Assessment of Agreement in Human Permanent Teeth Identification Relation to their Preservation

Introduction and aim: Human teeth represent a significant determinant in forensic sciences and they serve as an important source of data about human behavior in retrospective sciences. Correct identification of isolated teeth depends on their alteration influenced by biogenic and diagenetic processes which reduce marks appropriate to correct determination of the tooth. The aim of this study is to quantify the rate of agreement of isolated teeth in relation to teeth preservation. Methods: Assessment of agreement was accomplished according to four different aspects: 1. teeth category; 2. tooth position (upper or lower jaw); 3. teeth position; and 4. teeth siding. The evaluation was carried out on three sets differing by their preservation (Set 1: well preserved teeth, Set 2: teeth altered by biogenetic factors, Set 3: teeth altered by diagenetic factors. For statistical testing of concordance we use Cohen's kappa, which measures inter-rater agreement in observation with the correction of "hap-hazard" consent between two observers. Result: Results show gradual decrease of teeth identification agreement in all three sets. In the Set 1 we agreed in 93% in tooth category determination, otherwise agreement in side determination was only 38%. The influence of the teeth preservation is significant when determining the tooth sequence and tooth side. Agreement in teeth sequence determination was 55% in Set 1 (well preserved teeth) and only 10% in Set 3 (diagenetic altered teeth). The agreement in individual steps differed depending on tooth. We noticed lower agreement in frontal teeth in classification into category and whereas in sequence determination and siding agreement was lower among lateral teeth. Conclusion: Low agreement in human teeth identification between two observers is significant. The highest agreement is recorded in tooth category determination. The agreement markedly decreases from the stage of teeth positioning in jaws, depend on teeth preservation. In conclusion, we recommend biogenic or diagenetic altered teeth not to identify in unsure cases, or accomplished the identification with the respect of low reliability