Physicochemical and Microbiological Assessment of an Experimental Composite Doped with Triclosan-Loaded Halloysite Nanotubes

Abstract

This study is aimed at evaluating the effects of triclosan-encapsulated halloysite nanotubes (HNT/TCN) on the physicochemical and microbiological properties of an experimental dental composite. A resin composite doped with HNT/TCN (8% w/w), a control resin composite without nanotubes (HNT/TCN-0%) and a commercial nanofilled resin (CN) were assessed for degree of conversion (DC), flexural strength (FS), flexural modulus (FM), polymerization stress (PS), dynamic thermomechanical (DMA) and thermogravimetric analysis (TGA). The antibacterial properties (M) were also evaluated using a 5-day biofilm assay (CFU/mL). Data was submitted to one-way ANOVA and Tukey tests. There was no significant statistical difference in DC, FM and RU between the tested composites (p > 0.05). The FS and CN values attained with the HNT/TCN composite were higher (p < 0.05) than those obtained with the HNT/TCN-0%. The DMA analysis showed significant differences in the TAN δ (p = 0.006) and Tg (p = 0) between the groups. TGA curves showed significant differences between the groups in terms of degradation (p = 0.046) and weight loss (p = 0.317). The addition of HNT/TCN induced higher PS, although no significant antimicrobial effect was observed (p = 0.977) between the groups for CFUs and (p = 0.557) dry weight. The incorporation of HNT/TCN showed improvements in physicochemical and mechanical properties of resin composites. Such material may represent an alternative choice for therapeutic restorative treatments, although no significance was found in terms of antibacterial properties. However, it is possible that current antibacterial tests, as the one used in this laboratory study, may not be totally appropriate for the evaluation of resin composites, unless accompanied with aging protocols (e.g., thermocycling and load cycling) that allow the release of therapeutic agents incorporated in such materials.

The Effect of Finishing and Polishing Sequences on The Surface Roughness of Three Different Nanocomposites and Composite/Enamel and Composite/Cementum Interfaces

“…Nanotechnology applications in dentistry have shown constantly increasing interest, with a high number of studies on the topic. Nanocomposites are the most commonly used restorative materials in dentistry, due to their excellent mechanical characteristics [ 1 ], stable physicochemical assessment potential [ 2 ], high flexural properties [ 3 ], and potential remineralizing capabilities [ 4 ]. Depending on their chemistry and filler type, these materials exhibit a variety of handling properties and physical characteristics suitable for different clinical situations [ 5 ].…”

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

“…Finally, an article described the use of triclosanencapsulated halloysite nanotubes to dope a composite resin for microbiological inhibition. 252 In this case, the nanotubes proved to be too effective at encapsulating the triclosan as there was no antibacterial effect measured, proving that not every great idea pans out. While the entire field of incorporating antimicrobials continues, there remain many questions related to duration, microbial resistance development, maintenance of physical properties, host response, and likely route for regulatory approval for these combination materials.…”

Antimicrobial Applications of Clay Nanotube-Based Composites

“…Halloysite nanocontainers were used to obtain new dental materials with bioactive and antimicrobial properties, in order to improve clinical outcome in daily practice [105,106,107]. In [108], halloysite plays the role of a drug delivery system for dental implant coatings.…”