Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia.
Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia; Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Sai Ying Pun, Hong Kong Special Administrative Region.
Acta Biomater. 2019 Apr 1;88:491-502. doi: 10.1016/j.actbio.2019.02.020. Epub 2019 Feb 15.
Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the original structure of root dentine. Current treatments targeting the de-/re-mineralisation processes are not entirely satisfactory in terms of the protection of the dentinal organic matrix and the highly organised structure of dentine. In this in vitro study, a cross-linking agent - proanthocyanidin (PA) was used in conjunction with a fluoride-based treatment - silver diamine fluoride/potassium iodide (SDF/KI) to putatively stabilise the organic dentinal framework as well as strengthen the collagen-mineral phase interaction. The effectiveness of this strategy was evaluated 24 h after application in terms of the distribution of ion uptake and microstructure of dentine after treatment as well as analysis of the nano-mechanical properties using a dynamic behaviour model. Results showed that individual use of SDF/KI significantly improved the surface microhardness and integrated mineral density (Z) up to 60 µm depth and the recovery of creep behaviour of demineralised dentine in the surface area compared to that treated with deionised distilled water (DDW). The combined treatment of PA and SDF/KI achieved a more homogenous mineral distribution throughout the lesions than SDF/KI alone; a more significant incremental increase in surface microhardness and Z was observed. Specifically, a superior effect on the subsurface area occurred with PA + SDF/KI, with significant improvements in microhardness, elastic modulus and recovery of creep behaviour of the demineralised dentine. Application of SDF/KI induced small discrete crystal formation distributed over the dentine surface and PA contributed to the formation of slit-shaped orifices of the dentinal tubules that were partially occluded. STATEMENT OF SIGNIFICANCE: Demographic transitions and improved oral health behaviour have resulted in increased tooth retention in elderly people. As a consequence, the risk of root dentine caries is increasing due to the age-associated gingival recession and the related frequent exposure of cervical root dentine. Root caries is difficult to repair because of the complex aetiology and dentine structure. The recovery of dentine quality depends not only on reincorporation of minerals but also an intact dentinal organic matrix and the organic-inorganic interfacial structure, which contribute to the biomechanics of dentine. With the capability of dentine modification, cross-linking agents were applied with a fluoride regimen, which improved its treatment efficacy of root caries regarding the distribution of ion uptake and recovery of dentine biomechanics.
由于复杂的病理过程和难以恢复根牙本质的原始结构，对龋齿表面的治疗仍然具有挑战性。目前针对脱矿/再矿化过程的治疗方法在保护牙本质有机基质和牙本质高度有序结构方面并不完全令人满意。在这项体外研究中，使用了一种交联剂 - 原花青素（PA）与基于氟化物的处理 - 银氨氟化钾/碘化钾（SDF/KI）联合使用，以稳定牙本质有机框架并增强胶原-矿物质相的相互作用。在应用 24 小时后，通过处理后牙本质的离子摄取分布和微观结构以及使用动态行为模型分析纳米力学性能来评估这种策略的有效性。结果表明，与用去离子蒸馏水（DDW）处理相比，单独使用 SDF/KI 可显著提高表面显微硬度和整合矿化密度（Z）达 60μm 深度，并恢复脱矿牙本质在表面区域的蠕变行为。PA 和 SDF/KI 的联合处理在病变部位实现了更均匀的矿物质分布，比单独使用 SDF/KI 更为明显；观察到表面显微硬度和 Z 的显著递增增加。具体而言，PA+SDF/KI 对表面下区域的效果更好，对脱矿牙本质的显微硬度、弹性模量和蠕变行为恢复有显著改善。SDF/KI 的应用诱导了分布在牙本质表面的小离散晶体形成，而 PA 有助于形成牙本质小管的狭缝状孔口，部分阻塞了这些孔口。意义声明：人口结构的转变和口腔健康行为的改善导致老年人牙齿保留率增加。因此，由于与年龄相关的牙龈退缩和相关的颈部根牙本质的频繁暴露，根牙本质龋的风险增加。根龋难以修复，原因是病因复杂和牙本质结构复杂。牙本质质量的恢复不仅取决于矿物质的再矿化，还取决于完整的牙本质有机基质和有机-无机界面结构，这些结构有助于牙本质的生物力学。交联剂具有改性牙本质的能力，与氟化物方案一起应用，改善了根龋的治疗效果，表现在离子摄取的分布和牙本质生物力学的恢复方面。
