Combined effects of ageing and type 2 diabetes mellitus on human dental mechanics.

Dental collagen, a protein subject to essentially zero turnover, is highly susceptible to the accumulation of advanced glycation end-products (AGEs) due to elevated blood glucose in type 2 diabetes mellitus (T2DM). Progressive loss of collagen's structural stability likely increases the risk of tooth decay and fracture complicating the proper fixation of dental restorations. Our study aimed at investigating the structural and mechanical alterations in T2DM-affected teeth by measuring the stiffness and detecting micro-traumas and fractures. By using computed tomography (CT) and static compression tests, caries-free human molars and front teeth from healthy and T2DM patients were analyzed. Our results revealed a significantly reduced enamel/dentin ratio and larger dentin crack sizes in T2DM molars compared to controls, indicating increased susceptibility to mechanical damage. Although statistical analysis showed age as a dominant factor in tooth deterioration, T2DM was associated with a clinically relevant increase in dentin fracture size, suggesting that diabetes aggravates tooth fragility. Our findings underscore the importance of the cooperative effect of age and diabetes in dental biomechanics which bears significant implications in restorative treatments. Altogether, while ageing significantly affects tooth mechanical stability, T2DM contributes to additional structural weakening, particularly in molars, due to altered mechanical properties and higher occurrence of dental wears.