Quantitative evaluation of spatial heterogeneity in dentin attrition using combined spectroscopic and elemental profiling.

Background: Age-related attrition in dentin is associated with gradual mineral loss and collagen degradation, affecting its structural and functional integrity. However, there remains a need for standardized, quantitative indices to assess these degenerative changes. Objective: This study aimed to evaluate the structural, chemical, and elemental changes in healthy versus attrited dentin using a multimodal analytical approach and to introduce novel quantitative indices for assessing dentin degradation. Methods: Human teeth exhibiting signs of attrition were collected, processed, and analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma mass spectrometry (ICP-MS). Four novel indices-Crystallinity Loss Index (CLI), Mineral Integrity Index (MII), Collagen Degradation Ratio (CDR), and Structural Degradation Index (SDI)-were developed and applied. Results: Attrited dentin showed significantly reduced crystallinity (CLI = 25.2 %), decreased mineral integrity (MII = 0.38), and marked collagen loss (CDR = 0.60) compared to healthy samples. Elemental analysis revealed a decreased Ca/P ratio and lower concentrations of Zn and Sr, with elevated Fe and Cu levels in aged dentin. The SDI (0.237) provided a composite representation of overall dentin degradation. Conclusion: The combined use of spectroscopic and elemental analyses, along with the application of novel quantitative indices, enables a robust evaluation of dentin degradation associated with attrition. These metrics hold potential in clinical diagnosis, forensic dentistry, and restorative treatment planning.