**2.1.2 Methods**

Only those teeth with obvious cavities were recorded as being carious (Figure 2). Color changes to the enamel that lacked well-defined cavity edges, possibly as a result of erosion, were not considered to be evidence of caries. Caries was detected on nine different tooth surfaces: the occlusal surface; the distal, buccal, mesial, and lingual (palatal) surfaces of the crown; and the distal, buccal, mesial, and lingual (palatal) surfaces of the root.

Gingivitis leaves no trace in alveolar bone, whereas periodontitis causes alveolar bone loss. Accordingly, periodontitis can be evaluated using bone loss as an index. We measured the CEJ–AC distances only in jawbone specimens with alveolar bone remaining around the teeth using a periodontal probe. Up to four tooth surfaces (distal, buccal, mesial, and lingual/palatal) were examined, and the measurements are expressed in millimeters. For tilted teeth, we measured the vertical distance. Teeth with a fractured alveolar crest or that were missing were excluded from the analysis. Teeth were also excluded if the alveolar bone on the buccal side was lost due to physiologic fenestration or a lesion in the root apex.

Fig. 2. Caries in Yayoi people

448 Contemporary Approach to Dental Caries

We studied 5,010 teeth and the surrounding alveolar bones in 263 ancient human skeletal remains excavated at 49 archeological sites, and which are preserved at the Kyushu University Faculty of Medicine. The distribution of each site are shown in Figure 1. The remains, which were classified as belonging to the Yayoi period, included 152 males, 100 females, and 11 unknowns. The remains were further categorized by age as follows: young adults (estimated age 20–39 years, *n* = 126), and elderly (estimated age 40–59 years, *n* = 137). Gender and age were assigned in accordance with the standard procedures of the Department of Anatomy, Faculty of Medicine, Kyushu University. Only remains with teeth

Only those teeth with obvious cavities were recorded as being carious (Figure 2). Color changes to the enamel that lacked well-defined cavity edges, possibly as a result of erosion, were not considered to be evidence of caries. Caries was detected on nine different tooth surfaces: the occlusal surface; the distal, buccal, mesial, and lingual (palatal) surfaces of the

Gingivitis leaves no trace in alveolar bone, whereas periodontitis causes alveolar bone loss. Accordingly, periodontitis can be evaluated using bone loss as an index. We measured the CEJ–AC distances only in jawbone specimens with alveolar bone remaining around the

crown; and the distal, buccal, mesial, and lingual (palatal) surfaces of the root.

**2. Relationship between root caries and alveolar bone loss Yayoi people of** 

**ancient Japan 2.1.1 Material** 

and alveolar bone were selected.

Fig. 1. Location of sites

**2.1.2 Methods** 
