Purpose: To evaluate the effect of different forms of denture adhesives on the formation of biofilm and on adhesive strength, as well as the effectiveness of hygiene protocols for their removal.
Materials and Methods: Samples of a heat-cured polymethyl methacrylate denture base resin were made and divided into four groups: (1) control (no adhesive); (2) Ultra Corega Cream (UCC); (3) Corega Strip Adhesive (CSA); and (4) Ultra Corega Powder (UCP; GlaxoSmithKline). Biofilm formation was evaluated by counting colony-forming units and performing fluorescence microscopy. To evaluate the effectiveness of the hygiene protocols, the samples were divided into five subgroups: (1) brushing with distilled water; (2) brushing with Protex soap; (3) brushing with Colgate toothpaste; (4) immersion in water with Corega Cleaning Tablets (CCT); and (5) immersion in water with CCT followed by brushing with the CCT-water solution itself. The remaining adhesive was quantified with ImageJ software. The adhesive strength was tested at different time intervals after application. After verifying the data distribution using Shapiro-Wilk test, parametric or nonparametric analysis was applied (α = .05).
Results: Candida albicans formed more biofilm in the strip (P = .007) and the powder (P = .001), Pseudomonas aeruginosa formed more in the cream (P < .001) and the powder (P < .001), and Staphylococcus aureus formed more in the strip (P < .001). All forms of the adhesives promoted higher biofilm formation when compared to the control (P = .003). Brushing with Colgate toothpaste and Protex soap was most effective for removing the adhesives (P < .05). Independently, the powder had the highest adhesive strength (P < .05). Only the strip showed a change in adhesive strength, with higher values after 3 hours of application (P = .004).
Conclusion: Daily treatments with mechanical cleaning of the prosthesis are important for removing the adhesives, since the presence of this material can favor biofilm accumulation. The adhesive strength may vary depending on the commercial type, but all forms can be effective in retaining prostheses for a satisfactory period of time.
