A Periodontist is a dentist specializing in the treatment of the gums and supporting tissues of the teeth (the periodontium). Dentists must complete a 3 year postdoctoral program in periodontics and implant dentistry as well as several supplemental board exams to be recognized as a specialist.
Dentistry is made up of general dentists and numerous specialties: Periodontics, prosthodontics, orthodontics, endodontics, pedodontics, oral and maxillofacial surgery, oral pathology, etc. While a general dentist is not restricted from performing any or all of the procedures that a specialist does, many general dentists choose to refer certain cases to a specialist (i.e. gum surgery or dental implants to a periodontist) to best utilize their knowledge in their chosen discipline and provide the optimum treatment for their patients.