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n.
the branch of dentistry concerned with the tissues that support and attach the teeth and the prevention and treatment of periodontal disease.
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peri·odon·tol·o·gy (per″e-o-don-tolґə-je) [peri- + odont- + -logy] the branch of dentistry that deals with the scientific study of the structures and function of the periodontium in health and disease; broader in scope than periodontics, which is limited to the diagnosis, prevention, and treatment of periodontal disease, although the two terms are sometimes used interchangeably.Medical dictionary. 2011.