Perioodontists study the structure of teeth, diseases, and the conditions that cause these problems. To study and treat problems as an periodontist, they will have to first get their undergraduate and dental school degrees. After dental school, a potential periodontist has to attend a minimum of 3 years of postgraduate school. After successful completion of postgraduate school, the person has to apply for and pass the American Board of Periodontology exam. After completion, they are then an accredited periodontist.   What periodontists do is prevention, diagnosis, and treatment of periodontal disease and oral inflammation. Periodontal disease occurs when a bacterial infection breaks down fibers and bone in the mouth that hold teeth together. They generally focus on the roots and the bones in the oral cavity. Some procedures that periodontists do to prevent and treat infections are infection removal, crown lengthening, bone grafting, and soft tissue grafting. Crown lengthening is when the periodontist removes excess bone and gum tissue. Bone and soft tissue grafting is replacing bone or soft tissue where some is missing. Some other procedures that they do are dental implants and ridge augmentation. They will do whatever is necessary to help a patient have a healthier mouth.