Abstract
Introduction: Surface characteristics of denture base materials influence microbial adhesion and oral biofilm formation. Heat-cured polymethyl methacrylate (PMMA) and polyamide are widely used; however, comparative evidence regarding their susceptibility to microbial colonization under standardized in vitro conditions remains limited. The present study compared oral biofilm formation on removable partial dentures fabricated from heat-cured PMMA and polyamide denture base materials under standardized in vitro conditions.
Methods: This in vitro experimental study evaluated 20 heat-cured PMMA and 20 polyamide removable partial denture specimens. The specimens were inoculated with standardized cultures of Streptococcus mutans and Candida albicans. Biofilm formation was assessed by colony-forming unit analysis on days 7, 14, and 21. Surface roughness was measured at baseline and on day 21 using a contact profilometer, and biofilm morphology was qualitatively evaluated by scanning electron microscopy. Statistical significance was set at P<0.05.
Results: No significant difference in Streptococcus mutans adhesion was observed on day 7 (P=0.340). However, polyamide showed significantly higher S. mutans counts on days 14 and 21 (P<0.001). C. albicans adhesion was also significantly greater on polyamide on days 14 (P=0.006) and 21 (P=0.027), with no difference from day 7. Polyamide exhibited greater surface roughness at baseline and day 21, while SEM confirmed mature biofilm formation on both denture materials.
Conclusion: Polyamide demonstrated higher microbial adhesion and surface roughness than PMMA. Improved denture hygiene and antimicrobial approaches may help reduce biofilm formation on flexible dentures.