"the branch of dentistry concerned with the periodontal tissue and its disorders," 1948, from periodontia "periodontal membrane" (1914; see periodontal) + -ics. Periodontic (adj.) is attested by 1889.
Entries linking to periodontics
periodontal adj.
"surrounding a tooth, pertaining to the lining membrane of the socket of a tooth," 1848, literally "around the tooth," from peri- "around" + Greek odon (genitive odontos) "tooth" (from PIE root *dent- "tooth").
-ics
in the names of sciences or disciplines (acoustics, aerobics, economics, etc.), a 16c. revival of the classical custom of using the neuter plural of adjectives with Greek -ikos "pertaining to" (see -ic) to mean "matters relevant to" and also as the titles of treatises about them. Subject matters that acquired their English names before c. 1500, however, tend to be singular in form (arithmetic, logic, magic, music, rhetoric). The grammatical number of words in -ics (mathematics is/mathematics are) is a confused question.