**2. Materials under study**

In anthropological studies, skeletal samples are often limited for reliable statistical comparisons (little sample size), and thus we interpret result with many biases. It is all the more so real when we attempt to compare individuals with different lifestyle and/or socioeconomic status.

2002; Wright, 1997), while it is well accepted that juveniles, and thus their skeletons, are the most sensitive to social and environmental conditions (Bennike et al., 2005; Humphrey & King, 2000; Lewis, 2007; Lewis & Gowland, 2007; Pinhasi et al., 2005). That is why this new study is focused only on juveniles. Several biases must be taken into account with this type

We will assess the dental health of juvenile individuals. To be clear till the beginning of this

 Enamel hypoplasia is a macroscopically observable quantitative dental defect where enamel thickness has locally decreased on the surfaces of tooth crowns (Clarkson, 1989). As enamel is not remodeled during one's lifetime once it had been formed, hypoplasia provides significant information about stress during development of the dentition

 *"Dental caries may be defined as the localized destruction of tooth tissue by bacterial action"* (Gibbons and van Houte, 1975). Carious lesions lead a process which begins by the enamel surface, and which can conduct, without any care, to the tooth loss (Hillson, 1979). Carious lesions in past populations bring information about their adaptation to

 Both dental traits suffer from the scoring techniques used to evaluate them (Hillson, 2001; Ulijaszek and Lourie, 1997), and comparisons must be careful, when the dental evaluation differs from the samples under study. That is why we have attached a great

 Both dental caries and enamel hypoplasia are linked to time (Hillson, 1979; Reich et al., 1999), but in a different way. For dental caries, it is the severity which is the marker of time. Longer the individual will survive; more serious will be the lesion. That is why the age-at-death estimation is important to compare the health state of the juveniles. For dental enamel hypoplasia, the time is important for the moment of appearance of the defect. Thus, it is directly linked to the enamel development. Age-at-death estimation will be used in this way to define when the individuals have suffered from biological stress. This information of time will provide other discussion topics and give different

The aim of this study is to compare two contrasting populations (upper social class *vs.* middle social class in a settlement in expansion), in order to understand how these biological traits are linked to socioeconomic conditions. Bearing in mind the limitations of such studies, such as the osteological paradox effect (Wood et al., 1992) and some methodological biases (Hillson, 2001), special care has been taken in order to ensure the reproducibility of the results and reliable interpretations. We also would like to discuss the difficulty to differentiate the environmental part from the genetic part in dental

In anthropological studies, skeletal samples are often limited for reliable statistical comparisons (little sample size), and thus we interpret result with many biases. It is all the more so real when we attempt to compare individuals with different lifestyle and/or

mineralization and thus in enamel susceptibility to develop caries and hypoplasias.

of analysis (e.g. Hillson, 2001), but they will be discussed later in the chapter.

their physical and cultural environment (Erdal and Duyar, 1999).

importance to our methods of recording and analysis.

analyses of dental development and care.

**2. Materials under study** 

socioeconomic status.

chapter, the main definitions used in this study are given below:

(Ubelaker, 1978).

In this way, the archaeological site of Mikulčice-Valy (cf. Fig. 1) offers many advantages and the Great Moravian Empire is a specific historical period which allows studying the transition between a rural life and a progressive urbanization.

Fig. 1. Situation of the archaeological site under study in relation to current Czech Republic and the location of the Great Moravia in medieval Europe (box adapted from Havelkova et al., 2011).

#### **2.1 Historical background**

Till the end of the 8th century, life in Eastern Europe is rather rural with no clear organization and subject to the different waves of migration. Great Moravia was the first Slavic state formation. It was accompanied with a progressive Christianization. The Great Moravian Empire was funded by the Prince Mojmír the 1st (833-846) (Böhm et al., 1963), from different Slavic populations of the northern Danube River. They took advantage from the conflicts between Frankish and Avars in order to found a structured state, bringing together different principalities (Leger, 1868). On the whole, the hierarchic organization is similar to those in Western Europe, with a clear dependency of the peasant farmer to the aristocratic class (Poláček, 2008). With its small territory, the Great Moravian Empire is a privileged area to study the mutation between rural lifestyle to urbanization. Moreover, the principalities are founded around centres of power such as Staré Město, Nitra, or Děvín (Conte, 1986). Mikulčice-Valy was one of these power centres, bringing together the different socioeconomic classes at that time.

Socioeconomic Influence on Caries Susceptibility in Juvenile Individuals

thinking that we have no clues.

abbreviated "MkK".

with Limited Dental Care: Example from an Early Middle Age Population … 39

individuals buried around the basilica. Once again, we must be cautious because of the possible mixture between the parts of the population and the part of the cultural way of

The second sample under study comprises 425 burials holding 235 juvenile individuals. The skeletons, correctly preserved, present the same age-at-death range than the "Basilika" sample. In the figures and table, this sample is named Mikulčice Kostelisko and is

Fig. 2. Mikulčice-Valy, general plan of the site and topography (adapted from Poláček, 2008)

#### **2.2 Mikulčice-Valy, how to gather different socioeconomic status in a same archaeological site?**

The archaeological site of Mikulčice-Valy is the vastest site in Czech Republic, which is registered as national cultural heritage, and has competed for the World's heritage centre of Unesco since 2001 (http://whc.unesco.org). Situated at 7 km southern from the town Hodonín, near the border of Slovakia, the power centre of Mikulčice was established at the beginning of the 6th century and knew its height between the 9th and 10th centuries (Poláček, 2000; Třeštík, 2001).

#### **2.2.1 The power centre organization**

The power centre of Mikulčice is a large fortified settlement, discovered at the end of the 19th century. It is constituted by remains of a palace, at least 12 churches accompanied by several cemeteries, representing more than 2500 burials (Poláček, 2000; Poláček & Marek, 2005; Třeštík, 2001). The remains of the palace were found at the top of some hill above the ancient channel of the Morava River (Fig.2).

The different churches were built around the palace and the basilica (church n°3 on the plan). Archaeological remains suggest that the highest social class (aristocratic part of the population and churchmen) was buried in the cemeteries near these areas. Further the other churches are, lower are the socioeconomic status of the people buried in the adjacent cemeteries.

This organization shows that we could study different social groups in a same site belonging to the same historical period. This is the case and an incredible chance for an anthropological study. However, we must be cautious, because in such settlement moving from urbanization, the limits of each burial place are often difficult to separate and cultural data are missing to exactly differentiate each part of the population. That is why the collections under study come from clear different part of the site in order to have different socioeconomic classes.
