Intentional tooth removal in Neolithic Italy

The Italian Neolithic (c. 6500-3200 B.C.; Skeates 1994), while not a homogeneous period, displays continuity in many aspects of culture. Social life was based upon small villages of 25-200 people, supported by unintensified agricultural economies. In spite of a rich record of art and burial practices, little is known about gender-related behaviour and ritual practices.

Neolithic Italian burials usually occur singly or in small groups, but as sufficient skeletal data accumulate, cultural patterns can be discerned statistically. This analysis is based on data from 30 adult females and 22 adult males from 27 sites in central and southern Italy; a pooled sample is both necessary for most Italian skeletal analysis prior to the Iron Age, and consistent with the social reality of the Italian Neolithic. None of the sites studied would have been demographically or culturally self-sufficient, and traditions would have been maintained and reproduced by groups living at many villages.

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Data were collected directly on 36 skulls, and data on 16 specimens taken from published sources. About half of the sample are moderately well-preserved skulls; the rest include only the upper or lower jaw, often quite fragmentary. Most were associated with postcrania. The specimens were sexed morphologically, using both cranial and postcranial indicators as available; juveniles and unsexed adult skeletons were excluded.

The basic method followed was to make a standard dental census of each specimen. When a tooth is lost during life, the alveolus does not remain an empty socket but resorbs to become solid bone; Teeth present at death (including ones still in place and ones lost archaeologically after death) can be distinguished accurately from teeth lost during life. While assigning teeth to these categories is usually unproblematic, it can occasionally be difficult when using published data, due both to variation in observational standards and to incomplete publication. Consequently, published specimens were included in this analysis only when the status of each tooth socket in the surviving dentition was explicitly noted or when published photographs show their status.

Eight women of 30 in the Neolithic Italian sample lost incisors and/or canines during life. Statistically, for females, a total of 6.0% of all anterior teeth were lost before death; none of the 22 males lost incisors or canines at all. The teeth most commonly affected were the central and lateral incisors.

While the sample of Neolithic Italian teeth is large, the number of front teeth lost before death is small; it is important to establish that the male-female difference observed could not be due to random fluctuations. The standard statistical methodology for testing the probability of nominal data is the χ² test of independence. When this test is carried, the male-female difference in ante-mortem loss of incisors and canines is highly significant: the χ² value of 9.88 has a probability value of .002, suggesting that there are only about two chances in a thousand of these results arising through random fluctuations. As a second method of assessing the observed results, random simulation was used, as this can provide a helpful context for understanding small samples. For each simulation run, a hypothetical ‘collection’ was generated identical to the actual dataset in its aggregate characteristics of total size, male-female proportions and proportion of teeth lost before death. In these replica samples, the status of each tooth and the sex it was assigned to were generated randomly. In all, 100 random samples were created. To compare them, the χ² statistic was used to measure how far each sample departed from having equal rates of ante-mortem tooth loss for males and females. The actual data have a sex difference in tooth loss greater than do any of the 100 random ‘samples’. Both statistical significance testing and the simulation study suggest the sex difference in tooth loss is genuine rather than a statistical fluke.

The same result appears if we analyse the data by individuals instead of by teeth. Among females, 8/30 (26.7%) lost at least one incisor or canine before death. For males, the corresponding figure is 0% (0/22). As before, since sample sizes are small, it is important to assess the probability of these results statistically. The χ² test of independence yields a highly significant result χ² = 6.9, p = .009; with Yates’correction for continuity (χ² = 5.0, p = .025). Fisher’s Exact Test, more suitable for data with low expected frequencies, assigns these results a probability of .008, which again suggests that the sex difference in anterior tooth loss is highly unlikely to be chance.

The proportion of women experiencing anterior tooth loss can be estimated in a very general way. Using the raw data, about a quarter of female skeletons display lost anterior teeth. However, these remains are fragmentary, and the rate is likely to be higher if we estimate a rate for complete remains. If 24% of all women lost one or more anterior teeth in their upper or lower dentition, around 40% of all women would have lost teeth in either the upper or the lower dentition or both. Likewise, if every anterior tooth had a probability of being lost during life of .06, the chance of a woman’s losing at least one of her 12 canines and incisors would have been slightly over half. These rough calculations serve to make the point that probably between a quarter and a half of Neolithic women would have lost incisors or canines during life.

Anterior tooth loss is known through-out the adult age range. While molar wear does not bear a simple linear relationship to age, it may be a proxy for it. On the average, women losing front teeth during life had slightly higher molar wear scores than their fellows. Median wear scores (using Scott’s (1979) scale of 1-40) for women losing front teeth during life were 31.75, 29.875 and 11.0 for the first, second and third molars respectively; the corresponding values for women who had not lost anterior teeth were 23.625, 17.375 and 8.5. The difference between the two groups of women is statistically significant for the first molars and second molars but not for the third molars. While this establishes the high probability that there is a relationship between tooth wear and anterior dental loss, the relationship is a weak one.

This result is open to several interpretations. It may mean that anterior tooth loss increased as the individual grew older. This pattern would make sense in terms of both natural causes, such as dental disease, and cultural causes. If adult women removed a tooth to mark life-events (such as to express grief at the death of kin), the longer they lived, the greater the possibility that such an occasion would arise. Alternatively, since it is impossible to tell from a completely resorbed socket how long before death the tooth was lost, all anterior tooth loss may have taken place at a prescribed and relatively early age.

Possible causes of anterior tooth loss in Neolithic Italian women

Several analysts have discussed criteria for identifying ritual tooth ablation in
skeletal remains and for distinguishing intentional dental modification from attrition due to craft activity. While individual criteria may be argued, there are two key general points. First, other possible causes must be excluded; these include post-mortem damage, congenital absence, traumatic fractures, activity-related loss and dental pathology. Secondly, it is desirable to establish that tooth loss displays cultural patterns of some sort; criteria frequently cited include symmetrical tooth loss, selection of visible teeth, differential distribution for the sexes or other categories, and age patterns which distinguish tooth loss from progressive age-related loss.

Why did Neolithic Italian women lose their anterior teeth? Post-mortem damage can be ruled out at once; the alveolar remodelling evident in all cases could only have occurred in life. Genetic causes are also unlikely. Congenital absence of the third molars is relatively common in Italian Neolithic people; but the congenital absence of other teeth is rare, and the absence of several teeth in different positions within the same dentitions virtually unknown. Anterior teeth may be broken off or knocked out by traumatic injuries due to accidents or violence. Trauma rates often do vary between the sexes, although it is not known whether this was the case in the Italian Neolithic. However, trauma seems an unlikely cause in the present case. It is hard to imagine trauma knocking out Symmetrical pairs of teeth, as occurs in several cases. Moreover, only a fraction of facial traumas would have resulted in tooth loss. If Neolithic women suffered enough facial traumas to result in tooth loss in a quarter of the individuals studied, we would expect to see numerous traumatic injuries to the mandible, maxillae, nasals, zygomatics and adjacent bones. None of the female skulls studied displayed healed facial injuries.

What about tooth loss due to specialized craft activities performed only by females? Craft activities can affect the teeth through general attrition, and Merbs (1968) argues that paramasticatory use resulted in traumatic tooth loss in some Arctic groups as the front teeth were chipped and fractured during forceful gripping. The anterior teeth of Italian Neolithic women are often heavily worn, possibly from paramasticatory activities. That wear clearly represents a phenomenon different from whatever produced anterior tooth loss: it affects all anterior teeth, wearing them down to a common occlusal plane, rather than singling out one tooth and destroying it completely. Moreover, if paramasticatory use caused anterior tooth loss in Neolithic Italian women, we would expect to see other signs of such activities, such as frequent crown chips and fractures. Except for some teeth apparently broken off at the root during life, there are few such traces.

Another possibility is that the teeth were intentionally removed to create an artificial gap to facilitate some activity such as holding a cord or handle with the teeth, or passing a straw into the mouth while the teeth were clenched. If this were so, it might have left distinctive wear upon the surfaces of adjacent teeth where contact actually occurred, as in the case of people who habitually grip an object such as a pipe or wear a labret which rubs against their teeth. The variation in locations affected -there is no standard location for missing teeth- may also argue against tying tooth loss to a specific, and presumably standardized, habitual activity.

Dental disease, the most common cause of tooth loss during life, leaves a characteristic pattern of tooth loss which may be compared against the Italian data:

1 Dental caries and ante-mortem tooth loss due to dental disease virtually always begin with the molars and proceed from the rear of the dentition to the front, reaching the anterior teeth only after all or most other teeth have been lost

2 Tooth loss due to disease is associated with other manifestations of dental disease, particularly carious lesions

3 The distribution of teeth lost during life should mirror the distribution of dental disease among subgroups such as males and females

4 Tooth loss proceeds progressively, becoming more advanced in older people

According to three of four criteria, anterior tooth loss is quite distinct from tooth loss due to dental disease; the fourth criterion is inconclusive. A reasonable interpretation is to resolve tooth loss in the Italian Neolithic sample into two patterns. The first is the pathological pattern of loss proceeding from back to front, accompanied by dental disease and found in both sexes. The second is the idiosyncratic loss of incisors and canines in females.

Anterior tooth loss in Neolithic Italian women is unlikely to have resulted from taphonomic, genetic, traumatic, activity-related or pathological causes; its primary cultural pattern is a marked sex distribution in favour of females. Ethnographically, many groups around the world are known to have practiced intentional dental ablation for cultural reasons, and this seems the most likely possibility for Neolithic Italian women.

(Source: “Intentional tooth removal in Neolithic Italian women”, by John Robb)

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Research-Selection for NovoScriptorium: Maximus E. Niles

 

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