1Department of Sedation and Special Care Dentistry, Floor 26, Guy's Tower, King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, London Bridge, London, SE1 9RT, UK
2Department of Conservative Dentistry, Floor 26, Guy's Tower, King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, London Bridge, London, SE1 9RT, UK