Enhancing Presurgical Infant Orthopedic Appliances: Characterization, Mechanics, and Biofilm Inhibition of a Novel Chlorhexidine-Halloysite Nanotube-Modified PMMA

Abstract

Objectives: This in vitro study aimed to develop a novel nanocomposite acrylic resin with inherent antimicrobial properties. This study evaluated its effectiveness against microbial biofilm formation, while also assessing its physical and mechanical properties.

Methods: Polymethylmethacrylate (PMMA) was modified with four different concentrations of chlorhexidine halloysite nanotubes (CHX-HNTs): 1%, 1.5%, 3%, and 4.5 wt.% by weight, along with a control group (0 wt.% CHX-HNTs). The biofilm inhibition ability of the modified CHX-HNTs acrylic against Candida albicans, Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus agalactiae was assessed using microtiter biofilm test. In addition, ten samples from each group were then tested for flexural strength, surface roughness, and hardness. Statistical analysis was performed using one-way ANOVA and Tukey's test for comparison (P < 0.05).

Results: CHX-HNTs effectively reduced the adhesion of Candida albicans and bacteria to the PMMA in a dose-dependent manner. The higher the concentration of CHX-HNTs, the greater the reduction in microbial adhesion, with the highest concentration (4.5 wt.%) showing the most significant effect with inhibition rates ≥98%. The addition of CHX-HNTs at any tested concentration (1%, 1.5%, 3%, and 4.5 wt.%) did not cause any statistically significant difference in the flexural strength, surface roughness, or hardness of the PMMA compared to the control group.

Conclusions: The novel integration of CHX-HNT fillers shows promising results as an effective biofilm inhibitor on acrylic appliances. This new approach has the potential to successfully control infectious diseases without negatively affecting the mechanical properties of the acrylic resin. Clinical Relevance. The integration of CHX-HNTs into presurgical infant orthopedic appliances should be thoroughly assessed as a promising preventive measure to mitigate microbial infections. This evaluation holds significant potential for controlling infectious diseases among infants with cleft lip and palate, thereby offering a valuable contribution to their overall well-being.

Figure 1

Microtiter plate test: (a) washing planktonic cells after 24 hrs of incubation, (b) drying samples, (c) crystal violet pigmentation, (d) samples after pigmentation, and (e) washing samples in ethanol.

Figure 2

FE-SEM images: (a) halloysite nanotubes, (b) halloysite loaded with CHX, and (c) acrylic surface incorporated with HNTs-CHX.

Figure 3

(a) EDS and (b) elemental mapping results for the CHX sample.

Figure 4

(a) EDS and (b) elemental mapping results for the HNT sample.

Figure 5

(a) EDS and (b) elemental mapping results for the CHX-HNT sample.

Figure 6

Raman spectra of CHX, HNT, and CHX-HNT samples in the Raman shift range of 0–1800 cm⁻¹.

Figure 7

XRD patterns of CHX, HNT, and CHX-HNT samples in the 2θ range of 5°–80°.

Figure 8

Effect of different percentages of CHX-HNT incorporation of acrylic samples on microbial biofilm formation.

Figure 9

AFM images of the surface topography of PMMA denture base specimens with different HX-HNT fillers loading (scan of 10 × 10 μm).