The mechanical properties of 3D printed denture base resin incorporating essential oil microcapsules.

Purpose: The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils. Materials and Methods: Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05). Results: The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance. Conclusion: Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

Overview of incorporation of inorganic antimicrobial materials in denture base resin: A scoping review.

STATEMENT OF PROBLEM: Dental hygiene for institutionalized patients and recurring Candida-associated denture stomatitis remain problematic because of a patient's limited dexterity or inability to eliminate Candida from denture surfaces. Although there has been extensive research into antimicrobial modification of denture base resins with inorganic materials, scoping reviews of the literature to identify knowledge gaps or efficacy of inorganic antimicrobial materials in denture base resins are lacking. PURPOSE: The purpose of this scoping review was to provide a synopsis of the efficacy of the major classes of inorganic antimicrobial materials currently incorporated into denture base resins. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews was applied. Four electronic databases, including Embase, PubMed, Web of Science, and Google Scholar, were accessed for articles in the English language, up to February 2019, without restrictions on the date of publication. RESULTS: From the 53 articles selected, 25 distinguishable inorganic materials were found and divided into 3 subgroups. Forty-three articles evaluated nanomaterials, where mostly silver ion nanoparticles and/or titanium dioxide nanoparticles were incorporated into denture base resins. Fourteen articles examined antimicrobial drugs and medications, including azole group medications, amphotericin-B, Bactekiller, chlorhexidine, Novaron, and Zeomic. Two articles classified as others explored hydroxyapatite- and fiber-incorporated denture base resins. CONCLUSIONS: Although nanotechnology and antimicrobial medications or drugs have been successfully used to reduce Candida-associated denture stomatitis, long-term solutions are still lacking, and their disadvantages continue to outweigh their advantages.

Incorporation of antimicrobial agents in denture base resin: A systematic review.

STATEMENT OF PROBLEM: Denture base resins (DBRs), such as polymethyl methacrylate, are commonly used in the fabrication of removable dentures because of their physical, mechanical, and esthetic properties. However, the denture base acts as a substrate for microorganism adherence and biofilm formation, which may lead to denture stomatitis and be further complicated by fungal infections, of especial importance with geriatric and immunosuppressed patients. Therefore, methods to enhance the antimicrobial property of DBRs will be beneficial. PURPOSE: The purpose of this systematic review was to evaluate the literature on the antimicrobial activity of DBRs incorporating antimicrobial agents or materials. MATERIAL AND METHODS: A search of English peer-reviewed literature up to February 2019 reporting on antimicrobial activity of DBRs with respect to antimicrobial agents or materials, antimicrobial test effects and methods, and conclusion or knowledge gaps was conducted by using Embase, Google Scholar, PubMed, and Web of Science databases. Search terms included denture base resin and antibacterial, denture base resin and antifungal, and denture base resin and antimicrobial. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied for subsequent data analysis. RESULTS: Of 2536 identified articles, 28 met the inclusion criteria for the systematic review. Antimicrobial materials were divided into 3 groups: antimicrobial monomer or copolymer, phytochemical or phytomedical components, and other compounds. Strategies on how to incorporate these substances into DBRs and their impact on the reduction and prevention of the growth of microorganisms were identified. CONCLUSIONS: Although many efforts have been made to improve the antimicrobial ability of DBRs, this systematic review found that the effectiveness of incorporating of antimicrobial agents into DBRs has not been demonstrated conclusively.