The aim of this study was to evaluate whether 2.5% chitosan applied after dentin acid etching or incorporated into the adhesive system interferes with the microtensile strength of the interface tooth-resin. Sixty healthy bovine teeth had the incisal thirds and the roots sectioned and were randomly allocated into three groups (n = 60). G1 (control): acid attack + Clearfil SE Bond + Z350 resin; G2: treatment with 2.5% chitosan + Clearfil SE Bond + Z350 resin; G3: treatment with 2.5% chitosan incorporated into dentin adhesive + Z350 resin. The stick-shaped specimens made in each group were randomly divided into two subgroups and subjected to degradation of the adhesive interface (with aging: specimens immersed in 2.5% sodium hypochlorite for 12 h and washed in distilled water for 1 h, and without aging). The groups were submitted to a microtensile strength test with a 0.5 mm/min speed until rupture. Statistical analysis of the data was performed according to normal distribution. Microtensile data were obtained by calculating the area of each toothpick, obtaining values in megapascal. No aging: G1 - 5251.69, G2 - 5.52 ± 1.46, and G3 - 3.91 ± 1.21. With aging: G1 - 3.45 ± 1.29, G2 - 2.75 ± 0.78, and G3 - 3.53 ± 1.33. Statistical analysis showed that the aging factor and adhesive modification decreased the bonding strength of the resin-dentin (P = 0.001). As well, the interaction between the analyzed factors showed statistically significant differences (P = 0.002). Accelerated aging decreases the adhesion strength in G1, even when chitosan is previously applied to the adhesive system. However, when adding chitosan to the adhesive, adhesion remained similar after aging but lower when compared to the other groups.

Acrylic resin is widely used in removable dental prostheses due to its biocompatibility, low cost, and ease of handling; however, it presents mechanical limitations and a high susceptibility to microbial colonization, particularly by Candida albicans. The incorporation of nanoparticles into polymethyl methacrylate (PMMA) has been investigated as a strategy to mitigate these drawbacks. This scoping review evaluated the impacts of incorporating chitosan (CTS) nanoparticles into PMMA on antimicrobial activity and mechanical properties. A comprehensive search of the PubMed, Scopus, Web of Science, and BVS databases resulted in the retrieval of 1912 records. After removing 557 duplicates and applying the eligibility criteria, 9 in vitro studies were included. Despite methodological heterogeneity, most studies reported enhanced antifungal activity against C. albicans and improvements in mechanical properties, such as microhardness and overall strength, when CTS was incorporated. Thus, CTS appears to be a promising additive for denture base resins, with the potential to reduce denture-associated infections and increase the longevity of prostheses. Nevertheless, standardized methodologies and well-designed in vivo and clinical investigations remain essential to determine optimal concentrations, incorporation techniques, and long-term clinical performance before implementation. A scoping review design was selected due to the exploratory nature of the study and the heterogeneity of available evidence, which precludes direct comparisons and quantitative synthesis.