Different dental tissues as source of DNA for human identification in forensic cases

To evaluate different dental tissues (pulp, dentin, and cement) as sources of DNA for forensic analysis.

A total of 20 teeth were obtained from unidentified bodies buried at the Central Cemetary in Bogotá in 1995 and exhumed in 2000. The tissues from three teeth obtained after surgery were used as controls. The pulp cavity was exposed after cutting each tooth with a high-speed handpiece. The pulp was removed and processed separately from the dentin and cement. The dentin and cement were obtained by drilling with a high-speed handpiece and placed into separate tubes. DNA was extracted from mineralized tissues after a short decalcification step with EDTA. The DNA was quantified by dot-blot hybridization with D17Z1 probe, a primate- and human-specific alpha satellite DNA for the D17Z1 locus. Polymerase chain reaction was carried out for the hypervariable control region between nucleotides 29 and 408 bp (HV2 region) of the mitochondrial DNA, followed by gel electrophoresis to evaluate the amount and efficiency of the amplification.

The pulp yielded the strongest amplification signals. The signals for dentin and cement were very similar because of the presence of cells of the periodontal ligament in the cement. The results of the amplification of the HV2 region of the mitochondrial DNA showed that dentin and cement acted as protective factors for the cells and allowed the conservation of the DNA.

Cementoblasts and odontoblasts located within the cement and dentin are surrounded by the mineral matrix of the dental structure and thus protected from any environmental degradation forces, which makes them suitable sources for the DNA analysis.