Antimicrobial and mechanical assessment of cellulose-based thermoformable material for invisible dental braces with natural essential oils protecting from biofilm formation.

Controlling biofilm formation in the oral cavity during orthodontic treatments is crucial. Therefore, antimicrobial surfaces for invisible dental appliances are of interest to both therapists and patients. Here we present a cellulose-based thermoformable material used for invisible braces that can be loaded with essential oils (EOs) having antibacterial and antifungal properties. We hypothesize that this material can absorb and release EOs, thus providing an antimicrobial effect without compromising the safety and mechanical properties necessary for dental invisible braces. Conventional microbiology and isothermal microcalorimetry analyses revealed that the thermoformable material loaded with essential oils significantly delayed the biofilm formation of oral streptococci (S. mutans and S. mitis) under static conditions (p < 0.05) and while simulating saliva flow (p < 0.05). In addition, cytotoxicity tests (ISO 10993-5), revealed that the loaded material is well tolerated by human gingival fibroblasts. Finally, the loading with antibacterial agents did not significantly alter the mechanical properties and stability of the material (initial force (p = 0.916); initial stress (p = 0.465)). Compared to gold-standard clear aligner materials, this material offers a reliable transmission of forces for orthodontic treatments. Moreover, this approach exhibits the potential for acting as an oral drug delivery platform for multiple compounds.

Cinnamaldehyde as antimicrobial in cellulose-based dental appliances.

AIMS: In the context of minor orthodontic intervention using clear aligner technologies, we determined antimicrobial properties of a cellulose-based material loaded with essential oils such as cinnamaldehyde. METHODS AND RESULTS: Isothermal microcalorimetry was used to assess the growth of bacterial biofilms at the interface between the tested material and the solid growth medium. The calorimetric data were analyzed using conventional growth models (Gompertz and Richards), and inhibition at 12 and 24 h was calculated. CONCLUSIONS: The tested material showed antimicrobial properties against Staphylococcus epidermidis as well as Streptococcus mutans and Streptococcus mitis clinical isolates. The inhibition was more pronounced against S. epidermidis, for which growth rate was reduced by 70% and lag phase was extended by 12 h. For S. mutans and S. mitis, the decrease in growth rate was 20% and 10%, and the lag phase increased by 2 and 6 h, respectively. SIGNIFICANCE AND IMPACT: Clear aligners for minor teeth alignment are becoming very popular. As they must be worn for at least 22 h per day for up to 40 weeks, it is important that they remain clean and do not promote caries formation or other oral infections. Therefore, introducing material with antimicrobial properties is expected to maintain oral hygiene during the aligner therapy. Here, we demonstrate the use of cinnamaldehyde for reducing microbial growth and biofilm formation on cellulose-based dental clear aligners.