Dr. Gale Ann Sebastian, BDS, MDS, MSD

Oral Medicine & Oral Oncology Specialist. Oral & Maxillofacial Surgeon Clinical Assistant Professor & Graduate Faculty — Department of Oral Medicine, University of Washington School of Dentistry Attending Provider — Oral Medicine / Oral Oncology, Fred Hutch Cancer Center

Dr. Gale Ann Sebastian is a dual-trained oral and maxillofacial surgeon and oral medicine specialist known for her advanced expertise in the diagnosis, medical management, and surgical care of complex oral and maxillofacial conditions. She brings a rare combination of surgical training, oncologic experience, and oral-medicine–focused medical insight, offering patients an unusually comprehensive and sophisticated level of care.

Dr. Sebastian serves as a Clinical Assistant Professor and graduate faculty member in Oral Medicine at the University of Washington School of Dentistry, where she teaches and mentors dental students, residents, and graduate trainees. She also practices as an attending provider in the Oral Medicine / Oral Oncology Service at Fred Hutch Cancer Center, caring for patients undergoing cancer therapy and hematopoietic stem cell transplantation.

Her approach integrates evidence-based medicine, surgical precision, and a deep understanding of the medical complexities that affect the mouth, jaws, and facial structures. Patients under her care benefit from her ability to manage the full spectrum of oral mucosal disease, graft-versus-host disease, transplant-related and cancer-therapy–related complications, bony and soft-tissue pathology, and conditions requiring advanced oral surgery.

Clinical Expertise

Oral Medicine & Oral Oncology

Oral mucosal disease (ulcers, erosive conditions, lichenoid disease, leukoplakia, dysplasia)
Graft-versus-host disease (acute and chronic)
Pre- and post-transplant oral care for hematopoietic cell transplant patients
Complications of chemotherapy, immunotherapy, and radiation therapy
Oral infections, salivary gland disorders, taste disturbances
Medication-related osteonecrosis of the jaw (MRONJ)
Osteoradionecrosis and complex wound healing concerns

Oral & Maxillofacial Surgery

Diagnosis and surgical treatment of soft- and hard-tissue pathology
Biopsy and surgical management of oral lesions
Management of temporomandibular disorders
Facial trauma and post-traumatic reconstruction (background specialization)
Oral oncology and surgical pathology (international surgical training)

What Dr. Sebastian Offers Her Patients

Dr. Sebastian provides an elevated level of care tailored to patients who require more than conventional dental or surgical management. She offers:

1. Expertise With Medically Complex Patients

Ideal for those undergoing cancer treatment, transplant, or living with systemic disease affecting oral health.

2. Integrated Medical–Surgical Perspective

Seamless care from diagnosis to medical therapy to surgical management when needed—without fragmentation between specialties.

3. Oncology-Informed Oral Care

Advanced management of mucositis, salivary dysfunction, GVHD, bone necrosis, radiation complications, and pre-treatment dental optimization.

4. Precision Diagnosis of Oral Lesions

Meticulous evaluation of mucosal changes, early cancer detection, and long-term monitoring of dysplasia and pre-malignant conditions.

5. Compassionate, High-Touch Care

Clear communication, coordinated treatment planning, and a patient-centered approach designed for comfort, clarity, and long-term well-being.

Academic Roles

Clinical Assistant Professor, Department of Oral Medicine — University of Washington
Graduate Faculty, University of Washington
Faculty mentor for dental students, residents, and graduate trainees
Clinical researcher and contributor to oral oncology and transplant-related research

Selected Publications

Ebadi M, Gem H, Sebastian G, et al. Different patterns of oral mucositis and microbiota injury after total body irradiation– vs chemotherapy-based myeloablative HCT. Advances in Radiation Oncology. 2025.
Samady H, Drangsholt M, Sebastian G, Dean D. Osteonecrosis of the Jaw as a Possible Adverse Effect of Tocilizumab. Oral Surg Oral Med Oral Pathol Oral Radiol. 2025.
Ebadi M, Gem H, Sebastian G, et al. Differential impact of TBI vs chemotherapy-based conditioning on oral microbiota and mucositis after allo-HCT. IJROBP. 2025.
Ebadi M, Gem H, Sebastian G, et al. Differential impact of TBI vs chemotherapy on oral microbiota after allo-HCT. Am J Clin Oncol. 2025.
Gem H, Ebadi M, Sebastian G, et al. Dental plaque microbiota following allo-HCT and risk of chronic GVHD. Haematologica. 2020.Gem H, Ebadi M, Sebastian G, et al. A sex-dependent salivary bacterium influences oral mucositis severity after allogeneic HCT. npj Biofilms and Microbiomes. 2024.
Rashidi A, Gem H, Ebadi M, Sebastian G, et al. Baseline salivary microbiota predicts severe oral mucositis after allo-HCT. Blood. 2024.
Teymouri F, Sebastian G, Gem H, Minot SS, Rashidi A. Oral acute graft-versus-host disease. EJHaem. 2024.
Rashidi A, Ebadi M, Gem H, Tseng YD, Sebastian G, et al. Impact of conditioning regimens on supragingival plaque microbiota and mucositis after allo-HCT. Blood. 2024.
Sebastian GA, Hess TA, Drangsholt MT. Long-term orofacial pain reduction after repeated botulinum toxin injections into the masseter muscle. Oral Surg Oral Med Oral Pathol Oral Radiol. 2021.
Sebastian GA. Patient profiles and treatment outcomes in oral tongue SCC. University of Washington. 2021.

Philosophy of Care

Dr. Sebastian believes that exceptional care begins with time, attention, and trust. Her practice is grounded in a thoughtful, whole-patient approach—one that respects each individual’s medical history, personal experience, and long-term goals. Whether a patient is navigating a complex diagnosis, recovering from cancer treatment, seeking clarity about an oral lesion, or managing chronic symptoms, Dr. Sebastian provides care with precision, compassion, and clinical expertise.