Department of Restorative Dentistry, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran.
Social Determinants of Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
BMC Oral Health. 2024 Nov 21;24(1):1419. doi: 10.1186/s12903-024-05194-6.
Dental caries is a prevalent chronic disease globally, arising from an imbalance between tooth remineralization and demineralization. Early detection of lesions is crucial, with non-invasive methods preferred in the initial stages of caries for enamel remineralization and demineralization prevention. This study aimed to assess the impact of varying contents of boron-doped hydroxyapatite-chitosan nano-composite on the microhardness of demineralized enamel.
Boron-doped hydroxyapatite-chitosan nano-composites at concentrations of 0%, 5%, 10%, and 15% were prepared using the sol-gel method. Thirty intact human premolars were collected to evaluate tooth remineralization. The teeth were divided into buccal and lingual halves, subjected to pH cycling for 14 days to demineralize the enamel surface. Subsequently, the specimens were randomly divided into four groups (n = 15) based on the application of remineralizing materials: Group 1 - Hydroxyapatite-chitosan nano-composite (HApC); Group 2 - Boron-doped hydroxyapatite-chitosan nano-composite (B@HApC) with 5% boron concentration; Group 3 - Boron-doped hydroxyapatite-chitosan nano-composite (B@HApC) with 10% boron concentration; and Group 4 - Boron-doped hydroxyapatite-chitosan nano-composite (B@HApC) with 15% boron concentration. Microhardness was measured at three points using a Vickers hardness test (300 g force for 10 s).
The study revealed a significant difference between the nano-composite groups containing 5%, 10%, and 15% boron compared to the control group (p < 0.001). The highest microhardness was observed in the 15% boron group (49.42), with the control group showing the lowest microhardness (20.15). Pairwise comparisons of microhardness indicated a significant difference between Group 4 and the control group (p < 0.05). However, no significant differences were found between Groups 2 and 3, Groups 2 and 4, and Groups 3 and 4 (p > 0.05). Scanning electron microscope (SEM) results supported the microhardness findings, showing a mineral layer covering the porous structure resulting from enamel surface demineralization in the intervention groups, highlighting the effectiveness of boron in enhancing the microhardness of demineralized enamel.
The study demonstrated that a content of 15% boron in B@HApC and higher led to increased microhardness of demineralized enamel. Additionally, content of 5% and 10% boron in the nano-composite also improved microhardness, although not to a statistically significant extent.
龋齿是一种在全球范围内普遍存在的慢性疾病，它是由于牙齿再矿化和脱矿之间的失衡引起的。早期发现病变至关重要，在龋齿的初始阶段，优先采用非侵入性方法，以促进牙釉质再矿化和预防脱矿。本研究旨在评估不同浓度硼掺杂羟基磷灰石-壳聚糖纳米复合材料对脱矿牙釉质显微硬度的影响。
采用溶胶-凝胶法制备 0%、5%、10%和 15%浓度的硼掺杂羟基磷灰石-壳聚糖纳米复合材料。收集 30 颗完整的人前磨牙来评估牙齿再矿化。将牙齿分为颊侧和舌侧两半，进行 pH 循环 14 天以脱矿牙釉质表面。随后，根据再矿化材料的应用，将标本随机分为四组（n=15）：第 1 组 - 羟基磷灰石-壳聚糖纳米复合材料（HApC）；第 2 组 - 含 5%硼浓度的硼掺杂羟基磷灰石-壳聚糖纳米复合材料（B@HApC）；第 3 组 - 含 10%硼浓度的硼掺杂羟基磷灰石-壳聚糖纳米复合材料（B@HApC）；第 4 组 - 含 15%硼浓度的硼掺杂羟基磷灰石-壳聚糖纳米复合材料（B@HApC）。使用维氏硬度测试（300 克力 10 秒）在三个点测量显微硬度。
研究表明，与对照组相比，含有 5%、10%和 15%硼的纳米复合材料组之间存在显著差异（p<0.001）。含 15%硼的组显示出最高的显微硬度（49.42），对照组显示出最低的显微硬度（20.15）。显微硬度的两两比较表明，第 4 组与对照组之间存在显著差异（p<0.05）。然而，第 2 组和第 3 组、第 2 组和第 4 组以及第 3 组和第 4 组之间未发现显著差异（p>0.05）。扫描电子显微镜（SEM）结果支持了显微硬度的发现，显示出干预组中牙釉质表面脱矿导致的多孔结构上覆盖着一层矿物质层，突出了硼在提高脱矿牙釉质显微硬度方面的有效性。
本研究表明，B@HApC 中硼含量为 15%及以上可提高脱矿牙釉质的显微硬度。此外，纳米复合材料中 5%和 10%的硼含量也提高了显微硬度，但没有达到统计学显著水平。
