Dental nonmetric trait intraobserver precision: three observations of a large sample

Abstract

The utility of nonmetric dental traits in population phenetic studies is well documented. However, consistency in scoring trait expression is a concern due to the subjectivity in scoring quasicontinuous variables with graded scales. The aims of this study are to 1) analyze intraobserver results from an independent scorer and 2) interpret the least precise results. Six hundred individuals (300 of each sex) were scored for 48 dental nonmetric traits using ASUDAS, in one preliminary (100 individuals) and two full observations. Intraobserver precision between scoring sessions yielded adequate results (85% to 100%), with two notable exceptions (UI2 and LC distal accessory ridge) and three somewhat problematic cases (UM2 hypocone, UM1 Carabelli's trait, and LM1 anterior fovea). Kendall's τ-b rank correlation coefficients are usually moderate to strong (> 0.3). The results are similar to previously published studies of observer error. Error rates are likely caused by inexperience in observable surface selection and trait/grade definition. ASUDAS requires restraint from scoring teeth that are too worn or modified by caries or chipping. A careful study of trait and grade definitions is strongly encouraged. The key element in achieving high precision rates is experience. Intraobserver (and, if needed, interobserver) error should always be calculated. Overall, ASUDAS is a reliable and useful method, especially if the author's recommendations are followed.

Heritability and genetic integration of anterior tooth crown variants in the South Carolina Gullah

“…These results align with those of Scott (), whose intra‐observer error equaled one grade in 14% of cases and exceeded a single grade in only 2% of cases. They also corroborate Marado's () ASUDAS intra‐observer study that yielded a mean overall precision value exceeding 92% when considering variation within a single scoring grade.…”

Quantitative genetic analyses of postcanine morphological crown variation

“…All data were scored by a single investigator (WND) to minimize interobserver error. We have previously discussed assessment of intraobserver error for this dataset (Stojanowski et al, ), which produced estimates within an acceptable range (cf., Marado, ; Scott, ). Mesiodistal dimensions were recorded by CMS and are used here as markers of crown size.…”

Sex Identification Based on Tooth Crown Trait Analysis Among the Mongoloid Race

“…The teeth are composed of calcified biological material that is hard, stable, and able to withstand environmental changes [8], making them suitable for forensic identification. The morphology of both anterior and posterior teeth is rather unique with some varying characteristics [9].…”

“…In fact, the Arizona State University Dental Anthropology System (ASUDAS) has described several morphological dental characteristics, a project that had been initiated by Christy Turner II in 1970 and continue by G. Richard Scott and Christian R. Nichol in 1991. The aforementioned project aimed to standardize graded guidelines that other studies worldwide can compare their scoring system [3,9]. Some of the morphological characteristics introduced by Turner and Scott include winging, shoveling, double shoveling, canine mesial ridge, canine distal accessory ridge, hypocone, metaconule, and Carabelli's cusp for anterior teeth and protostylid, metaconulid, enteconulid, and hypoconulid for posterior teeth.…”