Clinical Dentistry, Restorative Division, Faculty of Dentistry, International Medical University Kuala Lumpur, 126, Jalan Jalil Perkasa 19, Bukit Jalil, Bukit Jalil, Wilayah Persekutuan Kuala Lumpur, 57000, Malaysia.
UWA Dental School, University of Western Australia, Nedlands, WA, 6009, Australia.
Dent Mater. 2020 Mar;36(3):456-467. doi: 10.1016/j.dental.2020.01.005. Epub 2020 Jan 31.
The aim is to investigate the potential significance of combining minimally invasive high-intensity focused ultrasound (HIFU) with hydroxyapatite (HA) nanorods treatment for the remineralization of demineralized coronal dentine-matrix.
HA having nanorods structure were synthetized using ultrasonication with precipitation method. HA nanorods were characterized by TEM for average-size/shape. Following phosphoric acid demineralization, dentine specimens were treated with HA-nanorods with/without subsequent HIFU exposure for 5 s, 10 s and 20 s then stored in artificial saliva for 1-month. Dentine specimens were characterized using different SEM and Raman spectroscopic techniques. In addition, the biochemical stability and HA-nanorods were examined using ATR-FTIR to observe attachment of nanoparticles. Also, surface nanoindentation properties were evaluated using AFM in tapping-mode.
HA-nanorods displayed well-defined, homogenous plate-like nanostructure. TEM revealed intact collagen-fibrils network structure with high density due to obliteration of interfibrillar spaces with clear evidence of remineralization in combined HA/HIFU treatment. With HA-nanorods treatment collagen-network structure was visible, consisting of fibrils interlaced into a compact pattern with evidence of minerals deposition. AFM investigation revealed clear mineral formation with the increase of HIFU exposure time. Bands associated with inorganic phase dominate well in HIFU exposed specimens with PO stretching within dentine mineral identified at 960 cm. Characteristic dentine structure for control and HIFU 20 s specimens is reflected as oscillatory mean Amide-I intensity with measurement giving a precise sinusoidal response of polarization angle β within dentinal tissue. Nanoindentation testing showed a gradual significant increase in elastic-modulus with the increase in HIFU exposure time after 1-month storage. FTIR spectrum of the HIFU exposed dentine displayed bands at 1650 cm, 1580 cm and 1510 cm that can be attributed to Amide-I, II and III.
The synergetic effect of HIFU exposure on remineralization potential of demineralized dentine-matrix following nano-hydroxyapatite treatment was revealed. This synergetic effect is dependent on HIFU exposure time.
研究微创高强度聚焦超声（HIFU）联合纳米羟基磷灰石（HA）处理对脱矿牙本质基质再矿化的潜在意义。
采用超声沉淀法合成具有纳米棒结构的 HA。用 TEM 对 HA 纳米棒的平均尺寸/形状进行了表征。磷酸脱矿后，将牙本质标本用 HA 纳米棒处理，随后进行/不进行后续 HIFU 照射 5 s、10 s 和 20 s，然后在人工唾液中储存 1 个月。采用不同的 SEM 和拉曼光谱技术对牙本质标本进行了表征。此外，采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）观察纳米粒子的附着情况，对 HA 纳米棒的生物化学稳定性进行了研究。同时，采用原子力显微镜（AFM）在轻敲模式下对表面纳米压痕性能进行了评估。
HA 纳米棒呈现出定义明确、均匀的片状纳米结构。TEM 显示胶原纤维网络结构完整，由于纤维间空间的闭塞，纤维间空间密度高，有明显的再矿化证据。在 HA/HIFU 联合处理中，胶原网络结构可见，由纤维交织成紧密的图案，并有矿物质沉积的证据。AFM 研究表明，随着 HIFU 照射时间的增加，明显形成了矿物质。在 HIFU 暴露的标本中，PO 伸缩在牙本质矿物中被识别为 960 cm 处，无机相的特征带占主导地位。控制和 HIFU 20 s 标本的特征牙本质结构反映为在牙本质组织内测量得到的偏振角β的精确正弦响应的振荡平均酰胺-I 强度。纳米压痕测试表明，在 1 个月储存后，随着 HIFU 照射时间的增加，弹性模量逐渐显著增加。HIFU 暴露后的牙本质的 FTIR 光谱显示 1650 cm、1580 cm 和 1510 cm 处有酰胺-I、II 和 III 带。
揭示了 HIFU 暴露对纳米羟基磷灰石处理后脱矿牙本质基质再矿化潜力的协同作用。这种协同作用取决于 HIFU 暴露时间。
