Evaluation of polymethyl-methacrylate and acetal denture base resins processed by two different techniques before and after nano-chlorohexidine surface treatment

Abstract

Background Flexible denture base polymers have gained popularity in modern dentistry however, their biofilm formation tendency, adversely affecting the oral tissue heath, remains a concern. Consequently, this study aimed to evaluate surface roughness and biofilm formation tendency of two types of denture base resins manufactured with two techniques before and after surface coating with chlorohexidine (CHX) NPs. Materials and methods Acetal (AC) and Polymethyl-methacrylate (PMMA) resins manufactured by conventional and CAD/CAM methods were shaped into disk (10 X 10 X 1 mm). They were dipped for 8 h and 24 h in colloidal suspension prepared by mixing aqueous solution of CHX digluconate and hexa-metaphosphate (0.01 M). Surface roughness, optical density (OD) of microbial growth media and biofilm formation tendency were evaluated directly after coating. Elutes concentrations of released CHX were evaluated for 19 days using spectrophotometer. Three-way ANOVA and Tukey’s post-hoc statistical analysis were used to assess the outcomes. Results AC CAD/CAM groups showed statistically significant higher roughness before and after coating (54.703 ± 4.32 and 77.58 ± 6.07 nm, respectively). All groups showed significant reduction in OD and biofilm formation tendency after surface coating even after 19 days of CHX NPs release. Conclusions Biofilm formation tendency was highly relevant to surface roughness of tested resins before coating. After CHX NPs coating all tested groups showed significant impact on microbial growth and reduction in biofilm formation tendency with no relation to surface roughness. Significant antimicrobial effect remained even after 19 days of NPs release and specimens storage.

Effect of Thermal Aging and Chemical Disinfection on the Microhardness and Flexural Strength of Flexible Resins

“…Sci. 2024, 14, 361 2 of 11 Among other disadvantages of flexible resins, such as the low modulus of elasticity and low tensile strength [18], they can lead to a greater accumulation of microorganisms [19] and to stains on the material caused by the pigmentation of food or after prolonged use of denture cleansers [5,13,16,20].…”

“…A denture hygiene protocol can be established using mechanical methods, chemical methods or a combination of both [16,19]. Although mechanical brushing of dentures is recognized as a simple and efficient method to remove biofilms, it should be combined with chemical methods for better disinfection [23,24].…”