Supplementary Material for: New Theory Illustrates the Formation of Enamel Cup-Shaped Lesions on Occlusal Surfaces

We propose a new theory for enamel cupping lesions formation. At early stages, naturally-formed cupping lesions showed increased porosity at two structural prismatic traits: the central cone extending into the enamel-dentine junction and the type-I Hunther-Schreger bands (HSB), suggesting them to be the main drivers for cupping lesion formation and development. In addition, these lesions were circumscribed by type-II HSBs, which present lower surface porosity and higher resistance to wear. This theory was verified in in vitro observations, where both the central cone and the type-I HSB of cuspal enamel showed higher susceptibility to wear, potentially elucidating the mechanisms involved on cupping lesion formation.

本研究提出了一套全新的牙釉质杯状缺损（enamel cupping lesions）形成理论。在病变早期阶段，自然形成的杯状缺损在两类釉柱结构特征处呈现出孔隙率升高的表现：一是延伸至釉牙本质界（enamel-dentine junction）的中央锥结构，二是I型亨特-施雷格带（Hunter-Schreger bands, HSB），这提示二者为牙釉质杯状缺损形成与发展的核心驱动因素。此外，此类缺损被II型亨特-施雷格带所包绕，该结构表面孔隙率更低、耐磨性能更强。该理论已通过体外实验观察得到验证：牙尖釉质的中央锥与I型亨特-施雷格带均表现出更高的磨损易感性，这有望阐明牙釉质杯状缺损形成的相关机制。