Dental morphological traits provide valuable insights into global human variation and population structure. The Arizona State University Dental Anthropology System (ASUDAS) has long been a cornerstone for documenting crown and root morphology, yet recent discussions have questioned its reliability for characterising population differences. This study aimed to (i) identify the ASUDAS traits most commonly analysed in recent research, and (ii) compare their reported frequencies with those documented in the foundational work of Turner and Scott. A systematic review identified 43 eligible studies comprising 36,919 individuals representing all major subdivisions of humankind. Thirty variants across 27 distinct traits were recorded most frequently, and 29 of these were subjected to meta-analysis using random-effects models. Nearly all traits showed significant between-group and within-group heterogeneity, indicating strong discriminatory potential but also substantial population-level variability. While broad patterns remain consistent with classic ASUDAS expectations, several traits exhibited expanded regional ranges, reflecting both greater sample diversity and admixture effects. These findings reaffirm the value of ASUDAS traits for describing broad-scale morphological patterns while underscoring the need for multi-trait, population-specific, and context-specific approaches when interpreting dental morphology in anthropological research.

Documenting naturally occurring variations in the dental morphology of sharks is important to better contextualize and assess the putative informativeness and diagnostic value of dental characters in selachian taxonomy and phylogenetic systematics. Here we report the occurrence of atypical tooth morphology, specifically the number and arrangement of lateral cusplets, and the presence of a supernumerary symphyseal tooth file in a mature female Porbeagle Shark, Lamna nasus (Lamniformes: Lamnidae). This is the first time such an occurrence has been documented in the Porbeagle using high-resolution computed tomography (CT). The occurrence of symphyseal teeth in the genus Lamna is regarded as an expression of a plesiomorphic condition. This condition is deeply rooted in the lamniform phylogeny, extending as far back as the Mesozoic, and it reflects that the secondary loss of tooth files is likely a key process in the evolution of modified patterns of tooth replacement in galeomorph sharks.

Forensic odontology has traditionally relied on dental morphology and odontometric measurements for identification and profiling purposes. Innovations in imaging technologies (high-resolution two-dimensional [2D] radiography, cone-beam computed tomography [CBCT], and intraoral three-dimensional [3D] scanning), geometric morphometrics analysis (GMA), and artificial intelligence (AI) have revolutionized the collection, analysis, and interpretation of dental data. Relevant literature was identified through searches in PubMed, Scopus, and Web of Science using the keywords forensic odontology, CBCT, GMA, AI segmentation, and human identification, focusing on English-language studies published between 2010 and 2025. This narrative review consolidates the existing evidence regarding (1) the enhancement of data acquisition and comparability through 2D and 3D imaging; (2) the quantification of dental sexual dimorphism by GMA and its application in machine learning (ML) classifiers; (3) recent advancements in sex-prediction models derived from tooth metrics and 3D shape data; and (4) the facilitation of dental model creation and identification workflows through AI-driven segmentation. The discussion encompasses practical benefits, existing limitations, validation requirements, and prospective directions for the adoption of this technique in forensic applications.

Tooth morphology is a fundamental aspect of dental education, essential for various clinical disciplines. Traditional teaching methods, such as 2D visualizations, gypsum models, and wax or soap carving, have been widely used to develop students' spatial understanding and manual skills. However, the integration of 3D-printed models offers a novel approach that may enhance learning by providing a more accurate representation of dental morphology. This study aimed to assess the effectiveness of 3D-printed models in learning tooth morphology by comparing their impact on students' practical and theoretical performance with traditional teaching methods. Dental students were divided into two groups: one utilizing 3D-printed models alongside traditional methods and another relying solely on conventional gypsum and 2D visualizations. Practical assessments included soap tooth carving and wax modelling, while theoretical knowledge was evaluated through a written examination. Additionally, students completed a questionnaire to provide feedback on their experience with the 3D-printed models. Students who used 3D-printed models achieved significantly higher scores in the soap tooth carving task, demonstrating improved accuracy and anatomical detail. However, there was no significant difference in the wax modelling scores between the two groups, suggesting that advanced manual dexterity skills are not solely dependent on 3D visualization. Theoretical examination results also showed no significant difference, indicating that 3D models primarily enhance practical skills rather than theoretical comprehension. Over 80% of students reported that 3D-printed models were highly beneficial in understanding tooth anatomy and improving carving skills. The findings suggest that 3D-printed models serve as a valuable tool for enhancing practical skills in dental education. While they do not replace traditional methods, they effectively support hands-on learning and visualization.

Physical anthropology is a discipline that studies human physical characteristics and their evolutionary patterns through the analysis of human biological remains. Oral tissues such as teeth and jawbones, serving as crucial or even exclusive materials among human biological remains, establish oral medicine's central role in this field. This paper reviewed the advances in oral medicine's research on key physical anthropology topics and methodologies, including human origins and evolution, paleopathology, paleodietary reconstruction, and paleomicrobiology. In human origins and evolution research, dental morphology provides crucial evidence for identifying population relationships. Paleopathology reflects ancient survival pressures, subsistence economies, and cultural behavioral patterns through oral diseases. Paleodietary research reconstructs ancient dietary structures using dental microwear, trace elements, stable isotopes, and calculus microfossils (e.g., starch grains, ancient DNA, ancient proteins). Paleomicrobiology explores the evolution of health and disease through the oral microbiome. Current research faces limitations including narrow observation of oral diseases, inconsistent diagnostic criteria, and insufficient interdisciplinary integration. Future efforts should enhance multidisciplinary collaboration among oral medicine, archaeology, anthropology, and other fields. This multi-perspective approach will systematically elucidate the evolutionary trajectory of oral health and disease, enrich the historical context of oral medicine, and provide insights for contemporary prevention and treatment of oral diseases.

Biodistance analysis using dental nonmetric traits is a key method to examine population structure in the past. Researchers often favor permanent teeth rather than deciduous dentitions when examining biodistance in archaeological assemblages, despite being correlated. We compare the results of biodistance analyses using 79 permanent and 32 deciduous dental morphological traits from the ancestral remains of 351 individuals with permanent teeth and 122 individuals with deciduous teeth from the pre-Spanish Southwest United States. Biodistance was estimated between six regions based on the archaeological sites where individuals were found: Chaco, Gallina, La Plata, Middle Rio Grande, Mogollon, and Northern Rio Grande. Observations were first dichotomized, then traits were compared using tetrachoric correlation. Distance matrices of mean measure of divergence were then compared using a Mantel test. Biodistance estimates were similar between deciduous and permanent dentitions (r = 0.55, p < 0.05). Deciduous traits are thought to be a better reflection of underlying genetic variation since they are less impacted by environmental stress. Therefore, they may reveal additional trends that are hidden when only studying permanent teeth. We suggest researchers consider both the deciduous and permanent dentitions when using biodistance to more fully understand population structure.

Reports of great white sharks (Carcharodon carcharias) in the Mediterranean Sea attract strong scientific and public attention but are frequently based on limited or unverified evidence. This study evaluates the reliability of citizen-science imagery for shark species identification using a comparative morphological framework. A recent Adriatic record was used as a representative case to demonstrate the application of diagnostic criteria for distinguishing lamnid sharks. Dentition and external morphological traits were compared with published reference material and field guides. The analysis indicates that the absence of lateral cusplets and overall dental morphology are inconsistent with C. carcharias, confirming the specimen as a porbeagle (Lamna nasus). Beyond this case, the findings emphasize the importance of expert validation, standardized morphological criteria, and proper reporting for protected species. Establishing clear validation protocols can ensure that citizen-science observations strengthen rather than distort the scientific understanding of Mediterranean shark populations.

To evaluate the mean overbite depth indicator (ODI) and anteroposterior dysplasia index (APDI) values in a sample of Arab Jordanian individuals and compare these findings to the original reference norms. A total of 240 subjects (mean age: 10.54 ± 2.3 years), comprising 123 females and 117 males, were selected based on the presence of an angle class I molar relationship and average vertical and sagittal skeletal and dental patterns. Participants were evenly distributed into four age-based cohorts: group I (7-8 years), group II (9-10 years), group III (11-12 years), and group IV (13-14 years). The mean values of the ODI and APDI were calculated for each age and gender subgroup. These values were statistically analyzed and compared with the original reference norms using SPSS software. A significance threshold of p < 0.05 was applied. Across the total sample, the mean ODI value was significantly lower (72.10° ± 3.34°), while the mean APDI value was significantly higher (82.70° ± 3.03°) compared to the original reference norms. No statistically significant differences in ODI or APDI values were observed among the four age subgroups. Gender-based analysis revealed no significant differences in APDI values between males and females. However, females exhibited significantly higher ODI values compared to males. The derived mean values for the ODI and APDI serve as clinically relevant benchmarks for orthodontic diagnosis and treatment planning in Arab populations and contribute to the refinement of global cephalometric standards through population-specific insights. This study shows that Arab Jordanian children have different average ODI and APDI values compared to the original standards. Knowing these differences helps orthodontists make better treatment decisions that match the needs of this population. How to cite this article: Alrbata RH, Rahamneh AS. Evaluation of the Overbite Depth Indicator and Anteroposterior Dysplasia Index in a Sample of the Arab Population. J Contemp Dent Pract 2026;27(1):51-54.

The impact of artificial intelligence evolution on the dental morphology sculpting education

Elasmobranch teeth are highly mineralized structures that constitute the majority of the fossil record for this group. Despite their taxonomic and evolutionary significance, detailed descriptions of dental morphology remain scarce. The order Carcharhiniformes, the most diverse among sharks, comprises 304 valid species that display remarkable diversity and complexity in dentition. This study aims to describe and illustrate crown morphological variation within Carcharhiniformes, with a focus on family-level patterns and types of heterodonty. Tooth samples were obtained from specimens preserved in 70% ethanol and from dry jaws. A total of 66 samples, representing all families except Dichichthyidae, were examined and photographed using a scanning electron microscope (SEM). The types of heterodonty considered include dignathic, gynandric, monognathic, and ontogenetic. Dignathic and monognathic heterodonty were further classified as weak, moderate, and strong. Four sub-arrangements were recognized: imbricate, independent, mixed, and overlap, as well as the pavement and independent dentition arrangements. New data reveal previously unrecognized patterns of variation across the four types of heterodonty in Carcharhinidae, Scyliorhinidae, Proscylliidae, Triakidae, and Pentanchidae. High-resolution SEM images allowed detailed characterization of crown morphology, highlighting subtle diagnostic features and family-level differences across heterodonty types. Dental complexity in Carcharhiniformes is largely driven by the distribution and combination of heterodonty types. These detailed dental descriptions provide a valuable framework for understanding the diversity and evolutionary significance of dentition within the most diverse order of sharks.

The extinct elasmobranch Protospinax is an intriguing shark known mostly from isolated teeth and rare complete skeletons. Most previous studies focused on differences in isolated teeth for taxonomic assignments, with little to no considerations of dental variations. In this study we provide a detailed morphological evaluation of the dentition of the squalomorph shark, Protospinax based on three skeletal remains of Protospinax annectans from the famous Upper Jurassic lithographic limestone of the Solnhofen area (Bavaria, Germany) with partially preserved dentitions and isolated teeth from the Kimmeridgian of Mahlstetten (Baden-Württemberg, Germany). The aim of this study is to clarify ambiguities in dental morphologies and to establish heterodonty patterns, allowing to taxonomically reassess species previously assigned to Protospinax. Accordingly, we consider Protospinax annectans (Callovian–Aptian?), Protospinax carvalhoi (Bathonian), Protospinax lochensteinensis (Oxfordian), and Protospinax planus (Kimmeridgian) as valid species. The species of Protospinax bilobatus is considered a junior synonym of Protospinax magnus. Furthermore, our results show that the dental morphologies of P. magnus and Protospinax? muftius are very different from those of other Protospinax species and rather resemble those of orectolobiforms. Consequently, we introduce two new orectolobiform genera, Jurascyllium gen. nov. and Archaeoscyllium gen. nov., to accommodate these species. The review of the species confirms a stratigraphic range of Protospinax extending from the Toarcian (Lower Jurassic) to the Valanginian (Lower Cretaceous).

The Dmanisi paleoanthropological assemblage from Georgia is among the most debated collections of hominin fossils due to its early age and extreme morphological diversity relative to other Homo assemblages. This variability has been interpreted as a result of sexual dimorphism in the Homo erectus clade, in which Dmanisi hominins were traditionally classified. However, this hypothesis has been challenged by the proposal that the Dmanisi fossils represent more than one Homo species. Taxonomic assessments of the Pleistocene Georgian hominins have focused primarily on craniometric analyses, with fewer studies addressing dental morphology through metric approaches. Considering the value of dental crown area in reconstructing evolutionary relationships, a comparative sample of fossil hominins, consisting of 51 maxillary and 71 mandibular specimens (583 teeth in total), was analyzed using Linear Discriminant Analysis (LDA) to evaluate the diversity in the Dmanisi fossil assemblage. Morphological affinities were examined visually through the first two discriminant functions, and taxonomic relationships were tested via classification analyses based on posterior probabilities. The analyses show a strong association of the D4500-D2600 specimen with australopiths, and of the D2282-D211 and D2700-D2735 specimens with Homo species. The sexual dimorphism hypothesis was tested by comparing the ratios of mandibular postcanine dentition of Dmanisi specimens with male and female gorillas and chimpanzees, which suggests that dental crown area of the Pleistocene Georgian hominins could be the product of sexual dimorphism only if they came from species with similar levels of dimorphism than these great apes. We conclude that differences in crown dimensions support the hypothesis of two distinct taxa coexistent at the Dmanisi site, previously proposed to be Homo georgicus and Homo caucasi. This proposal has important implications for the dispersal of Homo out of Africa at the beginning of Pleistocene.

Spatiotemporal dynamics of Chionomys nivalis from the Late Pleistocene to the present: insights from ancient DNA and dental morphology

The rehabilitation of patients with severely worn or partially edentulous dentition requires restorative solutions that balance structural integrity with aesthetic requirements.1 Overlaid prostheses (overlay dentures) offer a conservative alternative to traditional extractions or high-risk implants, yet their success depends heavily on the precision of the manufacturing process. Objective: This study describes an advanced manufacturing method for overlaid prosthesis structures, focusing on the integration of digital workflows and material science to enhance the fit, durability, and functional occlusion of the final restoration. Methods: The manufacturing protocol involves a multi-stage approach: Utilizing intraoral scanning to create a high-resolution 3D topographical map of the existing teeth and alveolar ridges.2 Designing the framework with specific attention to the "overlaid" zones, ensuring uniform stress distribution across the supporting natural teeth. A comparative analysis between Computer-Aided Manufacturing (CAM) milling of cobalt-chrome or high-performance polymers (PEEK) and Additive Manufacturing (3D Printing) for the framework. The application of aesthetic composite or ceramic layers to replicate natural dental morphology. Results: The implemented digital manufacturing method demonstrated a significantly higher degree of marginal fit (within $50-100 \mu m$) compared to traditional lost-wax casting techniques. The use of high-performance polymers in the framework reduced the "heavy" sensation for the patient while maintaining sufficient flexural strength to withstand masticatory forces. Conclusion: Transitioning from analog to digital manufacturing methods for overlaid prostheses significantly minimizes human error and material shrinkage. This approach provides a predictable, repeatable, and bio-compatible solution for complex pediatric or adult dental reconstructions.

Abstract Bilophodont tooth morphology is found in various groups of extant and fossil herbivores, including tapirs, marsupials, deinotheres, and two groups of Paleogene South American native ungulates: the xenungulates and pyrotheres. Mesowear angles, an extension of the traditional mesowear method for reconstructing diet based on the balance between attrition and abrasion, have been previously applied to deinotheres using the inclination of their wear facets. We measured mesowear angles from South American fossil bilophodonts (tapirs, xenungulates, and pyrotheres) from wear facet inclination or dentine valleys and compared those to results from some modern bilophodont taxa. Mesowear angles in modern bilophodonts match the dietary predictions based on observed diet and highlight the potential of these angles for dietary reconstruction in fossil groups. Xenungulates and fossil tapirs all show sharp mesowear angles (&lt; 106˚), indicating a browsing feeding behaviour. In contrast, pyrotheres show significant dietary variation. Some taxa (e.g., Griphodon peruvianus and Pyrotherium romeroi ) show steeply inclined facets indicating browsing. Rounded, shallower facets in Propyrotherium saxeum are interpreted as evidence of frugivory, while Pyrotherium macfaddeni has relatively shallow facets indicating a mixed-feeding ecology. High mesowear angles in Proticia venezuelensis and Colombitherium tolimense support grazing in the colombitheriids, a group with controversial phylogenetic affinities. There is huge potential for the further application of mesowear angles in other bilophodont taxa for dietary reconstruction, and we propose that angles measured in bilophodonts could be compared to those from other dental morphologies for palaeoenvironmental reconstruction.

This study aims to elucidate the morphometric and morphological details of teeth in the Syrian hamster (Mesocricetus auratus, Waterhouse, 1839) and guinea pig (Cavia porcellus, Linnaeus, 1758) using µ-CT and stereology (n = 5). Notably, the hamsters exhibited distinctive roots in their cheek teeth, in contrast to the guinea pigs, where the tooth body extended as a dental root into the alveolar socket, making anatomical diagnosis challenging. The first and second cheek teeth of the hamster had four roots, but the last one had three roots. The hamster incisor teeth had a more voluminous pulp cavity compared to those of guinea pigs. While the ratio differences of arch parameters and enamel thickness were not statistically significant (P ≥ 0.05). The enamel layer in guinea pig incisor teeth were significantly thicker than that in the hamster teeth (P ≤ 0.05). Regarding the dentine-tooth width, the difference between the upper incisor teeth of the hamster and guinea pig was significant (P ≤ 0.05). The ratio of pulp-tooth volume in all incisor teeth of the hamster was significantly higher than that in the guinea pig's teeth (P ≤ 0.05) indicating hamsters might have better regenerative dental health despite dietary variances. These insights contribute to deeper understanding of the evolutionary adaptations in rodent dentition and suggest improved information and methodologies for translational dental studies and selecting more appropriate animal models in dental research.

Abstract The enchanting diversity of large mammalian herbivores in African savannas has long challenged ecologists: How can so many species of large, generalist plant eaters coexist? Variation in body size and craniofacial/dental anatomy are key morphological determinants of ecological niche differentiation, shaping foraging behavior in ways that stabilize coexistence by limiting interspecific competition for space and food. Variation in water requirements may be another important dimension of niche differentiation, but whether and how variability in water requirements affects the partitioning of other resources is unknown. Here, we investigate how body size, dental morphology, and water requirements interactively affect space use and diet of 15 large‐herbivore species in Serengeti National Park. Water requirements predicted space use in relation to permanent water sources, while diet type (percentage grass) was best predicted by dental morphology. Food partitioning was best predicted by a combination of all three traits in both wet and dry seasons. Furthermore, the total explained variation of diet dissimilarity explained almost tripled when these three traits were combined compared to single traits, emphasizing the importance of multiple dimensions of niche differentiation. Our results show that variation in water requirements is strongly associated with spatial and dietary niche differentiation among large herbivores, emphasizing the importance of spatial heterogeneity in surface water and vegetation structure for maintaining the world's last mega‐diverse megafaunal assemblages. Integrating multiple dimensions of resource partitioning is a crucial step toward predicting how species will respond to homogenization of savanna landscapes due to changes in land use, surface water availability, and rainfall.

ABSTRACTBackground and AimForensic odontology utilizes dental morphology to estimate population affinity in medico‐legal cases. This review examines the role of dental traits in human identification, emphasizing their limitations in conclusively estimating ancestry or ethnicity.MethodsA comprehensive search was conducted across databases such as PubMed, ScienceDirect, Scopus and Web of Science using key terms ‐ race, ancestry, ethnicity, population affinity and forensic odontology. Literature studying race/ancestry (older studies) and population affinity (newer studies) was reviewed.ResultsAll dental features are characterized by a certain degree of variation across human populations. On one hand, tooth characteristics may seem useful for identifying ancestry and ethnicity. Yet, combining dental traits with other evidence may improve ancestry estimation. Training observers with additional sources and practical skills improves accuracy and produces more reliable results. The observational method, while systematic, risks oversimplifying contextual factors. However, in forensic odontology, the broader social context of this approach must be considered, as it evaluates whether race is a biological notion.ConclusionsTraditional terms like race and ancestry should be replaced by population affinity. Future recommendations include developing improved methods to enhance result accuracy.

Global shark biodiversity is in decline, with numerous species facing extinction because of anthropogenic influence. Loss of species richness is expected to diminish trait diversity, encompassing ecological roles and physiological adaptations. We investigate whether the extinction of threatened species, as classified by the International Union for Conservation of Nature, drives morphological and ecological homogenization within Carcharhinus, a speciose genus of requiem sharks. We assembled a dataset of tooth morphology from 30 species and combined it with functional data such as diet, habitat, and body size. Simulated extinction scenarios, where species were sequentially removed from the highest to lowest threat level, revealed that the loss of threatened species would result in marked homogenization of morphology and ecology. Along this extinction trajectory, trait structures become increasingly depauperate, marked by contracting depth ranges and declining body-size diversity. Our results indicate that the diverse dental morphologies, shaped over millions of years, are at risk of disappearing—eroding the genus’s capacity to support varied ecological roles.

Forensic odontology is a fundamental approach to identifying people, especially if alternative methods may not be attainable. Dental pattern variation, such as virgin, decaying, filled, and missing teeth, constitutes a valuable resource enabling the identification of individuals and acts as a distinct characteristic. This research explores the relevance of the diversity of dental patterns by employing the nonradiographic dental records method in forensic odontology, assessing their efficacy and reliability for individual identification in Delhi NCR populations, and highlighting the necessity for keeping thorough and precise dental records. Clinical examination, though often overlooked, provides a wealth of information that can supplement forensic investigations, particularly in the absence of radiographic records. The study incorporated 120 individuals (60 males and 60 females) aged 18–55 years from Delhi NCR clinics. The criteria comprised virgin (V), decayed (D), filled (F), and missing (M) teeth, which were assessed using SPSS software version 27.0 and Simpson’s Index of Diversity for determining diversity of dental patterns. The findings revealed a significant difference in virgin teeth across age groups ( p = .001). Simpson’s Diversity Index indicated that age was the predominant factor influencing dental diversity, while sex differences were not statistically significant. Clinical dental examination yields valuable forensic insights, offering a practical nonradiographic method of assessing dental diversity. While antemortem dental records remain the gold standard for accurate identification, clinical examination plays a crucial role where radiographic facilities are unavailable, thereby strengthening forensic investigations.