J. Anthrop. Soc. Nippon人 類 誌 100(1):1-29(1992)

Morphometrical and Dental Pathological Studies on Skulls from Yin-Shang Period

Naohiko INOUE1), Yoshihiko TAKAHASHI1), Reiko SAKASHITA1), Ming-Li WU1), Tadashige NozAKlI1), Chi-Wen CHEN2), Tetsuya KAMEGAI3) and Koichi SHIONO4)

1) Department of Oral Surgery, Branch Hospital, The University of Tokyo 2) Union Dental Group, Taipei, Taiwan, Republic of China 3) Department of Orthodontics, Faculty of Dentistry, Iwate Medical College 4) Department of Pedodontics, Kagoshima University Dental School

Abstract Three hundred and ninety eight skulls from the Yin-Shang period of China were investigated. The purpose of the present study is (1) to test inter-group difference in morphometrical characters since the samples were reported to be classified into several subgroups (YOUNG, 1985a, b); (2) to analyze the distribution pattern of dental disorders; (3) to find relationships between morphological characters and food culture. On the basis of preliminary examination, 186 male skulls from the six subgroups were selected for craniometric as well as roentgenographic cephalometric measurements and the examination of dental disorders. The results obtained are as follows: (1) statistically significant inter-group differences in morphometrics support YOUNG's initial classification of subgroups; (2) insignificant inter-group difference in dental disorders may suggest that there was no apparent dietary difference among subgroups; (3) it does not seem inducible that the dental disorders are modified by morphological characters; (4) a unique distribution pattern of dental caries in the subgroup II is likely to suggest life history different from those of the other subgroups; (5) the dominant reductive trend of lower face in the subgroup V may suggest their superiority in social status.

Key Words Yin-Shang period, Skeletal remains, Craniometrics, Roentgenographic cephalometrics, Dental disorders

Introduction sisted of 398 skulls which were excavated from In the spring of 1990, the present authors had Houchiachuang, Anyang, Henansheng, China, an opportunity to investigate skulls from the through an extensive and systematic project Yin-Shang period, a collection of the Institute of during the period from 1928 to 1937 by the History and Philology, Academia Sinica, the excavating party of the National Research Republic of China (Taiwan). This collection con- Institute of History and Philology. According to

Article No. 9103 Received November 13, 1991 2 N. INOUE et al literature (XIA, 1985; LI, 1982, 1985; YOUNG, as analysis of anthropometrical data (LI, 1982). 1985a), they originally included thousands of Though the final consensus is not yet obtained, skulls as well as postcranial skeletons, among it is considered today that this skeletal popula- which there were many complete sets. However, tion consists of five anthropologically different more than a half of the skulls were either ruined races (YOUNG, 1985a): Group I - Classical through World War II or lost during the time of Mongoloid type; Group II - Oceanic Negroid repeated long distance conveyance following the type; Group III - Caucasoid type; Group IV - move of the Academia Sinica through Nanjing, Eskimoid type; and Group V - Morphologically Yunnansheng, Sichuansheng, and Nanjing again, unidentified type [Fig. 1 to Fig. 3 (upper)]. to avoid the disturbances of the war. Besides the traditional anthropometric method There were also lots of cultural remains such of studies, there is a new trend in which the as bronze ware, potteries, bone ware, gem ware, skeletons are archaeologically utilized as carriers ornaments of vehicles and horses, from which the of the records of culture and life history in the date of the ruins of Anyang was estimated to be past (KATAYAMA, 1990). Traits of dental 1,400-1,100 years B.C., or the later half of the pathological conditions seem to be the most Yin-Shang period. KAIZUKA(1974) described the enduring and informative ones among these history of the dating in detail, pointing out that archaeological data, because dental diseases are it was essentially significant that a large mass of strongly affected by the contemporary diet and "Jiaguwen" , inscription on bones and tortoise eating habits, and the tooth-to-denture-base carapaces, were decrypted and decored. Thus, the discrepancy resulting from cumulative effects of collection must be the oldest one certified by diet life in the preceding periods (INOUE et al., historical and archaeological evidences. 1986a). On the basis of these interrelations There were many riddles around these skulls between the dental disorders and diet, the present which have caused long controversies over the authors applied multivariate analysis to 17 composition of this skeletal population. One of morphological and dental pathological variables the most important themes seemed who and what from 18 skeletal populations from the early kind of race was the founder of the Yin-Shang Jomon to the Kofun periods in Japan, and found dynasty (YOUNG, 1985a). Derived from these that the dental disorders expressed the geo- questions, it was also a matter of interest whether graphical peculiarity of the groups, while the there were any people who were to be called tooth-to-denture-base discrepancy was subject to original Chinese, or they were just the eastern or their chronological period. From these facts, the western barbarians. According to YOUNG, present authors have deduced that the dispersal TURNER (1979) stated after a study on nonmetric of physical character and the diffusion of culture dental characters that they must be a homo- progress independently of each other, namely the geneous Mongoloid population. HOWELLS former goes on slowly and the latter advances (1979), on the basis of multivariate analysis using rapidly (INOUE et al., 1986b). craniofacial morphological data, also insisted on If the collection of skulls from the Yin-Shang the unity of the samples. In opposition to these period consisted of several different subgroups, opinions, YOUNG (1985b), COON (1958), and LI then it must be one of the rare cases in which (1982, 1985) advocated that the collection con- several ethnic groups existed at the same time and sisted of several different races on the basis of in the same area. In the present study, it was morphological comparison of the skulls as well attempted first to examine whether each sub- Skulls from Ying-Shang Period 3 group had sufficient basis to be approved of its ments projected on the median sagittal plane were independence, not to participate in the long measured on roentgenographic cephalograms. lasting discussion on the races constituting the However, the measurements of the cranial and collection. It was also intended to ascertain the facial breadths, cranial length, and the size of distribution of dental disorders resulting from the mandible were measured directly on skulls using cultural environment in different subgroups, and pelvimeter and sliding calipers. Measurements of to confirm the independency between dentofacial teeth were also carried out directly on skulls using morphology and culture. sliding calipers. Items of measurement were as described below. Materials and Methods 1) Direct measurements Materials Direct measurements on skulls were carried Materials used were 220 well preserved out for 11 items shown in Table 2. samples selected from 398 skulls from the Yin- 2) Indirect facial measurements on roentgeno- Shang period. For the purpose of discussing the graphic cephalograms inter-group difference of morphometrical and Roentgenographic cephalograms of skulls dental pathological data, the YOUNG's classifica- were taken by "Veraview" Roentgenographic tion was adopted [Figs. 1-3 (upper)]. In addi- Cephalo-Pantomostat (Morita Co.). The tion to his five groups, the remaining skulls [Fig. measurement was carried out indirectly on the 3 (lower)] were also used as the 6th group tracing films of cephalograph(INOUE andSUZUKI, according to the previous report (Institute of 1971) using the landmarks and reference lines as History and Institute of Archaeology, CASS, illustrated in Figs. 4 and 5, respectively. As shown 1985). in Table 3, the measuring items consist of 11 These materials consisted of 143 males, 16 linear (Fig. 6) and 18 angular (Fig. 7) measure- females, and 59 uncertain or unknown sex. ments (INOUE et al., 1982). In addition, 9 linear Because of the very low rate of females, and the and angular measurements (Fig. 8), which were largely different sex ratios among groups, the used for discriminant analysis in the previous inter-group comparison was carried out only for study of the present authors (INOUE et al.,1991), the males. For the purpose of obtaining enough were also employed in this study. sample numbers, re-classification of the group of 3) Measurement of teeth unknown sex was carried out using discriminant The mesio-distal and bucco-lingual crown analysis of roentgenographic cephalometric data diameters were measured on all the teeth, except (INOUE et al., 1991). The final number of for those showing tooth impaction, incomplete materials resulted from this procedure was 186 eruption, or severe attrition. as shown in Table 1. Table 1. Number of materials used Method of study Method of study mainly consisted of mor- phological measurement and examination of dental disorders.

1. Morphological measurement All the items of linear and angular measure- 4 N. INOUE et al.

Fig. 1. Skulls from the Yin-Shang period: Group I (upper) and Group II (lower). Skulls from Ying-Shang Period 5

Fig. 2. Skulls from the Yin-Shang period: Group III (upper) and Group IV (lower). 6 N. INOUE et al.

Fig. 3. Skulls from the Yin-Shang period; Group V (upper) and Group VI (lower). Skulls from Ying-Shang Period 7

Table 2. Items for anthropometry maxilla and mandible was confirmed. Occlusion was classified into 6 categories, i.e. normal occlusion, maxillary protrusion, anterior cross- bite, crowding, bimaxillary protrusion (including bialveolar protrusion), and unknown. One or more of the following pathogenic factors, i.e. skeletal type, functional type, discrepancy type, and others, were recorded for each skulls. Such cases with single jaw which showed evident tooth crowding were also classified into crowding and discrepancy type, respectively. (4) Tooth attrition Tooth attrition is not disease, but just the wear of tooth resulting from physiological masticatory function. However, it is usually observed at the time of dental examination, so that it is described here as part of dental diseases. Tooth attrition 2. Dental disorders was classified into score 0 to 4 by severity (INOUE 1) Examination of dental diseases et al., 1982). Examination of dental diseases was carried out 2) Measurement of tooth-to-denture-base by ocular inspection under bright illumination discrepancy with the method of dental health examination for The total discrepancy, the size of the tooth- living body. Classification was based upon the to-denture-base discrepancy was calculated by the criteria for examination of skulls (INOUE et al., next formula (TWEED, 1945). 1982). TD = AAL - RS + HP (1) Dental caries TD is total discrepancy, AAL is available arch Examination of dental caries was carried out length between mandibular first molars on both for all the teeth existed. According to the morbid sides measured directly on jaws using annealed condition, they were classified into 9 categories, brass wire, and RS is the sum of the mesio-distal i.e. healthy, C1, C2, C3, C4, missing, extracted, crown diameter of 10 teeth from a mandibular lost, and unknown. second premolar on one side to the second (2) Periodontal disease premolar on the other side. HP is a variable for Periodontal disease was diagnosed from the indicating the forward inclination of the mandi- traits of marginal resorption of alveolar bone, bular incisors, which is available from Frankfort and classified into score 0 to 4 by severity, using mandibular incisor angle (FMIA) by using the RUSSEL's criteria modified for adapting to the following conversion formula (TWEED, 1945). skeletal materials (RUSSEL, 1956; INOUE et al., HP = (FMIA - 65) / 1.25 1982). (3) Malocclusion and its pathogenic factor 3. Method of analysis Examination of malocclusion and pathogenic Calculation and analysis were carried out by factors of malocclusion was carried out for the M-680 system at Computer Center, the University skulls in which the occlusal relationship of of Tokyo, using FORTRAN program and SAS 8 N. INOUE et al.

Fig. 4. Landmarks for roentgenographic cephalometry.

program package. Significance of the difference missing values than in the others. There were not were tested by t test for the means, by x2 test many skulls on which bicondylar breadth, for the prevalence. The inter-group similarity was bizygomatic breadth, bicoronoid breadth could estimated by PEARSON's coefficient of be measured. Significance of inter-group correlation. difference of means of each measurement is shown in Table 5. Findings Results of morphological measurement 2. Roentgenographic cephalometry 1. Direct measurement Number of cases actually measured, means Number of cases actually measured, means and standard deviations of each measuring item and standard deviations of each measuring item in roentgenographic cephalometry are shown in are shown in Table 4. In the group III which Table 6. Many missing values were observed in consisted of only two skulls, there were more group III. Significance of inter-group difference Skulls from Ying-Shang Period 9

Fig. 5. Reference lines for roentgenographic cephalometry.

of means of each measurement is shown in Table caries of the pooled samples of teeth on both sides 7. by kind of tooth, and the distribution of dental 3. Tooth measurement caries by severity are shown in Table 10. Signifi- Number of teeth actually measured, and cant inter-group difference was observed among means and standard deviations of the pooled no pair of groups, but for the prevalence of samples of teeth on both sides by each kind of missing teeth between group I and group V. The tooth, are shown in Table 8, and the significance patterns of the tooth to tooth distribution of of inter-group difference is shown in Table 9. dental caries were highly similar in each group, except group II, as shown in Fig. 9. Examination of dental disorders 2) Periodontal disease 1. Dental diseases Prevalence of periodontal disease and mean 1) Dental caries periodontal score of the pooled samples of teeth Prevalence, rate and average number of dental on both sides by kind of tooth are shown in Table 10 N. INOUE et al.

Table 3. Items for roentgenographic cephalometry

* Linear and angular measurements adopted in the previous research (INOUE et al., 1991). Skulls from Ying-Shang Period 11

Fig. 6. Illustration for items of linear measurement (1-11).

11. No significant inter-group difference was cases were very few. The pathogenic factors of observed between any pair of groups. The malocclusion were not detected often, but the patterns of tooth to tooth distribution of the discrepancy type showed relatively higher rate mean periodontal score were highly similar in than the others. The skeletal and functional types each group. were quite rare. 3) Malocclusion and its pathogenic factors There was no significant inter-group Frequency of the malocclusion and its patho- difference of frequency of either malocclusion or genic factors are shown in Table 12. There were its pathogenic factors. only 82 skulls of which the occlusion could be 4) Tooth attrition diagnosed, because the maxillae or mandibles Frequency of the occlusal and proximal tooth were lost in many cases. The distribution of attrition are shown in Table 13.Occlusal attri- malocclusion by type of occlusion showed no tion was observed in most cases in every group, distinctive features, because the malocclusion and the cases of score 2 or over amounted to a 12 N. INOUE et al.

Fig. 7. Illustration for items of angular measurement (12-29).

range from 50.0% to 73.9%. Concerning the Discussion proximal attrition, cases in a range from 77.8% to 100.0% in each group were distributed in score Morphological evaluation of groups 1, and no case showed score 3 attrition. Distribu- The most remarkable characters of group I tion of the attrition by severity showed no signi- were broad cranium and face, as indicated from ficant inter-group difference. the measurement of maximum cranial breadth, 2. Tooth-to-denture-base discrepancy bicondylar breadth and bicoronoidal breadth. On Total discrepancy and its component factors the other hand, maximum cranial length was not in each group are shown in Table 14. In this long, and the cranial base length, maxilla, and Table, rectified total discrepancy was also in- mandible were short, showing the short cranial cluded as *TD, which was calculated by sub- and facial depth. From small mandibular plane stituting the missing values of component factors angle and gonial angle as well as large facial by mean values of corresponding items of the angle, forward drift and deep over bite of group. There was no significant inter-group mandible was suggested. Maxillary incisors were difference of total discrepancy. However, there in upright position, and inter-incisal angle was was an extreme case of severe malocclusion in wide. These characteristics except the larger facial group V with as large total discrepancy as height seemed to be in common with the facial -18 .9mm, as shown in Fig. 10. pattern of the Japanese neolithic Jomon popula- tion. Glabella was prominent. Skulls from Ying-Shang Period 13

Fig. 8. Illustration for items of linear and angular measurement (30-38).

Group II might be characterized by not so definite conclusion because of lack of control wide cranial width, broad face, short upper facial data. height, and antero-posteriory deep face. The For group III, a very small group of only two sharp inter-incisal angle formed a trend of skulls and one of which lacked mandible, it was bialveolar protrusion. Glabella was rather flat hardly possible to discuss statistically the and the angles of glabella-menton to porion- difference from the other groups. However, they nasion (GMPN) and to Frankfort plane (GMFH) should be a very interesting group for they were were the largest among the subgroups, showing named "Caucasoid". Maximum cranial length an upright forehead and a smooth profile line. It was a little longer and maximum cranial breadthh might be appropriate to classify the group as was narrower than the others. The measurement Oceanic negloid, but it was hard to reach a of lower face such as bigonial breadth and *,* : P<0.05 *,*: P<0.01 *,*: P<0.001

14 N. INOUE et al.

Table 4. Results of direct measurement of skulls

Table 5. Significance of inter-group difference in direct measurement

The significance of difference of the means between each pair from A and B groups is expressed by number of the sign of inequality. For example, mean value of MCW is significantly larger in Group I than in Group II. Skulls from Ying-Shang Period 15

Table 6. Results of roentgenographic cephalometry ** : P<0.05 *,*: P<0.01 *,*: P<0.001

16 N. INOUE et al.

Table 7. Significance of inter-group difference in roentgenographic cephalometry

The significance of difference of the means between each pair of A and B groups is expressed by number of the sign of inequality. For example, mean value of CG is significantly larger in Group I than in Group II. Skulls from Ying-Shang Period 17

Table 8. Results of measurement of tooth size 18 N. INOUE et al.

Table 9. Significance of inter-group difference in tooth size

The significance of difference of the means between each pair of A and B groups is expressed by number of the sign of inequality. For example, mean value of mesio-distal diameter of maxillary central incisors is significantly larger in Group I than in group IV. <,> : P 0.05, *,*: P 0.01, *,*: P 0.001 Skulls from Ying-Shang Period 19

Table 10. Prevalence of carious teeth and missing teeth, and distribution of carious teeth by seriousness

anterior breadth were narrow. On the other hand, a turning up shape to outer and upper direction. the antero-posterior depth of maxilla, accordingly Probably it means an eversion, which is in the facial depth was extremely long. Alveolar common with the neolithic Jomon and Yayoi profile angles were very wide, and the maxillary skulls in Japan. Glabella was slightly prominent. central incisors were in upright position. Pro- In the group V, all the measurements relating minence of glabella was dominant. to the breadth such as cranial, zygomatic arch, Mean cranial breadth of group IV was the middle face, nose, mandibular condyle, coronoid, second widest after group I, and bizygomatic and anterior mandible were small, and facial breadth was the broadest in six groups. The height was high. Antero-posterior length of antero-posterior length of maxilla was small, cranial base was long, but maxilla and mandible SNA, SNB and facial angle were also small, and were short, resulting in a large cranium and small total and alveolar profile angles were wide, to face. Maxilla was slightly protruded and the form an orthognathic profile. The maxillary and incisors were forward inclined. These shapes well mandibular incisors were predominantly upright, correspond to the medieval Kamakura and even and accordingly the interincisal angle was large. to the modern Japanese, and they might be the LI (1982) pointed out that the gonial angle had most advanced type in the Yin-Shang period. 20 N. INOUE et al.

Table 11. Prevalence of periodontal disease and mean periodontal score

Glabella showed slight prominence. diameters. In group V also, maxillary incisors The group VI had the middle cranial size of were large, and mesio-distal diameter of the the six groups, but the mandible was large and maxillary second molar was large, but the third laterally wide. In other words, these molar was small. This trend is common in the characteristics expressed a facial type with small modern Mongoloid. From this point, it might be cranium and large face, standing in contrast to estimated that this group was the most evolved group V. They had small gonial angle, upright population in that period. In group II, maxillary maxillary incisors, large total profile angle, and teeth were generally large in labio-lingual direc- no maxillary protrusion. Glabella was slightly tion, and especially significant in the molar prominent. region. Group III showed only few significant There were several inter-group difference in difference from others, because the number of tooth size. In group I, maxillary incisors were skulls was minimal. But the anterior teeth were large in both mesio-distal and labio-lingual very small both in mesio-distal and labio-lingual Skulls from Ying-Shang Period 21

Table 12. Frequency of malocclusion and its pathogenic factors

Table 13. Distribution of tooth attrition by degree

-: no evidence of attrition + : evident attrition limited within the enamel layer ++: evident attrition reached into dentin +++: evident attrition reached to dental pulp 22 N. INOUE et al.

Table 14. Total discrepancy

* Rectified total discrepancy .

Fig. 9. Pattern of tooth to tooth distribution of rate of carious teeth. Skulls from Ying-Shang Period 23

Fig. 10. A case of group V showing severe malocclusion with the dominant total discrepancy of -17.1mm.

direction and both in maxilla and mandible, which seemed to be in accord with that this group Estimation of tooth-to-denture-base discrepancy was named Caucasoid. In group IV also, The number of carriers of tooth-to-denture- maxillary anterior teeth were small in both mesio- base discrepancy was as few as 10 cases, 12.2% distal and labio-lingual direction, but the out of 82 total cases among six groups. This value maxillary third molar was large. Group VI is close to 14.8%, the frequency of discrepancy showed intermediate characters among six in the Jomon period in Japan, almost the same groups. period with the Yin-Shang period. On the other hand, the mean modulus, absolute value of 24 N. INOUE et at. means, of total discrepancy was the lowest in study, namely 1.1% at the lowest and 5.7% at group I as 2.4mm (*TD=0.1), and the highest the highest, had no essential difference from the in group II as 10.7mm (*TD = 4.0). This means data of MAO and YAN (1985a, 1985b), which that a population already existed in which the showed that the number of carious teeth was 12 discrepancy had progressed more severely than out of 327 existing teeth in male, and the rate of innthe Medieval Muromachi era (1400 A.D.) of carious teeth was 3.67%. which mean modulus of discrepancy was 4.lmm, Between the groups, there was no inter-group the highest value among the Japanese skeletal significant difference of prevalence, rate, and populations. average number of carious teeth, except the rate The prevalence of discrepancy was high in of missing teeth between group I and group V. groups I and II, but the mean modulus of total The inter-group similarity of the pattern of tooth discrepancy was the lowest in group I. On the to tooth distribution of the rate of carious teeth other hand, the highest mean modulus was was tested by coefficient of correlation, and it was observed in group V. This inconsistency may be highly significant in almost all the pairs, except explained by the fact that there was wide variance in the pairs which included group II on one side. of life level or life history by individuals among This seemed to occur because the group II had the group V, and their food must have been very the extraneous distribution pattern as shown in soft and nutritious, which required less work of Fig. 9. masticatory organ as in the moderns. The above- MAO and YAN (1985 a) reported that the traits mentioned extremely severe crowding case of of periodontitis were observed on96 teeth, 9.36% group V (Fig. 10), might support this assumption. out of 327 teeth, while the prevalence of perio- Other groups, except the group III, were quite dontitis were within a range from 27.8% to 50.0 similar to each other as far as the tooth-to- % by groups in the present study, which corre- denture-base discrepancy was concerned, and it sponded to the prevalence in the later Jomon, was difficult to presume dominant differences of Kamakura and Meijieras in Japan. The difference life style among their life history and life between MAO's and present study might occur be. environment. cause of the different diagnostic criteria. There were no significant intergroup difference of perio- Dental pathological consideration dontitis. Evaluating the dental disorders in the Yin- Prevalence of malocclusion was lower than Shang period, prevalence of dental caries, 16.7%, except for 33.3% in group I, which was periodontitis, and malocclusions was quite low. the same level as observed in the Japanese skeletal For instance, the prevalence of dental caries remains from the later Jomon to the Kamakura distributed within a range from 16.7% to era. According to MAO and YAN (1985b), the 41.9% except for a value of 100.0% of the group number of malocclusion cases was five, 27.8% III. These were lower than those of the Japanese out of 18 pairs of maxillae and mandibles, being skeletal populations from several periods except in accord with the result of the present study. the value 28.6% of the Muromachi era and There were no significant inter-group differences 30.0% of the recent Ainu (INOUE et al., 1988). of malocclusion. Compared with the Chinese skeletal remains Occlusal tooth attrition of score 2 and over from the same period and from the different was distributed in a range from 50.0% to 73.9% collection, the rate of carious teeth in the present by groups, and the cases in which no attrition Skulls from Ying-Shang Period 25 were observed were maximum 7.0% in group I. morphological characteristics of groups are con- This degree of attrition is in accord with the trolled by their geographic environment, while Japanese skeletal remains from the period from dental pathological properties of groups are the later Jomon to protohistoric Kofun periods. governed by the culture of the particular period. MAO and YAN (1985b) reported also on tooth They also suggested that culture can spread attrition, to which comparison could not be rapidly over a wide area, but morphological carried out because of different criteria. There characteristics are highly stable, corresponding were no significant intergroup differences in with geographic conditions. Inherited physical attrition of tooth. characters can be altered mainly through admix- From those discussions, there was essentially ture, which requires a long time to bring about no significant inter-group difference of dental changes. As there were only minimum inter- disorders, and if existed, it might be very minor group differences in the dental pathology among or local one. six groups except caries distribution in group II, it seemed evident that there were no dominant Morphology and culture difference of life style, especially the diet, and Through the morphological and dental that the dental disorders were not influenced by pathological analysis of 186 skulls in six groups, the morphological characteristics. In other words, a better understanding of the background of the morphology and culture are existing in- Yin-Shang populations seems to be obtained. dependently to each other. Concerning YOUNG's (1985a, 1985b) proposal However, several problems are still un- that there was a number of races in these skulls, resolved. The first one is that a unique distribu- the results of the present study well support his tion of dental caries by tooth has been observed opinions, because significant inter-group in group II. Namely, only the group II showed difference was observed in morphological dental caries of oral pollution type in which measurements of the cranium, which are not dental caries are more in anterior region and less easily changed by the influence of life environ- in posterior region, while in the other groups, the ment or life style. As regarding the unitarity of pattern of dental caries distribution by tooth is race claimed by TURNER (1979) and HOWELL discrepancy type in which dental caries are less (1979), it might be considered that these authors in anterior teeth and more in posterior region are discussing the macroscopic classification such (INOUE,1981). It might be possibly explained if as three major races, while YOUNG (1985a) and we might presume that the group II was originally others are dealing with the micro-races. an ocean race for instance, and had to face a The second point of discussion is the dental rapid change of their dietary life by being caught disorders which are considered easily to change as prisoner, while the other groups were consequent upon the alteration of the back- urbanized hunters. However, this explanation is ground of life. The present authors (INOUE et al., purely a speculation, and it is necessary to collect 1986b), as a result of the multivariate analysis, and study the distribution of skulls at the site of inferred that geographic differences and excavation, and other peripheral informations. similarities among the groups are defined Another matter of importance is that the by morphological characteristics, and that dolicocephalic character and reductive jaws were the difference between each period relates observed in skulls of the group V, namely the strongly to dental pathology. In other words, high and narrow face, small lower face, and wide 26 N. INOUE et al. opened gonial angle. Moreover, the mean inter-group difference of dental disorders, moment of total discrepancy in this group was except between group II and others. much larger than in the other groups, in accord 3. The group II, which YOUNG named Oceanic with the trend of modern face influenced by Negroid, seemed to have a specific dietary life urbanization of life. From those facts, an in- different from those of the other groups, distinct presentiment seems to be derived, that because only this group showed a different this group, which consisted of the rest of skulls pattern of tooth to tooth distribution of from which the groups from I to IV were ex- carious teeth. tracted according to each specific character, could 4. The group V, which YOUNG defined as be the original inhabitants of "Huaxia", the unidentified, seemed possibly to be the ancient China, and could have the most original inhabitants of China in the Yin-Shang urbanized life environment. The extremely severe period, because several characters, which were malocclusion case of group V that was mentioned common with those influenced by urbaniza- above, recalls the fact that there were high rates tion in the modern age, were observed in this of dental diseases and malocclusions in the family group. of TOKUGAWA in the Yedo era (SUZUKI, 1985). 5. These findings seem to accord with the However, if it might be true, another question authors' thesis built through the previous may arise; why the case of severe malocclusion studies that the morphological character and had to be excavated from a sacrificial pit? Was the culture, especially the culture of food, he a ruined peer defeated in a political strife? To altered independently of each other, and it approach these historic and even epic points of took a long time with repeated generations for discussion, an extremely detailed analysis which uniformalization of race, but the commoniza- is supported by historical and archaeological fact tion of culture progressed rapidly. must be requisite. However, such a conclusion should not be Acknowledgement made too hastly, as it might be better to steer The authors wish to express their sincere clear of a definitive commitment. appreciation to Dr. Ta-You WU, the President of Academia Sinica, Republic of China, for his Conclusions kindest permission to study the respective collec- One hundred and eighty six well preserved, tion of the skulls from the Yin-Shang period. male skulls of six groups selected from 398 skulls They are grateful to Dr. Tung-Kuei KUAN, the from the Yin-Shang period were studied morpho- Director of the Institute of History and logically and dental pathologically. The conclu- Philology, Academia Sinica, and all his staffs sions were as follows. for their co-operations in the case of in- 1. It was possible to support YOUNG's opinion vestigation. They would like to extend their that there was a number of races, because thanks to Dr. Tao-Ming WU for his support for significant inter-group differences were realizing the present research project. proven by craniometric and roentgenographic Finally, they are deeply indebted to Dr. Philip cephalometric data. HOUGHTON of the University of Otago, New 2. It was confirmed that the dental disorders Zealand, for his detailed revision and valuable were not strongly controlled by morphological advice in preparing the text in English. characters, because there was no significant Skulls from Ying-Shang Period 27

総 数398体(男 性251体,女 性39体,不 明 あ る い は不 確 実 の もの108体)の うち か ら選 ん だ 保 存 状 態 の 良 い 抄 録 もの220体(男 性143体,女 性16体,不 明 あ る い は 不 商 時 代 頭 骨 の形 態 学 的 な らび殷に歯 科 学 的 研 究 確 実 の もの59体)で あ るが,男 性 に 比 べ て 女 性 の 数 が きわ め て少 な く,ま た そ の 比 率 が 各 群 に お い て 大 井 上 直 彦 ・高 橋 美 彦 ・坂 下 玲 子 ・呉 明里 き く異 な って い た.そ こで,群 間 の 比 較 は,男 性 の 標 野 崎 中成 ・陳 李 文 ・亀 谷 哲 也 ・塩 野 幸 一 本 の み を用 い て行 う こ と と し,各 群 の 男 性 の 標 本 数 を で き るだ け増 や す た め,井 上 ほ か(1991)の 頭 部 中華 民 国(台 湾)中 央 研 究 院 に お い て,中 国 河 南 X線 規 格 写 真 の 計 測 値 を 用 い た判 別 関数 によ る不 明 ・ 省 安 陽 県殷墟 の犠 牲 坑 か ら出土 した398体 の頭 骨 標 本 不 確 実 群 の 再分 類 結 果 を 導 入 し た.こ の 結 果,本 研 の調 査 を 行 う機 会 を 得 た.侯 家 荘 西 北 高 に お け る, 究 の 資料 と した 標 本 数 は,総 数186例 とな った(Table 1928年 か ら1937年 ま で通 算15回 の 発 掘 に よ る標 本 の 1). 数 は,1,000体 に お よ ぶ もの で あ った とい う が,当 時 研 究 方 法 は,つ ぎ に述 べ る よ う に,主 と して 形 態 の 中央 研 究 院 が戦 乱 を避 け て 移 動 す る 間 に,現 在 の 学 的 な 計 測 と,歯 科 的 問 題 に関 す る診 査 と に よ っ た. 数 に ま で減 少 した とい う.甲 骨 文 字 の 解 読 に よ る 史 ま ず骨 標本 の 上 で,頭 蓋 お よ び 顔 面 の 幅,頭 蓋 最 大 実 と,同 時 に 出 土 した遺 物 との対 照 に よ れ ば,1,400 長 な らび に 下 顎 骨 な ど11項 目 の 計 測(Table 2)を ～1,100BC頃,す な わ ち殷 商 時代 の後 半 と推 定 さ れ 測 径両 脚 器 お よ び滑 動 両 脚 器 を用 い て 直 接 計 測 した. て い る.こ の 標 本群 は,歴 史 的 な 裏 付 け の あ る資 料 この 外 の,正 中 矢 状 面 上 に 投 影 可 能 な,長 さ お よ び と して は恐 ら く最 古 の も の で あ り,し か も,標 本 数 角 度 に つ い て の38項 目 の計 測(Table 3)は す べ て 頭 も大 きい 点 で,古 い 時 代 の形 質 と文 化 と の 関 わ りを 部X線 規 格 写 真 計 測 法 に よ って行 った.ま た,歯 の 知 るた め の 資 料 と して きわ め て 貴 重 な もの と 考 え ら 計 測 も,滑 動 両 脚 器 を 用 い て 直 接 計 測 した.歯 科 学 れ る. 的 に は,餉 蝕,歯 周 疾 患,不 正 咬 合 と不 正 要 因 な ど の この 資 料 に つ い て の 過 去 の 研 究 の 中 で と く に 関 心 歯 科 疾 患 お よ び咬 耗 につ い て 診 査 した.ま た,歯 と が もた れ た 重 要 な 課 題 は,殷 商 王 朝 の 創 建 者 は ど の 顎 骨 の 不 調 和 につ い て も,TWEED(1945)の 方 法 に よ うな 人 種 で あ った の か とい う点 で あ る と い う(楊, よ る総 デ ィス ク レパ ン シー 量 を求 め た. 1985b).す な わ ち,本 来 の 中 国 人 と い うべ き も の が 計 測 お よ び診 査 の結 果 と,こ れ らの 群 間 の 差 の 有 す で に 存 在 して いた の か,東 夷 あ る い は 西 戎 で あ っ 意 性 と はTable 4か らTable 14ま で に 示 す 通 り で た の か,ま た,単 一 民 族 で あ った の か,あ る い は楊 が あ る.計 測 値 で はSella turcica, Point A, 下 顎 な 指 摘 した よ う に数 種 の 異 民 族 を 包 括 して 統 治 して い ど に関 連 す る項 目 に欠 損 値 が 多 く,ま た,群 別 で は, た もの か な どで あ る(Fig.1～Fig.3).も し,複 標 本 数 が 極 端 に少 な い 皿 群 に 欠 損 値 が 多 くみ ら れ た. 数 民 族 の 存 在 が 事 実 で あ る な らば,そ れ は,同 一 の 各 群 の形 態 学 的 な らび に 歯 科 的 な 特 徴 につ い て 検 時 間,同 一 の 空 間 に異 民 族 が 共 存 して い た と い う比 討 し,相 互 の比 較 を行 った.こ の 結 果,第1に,楊 ら 較 的 まれ な 例 で あ る と い う こ とが で き る.本 研 究 は, が 提 起 した複 数 の人 種 の 存 在 とい う こ と に関 して は, 長 年 にわ た る人 種 論 争 にあ え て 参 加 す る立 場 は と ら 形 態 学 的 計 測 値,と く に 脳 頭 蓋 部 の,生 活 環 境 や 生 ず,各 群 が,群 と して 認 め ら れ る に 足 り る 形 態 学 的 活 様 式 に よ って容 易 に は変 わ る こ と の な い 部 分 の 計 な 根 拠 を もっ か ど うか を 検 討 し,さ らに 文 化 の 影 響 測 値 に有 意 の差 を認 め た こ と か ら,十 分 に 支 持 す る と して の歯 科 疾 患 が,同 じ生 活 圏 に 存 在 した と 考 え こ とが で きる と考 え られ た.第2に は,生 活 の 背 景 られ る異 な る民 族 群 にお いて ど の よ う に 分 布 す る か に よ っ て容 易 に影 響 を 受 け る こ と が 知 ら れ て い る 歯 を 知 り,著 者 らが す で に指 摘 し た形 質 と文 化 と の 独 科 疾 患 に関 して,群 間 の 差 が きわ め て微 少 で あ る こ 立 性 を さ らに確 か め る こ とを 目的 と した. と か ら,生 活 様 式,と くに 食 生 活 に も著 明 な 差 が な この よ う に,人 種 的 な 差 や 人 種 の 同 定 につ い て 論 く,ま た,歯 科 疾 患 が 形 態 学 的 な特 性 に 影 響 さ れ る ず る た めで は な く,人 種 的 な差 が 存 在 す る こ と を 仮 もの で は な い と考 え られ た.い い か え れ ば 形 態 と 文 定 した上 で 形 態 学 的 デ ー タ と 歯 科 学 的 デ ー タ を 対 比 化 は相 互 に 独 立 して 存 在 す る と い うこ と に な る. す る ため,本 研 究 で は,楊 に よ る分 類 を利 用 して,全 個 々 の群 に 関 して は,II群 お よ びV群 に 著 明 な 特 群 を6群 と して 比 較 す る こ と と した.用 い た 標 本 は, 徴 が認 め られ た.す な わ ち,他 の5群 に お い て は,鯖 28 N. INOUE et al.

蝕 の歯 種 別 分 布 が,歯 列 の 後 方 部 に 鯖 蝕 が 集 中 す る 〔井 上 直 彦,1981:Discrepancy型 鯖 蝕.歯 界 展 望, デ ィス ク レパ ン シ ー 型 の 分 布 を 示 した の に対 して, 57: 349-357.) 群 に お い て は,前 方 部 の 歯 に 鯖 蝕 が あ っ て 後 方II部 INOUE, N., G. ITO and T. KAMEGAI, 1982: Studies の歯 の鯖 蝕 が少 な い 口 腔 内 汚 染 主 導 型 の 分 布 を示 し on tooth to denture base discrepancy consequent upon human evolution. I. Researches in Japanese skeletal た こ とで あ る.こ の こ と は,そ の 他 の 群 が 恐 ら く は remains. 1. & 2. Report of Research Project, Grant- 狩 猟 牧 畜 民 の 系 列 に あ っ た の に 対 して,II群 が,例 in-Aid for Co-operative Research (A). え ば海 洋 民 族 と して の 生 活 を して い た もの が 急 激 に INOUE, N., G. ITO and T. KAMEGAI, 1986a: Micro- 食 生 活 を変 更 せ ざ るを 得 な くな っ た な ど,生 活 史 に evolution of Human Dentition and Dental Diseases. 特 異 性 が あ った こ とを 暗 示 す る もの か と考 え られ た. Ishiyaku Shuppan, Tokyo. (In Japanese) この よ うな 状 態 が 起 こ る可 能 性 と して は,捕 虜 あ る 〔井 上 直 彦 ・伊 藤 学 而 ・亀 谷 哲 也 ・1986a:咬 合 の い は奴 隷 な どの 場 合 を 想 定 す る こ とが 可 能 と思、わ れ 小進 化 と歯 科 疾 患.医 歯 薬 出 版,東 京.〕 INOUE, N., G. ITO and T. KAMEGAI, 1986b: Dental る. pathology of hunter-gatherers and early farmers in V群 に み られ た 特 徴 は,頭 蓋 な ら び に 顔 の 幅 が 小 prehistoric Japan. Univ. Mus., Univ. Tokyo, Bull., さ く顔 の 高 さが 高 い こ と,お よび 下 顔 面 部 が 小 さ く, 27: 163-198. 下 顎 角 が 大 き く開 い て い る こ と な ど の,長 頭 化 と顎 INOUE, N., S. KOCHI and T. KAMEGAI, 1988: Study 骨 の縮 小 変 化 とを 表 す もの で あ り,総 デ ィ ス ク レパ on food and reduction of human masticatory system. ン シー 量 の絶 対 値 の 平 均 値 も他 の 群 に比 べ て 大 き く, IV 1 Investigation of Recent Ainu. Report of Research Project, Grant-in-Aid for Co-operative Research (A). 現 代 に お け る都 市 化 の 影 響 と 共 通 す る 点 が 多 い.こ INOUE, N., R. SAKASHITA and T. NOZAKI, 1991: Sex れ らの こ とを 考 え る と,こ の 群 が 華 夏,す な わ ち 古 determination by discriminant analysis using roent- 代 中 国 の 本 来 の 住 民 で あ り,最 も文 化 的 な生活 を送 っ genographic cephalometric data and its application て い た 群 で あ る可 能 性 を 予 感 さ せ る も の の よ う に 思 to Yin-Shang skulls. J. Anthrop. Soc. Nippon, 99: わ れ た.さ らに,こ の 群 の 中 に は きわ め て 高 度 の 叢 423-44.0. (In Japanese with English summary) Institute of History and Institute of Archaeology, CASS, 生 症 例 が存 在 して い た が,こ れ は,江 戸 時 代 の徳 川 1985: Contributions to the study on human skulls 一 族 に 歯科 疾 患 が あ る もの ,あ る い は不 正 咬 合 の も from the Shang sites at Anyang. Cultural Relics の が多 か った と い う事 実(鈴 木,1985)を 想 起 させ Publishing House, Beijing, pp. 210-353. (In Chinese) る もの で あ った.し か し,そ れ な らば なぜ,こ の個 体 〔中国 社 会 科 学 院 歴 史 研 究 所 ・中 国 社 会 科 学 院 考 古 が犠 牲 坑 か ら発 掘 され た の か な どの 疑 問 が 残 さ れ る. 研 究 所 編,1985:安 陽 股 櫨 頭 骨 研 究.文 物 出 版 社, 今 後,歴 史 的 事 実 に よ る 裏 付 け を も考 慮 し,あ る い 北 京,pp.210-353.〕 は 時代 的,地 域 的 に 近 い周 辺 の 民 族 と比 較 す る な ど, KAIZUKA, S., 1974: A megalopolis - Prosperity of Yin よ り精 度 の 高 い 検 討 が 必 要 と考 え られ る. Dynasty. In: History of the World. 1 Discover of Ancient Civilization. Chuoukouronsha, Tokyo, pp. 58-100. (In Japanese) References 〔貝 塚 茂 樹,1974:大 い な る都-股 王 朝 の 栄 華.世 界 の 歴 史1古 代 文 明 の 発 見,中 央 公 論 社,東 京, COON, C.S., 1958: An anthropogeographic excursion around the world. Human Biology, 30: 29-42. pp. 58-100.) DOWNS, W.B., 1948: Variation in facial relationships, KATAYAMA,K.,1990; Skeletal Remain Talks. Douhou- their significance in treatment and prognosis. Am. J. shashuppan, Kyoto, pp. 1-210. (In Japanese) Orthod. and 0. Surg., 34: 812-840. 〔片 山 一 道,1990:古 人 骨 は 語 る.同 朋 舎 出 版,京 HOWELLS, W.W., 1979: Interpretations of the recent 都,pp.1-210.〕 evidence. (cited from YOUNG, S., 1985a.) LI, C., 1982: Anyang Excavation. Translated into INOUE, N. and Y. SUZUKI, 1971: New Atlas of Ortho- Japanese by KOKUBU, N., Shin-nihon Kyoiku dontics. Ishiyaku Shuppan, Tokyo, pp. 285-327. (In Japanese) Tosho, Shimonoseki, pp. 304-310. (In Japanese, Originally in Chinese) 〔井 上 直 彦 ・鈴 木 祥 井,1971:最 新 歯 科 矯 正 ア ト ラ ス.医 歯 薬 出 版,東 京,pp.285-327.〕 〔李 済,1982:安 陽 発 掘(国 分 直 一 訳),新 日 本 教 INOUE, N., 1981: Discrepancy type dental caries. 育 図 書,下 関,pp.304-310.〕 Shikaitenbou, 57: 349-357. (In Japanese) LI, C., 1985: Notes on some metrical characters of calvaria of the Shang Dynasty excavated from

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井 上 直 彦 東京大学医学部附属病院分院歯科口腔外科 〒112 東京都文京区目白台 3-28-6

Naohiko INOUE Department of Oral Surgery, Branch Hospital, The University of Tokyo 3-28-6 Mejirodai, Bunkyo-ku, Tokyo 112, Japan