ИСТИНА

Morphological studies of teeth through measurements are an expanding trend in anthropological research today. This tend ency is supported by developing close and advancing associ ations between dental morphological studies, 3D imaging and digital image processing techniques. Our scientific interests lie in the field of digital odontometric techniques (Gaboutchian et al., 2023), focusing, especially during recent years, on their fully automated versions. It should be noted that shapes of teeth, as well as their conditions, are very variable. In addition, teeth have different morphological types depending on their po sitions in dental arches. Whilst a number of previous studies were conducted on posteri orly located chewing teeth, namely molars and premolars, new automated algorithms are currently being developed for mor phologically specific incisors, which occupy the frontal sector of the dental arches. One of the major problems in palaeoanthropological (as well as in paleontological) research (Knyaz et al., 2022) is in the scarcity of study material. The number of findings cannot be, even remotely, compared to the availability of living species sample in their modern form. This circumstance increases the value of odontological materials found during excavations, and hence each tooth can actually be regarded as unique. Teeth can, however, be discovered in different conditions, which, on the one hand, depend on various individuals’ lifetime-conditioned factors, and on the other hand–taphonomic factors, i.e. those arising from post-mortem environments. In this article we focus on the latter factors’ influence on the studied teeth and impact on the applied study techniques. It is worth mentioning that fully automated odontometric study methods are rather sensitive to features of studied 3D models’ surfaces, and algorithms may therefore stumble on areas of vi olated surface integrity. Material and Method The material we have been most widely using while developing automated odontometric methods for different groups of teeth were taken from the renowned archaeological site of Sunghir.This relates to studies of incisors as well, among which one was split into two parts. Thus, the enamel layer of the up per right central incisor of the youngest individual (Sunghir-3) had been separated into labial and palatal fragments (Figure 1), most likely due to an influence of external factors. The dentine layer, while cracked, has retained the enamel fragments on the tooth. As the automated measurement algorithms use structures which are interrupted by clefts on the current sample, they do not perform correctly on this incisor. As we are interested in measuring this tooth as well as the other upper incisors of the Sunghirian individuals, conducting odontometrics requires res toration of the enamel cap integrity of the tooth in question. Digital 3D models of the upper right central incisor were gener ated after tomographic scanning of the Sunghirian adolescents’ skulls. Images related to the tooth, were separated from the en tire stack. High radio-opacity degree of enamel allowed to com plete segmentation and reconstruction stages. As direct close alignment did not provide the expected effect (Figure 2), the two separate enamel fragments were seamlessly merged in or der to restore the original tooth morphology. Conclusion The tooth model was uploaded to the latest version of the soft ware, which performs automated measurements on incisors. The proposed algorithm, through locating corresponding land marks on enamel cervical margin and incisal edge (both struc tures were restored as a result of this work), has successfully oriented and measured teeth. The obtained data has enabled the use of measurement results of the upper right central incisor of the Sunghir-2 individual in one row with other incisors in a comparative morphological metric study.