Gaston qualified in New Zealand in 1982, and gained his periodontal specialist qualification in Melbourne, Australia in 1992. He became a Senior Clinical Lecturer in Periodontology (London) and his doctorate focused on periodontal regeneration. His clinical research was recognised with awards by the British Society of Periodontology in 1994 and European Federation of Periodontology in 2000. In 2000, Gaston had a sabbatical year at the San Antonio Dental School, Texas, USA. He became an ITI Fellow in 2002. Gaston was invited to participate in the 4th European Federation of Periodontology Workshop in 2002, to set international standards for clinical practice. He now has his own private specialist referral practice in Saltford, Bristol.