This is a prospective study in a human model examining treatment of patients who have sustained damage to salivary glands following head and neck radiation, subsequent xerostomia, and who are currently indicated for hyperbaric oxygen therapy for treatment of osteoradionecrosis. Salivary flow rates, pH and buffering capacity before and after hyperbaric oxygen treatments will be collected using GC America (Alsip, Illinois) Saliva-Check BUFFER Kit and results will be recorded. The 6 tests take 10 minutes to complete per patient. According to GC America, these tests are simple, demonstrate salivary dysfunction, help identify factors affecting salivary dysfunction, and assist in the diagnosis of xerostomia. Salivary testing and data collection will occur on 8 independent visits over the course of hyperbaric oxygen treatment and during follow-up. Stimulated saliva samples will be used to measure proteins that are involved in salivary gland revascularization and repair. Saliva samples will be stored at less than or equal to -20C for up to 1 year. Measurements of salivary VEGF-A, IGF-1, and Thrombospondin-1 will be quantified using R&D Systems (Minneapolis, MN) ELISA kits and results will be recorded. Salivary Alpha-Amylase will be measured using Rocky Mountain Diagnostics, Inc (Colorado Springs, CO) Alpha-Amylase Saliva kit. Protein analysis will be done on stimulated saliva samples collected at 4 independent visits: first week, fourth week, eighth week, sixteenth week.