periodontium /per′ē·ō·don′shē·əm/ pl. periodontia [Gk, peri, around + odous, tooth] , 1. the tissues that invest or help invest and support the teeth, including the periodontal ligament, gingivae, cementum, and alveolar and supporting bone. Also called odontoperiosteum, paradentium, peridontium. 2. See periodontal ligament.
