Immune cells were present in low levels and mainly consisted of CD3+ T lymphocytes. The histomorphometric analysis showed an increased average vessel area (7607.95 μm² ± 3983.24 vs. 4038.42 μm² ± 1823.52), an increased number and caliber of vessels (49.82 ± 20.55 vs. 32.35 ± 16.64), and a higher microvessel density (7.89 ± 3.25 vessels/0.26 mm² vs. 5.13 ± 2.63 vessels/0.26 mm²) in the test group. <b>Conclusions:</b> Although further investigations are needed, TOT could improve and speed up oral wound healing through the local condition of hyperoxia.