Quantitative collagen and proteoglycan imaging reveal organic layering, gradients and regional texture in young mature dental cementum

Abstract Dental cementum is the bone‐like tissue that adjoins the tooth root to the jaw‐anchoring periodontal ligament while contributing to the transmission of mastication forces into the jawbones. Despite its essential role, important details about the organization of its organic extracellular matrix remain poorly understood. Here, we present a multiscale structural analysis of young, mature, healthy porcine dental cementum using an integrated imaging approach. Proteoglycan‐rich domains were identified by immunohistochemistry and histochemical staining (Biglycan and Alcian Blue), while quantitative polarized light microscopy was used to map collagen fiber orientation and retardance across upper (cervical), mid‐root and root‐tip (apical) levels, examined around the four premolar‐tooth aspects. Micro‐computed tomography and scanning electron microscopy of the mineralized‐structure are shown for reference. Our quantitative proteoglycan and collagen‐fiber results show that cementum is regionally heterogeneous with gradients seen along the root axis. Proteoglycan‐rich layers double in prevalence and thickness toward the apical region. Collagen fibers often comprise two principal, approximately orthogonal fiber populations, whose orientations and relative proportions vary along both the cervical‒apical and circumferential directions of the root. Together, these findings support a model in which mature non‐aged cementum exhibits coordinated regional variation in collagen organization and proteoglycan distribution. This architecture is consistent with a mechanically specialized damping structure made of layers of mineralized fibers, in which collagen orientations may contribute to tension load transfer while the hydrated proteoglycan matrix may support compression strain energy dissipation under occlusal loading. These findings provide new insights into the functional organization of the cementum and may offer useful design principles for biomimetic nanocomposite materials and regenerative dental therapies.