Objective: This systematic review had the purpose to collect existing data concerning the influence of food hardness on mastication in adults.
Design: The review was listed with PROSPERO (CRD42017069760) and was directed following with PRISMA and CRD (Centre for Reviews and Dissemination, University of York) statement. A database search of articles issued from 1998 up to December 2018 was carried-out using four databases: Pubmed, Cochrane Library, Web of Science and Scopus.