Is keratinized mucosa indispensable to maintain peri-implant health? A systematic review of the literature.

The significance of keratinized mucosa (KM) around dental implants is still not well explained and has been controversial. The aim of this systematic review was to evaluate the importance of KM around dental implants. The electronic databases Cochrane library, MEDLINE, EMBASE, and Virtual Health Library (VHL) databases were utilized to search original articles from 2006 to March 2013. The inclusion and exclusion criteria used to select the articles were: (1) Human studies published in the English language; (2) Study published in international peer-viewed journals; (3) Studies evaluated the association between KM width and the peri-implant tissue health; (4) Studies that have follow up of greater than 12 months; (5) Publication of studies not older than 10 years. The searches retrieved 285 citations. Seven articles fulfilled all of the inclusion criteria. Out of these, three studies were ranked as presenting high methodological quality, and four were judged to be of moderate quality. This systematic review concludes that the presence of an adequate zone of keratinized tissue may be necessary because it was shown to be related to better peri-implant tissue health. Further randomized controlled trials are necessary to support this statement.