Paleoepidemiology of a central California prehistoric population from CA-Ala-329 Dental disease.код для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 81:333-342 (1990) Paleoepidemiology of a Central California Prehistoric Population From CA-Ala-329: Dental Disease ROBERT JURMAIN Department of Anthropology, Sun Jose State University, Sun Jose, California 95192 KEY WORDS Dental attrition, Periodontal disease, Dental ab- scesses ABSTRACT Ala-329 is a prehistoric central California site located on the southeastern margin of San Francisco Bay, dating from approximately 500 AD up to pre-European contact. A large earth mound, Ma-329, has yielded many well preserved burials, approximately 300 of which are included in this study. The most common pathological lesions seen in this population are in the dentition. Advanced attrition is pervasive, affecting all individuals with teeth in occlusion for 2 years or more. Deciduous teeth are involved even in very young children and often show severe wear before replacement. In the permanent dentition, all elements are involved by the second decade; in the oldest age category (41+ years), all individuals show severe wear throughout their dentitions. In fact, by the end of the third decade, the majority of individuals have no enamel remaining. Mild periodontal involvement is found in 74%of adults, socket resorption in 53%,and abscesses in 31%of the relevant sample. Interestingly, although dental abscesses are found more than twice as often among males, socket resorption is seen more often among females. Dental caries are seen in only 10 individuals. The high incidence of periodontal remodeling, socket resorption, and dental abscesses is probably a secondary result of severe dental attrition. It is hypothesized that a large quantity of abrasives in the diet is responsible for the extreme degree of attrition, in fact, among the most severe for any population yet described. “Something is always going wrong with our teeth. They don’t last anything like a lifetime, usually. What chain of events in evolution should we thank for our mouthfuls of rotting crockery?” -Kurt Vonnegut, Galapagos, 1985 The dentition acts as a primary interface with our environment. The teeth function crucially as the first agents of food processing and secondarily as tools. Through their repeated exposure t o wear and infectious organisms, the teeth can also be among the first vital systems to fail, and the consequences can be catastrophic. Dental diseases have long been a problem in human evolution. For exam le, the Broken Hill cranium shows marke c rdental wear and multiple abscesses, and the La Chapelle-aux-Saints 1individual had lost 14 and possibly 15 teeth by the time he died (Trinkaus, 1985). Moreover, contemporary nonhuman primates also are commonly af- @ 1990 WILEY-LISS, INC. fected by poor dental health. In one group of Gombe chimpanzees, severe attrition and resultant abscesses are the most common pathological lesions encountered (Kilgore, 1989). The health consequences of dental disease have been noted by paleopathologists in a wide variety of recent human populations (e.g.,Hinton, 1981; Costa, 1982; Puech et al., 1983; Tal and Tau, 1984; Molnar and Molnar, 1985; Hall et al., 1986; Clarket et al., 1986).Among prehistoric California populations, some of the most frequent and severe Received December 9,1988; accepted May 11,1989. 334 R. JURMAIN manifestations of dental involvement have been seen (Leigh, 1928; Molnar, 1971; Walker, 1978; Reinhardt, 1983). The prehistoric central California population reviewed here is certainly among the most severely affected of any group yet reported. MATERIALS AND METHODS Ala-329 is a large earth mound site located on the southeastern side of San Francisco Bay, approximately 20 miles north of San Jose (Fig. 1). This central coast region between San Francisco and Monterey Bays was populated at the time of European contact by a group of linguistically related tribes of the Costanoan language family. Not representing any actual political entity, Costanoans (or Ohlones, as they are often called) were segmented into relatively small ethnic groupings or tribelets, each speaking its own language, as different from each other as French from Spanish, and inhabiting its own local territory. In the eighteenth century, along the eastern bay, about 2,000 individuals spoke dialects of the Chochenyo language, and this linguistic group in turn was made up of several tribelets, comprising anywhere from 50 to 500 people each. The annual subsistence round probably crossed ecological zones that took the inhabitants from the bayshore at least as far inland as the (, SAN JOSE 0 scale 0 20 miles i Fig. 1. Location of site Ca-Ala-329,southeastern San Francisco Bay, central California coast. uplands of the neighboring eastern mountain range. Large mound sites such as Ala-329 have traditionally been interpreted as habitation sites of fairly large, mostly sedentary populations. However, ongoing analysis of the rich archeologicalassemblages from this site (Leventhal, 1989) suggests that this mound may have served as a special-purpose mortuary complex. Ala-329 thus may include the accumulated burials from more than one large village community. The representativeness (culturally and biologically) of this important site, with its obvious demographic implications is also currently under review. Although it is now located approximately 2.5 miles inland, the site probably once stood adjacent to the bayshore, surrounded by saltwater marshes. Radiometric (14C) age estimates indicate that most burials were interred between 500 AD and just before European contact (Leventhal, 1989). An extensive site, the earth mound extend 133m x 90 m x 4 m (high) and no doubt still contains several hundred burials. Favorably positioned as it was along the bayshore, the area allowed easy access to shellfish, fish, and waterfowl as well as upland stands of oak, yielding their all-important acorns. In addition, seeds, berries, roots, and varied small, medium-sized, and large mammals were locally abundant. Without question, this region had one of the richest and most diverse subsistence bases in all of North America. Accordingly, it is no surprise that central California is estimated to have had, at the time of European contact, among the highest population densities anywhere north of Mexico (Cook, 1976; Ubelaker, 1988). As we will see, however, this rich subsistence base with its patterned means of extraction was not without its costs. The number of burials retrieved from Ala329 from excavations conducted primarily during the 1960s totaled more than 400. The sample available for analysis in this study, that portion excavated by San Jose State University field classes, consists of 298 individuals. Of these, the most relevant group for most of the present analyses is the 195 aged and sexed individuals with adult dentitions (311 years of a g e b 1 0 7 males and 88 females. Individuals were sexed and aged using standard osteological procedures. Subadults were aged on the basis of dental fmmation and eruption (Ubelaker, 1978) as well as epiphyseal union (Bass, 1987). Adults were assessed primarily on the basis DENTAL. DISEASE IN PREHISTORIC CALIFORNIA of pubic symphysis remodeling, initially using the Todd system (Todd, 1920), but later rechecked for the entire collection using the modification developed by Katz and Suchey (Katz and Suchey, 1986; Gillett, 1987).In all cases sex and age were independently assessed by the author and a minimum of two other observers. Overall, the condition of burials is good to excellent; this collection represents one of the largest and best preserved osteological samples from any single site in the western United States. Paleopathological changes of the teeth and jaws were evaluated by visual means on the gross specimens, occasionally supplemented by radiogra hs. All dentitions were ineluded, whet er complete or fragmentary. Dental attrition was scored using Molnar’s (1971) eight-stage system. This method and others much like it (Murphy, 1959) have been the most widely applied (e.g., Hinton, 1981; Reinhardt, 1983; Smith, 1984; Hall et al., 1986). Other more complex systems to measure dental attrition have been used, with some success for the molar row especially (Walker, 1978; Scott, 1979). However, the easily applied ordinal scale was chosen because it differentiates primary from secondary dentin and can be used for all dental elements, and the results can be compared with those of other studies. In addition, an ordinal scale was used to describe surface periosteal changes, scored as slight, moderate, or severe on the basis of how much periosteal hypertrophic bone was deposited. 335 ! RESULTS Attrition The most common dental pathology is severe attrition, manifested throughout the dental row. Such involvement is pervasive in this population, affecting all individuals with teeth in occlusion for 2 years or more. In fact, for adult dentition (age 11 years and above) in 98.8% of cases (N = 171), at least one tooth had moderate or severe involvement (score of 4 or higher). Of these, 82.5% had more than 10 elements at least moderately worn. Looking at only severe involvement (6 and above), 82.5% of cases had at least one tooth affected, and, for extremely severe involvement (Molnar’s 81, where no enamel remains, 66.1% of individuals have at least one tooth involved (Fig. 2). When the upper or lower dentitions are considered separately, the results are similar; 97.5%of upper dentitions (N = 161)and 98.1% of lower dentitions (N = 160) display Fig. 2. Advanced dental attrition, typical of adults in fourth decade; male, aged 31-40 years. some moderate involvement. The most commonly affected element is consistently the first molar in both the upper and lower jaws, with the M l s displaying severe involvement between 69% and 72% of the time. Conversely, the least affected element is the third molar, again in both upper and lower jaws (severely involved 28% for the ULM3, 39% for the URM3, and 54% for both lower third molars) (Table 1). In fact, the modal involvement for all teeth (with the exception of third molars) is level 8, i.e., wearing down to the roots and consequently usually exposing the pulp cavity. This frequency of extreme involvement is all the more remarkable when we consider that this is by no means a population of older individuals. The average age at death for individuals aged 11years and above is 30.6 years for males and 31.7 years for females. The pattern with advancing age shows that, again except for the third molars, by the teens all elements are 100% involved to some degree. By the third decade (ages 21-30 years), the minimum wear on any tooth (excepting the third molars) is level 3, and severe involvement ranges from 30% to 80%. By age 41+ years, everyone shows severe involvement for all teeth, except for third molars. These age-related patterns are unambiguous in all relevant dental elements, but for purposes of demonstration are shown for two representative teeth, the upper right central incisor and upper right first molar (Tables 2 and 3). 336 R.JURMAIN TABLE 1. Patterns of dental attrition in adults (aged 11 years and older) N Upper RM3 RM2 RM1 RP2 RPl RC RI2 RIl LI 1 LIZ LC LP1 LP2 LM1 LM2 LM3 Mean C' M F C' M F Frequency severe (6 or higher)' (%) 98 120 111 115 130 132 103 107 103 111 132 126 119 112 120 85 55 66 60 66 68 72 55 60 58 56 72 66 67 63 65 49 40 48 47 44 57 55 46 43 40 51 56 56 47 44 49 32 4.33 5.54 6.52 5.77 5.85 5.83 5.53 5.59 5.61 5.59 5.74 5.56 5.63 6.39 5.57 4.36 4.62 5.79 6.58 5.82 5.98 5.99 5.58 5.68 5.71 5.78 5.72 5.58 5.60 6.46 5.72 4.67 3.98 5.25 6.45 5.61 5.72 5.67 5.50 5.40 5.48 5.31 5.70 5.48 5.68 6.39 5.39 4.03 39.2 58.3 70.3 63.5 63.1 61.4 52.4 56.1 58.2 56.8 64.4 56.3 58.0 72.3 59.2 28.2 98 140 134 123 129 134 108 80 82 99 138 132 125 131 136 95 53 76 72 66 67 72 63 48 48 57 72 69 69 70 73 54 40 59 56 52 58 56 40 28 30 38 59 57 50 54 57 38 5.24 5.77 6.26 5.75 5.78 5.79 5.58 5.89 5.66 5.72 5.95 5.74 5.62 6.31 5.66 5.22 5.47 5.86 6.24 5.73 5.80 5.86 5.75 6.27 5.85 5.93 5.89 5.58 5.56 6.35 5.71 5.54 4.80 5.59 6.25 5.60 5.76 5.73 5.40 5.39 5.30 5.39 6.05 5.91 5.56 6.15 5.53 4.60 54.1 64.3 72.4 64.2 63.6 59.7 51.8 57.5 53.7 56.6 64.5 61.4 60.0 71.8 61.8 53.7 Lower RM3 RM2 RM1 RP2 RP1 RC RI2 RI1 LI1 LIZ LC LP1 LP2 LM1 LM2 LM3 :Males and females combined. After Molnar (1971). TABLE 2. Upper right central incisor, pattern of attrition b y age category' Age category (years) N 1 2 3 4 5 6 7 8 11-20 21-30 31-40 41t 20 28 36 8 - 5 (25.0) l(3.6) 10 (50.0) 9 (32.1) l(2.8) 5 (25.0) 3 (10.7) - - - - 8 (26.8) 3 (8.3) 3 (10.7) 12 (33.3) 2 (25.0) 1 (3.6) 7 (19.4) 2 (25.0) 3 (10.7) 13 (36.1) 4 (50.0) - - - - - 'Percentage frequencies shown in parentheses. Attrition scores after Molnar (1971). TABLE 3. Upper right first molar, pattern of attrition b y age category' Age category (years) N 1 2 3 4 5 6 7 8 11-20 21-30 31-40 41+ 24 33 36 7 - 1 (4.2) 6 (25.0) - - - 8 (33.3) 5 (13.2) - - 9 (37.5) 2 (6.1) 6 (18.2) l(2.8) 10 (30.3) 8 (22.2) - - 10 (30.3) 27 (75.0) 7 (100.01 - - - - 'Percentage frequencies shown in parentheses. Attrition scores after Molnar (1971) DENTAL DISEASE IN PREHISTORIC CALIFORNIA 337 In the deciduous dentition, early onset of periodontal involvement. Molnar and Molsevere attrition is also seen, but the patterns nar (1985) suggest the term “ostetitis,” but are more difficult to delineate; only 34 indi- “gingivitis” is also frequently employed. viduals (age 10 years and under) have any Most researchers agree that more severe teeth preserved; and a substantial portion of disease leading to resorption of the alveolar these individuals are under 2 years of age. crest and involvement of the periodontal ligConsidering that infants were not weaned ament should be termed “periodontitis.” until 18-20 months (Roland, 19591, onset as In this study, only the mild surface lesions of the alveolar bone are scored, most seen as early as occurs is remarkable. Of those children with some teeth, 47.1% slight hypertrophic reactions. The more sehave at least one element moderately in- vere manifestations of alveolar resorption volved, and 14.7% have a t least one tooth were not systematically scored due to the severely involved. Only 5.9% of cases have confounding problems of overeruption of any “hypersevere” (grade 8 ) involvement. It teeth as well as postmortem damage (probappears that, in this population, following lems well recognized by others; Molnar and eruption, it takes about 2 years for a tooth to Molnar, 1985: Clarke et al., 1986). Among show moderate attrition and about 5-10 the Ala-329 population, frequent exposure years to become severely involved. The de- directly through the pulp cavity appears to ciduous teeth are obviously replaced before have been the major focus of severe infection. Some surface periodontal involvement is much severe wear can take place (Table 4). seen in 74% of adults, with moderate and Periodontal disease severe lesions displayed 46% of the time. In One immediate result of severe attrition the oldest age category, 82% (73%moderate/ and continued irritation by abrasives from severe) of upper jaws and 77% (48% the diet is inflammation of gum tissues. In moderate/severe) of lower jaws are involved certain circumstances, initial inflammatory (Fig. 3). However, no sex differences in perireactions can result probably more from mi- odontal incidences are observed. When bone loss proceeds to an advanced crotrauma to the soft tissue immediately adhering to the bone than directly from bac- degree or tooth anchors are weakened, anteterial infection. In the clinical as well as the mortem loss of teeth and socket resorption paleopathological literature, a variety of can ensue. Here again frequencies of such terms have been used for these mild forms of lesions are high. Among adults (221 years of age), 52% display socket resorption. For those individuals showing such antemortem tooth loss, the average number of sockets TABLE 4. Patterns of dental attrition in subadults resorbedis 4.6 in the upperjaw and 5.0 in the laeed 10 Years or less). deciduous dentition lower jaw. The most common location of Frequency severe antemortem loss and socket resorption is in N Mean (6 or higher) (W) the posterior row (premolars and molars), Upper accounting for 93% of involvement in the 2.53 RM2 19 upper jaw and 71% in the lower jaw. Again, 16.0 2.76 25 RM1 the trend with age is marked; among the 2.07 RC 15 oldest age group (41-t years of age), 75% of R12 4.5 2.23 22 RI1 2.06 18 upper and 66% of lower jaws are affected LI 1 4.5 2.65 17 (Fig. 4). When considering complete resorp5.2 2.53 L12 19 tion of sockets (where the alveolus is mostly 2.50 16 LC filled-in), a sex difference is manifested, with 24 20.8 3.04 LM1 LM2 18 5.6 2.61 females almost twice as affected as males Lower (P < .01). 10.5 19 RM2 2.84 The final sequel to advanced attrition is 22 9.1 RM1 3.00 severe infection once the pulp cavity has 6.7 15 2.20 RC 22 2.23 RI2 been exposed, often leading to abscesses. RI 1 19 2.53 Among individuals aged 11years and older, I,I 1 20 2.45 30% had at least one abscess. Most of the L12 19 2.32 5.2 individuals have only one or two abscesses, 6.2 LC 16 2.69 LMI 23 2.56 8.7 but one unfortunate victim (a 31-40-year-old LM2 19 2.47 5.2 male) had nine abscesses. Apparently untreated, some infections progressed t o a se‘After Molnar (1971). ~~ 338 R.JURMAIN 1O O % l 90% 80% 70% 60% 50% 40% 30% 20% 10% ' 0-10 ' 11-20 ' 21-30 31-40 I 41+ ' Fig. 3. Frequency of periodontal involvement by age. Males and females combined. 80% UPPER J A W 70% 60% 50% 40% 30% 20% 10% 11-20 21-30 31-40 41+ "Adult" Fig. 4. Frequency of involvement of socket resorption and antemortem tooth loss by age. Males and females combined. vere degree, yielding abscesses greater than 10 mm in diameter (Fig. 5 ) . Suggestive of an interaction with progressive wear, the frequency of abscesses also shows marked increase with age (Fig. 6). As with socket resorption, abscesses show a predilection for the posterior dentition, appearing there 79% of the time. In addition, there is a marked tendency for upper compared to lower jaw involvement. In those cases when only one jaw is affected, 78% of the time it is the maxilla that is involved. Here also a significant sex difference (P < .05) is observed, but in the opposite direction from the pattern for socket resorption; for abscesses, males are the more commonly affected, 39% compared to 21% for females. Other dental conditions In addition to severe attrition and the related periodontal involvement noted above, a few other types of dental problems are seen occasionally in the Ma-329 popula- 339 DENTAL DISEASE IN PREHISTORIC CALIFORNIA Fig. 5. Large, well healed abscess of maxilla; male, aged 41-50 years. 50% - 50 0 UPPER JAW 38% 40%- 30% - LOWER JAW 20% 10%- 1 8% Fig. 6. Frequency of involvement of dental abscesses by age. Male and females combined. tion. Dental caries are found but rarely, seen in only 10 individuals, who together have a total of 21 lesions. As in other studies, the molars are most often affected, accounting for 18 of the observed carious lesions. Although this is a preagricultural population, and the caries rate should thus be expected to be fairly low, the incidence in Ala-329 is unusually low compared to other nonagricultural groups (e.g., groups from Oregon; Hall et al., 1986). Indeed the caries rate at Ala-329 summed for all elements is a mere .57%,exceedingly low even in comparison to other California samples (one-tenth to one-twentieth as involved)(Walker and Erlandson, 1986)(Table 5).A simple explanation may account for the low caries rate at Ala-329. In that caries are diagnosed as characteristic defects in enamel, the lack of enamel from wear in most adults makes complete ascertainment of caries impossible. Of note in this regard is that, 340 R. JURMAIN 1928).Precise comparative data are difficult to locate owing to differences in methodology. Among the best data available are those Canada Verde Skull Gulch A Skull Gulch B reported by Hall et al. (19861,using Molnar’s N2 Freq. N2 Freq. N2 Freq. rating system, for prehistoric residents of 1,718 13.3 251 10.8 934 6.3 Oregon. Average attrition levels for their total ‘Data from Walker and Erlandson (1986). Males and females combined. sample (from five locations) for individuals *N = total for all dental elements. aged 15 years and older range between 3.8 and 5.7 for the maxilla and between 4.2 and 5.4 for the mandible excluding third molars. In comparison with Table 1,it is obvious the Ala-329 individuals show markedly more of the 10 individuals with caries, eight are dental attrition, ranging on average between under 30 years of age. 5.5 and 6.5 in the maxilla and between 5.6 A few cases of supernumerary teeth were and 6.3 in the mandible (again, excluding also found (in nine individuals). Finally, third molars). eight cases of severe malocclusion or Another study (Molnar, 1971) does not maleruption were observed in this group. present the results in quite such an interThis lesion is not usually threatening, but, in pretable fashion, but comparative histoone dramatic case (a female 17-21 years old), grams indicate that a group from the Central a midline defect and maleruption of an incisor through the maxilla, just below the nasal Valley of California (nearby but distinct from cavity, apparently led to a severe inflamma- Bay Area populations) had teeth significantly more worn than comparative samples tory response (Fig. 7). from the southwestern United States or the Valley of Mexico. Indeed, for severe wear (score of 6 or higher), the California group DISCUSSION was two t o four times more frequently afBad teeth are perhaps a curse not just for fected than the other two groups and athumans but for all mammals that live suffi- tained maximum frequencies for the first ciently long. What is most striking in the molars approaching 85%. These frequencies Ala-329 population is not that dental disease actually exceed those from Ala-329, where is common but its early onset and severity of incidence of “severe” wear (i.e., 6 or higher) involvement. Osteologists have realized for ranges as low as 28.2% for the upper left some time that dental problems are often third molar and reaches a maximum of dramatic among native Californians (Leigh, 72.4% for the lower first molar. TABLE 5. Caries Frequency in three California Populations from Santa Rosa Island’ Fig. 7. Malerupted teeth as a result of midline developmental defect; female, aged 17-21 years. DENTAL DISEASE IN PREHISTORIC CALIFORNIA Reinhardt (1983) does not present quantified data for dental attrition but does describe how severely wear can progress in materials he surveyed from southern California. In fact, he extends Molnar’s scale t o a stage 9 defined as “NOcrown enamel, roots functioning in occlusion, all teeth very short and multiroot teeth dehisced or nearly so” (p. 231).Reinhardt hypothesizes that the severe wear can lead to lingual tilting of teeth and other problems and defines a “severe attrition syndrome.” In the Ala-329 sample, individuals frequently showed attrition patterns this severe; in these cases, they were coded as “8+” in a manner very similar t o that of Reinhardt but for purposes of analysis were included with other stage 8 scores. The underlying etiology for the extreme degree of dental attrition seen at Ala-329 and in other native California groups most probably is related to the abrasive nature of the diet consumed by these peoples. Smith (1984) finds that the buccolingual angle of molar wear is increased in agriculturists compared to hunting-gathering groups. She hypothesizes that the difference in patterning results from less lateral excursion or less puncture-crushing in agriculturists, perhaps as a function of the less tough and less fibrous nature of their food. In addition, Hinton (1981, 1982) also suggests that in hunter-gatherers more extreme wear is found, since in agriculturists, with fewer seeds, etc., in their diets, less strenuous mastication may have been required. At this point, it is not possible to state conclusively which components of the diet among prehistoric Californians, such as those at Ala-329, exerted the most stress on their teeth. It can be argued, however, that the amount of grit in the diet should have been a major factor. The diet of prehistoric inhabitants along San Francisco Bay no doubt contained large amounts of abrasives. Quartz grit from sandstone mortarshnd pestles along with spalled fragments of cooking stones, all used in the preparation of acorns, as well as other abrasives introduced with shellfish processing, inevitably placed severe stress on the teeth of all individuals. In addition, anterior teeth may have been further abraded through use in processing fibers for baskets and cordage for twine (Molnar, 1972; Schulz, 1977; Larsen, 1985). In any event, by the time individuals were in their midtwenties, little enamel remained anywhere in their dentitions. High frequencies of periodontal inflammation, tooth loss, 341 socket resorption, and dental abscesses can all be explained as results of severe attrition. Moreover, once the teeth could no longer perform normal mastication, intake of adequate nutrients must have posed a major problem. In fact, the high rate of mortality in this population before age 40 years (17.4% lived past age 41 years) may in part be explained by this phenomenon. 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