Meet the team

Dr Jonathan Chi



Dr Chi graduated from Sydney University in 1994 and  obtained his specialist orthodontic qualifications from  Otago University in 1999. Since then, he has been  practicing as an orthodontic specialist in the Sydney  area and rural New South Wales. Dr Chi sees both  children, teenagers and adults and is a firm believer in  listening to a patient’s needs.


Dr Chi has authored a number of articles published in  both Australian and International academic journals  and has been an examiner of both general and specialist dental students. He maintains an active involvement in postgraduate education and has a special interest in adult orthognathic surgery, orofacial pain and prosthodontic rehabilitation.




Dr Genevieve Ton

BDS (Syd)


Dr Ton graduated from Sydney University in 1994 and has worked at Concord Dental for over ten years now. She is well known amongst the locals as being a caring practitioner who is especially popular with families and children.


Always up to date with the latest in modern cosmetic techniques, Dr Ton offers a warm and empathetic approach to dentistry. She takes the time to get to know all of her patients and understands that many people area anxious about visiting the dentist. This is why she has built up a reputation as being one of the premier caring dentists in the Concord area. When not working, most of Dr Ton’s time is taken up caring for her three young daughters.



Dr John Vassiliadis


Clinical Associate Professor John Vassiliadis provides all the administration of sedation at Castle Hill Orthodontics. He is a Senior Emergency Medicine Specialist at Royal North Shore Hospital.

He has had training in sedation, anaesthesia, trauma management, trauma ultrasound and toxicology. John is also a Commander in the Royal Australian Navy Reserves and was part of Australia’s medical relief force that was sent to Indonesia after the Boxing Day tsunami.

He has a keen interest in medical education and is involved in training doctors at all levels and is a Clinical Associate Professor at the Sydney Medical School, University of Sydney.



Dr Stef Calladine

BChD (Leeds) MJDF RCS (Eng), Lecturer of Oral Surgery, Sydney University


Dr Calladine graduated from Leeds University and subsequently moved to London to complete her Vocational Training. After this, she secured Senior House Officer positions at St George Hospital, London and Wythenshaw Hospital, Manchester where she gained her Membership of the Royal Colleague of Surgeons. On travelling to Australia, Dr Calladine was appointed as a Lecturer in Oral Surgery at Sydney University and has been actively involved in undergraduate teaching over the past few years. She also holds oral surgery posts at Coffs Harbour Base Hospital and Westmead Hospital where she treats patients under both Intra Venous Sedation and General Anaesthesia.

When not conducting oral surgery, Dr Calladine enjoys getting sunburnt and discovering what real fresh fruit and vegetables taste like...”



Dr Cecilia So

BDS Hons (Syd), MFDS (Lond), Grad Dip Clin Dent (Oral Implants) (Syd)

Dr Cecilia So completed her Bachelor of Dental Surgery at University of Sydney, with Honours in 2003. She has a keen interest in surgical dentistry and has advanced her training in the department of Oral & Maxillofacial Surgery at the Royal Exeter and Devon hospitals in the UK, following which she completed her Fellowship in the Royal College of Surgeons (Eng) 2005. She has completed additional training in oral implant surgery, with a Graduate Diploma in Clinical Dentistry at University of Sydney and is now part of the steering committee for the program. She is involved in teaching with the University of Sydney in both Oral Surgery and Oral Implants.

Her main interest lies in providing her services to several private practices around Sydney and in the Blue Mountains region. Additionally, she is currently employed in the Department of Special Care at Westmead Hospital where she provides mainly surgical care for those patients with special needs including phobic patients. She is also actively involved in mentoring and training other dentists interested in the field and ensures continual professional development.



Dr David Hatten

BDS (Syd)


Dr David Hatten graduated from Sydney University in 1984. After four years as a Dental Officer in the Royal Australian he has been in General Dental Practice in Sydney. He enjoys getting to know his patients & keeping up to date with current techniques in Dentistry. He is married with two teenage sons.  His other interests include travel & trying to keep fit.