Dentition of Bedouin in Israel 11. MORPHOLOGY ’ KURT A. ROSENZWEIG A N D YERUCHAM ZILBERMAN The Hebrew University-Hadassak School of Dentul Medicine, Jerusalem, Israel Plaster casts of the dentition of 137 Bedouin, mostly members of the Abu Rabiya tribe in the Negev desert, were subjected to odontometric and morphologic analysis. They show a marked sexual dimorphism, very strongly developed maxillary and mandibular first molars and much reduced second molars. They exhibit the characteristics of middle-eastern populations with a rather weak expression of the shovel trait, upper premolars with relatively short BL diameters, a high prevalence of Carabelli’s complex on the first maxillary molar and virtually complete absence of the protostylid. In general, the Bedouin have larger teeth than three other ethnic groups living in Israel whose dentitions have been recently investigated. Further similarities and differences are discussed. ABSTRACT In 1963 a n epidemiological survey of different ethnic-Jews and non-Jewsgroups residing in Israel, was conducted. Included were about 600 Bedouin of all ages. In the course of the field work a maximum of impressions from dentulous subjects were secured, mostly from young adolescents 13 to 15 years of age. While the epidemiological findings have been recently published (Rosenzweig, ’ 6 8 ) , the following report is concerned with odontometry and morphologic aspects of the permanent teeth. the last century they were joined by a number of families who had been fellaheen (peasants), but felt compelled to leave their villages because of drought or for other reasons. Those who were accepted into the tribe, together with the descendants of freed negro slaves, assumed the name of their former masters. None of these “new Bedouin” are considered as equals by the members of the original tribe and there is no intermarriage. They number about 500 persons and recently they have been seeking recognition as a n independent tribe. The The population Bedouin pattern of life has been changing Almost all of the subjects investigated fast during the last two decades. Instead belonged to the Abu Rabiya tribe. They of roaming the desert in search of pasture live in the Negev desert South-East of the for their herds of goats, sheep and camels, city of Beer-Sheba. The Abu Rabiya are which supplied them with meat, milk and the largest tribe among the 17,000 wool predominantly destined for their own Bedouin registered in Israel and comprise use, they now devote more and more effort approximately 3,200 persons. The name to growing wheat and other cereals, using of the tribe is derived from the family modern agricultural equipment and fertiname of the Sheikh (fig. l ) , whose office lizers. Simultaneously they leave their is inherited. Originally the Sheikh was tents and build permanent settlements. the highest authority of the tribe in all Today all Bedouin children attend grade matters, even those concerning life and schools. Many Bedouin are employed in death. The tribe is subdivided into ex- industrial plants and in other trades and tended families and as a rule spouses are a few are entering the free professions. selected from within these groups. Mar- These developments are causing a change riages between first cousins are favored. in the social structure of the community The Abu Rabiya proper hailed, according and as of now the Sheikh is little more to their tradition, from the Arabian penin1This investigation was supported by USPHS Resula, whence they migrated hundreds of search grant DE 01724, National Institute of Dental years ago to their present area. During Research, National Institutes of Health, Bethesda, Md. AM. J. PHYS.ANTHROP.,31: 199-204. 199 200 K. A. R O S E N Z W E I G A N D Y. Z I L B E R M A N Fig. 1 Sheikh Hammad Abu Rabiya (left) and his uncle Hassan, the “Elder Statesman” of the Negev Bedouin. Fig. 2 Two little girls of the Abu Rabiya tribe. DENTITION O F BEDOUIN I N ISRAEL: 11. MORPHOLOGY 20 1 than the mediator between the population and the governmental authorities. Bedouin of both sexes. The first molars in both jaws and the lower incisors and canines are relatively large. Sex-dimorMETHODS phism manifests itself by the larger When this investigation was carried out measurements of male teeth (table 1). the Abu Rabiya still adhered very much The difference is greatest in the manto their traditions. Thus all the impres- dibular canines and least in the maxillary sions-with the exception of the students lateral incisors. A comparison of the preof the grade school at A Ksephah-were molars and the second molar with the taken in tents, using algenate material. first molar is presented in table 2. The They were stored in humidors and poured shape of these teeth is further indicated in stone plaster within a period of eight by the Crown Index, while the overall hours at most. Measurements were taken size is expressed by the Crown Module. to 0.05 m m by means of a sliding caliper The very low maxillary BL P2,'Ml ratio, with a Vernier scale. Morphologic traits 81.21 per cent in males and 77.76 per were determined as described in a previous cent in females, are typical for this publication (Rosenzweig and Zilberman, Eastern-Mediterranean population. '67). Calculations were based on the teeth Tooth variability, expressed by the coof the right side. Only when these teeth efficient of variation, is of the same order were missing or mutilated by caries, in both sexes, with the exception of the abrasion of technical faults were they re- MD diameters of maxillary T2 and P2 placed by their antimeres. which are more variable in females. In males the second molar is more variable RESULTS in both jaws. The least variable tooth is Table 1 contains the absolute mean the first molar. values of the tooth diameters, standard The maxillary molars are very strongly deviations and coefficients of variation. developed. The metacone of the first molar The dimensions of the teeth of Bedouin is uniformly of the highest possible degree are within the range of those reported for of expression. The hypocone is somewhat other Caucasoid populations, although more variable but still generally well somewhat below the mean in the MD di- formed. I n n o instance was any of the mension, with the sole exception of the two cusps absent. The second molar exupper central incisor, which is larger in hibits the usual criteria of reduction. The TABLE I Tooth nzeasurements of Bedouin-Mesiodistal __- Male ith MD n I x u v (MD) a n d Buccoliriguul ( B L ) , by sex Female _ _ ~ X ~ ~ _ _ _ _ -~ ~~~ EL a - n v - _X __ MD d V ~ _ _ _ -x BL .~ u V ~~ xilla 1 2 '1 '2 41 62 83 80 58 62 60 78 35 8.76 6.89 7.80 7.02 6.75 10.63 10.03 0.55 0.48 0.49 0.46 0.47 0.58 0.70 6.29 6.98 6.13 6.52 6.91 5.47 7.00 75 77 59 63 51 75 39 5.45 6.09 7.03 7.03 7.21 11.27 10.49 0.37 0.39 0.49 0.46 0.47 0.55 0.69 6.82 6.37 6.97 6.57 6.49 4.91 6.64 53 38 8.49 6.79 7.46 6.72 6.53 10.22 9.52 0.59 0.63 0.49 0.39 0.59 0.62 0.57 6.95 9.32 6.66 5.90 8.99 6.03 5.96 8.87 9.03 11.12 11.03 0.54 0.58 0.61 0.60 6.15 6.47 5.53 5.45 51 53 47 47 46 54 40 5.23 0.33 5.88 0.44 6.52 0.44 6.78 0.40 6.92 0.44 10.76 0.64 10.05 0.50 6.22 7.53 6.76 5.94 6.38 5.94 4.97 7.40 0.49 8.04 0.54 10.34 0.49 10.06 0.52 6.58 6.66 4.79 5.20 54 53 46 9.20 9.42 11.54 11.55 0.66 0.63 0.65 0.76 7.20 6.65 5.64 6.54 45 46 ndible 1 2 '1 '2 41 42 7.96 8.49 10.77 10.44 0.48 0.71 0.53 0.61 5.99 8.39 4.94 5.87 K. A. ROSENZWEIG AND Y. ZILBERMAN process is more evident in the hypocone than in the metacone. The mandibular first molar has as a rule 5 and the second molar 4 cusps; these traits are associated with the occlusal pattern, which is predominantly the dryopithecoid Y in the former and in the latter. This association is weak for the first molar (Xz with Yates' correction = 2.74; p > 0.05). It is very strong for the second molar (Xz = 17.33; p < .OOl). The coefficient of association Q = 0.95. Cusp number is also correlated to tooth length (MD diameter). The association is statistically significant at the 0.05 level only for males, (median MD = 11.40 mm. X2 = 4.04; Q = 0 . 8 0 ) , while X2 for females (median MD = 10.35) was only 2.82. Because of the small number of teeth these calculations could not be carried out with regard to the second molar. The distribution of the shovel trait is about equal in both the central and lateral maxillary incisors. Carabelli's tuberculum is found on almost three out of four teeth. One fifth have pits of different forms, while about 50% show cusps of various degrees. + :I DISCUSSION c7 w al : 3 B With the small upper premolars (in comparison to the first molar), the low prevalence and expression of the shovel trait, an almost complete absence of the protostylid and a highly developed tuberculum Carabelli, the Bedouin's dentition is evidently typical middle eastern (Dahlberg, '63). Therefore it appears appropriate to compare the data with those of several other ethnic groups of the area, which were recently explored using identical methods (Rosenzweig and Zilberman, '67; Rosenzweig, Mass and Smith, '69). Of these four groups (Jews from Yemen and Cochin, Samaritans and Bedouin) the sum of all MD measurements in males is smallest in the Yemenites (53.11 mm), larger (54.05 mm) in the Samaritans; the Cochini are in third place with 54.85 mm an the Bedouin are fourth (56.22). Cochini females have the smallest teeth (52.33 mm), followed by Samaritans (53.45 mm), Yemenites (53.46 mm) and Bedouin (53.93 mm). However, while the range is 3.11 mm in males it is only 0.48 in females. Accordingly Cochini show the highest de- DENTITION O F BEDOUIN I N ISRAEL : 11. MORPHOLOGY 203 molar of the Samaritans is remarkable in that the metacone is more and the hypocone less reduced that in either Jewish group. The Bedouin occupy an intermediate position with regard to both traits. The distribution of Carabelli's complex in its various forms is similar in Bedouin and Samaritans. It has its strongest expression in Yemenites and its weakest in Cochini. The rank correlation coefficient between male first molar size and the occurence of Carabelli's anomaly is negative (R = - 0.60). The shovel trait is in Bedouin slightly less prevalent on the central rnaxillary incisor and more common on the Y pattern .40 .80 lateral than in both Jewish groups though the differences are not statistically significant. The incisors of the Samaritans are Fig. 3 Rank correlation coefficients for tooth practically free from the trait. The pattern size, five cusps form and Y pattern in Yemenite observed is the reverse of that encountered and Cachini Jews, Samaritans and Bedouin. by Carbonell ('63) who found the lateral incisor more universally exhibiting the gree of sex-dimorphism among the four shovel trait. groups, followed by Bedouin, Samaritans The Bedouin have the same proportion and Yemenites-the latter with a Male/Fe- of 4 and 5 cusped mandibular molars male ratio of 99.5. It would thus appear as Yemenites and Cochini ( p > 0.05), that the females of these four groups are while the share of the four cusped teeth more similar than the males, and it is is significantly lower in Samaritans. The preferable to base a classification into latter and the Bedouin have preserved the large-and small-toothed populations on five cusps pattern slightly better than either the males alone. Interestingly the popula- Jewish group (Dahlberg, '61). The close tions rank in the same order by the sex association between number of cusps and ratios of both upper and lower canines as by the overall sex ratio (table 3; coefficient TABLE 4 of concordance W = 0.80, p < 0.01). a Development of molar cusp in Bedouin fact which would support the postulate, PerTooth Cusp Degree that sex-dimorphism in tooth size is centage ~due to Y-chromosome involvement (Garn, Upper Lewis and Kerewski, '65). NI 1 Metacone 4 99.3 The Bedouin have not only the largest 3 0.0 upper first molar among the four groups, 0.7 2 but also the strongest development of 80.9 Hypocone 4 16.8 4metacone and hypocone, however, the dif2.3 3+ ferences are not very marked. The second 79.9 I I M2 Metacone TABLE 3 Hypocone Sex ratio of maxillary and mandibiilar canines and of entire dentition i n four ethnic groups Yemen szFt:- 43 Cochin Bedouin U. Canine 103.2 103.3 106.5 104.6 L. Canine 100.9 104.6 106.8 107.8 Entire dentition 99.5 101.4 104.7 104.7 4 3 2 4 M1 M2 Lower 6 cusps 5 cusps 4 cusps 5 cusps 4 cusps 17.6 2.5 6.9 23.6 69.5 2.0 81.6 16.4 7.0 93.0 204 K. A. ROSENZWEIG AND Y. ZILBERMAN TABLE 5 Morphologic traits of teeth of Bedouin Tooth I1 I2 M1 Trait Percentage no shovel trace shovel semi shovel no shovel trace shovel semi shovel Carabelli a b C M2 M1 M2 Y +Y + d e f g h a b 58.5 34.7 6.8 60.7 33.3 6.0 27.7 21.5 - 0.8 0.8 16.2 23.0 10.0 98.7 1.3 70.4 29.6 7.0 93.0 occlusal pattern is again apparent in the fact that Samaritans exhibit the Y pattern significantly more frequent than Bedouin, who in turn show it more frequently than both Jewish groups. The difference is more marked between the first (X2 = 10.74; p < 0.01) than between the second molars (X’ = 4.02; p < 0.05). The relationship be- tween tooth size, Y pattern and five cusp form in the first molars of all four groups is well expressed by the rank correlation coefficients which are presented i n figure 3. Evidently Y pattern and five cusps are strongly associated; the relation between size and Y pattern is weak, while there is no association between five cusps and tooth size. LITERATURE CITED Carbonell, V. M. 1963 Variations in the frequency of shovel-shaped incisors i n different populations. In: D. R. Brothwell, ed. Dental Anthropology. Oxford, Pergamon Press, pp. 211-234. Dahlberg, A. A. 1961 Relationship of tooth size to cusp number and groove conformation of occlusal surface patterns of lower molar teeth. J. Dent. Res., 40: 34-38. 1963 Analysis of the American Indian dentition. In: D. R. Brothwell, ed. Dental Anthropology. Oxford, Pergamon Press. pp. 149177. Garn, S. M., A. B. Lewis and R. S. Kerewski 1965 X-linked inheritance of tooth size. J. Dent. Res., 44: 439-441. Rosenzweig, K. A., and Y. Zilberman 1967 Dental morphology of Jews from Yemen and Cochin. Am. J. Phys. Anthrop., 26: 15-22. Rosenzweig, K. A. 1968 Dentition of Bedouins. I. Epidemiology. J. Dent. Res., 47: 407-410. Rosenzweig, K. A., E. Mass, and P. Smith 1969 The Samaritan dentition. Bull. Group. Internat. Rech. Sc. Stomat., 12: 95-106.