CARTES AND ATTRITION I N T H E MOLAR T E E T H O F T H E ESKIMO MANDIBLE MARCUS S. GOLDSTEIK Division of Physical Anthropology, 17. 8. National Museum A. CARIES The subject of carious teeth has received a wealth of attention, largely it is true, on the etiology of the scourge, but much also on its occurrence in the various groups of man. A number of observers have noted the incidence of caries in the Eskimo dentitions. Ritchie (’23, p. 64c) observed “not the slightest trace of caries’’ in the teeth of thirty-one Eskimo skulls; Hellman ( ’25) gives 12.5 per cent of eight crania: Leigh (’25 b ) , only four out of 395 crania, or 1 per cent; Martin (’as),2.5 per cent of Eskimo dentitions; and Drennan (’29) tabulates 1.4 per cent of Eskimo with carious teeth. The numbers of Eskimo crania examined by the above authors, where given, are seen to be quite small. The only exception is that of Leigh, where the teeth of 395 crania mere observed. A much larger series than Leigh’s, representing a greater geographical area, forms the basis for the present study, although the lower jaws and molars only were. considered. METHOD Caries is defined in the present study a s a cavity, small or large, caused by decay, or probable decay. Cases of pulp exposure caused by attrition were not counted as caries. Niches or hollows, which occurred especially in the third molar, where obviously due to poor development of the crown, also were not considered as caries. Although usually tiny lesions, the caries were nevertheless nearly always plainly discernible. 421 AAIERICAN J O C R I A L O F PHYSICAL ANTHROPOLOGY, VOL. XVI, NO. 4 APRIL-JUNE, 1932 422 MARCUS S. GOLDSTEIK INCIDENCE OF MANDIBLES AFFECTED Table 1 shows the percentage of Eskimos with carious lower molars. This percentage, 6.6, is higher than that of any of the previous observers, with the exception of Hellman. Now HrdliEka (’09, p. 210), observing the dentition of the Louisiana and Arkansas Indians states, “the first teeth affected by caries, both in frequency and time, were the molars,” and, in a later monograph on the Delaware Indians (’16, p. 48), after making a similar statement, adds “especially in the lower jaw.” Leigh (’25a, p. 188) noted in the Zuni Indians that the “second molar of the lower jaw was the most susceptible” to caries, and (’23, p. 183) quotes HopewellSmith on Europeans thus: “By most writers the first TABLE 1 Percentage of Eskimo mandibles uith carious molars BPS Males (366) Females (385) Unknown ( 5 6 ) _.__ 1 E”,f,”l”,”,”,: 1 23 ; - Total (807) __ Children (29) ’ 1- ’ 4 1 - PERCENT 6.0 1 -~ . . . ~ 53 I ! 6.6 ___- : 9.5 ~ mandibular permanent molar is believed to be the most frequently carious of all teeth.” I t seems, therefore, that the teeth of the lower jaw, and especially the molars, a t least in some peoples, are the most liable to caries. And since coinparaiively few Eskimo crania, particularly with lower jaws, had been collected until four or five years ago, my larger percentage of Eskimos with caries may be due to the examination of lower rather than upper jaws, as well as a much greater number of specimens. There is also the possibility that a part of my series may be a comparatively modern group, which had perhaps subsisted more on white man’s foods. Further, the discrepancy may be due to a difference in method of observation or definition of caries. I n all events, though the extent of caries in the Eskimo according to the 423 DENTAL CARIES AND ATTRITION IN THE ESKIMO present paper is somewhat greater than has been recorded by others, the Eskimo probably still enjoy the lowest racial incidence of this disease. S E X DIFFERENCES Table 1likewise indicates that the males a r e somewhat more prone to caries than the females. This condition appears uiiusual ; the females of other peoples (Drennan, HrdliEka, Leigh, et al.) a r e said to be more susceptible to caries than the males, although such statements usually refer to the TABLE 2 Caries of each mandibular molar ( E s k i m o ) __ . Male Female Unknown Child .- 10 12 15 19 4 l j - -~ - Tot.al _ _ .___.~ . per cent (both sides) : Male 0.8' Female 1.4 Per cent. (both sexes) 1 1.1 ___ _ _ - Percentage derived from total ' Children excluded. I i (622) (639) (13.53)* I 1 1 8.4 (535) 2.0 (560) 2.3 (1159) ' 5.6 (394) 2.9 (380) , 4.3 (794) number of molars shown in parenthesis. dentition as a whole. Considering the individual molars, the females a r e more carious than the males in the first, but less carious in the second and third (table 2). This difference between the sexes in the molars affected is identical with the observation of caries in the lower molars of Peruvian Indians (Stewart, '31). I S D I V I D U A L MOLARS AFFECTED Table 2 presents the incidence of caries according to the molar affected, also indicating the sex and side of jaw. It is seen that the first molar is less frequently carious than the second, and that the second molar is less affected than the 424 MARCUS S. GOLDSBEIN third ; this molar sequence is the same in the two sexes. I t is worth noting at this point that the caries was closely associated with the degree of attrition i n the teeth: the greater the attrition, the more infrequent was the incidence of caries. This fact probably explains the least incidence of the affection i n the first, a n d of its greatest occurrence in t h e third molar, f o r attrition is most marked i n the first, decreasing in order iii the second and third molars (p. 428). Indeed, Drennail ( ' 2 9 , p. 79) found exactly the same relationship between attrition a n d caries in the African Bushmen, also remarking that the lower third molar was the most carious of the whole dentition. Developmental defects on the occlusal surface of the molars, especially the third, a r e common to all peoples, though probably to a lesser degree i n the case of the Eskimo. Such niches a n d hollows a r e usually a predisposing factor in decay. When, on the other hand, the progress of attrition opens u p these pits, decay would seem to be arrested. Considering the late eruption and back position of the third molar, however, it is easily seen that in this tooth the decay originating in developmental defects is not usually overtaken by attrition a n d hence accounts f o r the higher incidence of caries here. It should be remarked, moreover, i n the case of the Eskimo, that even i n the third molar under these favorable conditions, caries does not progress rapidly, rarely exceeding the size of a pinhead. LOCATION O F CARIES ON LOWER MOLARS The location of the caries is given in table 3. The affection was mainly between the fissures demarcating the cusps on the occlusal surface. I n a few cases only was the affection marked; i n many instances the caries was little more than pin-point size. The center of the crown and buccal cusps appear the most liable to the disease. 425 DENTAL CAEIES A K D ATTRITION IN T H E ESKIMO ACCORDIKG TO GEOGRAPHICAL LOCALITY I n table 4 are given the number of individuals affected and their geographical locality. The classification of the main divisions of the Eskimo is according to Hrdli6ka ( ’30). The extent of caries is considerably greater in the Eskimo of the south-midwest (8.4 per cent) than in those of the northwest (3.8 per cent) and north-northeast (2.5 per cent). It must be nokd, however, that St. Lawrence Island, geographically and culturally, merges into the northwestern area, and might reasonably be included in the latter division. Such a shift TABLE 3 Location o f caries of Eskimo mandibular molars ~. ~. , .__.___ ____ .- FIRSTMOLAR I SECONDYOU& ~ 1 TIIIRDMOLAR TOTAL Anterior Posterior Labial Lingual Center of crown Anterior-labial No record -. Total a 5 1 1 - ‘ 1 ~ j 8 -. 1 1 1 1 - I - 1 8 - 1 3 6 1 _..- 1 6 , .- -. I 19 ._ _ _ I _ ~ 77 . - Child. of the St. Lawrence Island group would almost entirely eliminate the difference in the incidence of caries between the south-midwestern and northwestern Eskimo, although these latter groups would still each show a substantially higher prevalence of caries than the north-northeastern Eskimo. 13. ATTRITION IN THE MANDIBULAR MOLARS O F THE ESKIMO METHOD Leigh (’25 b) defines attrition as the “gradual wearing away of the hard parts of the teeth through the physical and TABLE 4 Eskimo mandibles with carious molars according to geographical locality LOOALITY South- and inidwest St. Lawrence and Punuk lslands Kuskokwim River Piunivak Island ___-______ I I_ _Male __ i I 'emale S e x ? - - ~ 'I_Total_'I- Male 44 I Yukon River 27 10 Pastolik Tanunuk (Nelson Island) Rocky Point ' 8 Golofnin Bay Koyuk and Norton B a y 5 Hooper Bay 7 P o r t Clarence 1 3 Muintrak 1 4 Cape Darby Togiak St. Michael Island Kanakanak I 1 1 Kulukak Cape Denbigh Cape Rornanzof Cape Nome Asiatic Totals I__ JAWS WITH CARIOUS MOLARS OBSEBVED UANDIBLES ~ I 9 8 l 2 1 - 1 19 1 131 - 4 -1 -- - I 11 1 -- 1 - I - ' 3 - 31 2 -- I - d i i 1 1 - - I! - I' , - - 8.4 1 Northwest : Point Hope Shishmaref Wales Konieruk Point Barrow Akeeveenuk 78 j 77 I 10 I 165 I 4 - I Kntwhii~ Totals Per cent of jaws affected North and northeast: Greenland Cumberland Bay Ungava Bay Totals P e r cent of jaws affected -- Locality indefinite : Alaska Dnknown . 426 - I - 1 - I - - - D E S T A L C A R I E S A N D A T T R I T I O N IN T H E E S K I M O 427 physiological agencies of mastication of food. ” The Eskimo make considerable use of their teeth in the preparation of skins, as well as in the mastication of foods ip which sand and grit a r e usually mixed. Teeth of adult Eskimo, therefore, especially the molars, might be expected to be, and they are, quite worn. Leigh (’25 b ) has already written on attrition of teeth in the Eskimo. The data presented here, however, a r e more in detail and represent a much larger series and wider geographical area. The molars of non-adults were not included (except a few subadults which were sexed) ; otherwise there was no selection. The observed wear is recorded according t o the method used by Doctor HrdliEka: slight wear, cusps showing a mere sign of abrasion; moderate wear, dentine beginning to show (the cusps may be wholly or not quite worn level, and the grooves may o r m ay not be obliterated i n this type of wear) ;medium wear, dentine visible 011 the greater part of occlusal surface of tooth; marked wear, all enamel on occlusal surface of tooth gone. This definition of the degrees of attrition is essentially like that of Leigh. RESULTS LXD DISCUSSION The observations on degree of molar attrition a r e given in table 5. In both sexes, the first molar is more worn than the second, and the second more than the third. The males present a n ideal distribution of attrition in the first two molars; beginning with a small percentage of ‘no’ attrition, rising to a peak under ‘medium’ wear, and dropping off somewhat in the extreme ‘marked’ wear. F o r the third molar the highest percentage of wear is of the ‘moderate’ degree. I n the female series, however, a continuous upward curve from ‘no’ to ‘marked’ wear obtains in the first molar, while the second a n d third molars show the highest percentages in the ‘moderate’ column. I n short, the lower molars of the females, even the first, manifest less wear than do those of the males. This point is clearly seen when the percentages f o r the two sexes a r e compared. I n the first three (least) degrees of wear, every female percentage is higher than the - 32 - R. ' 40 I1 - L. .9 - 18.-. 2.2 9.8 15.- .8.1 17.9 - -. 'er cent -. -. R. .,- 1 - L. - 30.4 57.1 24.9 - I - 65 26 98 13.7 ! 141 lpercent I R. -I--- __I-. TABLE 5 Attrition of Eskimo mandibular molars .- 114 78 35 . - - 32.3 25.5 16,l 35.24.4 4.4.4 'er cent - _. a4 135 8Q L. DENTAL CARIES AKD ATTRITION IN THE ESKIMO 429 percentages representing like molars in the males ; in the last two (marked) degrees of wear, every female percentage is less than the corresponding percentages for the males. This higher incidence of wear i n the teeth of the Eskimo males is at variance with the research of Leigh ('25 b), who found the female dentitions somewhat more subject to wear than the male. The latter finding is what might be expected, if this condition is attributed wholly to the chewing of hides, which duty falls entirely upon the women. The front, rather than the back teeth, would probably be used in skin chewing, a n d this is likewise i n agreement with the fact that Leigh observed the entire dentition. As ,already stated, a high content of grit is usually found i n the Eskimo diet and this is likely the chief factor i n the molar wear of these people. It is possible, on the other hand, that the present female series as a whole represented a younger group than the males, thereby accounting f o r their lesser molar attrition. I n all events, the Eskimo, both male and female, show marked attrition i n a substantial percentage of their lower molars. SUMMARY 1. Represented by their mandibles, 6.6 per cent of Eskimos were affected with carious molars. Caries in the Eskimo is associated with degree of attrition: the greater the degree of attrition in the lower molars, the less common was the occurrence of caries (see nos. 3 a n d 5 below). The Eskimo enjoy probably the least incidence of caries of a n y racial group. 2. The lower molar teeth of the males were somewhat more carious than those of the females. 3. The first, second, and third lower molars, in both sexes, were increasingly affected by caries in the order given. The carious affection was nearly always on the occlusal surface of the crown; in few cases was the affection marked. 4. The incidence of caries was greater in the Eskimo of the south-midwest than in the Eskimo of the northwest and northnortheast. However, the St. Lawrence Island Eskimo, considered more on geographical than somatic grounds, might 430 MARCUS S. GOLDSTEIN be placed with the northwest group, thereby eliminating practically altogether the difference between the south-midwest and northwest Eskimo. The north-northeast Eskimo would still be less carious than the other groups. 5. The crowns of Eskimo mandibular molars were usually very worn; this attrition was most marked in the first molar, less in the second, and least in the third. 6. The lower molars of the female showed somewhat less wear than those of the male. LITERATURE CITED DRENNAN, M. R. 1929 The dentition of a Bushman tribe. Ann. S. Afr. Mus., XXIV, 61-87. HELLMAN, M. 1925 Food and teeth. Dent. Cosmos, LXVII, 2. HBDLICKA,A. 1909 Report on an additional collection of skeletal remains from Arkansas and Louisiana. J. Acad. Nat. Sc. Phila., XIV. 1916 Physical anthropology of the Lenape or Delawares, and of the eastern Indians in general. Bull. 62, Bur. Am. Ethnol., Washington. LF~IQH, R. W. 1923 Incidence of caries i n the different teeth and their respective surfaces. Military Dent. J., VI, 4, 183-194. 1925 a Dental pathology of Indian tribes. Am. J. Phys. Anthrop., V I I I , 2. 1925 b Dental pathology of the Eskimo. Dent. Cosmos, LXVII, 9, 884-898. 1928 Dental pathology of aboriginal California. Univ. Calif. Pub. Am. Arch. and Ethn., X X I I I , 10. MARTIN,R. 1928 Lehrbuch der Anthropologie. Jena. RITCHIE, S. G. 1923 The dentition of the western and central Eskimos. Rep. Canad. Arctic Exped., 1913-1918, X I I , C. RUFFER, A. 1920 Study of abnormalities and pathology of ancient Egyptian teeth. Am. J. Phys. Anthrop., 111, 3. STZWAET, T. D. 1931 Dental caries in Peruvian skulls. Am. J. Phys. Anthrop., x v , 2.