Susceptibility of Dental Enamel of Different Ages to Caries-Like Lesion Development

Abstract

This study investigated the impact of estimated age, anatomical location, and the presence of wear facets on the susceptibility of enamel to develop caries-like lesions. Extracted human premolars (<i>n</i> = 261) had their age estimated between 10 and 93 years old, using established forensic methods. Specimens of enamel (4 × 4 mm) were prepared from the middle of the buccal surfaces, preserving the outer surface layer. The central area of the block (4 × 1 mm) was protected with nail polish and used as an internal control. The specimens were demineralized for 8 days (with 0.1 M acetic acid, 1.28 mM Ca, 0.74 mM Pi, and 0.03 µg F/mL, pH 5.0), to simulate caries-like lesion development. They were then scanned individually using microtomography, and digital 2D images were used to calculate the outcomes of integrated mineral concentration loss (Δ<i>Z</i> in µm/g/cm³) and lesion depth (LD in µm) at 3 locations, i.e., the cervical, middle, and occlusal thirds. The presence of natural surface wear facets was considered in the analysis. Data were evaluated using a linear mixed-effects models (α = 0.05). Δ<i>Z</i> increased significantly as a function of estimated tooth age at all 3 locations, and this increase was greater after the age of 30 years (<i>p</i> &#x3c; 0.001), when a higher Δ<i>Z</i> was found in the occlusal third than in the middle and cervical thirds (<i>p</i> &#x3c; 0.001). LD increased only in the occlusal third before the age of 30 years (<i>p</i> = 0.039) and this increase was significantly greater after 30 years at all 3 locations (<i>p</i> &#x3c; 0.01), with no differences among them (<i>p</i> &#x3e; 0.15). The presence of wear facets significantly increased Δ<i>Z</i> and LD (<i>p</i> &#x3c; 0.001 for both). Overall, we concluded that the susceptibility of enamel to developing caries-like lesions increased with estimated dental age. This effect was more pronounced after the estimated age of 30 years and in the presence of natural tooth wear facets.