Structural Composition, Mechanical Properties Of Dgi-|| Tooth Root Dentin

This study investigated structural and mechanical alterations in root dentin of Dentinogenesis Imperfecta type II (DGI-II) teeth to identify region-specific variations. Third molars from three DGI-II patients and age-matched controls were sectioned into cervical, middle, and apical root segments. Mechanical properties were assessed via three-point bending and atomic force microscopy. Morphological and compositional analyses employed scanning electron microscope (SEM), raman spectroscopy, X-ray Diffraction (XRD), and Energy Dispersive X-ray Spectroscopy (EDX). Statistical significance (p<0.05) was determined using ANOVA. DGI-II teeth exhibit shorter, thinner anterior roots and thicker posterior roots vs. normal (P<0.05). Biomechanically, DGI-II dentin shows reduced strength/modulus (P<0.05), lower Young’s modulus, higher residual stress (P<0.01), and fewer dentin tubules (P<0.05). Mineral deposition and disorganized collagen fibers were observed, with altered elemental ratios (C/O increase, Ca/P decrease; P<0.05) and lower crystallinity (P<0.05). DGI-II causes region-specific root deformities and dentin degradation characterized by structural mineralization defects and collagen disorganization, most severe in mid-root regions. These findings elucidate biomechanical vulnerabilities underlying dental complications in DGI-II patients.