Two-in-one strategy: a remineralizing and anti-adhesive coating against demineralized enamel

Ailin Hou,Jun Luo,Min Zhang,Wenlin Chu,Jiaojiao Yang,Kunneng Liang,Jiyao Li,Jianshu Li

doi:10.1038/s41368-020-00097-y

Abstract

Tooth enamel is prone to be attacked by injurious factors, leading to a de/remineralization imbalance. To repair demineralized enamel and prevent pulp inflammation caused by biofilm accumulation, measures are needed to promote remineralization and inhibit bacterial adhesion on the tooth surface. An innovative material, poly (aspartic acid)-polyethylene glycol (PASP-PEG), was designed and synthesized to construct a mineralizing and anti-adhesive surface that could be applied to repair demineralized enamel. A cytotoxicity assay revealed the low cytotoxicity of synthesized PASP-PEG. Adsorption results demonstrated that PASP-PEG possesses a high binding affinity to the hydroxyapatite (HA)/tooth surface. In vitro experiments and scanning electron microscopy (SEM) demonstrated a strong capacity of PASP-PEG to induce in situ remineralization and direct the oriented growth of apatite nanocrystals. Energy dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD) and Vickers hardness tests demonstrated that minerals induced by PASP-PEG were consistent with healthy enamel in Ca/P ratio, crystal form and surface micro-hardness. Contact angle tests and bacterial adhesion experiments demonstrated that PASP-PEG yielded a strong anti-adhesive effect. In summary, PASP-PEG could achieve dual effects for enamel repair and anti-adhesion of bacteria, thereby widening its application in enamel repair.

Highlights

Tooth enamel is the hardest mineralized tissue in the human body, consisting of the outermost layer of the dental crown.[1]Generally, the demineralization and remineralization of enamel maintain a dynamic equilibrium
The cells treated with PASP-Polyethylene glycol (PEG) displayed superior viability in the range of 97.75% to 114.79%, which was of no significant difference compared with the control group
The success to synthesize PASP-PEG was confirmed by 1H NMR and ATR-FTIR (Fig. 1a, b)

Summary

Introduction

Tooth enamel is the hardest mineralized tissue in the human body, consisting of the outermost layer of the dental crown.[1]Generally, the demineralization and remineralization of enamel maintain a dynamic equilibrium. Tooth enamel is the hardest mineralized tissue in the human body, consisting of the outermost layer of the dental crown.[1]. Attacked by acids or caries, the enamel lesions come to form as a result of the de/remineralization imbalance.[2,3] Once the enamel is damaged, whether by cariogenic bacteria, chemical acids, or mechanical stress, clinical treatments are needed to repair the demineralized enamel since it is a nonliving tissue and is not able regenerate.[1,4] Conventional interventions in clinical practice mainly consist of the usage of topical fluoride and restorative treatment. This treatment requires the sacrifice of surrounding healthy tooth tissue.[8]

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Conclusion