**3.3 Statistical procedures**

The analyses were performed in three steps. First, in order in order to calculate the frequencies of dental enamel hypoplasia, the total number of available teeth, fully erupted and/or isolated, has been used for observation. Tooth germs in both the mandible and maxilla were not taken into account. With the same objective, frequencies of dental caries were calculated using only the teeth in occlusion. The usual calibrations (Erdal & Duyar, 1999; Hillson, 2001; Lukacs, 1995) adjusting the proportions of tooth type and *ante mortem* tooth loss were applied.

In a second time, inter-population comparisons were conducted using the non-parametric χ² statistical. Finally, we studied the interrelationship between caries and hypoplastic defects

<sup>\*</sup> The emergence is a localized phenomenon, which corresponds to the appearance of the tooth in the mouth. We distinguish the clinical emergence where the tooth pierces the gingival tissue from the anatomical emergence where the tooth passes over the alveolar bone.

Socioeconomic Influence on Caries Susceptibility in Juvenile Individuals

**4.1 Prevalence of dental caries** 

evaluated for this second dental trait.

with Limited Dental Care: Example from an Early Middle Age Population … 45

Frequencies of caries in all observable teeth are presented in figure 6 & 7. The evaluated teeth are those observable in the oral cavity and/or in occlusion. This information is different for dental enamel hypoplasia, because tooth germs, when isolated, were also

As often mentioned, posterior teeth are more affected than anterior teeth, which confirm the differential susceptibility of the molars to be suffering from dental caries (Klein & Palmer, 1941; Oyamada et al., 2008; Saunders et al., 1997). But it is interesting to point out that some individuals are attained by carious lesions on anterior deciduous teeth in both area of Mikulčice. These lesions are often related to higher enamel susceptibility to develop dental

caries, even on permanent teeth (Li & Wang, 2002; O'Sullivan & Tinanoff, 1993).

Fig. 6. Caries frequencies per tooth type in the three collections (deciduous dentition)

Fig. 7. Caries frequencies per tooth type in the three collections (permanent dentition)

in order to evaluate the role of enamel structure on caries development. All statistical procedures and calculations were carried out by using Statsoft® Statistica version 7.1 and Microsoft® Office Excel 2007.

Fig. 5. Representation of the established groups from the dental mineralization sequences (adapted from Ubelaker, 1978)
