Multi-functional materials for the prevention of dental caries

Abstract

Introduction: Dental caries is currently one of the major global public health problems. More than 2.5 billion people worldwide have untreated caries lesions in their mouth. Dental caries is a multifactorial disease caused by cariogenic bacteria that decompose food and produce acid, leading to the disruption of the "demineralization-remineralization" balance. Streptococcus mutans (S. mutans) is the primary causative pathogen for the demineralization of the dental hard tissue. Demineralization is reversible if sufficient time and appropriate intervention are provided prior to the next acidogenic challenge. Antimicrobial peptides (AMPs) are a natural component of the host-defense system, and have been found to exhibit a wide range of antimicrobial activities with a broad-spectrum effect. Polyphemusin I is an AMP and possesses excellent potential for inhibiting biofilm formation. Lysozyme, an enzyme found in the natural defense system, has the ability to break down bacterial cell membranes, making it an effective antimicrobial agent in food.

Aims: In order to counteract the effects of S. mutans, prevent demineralization, and promote remineralization, a membrane has been developed to inhibit the growth of S. mutans and facilitate the process of remineralization on the enamel surface.

Methods: A multi-functional membrane was synthesized with assembled lysozyme and polyphemusin I. The adsorption of polyphemusin I on normal enamel surface and lysozyme coated enamel surface was measured by Pierce BCA Protein Assay and quartz crystal microbalance method. The membrane's ability to prevent biofouling was assessed by evaluating its effectiveness against planktonic S. mutans, biofilm formation of S. mutans on the normal enamel surface and lysozyme coated enamel surface. To assess the demineralization suppression capability, enamel slices coated with lysozyme and normal enamel slices were immersed in a demineralization solution. An Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) was used to measure the changes in mineral concentration in the demineralization solution. In order to evaluate the remineralization enhancement capability, both uncoated enamel slices and lysozyme-coated enamel slices were immersed in a remineralization solution. ICP-OES was used to measure the changes in mineral concentration within the remineralization solution. The biocompatibility of the polyphemusin I coated normal enamel slices and lysozyme coated enamel slices were measured with human gingival fibroblasts.

Results: For the in vitro study, enamel slices coated with lysozyme demonstrated a higher adsorption capacity for polyphemusin I compared to regular enamel. The majority of the adsorption process took place within the initial 10-minute period. The membrane exhibited promising anti-biofouling properties. Enamel slices coated with the membrane demonstrated impressive capabilities in inhibiting enamel demineralization in acidic conditions, as well as promoting enamel remineralization in a remineralization environment. Additionally, the lysozyme-coated enamel slices that absorbed polyphemusin I exhibited favorable biocompatibility.

Conclusion: To summarize, a novel anti-S. mutans membrane was created by integrating lysozyme nanofilm and polyphemusin I onto the enamel surface. The membrane generated in this study has the potential to be applied clinically for the prevention and treatment of initial dental caries lesions.