Laboratoire de Pathophysiologie Orale Moleculaire, Centre de Recherche des Cordeliers, INSERM UMRS, Université Paris Cité, Sorbonne Université, Paris 1138, France; Unité de Formation et de Recherche d'Odontologie, Université Paris Cité, APHP, Service d'Odontologie - Hôpital La pitié-Salpetrière, Paris, France; Fédération Hospitalo-Universitaire DDS-ParisNet, INSERM, Université Paris Cité, Assistance Publique-Hôpitaux de Paris, France.
Department of Materials Science and Engineering, Northwestern University, IL, USA.
Acta Biomater. 2023 Oct 1;169:155-167. doi: 10.1016/j.actbio.2023.08.011. Epub 2023 Aug 11.
Developmental Defects of Enamel (DDE) such as Dental Fluorosis (DF) and Molar Incisor Hypomineralization (MIH) are a major public health problem. Their clinical aspects are extremely variable, challenging their early and specific diagnosis and hindering progresses in restorative treatments. Here, a combination of macro-, micro- and nano-scale structural and chemical methods, including, among others, Atom Probe Tomography recently applied on tooth enamel, were used to study and compare MIH, DF and healthy teeth from 89 patients. Globally, we show that DF is characterized by an homogenous loss of mineral content and crystallinity mainly disrupting outside layer of enamel, whereas MIH is associated with localized defects in the depth of enamel where crystalline mineral particles are embedded in an organic phase. Only minor differences in elemental composition of the mineral phase could be detected at the nanoscale such as increased F and Fe content in both severe DDE. We demonstrate that an improved digital color measurement of clinical relevance can discriminate between DF and MIH lesions, both in mild and severe forms. Such discriminating ability was discussed in the light of enamel composition and structure, especially its microstructure, organics presence and metal content (Fe, Zn). Our results offer additional insights on DDE characterization and pathogenesis, highlight the potentiality of colorimetric measurements in their clinical diagnosis and provide leads to improve the performance of minimally invasive restorative strategies. STATEMENT OF SIGNIFICANCE: Developmental Defects of Enamel (DDE) are associated to caries and tooth loose affecting billions of people worldwide. Their precise characterization for adapted minimally invasive care with optimized materials is highly expected. Here In this study, first we propose the use of color parameters measured by a spectrophotometer as a means of differential clinical diagnosis. Second, we have used state-of-the-art techniques to systematically characterize the structure, chemical composition and mechanical optical properties of dental enamel teeth affected by two major DDE, Dental Fluorosis (DF) or Molar Incisor Hypomineralization (MIH). We evidence specific enamel structural and optical features for DF and MIH while chemical modifications of the mineral nanocrystals were mostly correlated with lesion severity. Our results pave the way of the concept of personalized dentistry. In the light of our results, we propose a new means of clinical diagnosis for an adapted and improved restoration protocol for these patients.
牙釉质发育缺陷（DDE），如氟斑牙（DF）和磨牙切牙矿化不全（MIH），是一个主要的公共卫生问题。它们的临床表现极其多变，这使得早期的特异性诊断变得困难，并阻碍了修复治疗的进展。在这里，我们使用了多种宏观、微观和纳米尺度的结构和化学方法，包括原子探针断层扫描技术（最近应用于牙釉质研究），对 89 名患者的 MIH、DF 和健康牙齿进行了研究和比较。总的来说，我们发现 DF 的特征是矿物质含量和结晶度的均匀丧失，主要破坏牙釉质的外层，而 MIH 则与牙釉质深度的局部缺陷有关，在那里，结晶矿物质颗粒嵌入有机相中。在纳米尺度上，仅能检测到矿物质相的元素组成的微小差异，例如在严重的 DDE 中，F 和 Fe 的含量增加。我们证明，一种改进的具有临床相关性的数字颜色测量可以区分 DF 和 MIH 病变，无论是在轻度还是重度形式。在讨论中，我们根据牙釉质的组成和结构，特别是其微观结构、有机物存在和金属含量（Fe、Zn），讨论了这种区分能力。我们的结果提供了对 DDE 特征和发病机制的进一步了解，突出了色度测量在其临床诊断中的潜力，并为改善微创修复策略的性能提供了线索。
牙釉质发育缺陷（DDE）与龋齿和牙齿松动有关，影响着全球数十亿人。对其进行精确的特征描述，以适应微创护理并优化材料，是非常值得期待的。在本研究中，首先，我们提出使用分光光度计测量的颜色参数作为一种差异化的临床诊断方法。其次，我们使用了最先进的技术，系统地描述了受两种主要的 DDE（氟斑牙或磨牙切牙矿化不全）影响的牙釉质牙齿的结构、化学成分和机械光学性能。我们证明了 DF 和 MIH 具有特定的牙釉质结构和光学特征，而矿物质纳米晶体的化学修饰主要与病变严重程度相关。我们的研究结果为个性化牙科的概念铺平了道路。根据我们的研究结果，我们提出了一种新的临床诊断方法，以适应和改进这些患者的修复方案。
