Dr Widmer received his Bachelors Degree from the University of Melbourne and his Masters Degree in Paediatric Dentistry also from the University of Melbourne. The majority of his paediatric clinical practice over the last 25 years has been at the Westmead Centre for Oral Health and The Children's Hospital at Westmead.
He is a very active clinician and lecturer, presenting to students and graduates in all branches of the health sciences, as well as being invited to present at conferences, both locally and internationally.
Dr Widmer is currently the Associate Clinical Professor in Paediatric Dentistry at the University of Sydney and Director of the Dental Department at The Children's Hospital at Westmead. He is a past President of the International Association of Paediatric Dentistry , the Australasian Academy of Paediatric Dentistry and the Australian and New Zealand Society of Paediatric Dentistry.