About Us

Ali Maddahi, MS, DMD

General Dentist

Dr. Maddahi received his Master of Science in Microbiology in 1986. He completed his dental education at Tufts University School of Dental Medicine, graduating with a DMD degree in 1990. In recognition of his academic record and clinical skills while at Tufts dental school, he was elected to participate in an implant program to restore implants and was elected to be a member of the Andrew Bates Dental Research Society. After his graduation he attended a postdoctoral research fellowship in medicine at Harvard School of Medicine in 1992.

Dr. Maddahi has over 30 years of clinical experience and more than 20 years of teaching and research in the field of dentistry. He holds a part-time position as a General Dentist at the Cambridge Health Alliance Dental Clinic’s General Dentistry Residency program and is a part-time faculty member at the Harvard School of Dental Medicine, Department of Oral Health Policy and Epidemiology.

Dr. Maddahi believes that it is important to keep current with evolving techniques and materials, and therefore completes many hours of continuing education courses and research every year. These include gum treatments, oral surgeries, dental implants, dental crowns, root canal therapy and removable dentures, as well as cosmetic ceramic and veneer restorations to provide the most advanced techniques and treatment options for his patients.

Dr. Maddahi is a respected member of the dental community, holding memberships in the American Dental Association and the Massachusetts Dental Society.

Dr. Maddahi and his wife, Jilla, (our office manager) established Orris Dental in 2010. Dr. Maddahi loves dentistry, his excellent staff, and our wonderful patients. He also enjoys reading and nature.

Caleb Tam, MS, DDS

General Dentist

Dr. Caleb Tam was born and raised in the Bay Area, California. He earned his BS in biology (2009) from the University of California, Davis, and his MS in biomedical engineering (2013) and DDS (2018) from the University of California, San Francisco (UCSF). During his time at UCSF, he received 4 Clinical and Research Excellence Day awards and has been presented with scholarships from the American Dental Association (ADA) Foundation, International/American Association for Dental Research (IADR/AADR), Colgate, Pierre Fauchard Academy, Academy of Osseointegration, and Academy of Dental Materials.

After graduating from dental school, Dr. Tam completed a General Practice Residency through Harvard School of Dental Medicine/Cambridge Health Alliance (2019), where he has since remained on board and currently serves as Chief of Dental Services. His primary academic/research interests include dental biomaterials, dental regenerative therapies, and the “Oral Physician” training model.

Dr. Tam also has a passion for outreach and education as he enjoys volunteering in his local community as well as serving as a mentor for future generations of dental professionals. He is currently involved with efforts such as the Healthy Smiles Project (Cambridge Health Alliance), African Community Health Initiatives (Boston), and Biomedical Careers Science Program (Harvard Medical School).