Evaluation of sjTREC Gene Expression in Dental Pulp for Human Age Estimation Using Real-Time Expand as Polymerase Chain Reaction - An Ex Vivo Forensic Study

Introduction: The sjTREC (signal joint T-cell receptor excision circle) gene, also known as the T-cell receptor excision circle (TRECs), is a biomarker for estimating age by measuring the number of TRECs in the blood or body fluids. Materials and Methods: A descriptive study was conducted on dental pulp samples from 90 teeth, which were divided into three groups: Group 1 (3–14 years), Group 2 (15–54 years), and Group 3 (55–78 years). DNA was extracted using the Nucleospin tissue isolation method, and real-time quantitative PCR was used to determine the concentration of the sjTREC gene. Statistical analyses were performed using SPSS version 24. ANOVA with Bonferroni post-hoc test was used to compare mean Ct (Ct = Threshold cycle) differences between age groups and logistic regression. ROC curve analysis established a cutoff Ct value to predict age group, and descriptive statistics for Ct values were presented for each age group. Results: DNA was successfully extracted from 90 dental pulp samples, and sjTREC was quantified. The results showed a significant decrease in sjTREC levels with increasing age. ANOVA confirmed significant differences in mean Ct sjTREC levels between the age groups. Linear regression analysis revealed a significant correlation between age and Ct sjTREC levels, resulting in the following formula: Y = −52.793 + 3.253 × Ct sjTREC. Conclusion: This study demonstrated that dental pulp can be used for age estimation, which is potentially useful in forensic scenarios where age is unknown.