Oral Irrigation and Microbiome Remodeling after Oral Cancer Reconstruction

Patients with oral cancer undergoing free flap reconstruction face significant surgical trauma, making the prevention of postoperative wound infection and the maintenance of oral microecological balance critical. This study systematically evaluated oral microbiome changes before and after surgery and assessed the effectiveness of postoperative oral irrigation using 2 different regimens. In an exploratory randomized controlled trial, 60 patients were assigned to receive oral irrigation with either bipolar water or a combination of hydrogen peroxide and sodium bicarbonate solution. Saliva and irrigation samples were collected at 7 time points, preoperatively and before and 5 minutes after oral irrigation on postoperative days 1, 4, and 7, and analyzed using specialized sequencing techniques to determine microbial abundance and diversity. Clinical outcomes, including wound infection rates and patient comfort, were also recorded. The results indicated that surgical treatment reduced the diversity of the oral microbiota and altered its composition. Before surgery, the oral cavity was dominated by potentially pathogenic taxa, which shifted toward oral resident microorganisms postoperatively. Continued oral irrigation promoted a transition from an unstable, anaerobic-enriched state toward a relatively stable community structure dominated by facultative anaerobes. While no differences were observed between the 2 groups regarding wound infection rates or microbial composition, the bipolar water group reported higher patient comfort and required shorter irrigation times. Furthermore, the bipolar water group maintained more stable microbial diversity, whereas the hydrogen peroxide group exhibited more pronounced fluctuations and higher fungal detection rates. In conclusion, surgery induces early microbial imbalance, but staged oral irrigation facilitates the stabilization of the oral microecosystem. Bipolar water is an effective alternative for perioperative care, helping to maintain microbial stability while improving the patient experience.