Despite the growing interest in oxygen-based medical interventions, limited evidence exists regarding the influence of Topical Oxygen Therapy (TOT) on oral mucosal tissues. This exploratory investigation sought to determine, through histological assessment, how palatal epithelial–connective tissue responds to localized oxygen exposure. Palatal tissue samples were collected from eight individuals undergoing free gingival graft (FGG) surgery. For each graft, one lateral section was randomly subjected to TOT (test), while the other remained untreated (control). Hematoxylin–eosin staining was used to assess overall tissue morphology, Picrosirius red staining evaluated collagen composition, and immunohistochemical assays identified inflammatory and angiogenic markers.
No structural abnormalities or cytotoxic effects were noted in either group, confirming that TOT did not compromise tissue integrity. Both groups predominantly exhibited type I collagen. Sparse immune infiltration, mainly of CD3+ T lymphocytes, was detected. Quantitative histomorphometric evaluation demonstrated that oxygen-treated specimens possessed a significantly larger mean vessel area (7607.95 μm² ± 3983.24 vs. 4038.42 μm² ± 1823.52), a greater number and caliber of blood vessels (49.82 ± 20.55 vs. 32.35 ± 16.64), and higher microvessel density (7.89 ± 3.25 vs. 5.13 ± 2.63 vessels/0.26 mm²). The findings suggest that topical oxygen application promotes microvascular development in palatal tissues without inducing morphological damage, indicating a potential role for TOT in accelerating oral wound repair through localized hyperoxia.
