In this study, chitosan was employed as a novel biomimetic mineralization model to repair damaged enamel to compare its performance with that of bioinspired zinc-doped nanohydroxyapatite. Fifty human premolar tooth slices were prepared, and artificial caries lesions were induced to produce demineralized enamel surfaces. The etched slices were randomly divided into two groups: a chitosan-hydrogel-treated group and a zinc-doped nanohydroxyapatite-treated group. In vitro assessment using energy-dispersive X-ray analysis, X-ray diffraction analysis and scanning electron microscopy was conducted at the baseline, demineralization and remineralization stages. Baseline results were matched with those for normal enamel; a marked reduction in the calcium (Ca)/phosphorus (P) ratio to 1·12 and the lack of the characteristic hydroxyapatite diffraction peaks were detected for demineralized enamel. The remineralization stage revealed evident recovery of the mineral contents (the calcium/phosphorus ratio was 1·61 for the chitosan-treated group and 1·58 for the bioinspired-nanohydroxyapatite-treated one), with apparent distinctive X-ray diffraction patterns of hydroxyapatite in both groups. Scanning electron microscopic analysis showed the absence of etched enamel porosity, with the formation of a newly formed rod-like apatite layer, similar to natural enamel, which extended over the treated enamel surfaces of both groups. Chitosan hydrogel is recommended as a biomimetic mineralization smart system for repairing demineralized carious enamel.

中文翻译：

---

仿生壳聚糖抗生物启发性纳米羟基磷灰石修复牙釉质表面

在这项研究中，壳聚糖被用作一种新型的仿生矿化模型来修复受损的牙釉质，以将其性能与生物启发的掺杂锌的纳米羟基磷灰石进行比较。准备了五十个人的前磨牙牙齿切片，并诱导了人工龋齿损伤以产生脱矿质的釉质表面。蚀刻后的切片随机分为两组：壳聚糖水凝胶处理组和锌掺杂纳米羟基磷灰石处理组。在基线，脱矿质和再矿化阶段使用能量分散型X射线分析，X射线衍射分析和扫描电子显微镜进行了体外评估。基线结果与正常牙釉质的结果相符；对于脱矿的搪瓷，检测到钙（Ca）/磷（P）比率显着降低至1·12，并且缺乏特征性的羟基磷灰石衍射峰。再矿化阶段显示出矿物质含量的明显恢复（壳聚糖处理组的钙/磷比为1·61，生物启发-纳米羟基磷灰石处理的组钙/磷比为1·58），并且羟基磷灰石具有明显的独特X射线衍射图在两组中。扫描电子显微镜分析显示不存在蚀刻的搪瓷孔隙，形成了新形成的类似于天然搪瓷的棒状磷灰石层，其延伸到两组的处理过的搪瓷表面上。推荐使用壳聚糖水凝胶作为仿生矿化智能系统来修复脱矿质龋牙釉质。