This study assessed how biofilm composition is affected by both time and denture material in complete denture wearers. Biofilm was formed during two phases of 14 days on acrylic resin and denture liner specimens mounted on the buccal surface of the mandibular dentures of 21 patients. Specimens were removed randomly on days 2, 7, and 14. Higher counts of Candida glabrata, total streptococci, Actinomyces, total microorganisms, and percentage of Actinomyces were observed after 7 and 14 days (P .05). C glabrata was the only species to show progressively rising counts from day 2 to 14, while no difference was found in biofilm composition among the materials tested.