Observations on dental structures when placed in contact with acids: experimental studies to aid identification processes.

In a "mafia" crime case, a magistrate asked us whether it is possible to destroy a cadaver by immersing it in acids, and would it be possible to identify any residues. The aim of this study was to observe the behavior of teeth exposed to four kinds of acid solutions. The teeth were placed in plastic containers with 25 mL of acid and observed. The experiences showed that teeth are completely dissolved after 14 h of immersion in 37\% solution of hydrochloric acid, while at 90h in 96\% sulfuric acid, the destruction of the samples is still incomplete. In nitric acid the teeth undergo a complete dissolution in 12 h, and in 17 h in aqua regia (chloroazotic acid-hydrochloric/nitric acid 1:3). It was possible to recognize the characteristic morphological features of dental tissues and structures up until the advanced stages of degradation. In 1998, the authors were contacted by a court judge in order to have an expert opinion about a “mafia” crime case. The request was to research whether it is possible to partially or totally destroy a human body by immersing it in acids, and to quantify how much time this would take. In addition, is it hypothetically possible to identify the residual remains? This theme is of great forensic interest in Italy because organized crime will often use acids or caustic substances to destroy bodies or part of bodies in order to avoid a personal identification process. Following a literature review we found no studies or notices regarding destruction of human remains by chemical substances. No positive identifications related to events of acid dissolution were reported. The only communication on this topic is a brief mention in the Italian journal “Archivio di Medicina Legale” concerning an experimental animal destruction in an acid environment (1). We started our investigation by adopting the hypothesis that it is possible to achieve a positive identification from the study of the final residual solution and the eventual organic human remains.