Changes in the composition and mechanical properties of dentin in mouse models of diabetes

Objectives: This study employed mouse models of type 1 (T1D) and type 2 (T2D) diabetes to characterize the changes in tooth dentin composition and its mechanical properties. Methods: Thirty-two mice were used in this study and divided into T1D, T2D and corresponding control groups. Mandibles were extracted 12 weeks after the onset of diabetes, and dentin from the first molars was evaluated in varying regions of the root. The composition was assessed using Raman Spectroscopy. Nanoindentation and Vickers indentation were employed to study the mechanical properties of the tissue. Statistical significance was evaluated by two-way analysis of variance with respect to the diabetic group and region of the tooth (p <= 0.05). Results: In the T2D model, the mineral-to-collagen ratio, hardness, and storage modulus of the intertubular dentin were significantly reduced compared to tissue from the controls, especially in the cervical regions of the tooth. The reduction in the mineral-to-collagen ratio was also observed in the T1D model, but changes in nanomechanical properties were not evident. However, the bulk hardness of the teeth in the T1D model was lower than in the littermate controls. Optical microscopy revealed significant wear of the tooth crowns in both models of diabetes, which appear to result from parafunctional activities. Conclusion: This study suggests that both type 1 and type 2 models of diabetes are associated with detrimental changes in dentin. Clinical significance: Better understanding of how diabetes affects dentin and the contributing mechanisms will be key to improving treatments for people with diabetes.