Following completion of his Bachelor of Dentistry Degree in 1995 and his Bachelor of Medicine Degree in 2002 from the University of Sydney, Dr. Mehanna completed his Oral and Maxillofacial Surgery training in NSW. He obtained his Fellowship in Surgery in 2007 , the FRACDS (OMS) which is the only recognised Oral and Maxillofacial Surgery qualification in Australia. He was also awarded the 2007 Examination Medal for the best examination performance in Australia and New Zealand. 

Dr. Mehanna also spent 5 years in the United Kingdom (England, Wales and Scotland) to further develop his surgical skills as well as completing a Head and Neck Surgical Fellowship. He holds, by examination, a Surgery Fellowship awarded by the College of Surgeons in London (FDSRCS Eng) as well as a General Dental Fellowship awarded by the Royal Australasian College of Dental Surgeons (FRACDS).

Dr. Mehanna is also employed part time at John Hunter Hospital as a Staff Specialist in Oral and Maxillofacial Surgery and also consults patients privately in Wood Street. His surgical interests range from dental extractions and implants to complex facial trauma, corrective jaw surgery and micro-surgical reconstruction and pathology.

He is an active member of the Oral and Maxillofacial Surgery community and a Conjoint Lecturer at the University of Newcastle. He also has presented at local, national and international conferences well as having over a dozen scientific papers published.