Early evidence of extra‐masticatory dental wear in a Neolithic community at Bestansur, Iraqi Kurdistan

Abstract This paper presents the first evidence of extra‐masticatory dental wear from Neolithic Bestansur, Iraqi Kurdistan (7700–7200 BC). Bestansur is a rare, recently excavated burial site of this period in the Zagros region, of Iraqi Kurdistan. A total of 585 teeth from 38 individuals were analyzed for features indicative of activities including oblique wear planes, notches, grooves, and chipping. Indications of extra‐masticatory wear were found in 27 of 38 individuals, and 277 of 585 teeth (47%) available for study. The most frequent features were chipping and notches suggesting activities such as processing fibers by using the teeth as a “third hand.” Evidence for these wear features was present in both males, females, and in children aged five and older. These aspects of childhood life‐course and dentition are rarely investigated. The presence of dental wear features in the deciduous dentition can indicate an age range at which activities began in different groups and highlights the importance of including juvenile remains in such studies. The variety of forms of dental wear may relate to the mixed diet and activities of these people. This study adds to our understanding of human behaviors and socio‐cultural aspects of life during this transitional period.

Juvenile individuals are rarely included in studies of extramasticatory wear, due to the complicating factors of deciduous dentition which include mixed dentition, variation in eruption sequences per population, weaning foods, and timing of weaning (Beck & Smith, 2019;Estalrrich & Marín-Arroyo, 2021).

| Aims and objectives
Through the analysis of the Bestansur dentition, this study aims to investigate the frequency and co-occurrence of extra-masticatory dental wear features, social bias in affected individuals, and the potential causes of these features. The objectives are to examine the dentition through macroscopic and microscopic analyses at both the individual and assemblage scale to demonstrate the presence or absence of extra-masticatory dental wear features.

| Archeological background
The site of Bestansur is on the Shahrizor plain, 33 km southeast of Sulaimaniya, Iraqi Kurdistan ( Figure 1). Excavations of Neolithic levels have revealed mudbrick structures, fire installations, burials, and areas of activities such as lithic working, and the site dates from c. 7700 to 7100 cal BC (Flohr et al., 2020;Matthews et al., 2019). Numerous F I G U R E 1 (a) Location map of Bestansur, (b) contour plan of Bestansur mound showing location of trenches, (c) plan of trench 10 burial deposits across the site have revealed human remains from at least 99 individuals, predominantly from two large buildings. The burial deposits range from complete articulated individuals to partially articulated comingled successive interments (Walsh, 2020).
The zooarcheological evidence from Bestansur indicates a community in the early phases of adopting goat and pig management, while utilizing a wide range of wild animals from wetlands, woodlands, and open areas (Bendrey et al., 2020;de Groene et al., 2021). Fecal evidence of grazing of herbivores and wild boar or pig provide further evidence of early animal management (Elliot, 2020). Small finds demonstrate evidence for the acquisition of objects and materials from both local and more distant sources. Ground stone tool types from Bestansur were likely used for food processing, hunting, and fishing (Matthews et al., 2019). In summary, the people of Bestansur were a transitional Neolithic group harnessing a variety of resources both for dietary and material purposes as part of the adoption of sedentism.

| Materials
A total of 819 teeth were available for study; 234 teeth were excluded due to lack of preservation or eruption, leaving 585 permanent and deciduous teeth for analysis. A total of 475 teeth were associated with distinct individuals, a further 110 teeth were disarticulated but included in the sample due to their potential to increase understanding of tooth wear in this group.
A total of 99 Neolithic individuals have been excavated so far, but due to the absence of dentition through development or post-mortem tooth loss it was only possible to analyze the dentition of 38 individuals. There were 18 adults and 20 juveniles, ranging in age from around 4 to 50+ years. Determination of sex was possible in 16 adults and four adolescents resulting in equal numbers of males and females (see Table S1 and Walsh, 2020).

| Methods
All teeth were assessed macroscopically for dental wear; specimens with features were selected for further analysis using light microscopy. A subset of these specimens underwent scanning electron microscopy (SEM) (FEI Quanta FEG 600) for clarification. These teeth were analyzed directly due to their fragile state, in low vacuum mode with a magnification of 54Â and a working distance of 11.2 to 12.2 mm.
The teeth were examined for features including notches, occlusal grooves, chipping, angled wear, and interproximal grooves using the methods associated with descriptions below.
A notch is defined as an indent at the incisal or occlusal edge, which may extend over the whole occlusal surface; notches have greater breadth than depth and are oriented on the median line (Bonfiglioli et al., 2004). Occlusal grooves appear as a narrow linear groove oriented transversely across the occlusal surface (Molnar, 2011). Interproximal grooves are located on the interproximal surfaces, near the cemento-enamel junction (Frayer, 1991;Lozano et al., 2013;Lukacs & Pastor, 1988). Chipping is defined as an irregular microfracture of enamel or dentine at the tooth margins (Bonfiglioli et al., 2004;Lozano et al., 2017). These fractures occur when the margins are exposed to high bite forces on hard objects (Scott & Winn, 2011;Willman, 2016, p. 50). These attributes are recorded by presence or absence only, as severity is likely to vary between populations.
In addition, the teeth were examined for oblique and differential wear using Molnar's (1971) categories, to allow categorization of directionality and extremes of wear. Skinner (1997) was used to assess the levels of dental wear in deciduous teeth and gave similar results to the lower wear stages of Molnar (1971).

| Limitations
The skeletal remains from Bestansur are often poorly preserved due to soil type, resulting in fragmented maxillary and mandibular bones. It was not possible to rule out ante-mortem movement of teeth such as lingual tilting as a cause of wear (Reinhardt, 1983). Due to these issues, angles of wear were not measured quantitatively (Smith, 1984). There is a lack of taphonomic methodology for teeth , and methods for the analysis of deciduous tooth wear are also limited (Beck & Smith, 2019;Hernando et al., 2020).

| RESULTS
Of the total 585 teeth, 277 (47.3%) were affected by some aspect of extra-masticatory wear ( Table 1). The types of extra-masticatory wear and features seen in the Bestansur assemblage include oblique wear, notching, occlusal grooves, and chipping. Of the 38 individuals analyzed, 27 have dental wear features from extra-masticatory activities, of these 10 are juveniles (see Table 2). Aside from oblique wear, the

| Forms of wear
Oblique dental wear was analysed to assess differential wear, and the impact of diet or activities. Oblique wear planes affected 165 (36.4%) permanent teeth and 31 (26.9%) deciduous teeth. Oblique wear was common in adult individuals (72%) with males and females affected equally ( Figure 2).
Buccal-lingual wear (from the outside of the mouth directed inwards) was the most common plane of wear affecting 80 teeth or 17.6% of the worn permanent teeth (see Table S2). Small amounts of buccal-lingual and distal-mesial angled wear affected four juvenile individuals aged 4 to 9 with mixed dentition that have additional features of extra-masticatory wear.
In terms of differential wear, there were two adult individuals of interest. A young adult male (SK1625-1) had high levels of anterior wear and fracturing of the incisors, in addition to differential wear to the right side. A young adult female (SK1788) had increased levels of wear to the upper first molars, which do not match the lower molars.
A total of 39 adult teeth (6.6%) from 10 individuals showed extreme levels of wear scoring 7-8 using Molnar (1971) with the roots functioning as tooth surfaces (see Figure 3). Two individuals (SK2286 and SK2373) each had nine extremely worn teeth; both are older probable females. Five isolated teeth, potentially from one individual also had root resorbtion, which may be caused by degeneration, or periodontal trauma (Hillson, 1996, p. 206;Nelson, 2016, p. 222).

| Notches and grooves
A total of 33 permanent and eight deciduous teeth were notched (

| Dental chipping, trauma, and abrasion
There are a variety of chipping alterations across all tooth types except third molars; these features range in size from around 1 to 3 mm in area. Chipping affected a total of 136 teeth (see Table S3 The results of the study show that there is no bias in the age or sex of the affected individuals. Schulz (1977) showed a similar lack of sex bias, whereas Larsen (1985) and Lukacs and Pastor (1988) had male bias in dental wear features.
In terms of specific features and age bias, oblique wear, notches, and chipping affected individuals aged from 5 to 50+ years; this includes deciduous teeth. A source of uncertainty especially in the Once all the individuals are split into age groups, these subsamples become too small to be informative; a larger sample is necessary for any further interpretation. However, the most affected age group is adults from around age 19 to 30 (Figure 6b). This is likely to relate to the progression of masticatory wear, with subtler features like grooves and notches being worn away with increased age.
The most frequent of features indicative of tooth use for activities are notches and chipping. Notches indicate the repeated use of the anterior teeth, and there are individuals with notched upper and lower teeth. Both occlusal grooves and notches are thought to be caused by processing fibrous materials that are pulled through the teeth . This could be for making baskets (Larsen, 1985), reed mats (Minozzi et al., 2003;Molleson, 1994), nets or ropes (Schulz, 1977), working sinew (Waters-Rist et al., 2010), or wool fibers (Lozano et al., 2021). The presence of pierced net sinkers, reed matting, and beads at Bestansur all support the use of teeth for processing fibers relating to the creation of matting, fishing nets, and threaded bead ornaments (Matthews et al., 2019). Notches can also be caused by the grasping and biting of hard materials, such as bone, wood, or stone tools (Alt & Pichler, 1998), or food items such as seeds (Kaidonis et al., 2012).
Dental chipping can also be caused by activities relating to these items (Molleson & Jones, 1991;Molnar, 2008;Turner & Cadien, 1969), in addition to other causes of trauma (Lovell & Grauer, 2018, p. 347). Generally, dental chipping is thought to affect the molars more in hunter-gatherers, and the anterior teeth in agriculturalists (Scott & Winn, 2011;Towle et al., 2017). Anterior chipping is more likely to be associated with nonmasticatory activities such as lithic retouching or clamping the teeth while applying force to an object (Hinton, 1981;Willman, 2016, p. 50).
At Bestansur, the greater number of maxillary and anterior teeth affected indicates extra-masticatory activities as a cause, although some of these activities may have been related to food preparation.
Within the literature, oblique wear planes have been associated with a less abrasive diet and flat wear planes to a more fibrous diet (Fidalgo et al., 2020;Smith, 1984). These differences have been used to differentiate the dentitions of hunter-gatherers and agriculturalists, with the latter having increased angled wear (Eshed et al., 2006). Archeological evidence from Bestansur indicates use of a broad range of animals, both wild and domesticated (Bendrey et al., 2020). Evidence of plant foods being processed at Bestansur include cereal grains such as glume and free threshing wheats, and wild plant remains including nuts and fruits (Whitlam et al., 2020 clear Valamoti et al., 2020). The effect of ground stone tools could be analysed through dental microwear analysis in future (Hernando et al., 2020). The variation in dental wear patterns seen in this assemblage could fit with a population practicing early agriculture, which is supplemented by hunter-gatherer practices; further studies are needed to confirm this.

| CONCLUSION
In this early Neolithic community at Bestansur, evidence of extramasticatory wear shows that individuals from age 5 upwards took part in activities that required the use of their teeth. These activities may have included the creation of netting for fishing, the weaving of reeds or similar materials, and the processing of fibers for threading items such as beads.
The inclusion of the deciduous dentition in this analysis demon-

CONFLICTS OF INTEREST
The author confirms there are no conflicts of interest.

DATA AVAILABILITY STATEMENT
Further data that support the findings in the study are in the supporting information.