Truhlar Michael, Katebifar Sobhan, Rosenberg Bradley, Kroger Roland, Deymier Alix C
School of Dental Medicine, UConn Health Center, Farmington, CT, United States.
Department of Biomedical Engineering, UConn Health Center, Farmington, CT, United States.
Acta Biochim Pol. 2025 Aug 18;72:14642. doi: 10.3389/abp.2025.14642. eCollection 2025.
Human and mouse incisors are both primarily composed of dentin and enamel, which meet at an interface called the dentin-enamel junction (DEJ). However, incisors in the two species have very different growth patterns, structures, and loading requirements. Since the DEJ is responsible for minimizing cracking at this at-risk interface between mechanically dissimilar dentin and enamel, its structure is expected to be significantly different between humans and mice. Here, structural and compositional gradients across human and murine incisors DEJs were measured via microcomputed tomography and Raman spectroscopy. Density gradients across the DEJ were significantly larger in humans compared to murine teeth, likely due to the larger size of the mantle dentin. Multiple gradients in mineral content and crystallinity were found at the murine DEJ, while the human DEJ only exhibited gradients in mineral content. Models predicting the modulus across the DEJ according to compositional results show that mineral crystallinity is critical in regulating gradients in tissue stiffness across the murine DEJ. Together, these results show the multiple ways in which the DEJ can adapt to variations in the loading environment.
人类和小鼠的门牙主要都由牙本质和牙釉质组成，它们在一个称为牙本质-牙釉质交界（DEJ）的界面处相接。然而，这两个物种的门牙在生长模式、结构和负载要求方面有很大差异。由于DEJ负责将机械性能不同的牙本质和牙釉质之间这个易出现裂纹的界面处的开裂降至最低，预计其结构在人类和小鼠之间会有显著差异。在此，通过微型计算机断层扫描和拉曼光谱测量了人类和小鼠门牙DEJ的结构和成分梯度。与鼠牙相比，人类DEJ的密度梯度明显更大，这可能是由于罩牙本质的尺寸更大。在小鼠DEJ处发现了矿物质含量和结晶度的多个梯度，而人类DEJ仅表现出矿物质含量的梯度。根据成分结果预测DEJ模量的模型表明，矿物质结晶度对于调节小鼠DEJ处组织硬度的梯度至关重要。这些结果共同表明了DEJ适应负载环境变化的多种方式。
