RESUMEN

OBJECTIVES: Sexual dimorphism in deciduous tooth crown size is often used to identify sex in sub-adults from archeological sites and forensic settings. Yet sexual dimorphism in deciduous dental attributes is less well documented than in permanent teeth. This analysis was conducted to document variation in sexual dimorphism within and between a global sample of populations. METHODS: Mean deciduous tooth crown size was culled from published literature, yielding a sample of 37 groups. Mean mesiodistal (MD) and buccolingual (BL) crown dimensions are the basis for computing percent sexual dimorphism [(M/F-1) * 100]. Three analyses were conducted: (1) a statistical analysis of mean % sex dimorphism (%SD) within and between populations, (2) an evaluation of rank-ordered %SD by tooth, and (3) an assessment of intergroup patterns in degree of sexual dimorphism. Univariate tests of significance, correlation and regression, and multivariate cluster analysis were used. RESULTS: Mean %SD is low overall (1.77) for 26 groups and the level of dimorphism is not significantly different for MD (1.68) and BL (1.72) dimensions. The most sexual dimorphic deciduous teeth include incisor, canine and molar tooth types, while in the permanent dentition canines are consistently most sexual dimorphic. Global variation in sexual dimorphism of deciduous tooth size is low with little inter-ethnic variation. CONCLUSIONS: Sexual dimorphism in crown size is lower and more variably expressed than in permanent teeth. Differences may relate to developmental, chromosomal, and hormonal factors. Degree of sexual dimorphism is not associated with ethnicity in this global sample.

Asunto(s)

RESUMEN

OBJECTIVE: This study documents deciduous tooth crown dimensions and sex dimorphism in modern Malay children of Indonesia. Comparisons are made with living and prehistoric East and South Asians to better understand tooth size variation in space and through time. DESIGN: Measurements of the dental crown were made with a Mitutoyo digimatic caliper, interfaced with a Dell laptop, running Microsoft Excel (2003). Buccolingual (BL) measurements of maximum crown breadth of modern Malay were made by the first author. All prehistoric South Asian comparative samples were measured by the first author, data for living East and South Asians were taken from published data. All statistical analyses were conducted using SAS, Inc. (9.1 for Windows). RESULTS: Crown dimensions, sex dimorphism and crown areas are presented and reveal consistencies in tooth size and level of sexual dimorphism with East and South Asian living samples. Sex dimorphism in Malay crown dimensions is low (1.1%) among Asians. Total crown area is 484.7 mm2, similar to living Japanese (486.3 mm2), but greater than Hindus (476.4 mm2) of India. Compared with prehistoric groups the Malay have reduced tooth size, especially when compared with Neolithic (MR 3, 535.3 mm2) and Chalcolithic (MR 2, 515.3 mm2) Mehrgarh, Pakistan. CONCLUSION: Sex dimorphism in Malay deciduous crown dimensions is lower than average among Asians and total tooth crown area is similar to living East and South Asians but is reduced when compared with prehistoric Asian samples.

Asunto(s)

RESUMEN

Deciduous teeth are occasionally well represented in archaeological skeletal samples, yet their potential value in reconstructing biological adaptations of prehistoric populations is often overlooked. Independent investigations of the metric dimensions of deciduous dental remains from the Chalcolithic site of Nevasa (Deccan Plateau, western India) yield a unique opportunity to compare odontometric methods and gain insight regarding dental variation in prehistoric India. Mesiodistal (MD) and buccolingual (BL) dimensions of deciduous teeth were measured by two researchers. Intra- and inter-observer precision in dental measurements are evaluated statistically using multiple methods of comparison. Mean MD and BL dental dimensions (mm) and crown areas (MD × BL; mm2) are reported for Nevasa and compared with mean crown dimensions for Inamgaon. Tooth crown size for Nevasa is evaluated using maxillary, mandibular and total crown areas. The apportionment of tooth mass to incisor and molar tooth classes permits assessment of inter-group variation. No significant differences in mean crown dimensions (MD, BL) or mean crown areas were found between Nevasa (493.6 mm2) and Inamgaon (504.6 mm2). While the apportionment of crown area to incisor and molar tooth classes differed, in overall size (total crown area) both sites are intermediate when compared with prehistoric and living groups from South, Southeast and East Asia. The well documented trend in reduction of permanent tooth size is paralleled by reduction in deciduous tooth size in South Asian prehistory.

Asunto(s)

RESUMEN

Systematic study of dental attributes yields insights regarding diet and subsistence that cannot be gained from the archaeological record alone. This analysis documents occlusal tooth wear, tooth crown dimensions and dental pathology of an expanded dental sample from Harappa (2550-2030cal BC; Pakistan). New floral and faunal evidence of subsistence indicates a mix of agriculture and pastoralism that can be integrated with evidence of dental attributes and disease to reveal the impact of Harappan diet on oral health. An enlarged dental sample (58 specimens, 910 teeth) from mature phase Harappa was analyzed using Scott's quadrant wear system, measures of crown size, and prevalence of seven pathological dental lesions. All data were collected by the author using standard methods. Sex differences were found in wear, tooth size and prevalence of dental diseases. Females exhibit greater caries prevalence and antemortem tooth loss than men, an attribute associated with higher rates of pulp exposure and abscesses in women. At Harappa antemortem tooth loss results from penetrating caries, while in foragers the cause is severe occlusal wear. In contrast to early Holocene foragers of north India (Damdama, 8800-8600 BP), Harappans have greater occlusal wear, smaller teeth, and a distinct dental pathology profile.

Asunto(s)

RESUMEN

The Ganga Plain of North India provides an archaeological and skeletal record of semi-nomadic Holocene foragers in association with an aceramic Mesolithic culture. Prior estimates of stature for Mesolithic Lake Cultures (MLC) used inappropriate equations from an American White reference group and need revision. Attention is given to intralimb body proportions and geo-climatic provenance of MLC series in considering the most suitable reference population. Regression equations from ancient Egyptians are used in reconstructing stature for MLC skeletal series from Damdama (DDM), Mahadaha (MDH), and Sarai Nahar Rai (SNR). Mean stature is estimated at between 174 (MDH) and 178 cm (DDM and SNR) for males, and between 163 cm (MDH) and 179 cm (SNR) for females. Stature estimates based on ancient Egyptian equations are significantly shorter (from 3.5 to 7.1 cm shorter in males; from 3.2 to 7.5 cm shorter in females) than estimates using the American White reference group. Revised stature estimates from tibia length and from femur + tibia more accurately estimate MLC stature for two reasons: a) these elements are highly correlated with stature and have lower standard estimates of error, and b) uncertainty regarding methods of measuring tibia length is avoided. When compared with Holocene samples of native Americans and Mesolithic Europeans, MLC series from North India are tall. This aspect of their biological variation confirms earlier assessments and results from the synergistic influence of balanced nutrition from broad-spectrum foraging, body-proportions adapted to a seasonally hot and arid climate, and the functional demands of a mobile, semi-nomadic life-style.

Asunto(s)

RESUMEN

The biological affinities of semi-nomadic, early to mid-Holocene foragers of the mid-Ganga Plain, North India are undetermined, yet understanding their place in the population history of South Asia is important. Non-metric tooth trait frequencies are reported for three broadly contemporary, bio-culturally similar, and geographically proximate samples, collectively known as Mesolithic Lake Culture (MLC). The Arizona State University - Dental Anthropology System was used to score 43 tooth-trait combinations (23 maxillary; 21 mandibular). Non-metric trait frequencies are used to determine biological affinities of MLC to a global sample of living populations and to prehistoric and living groups of South Asia. The MLC dental pattern includes lightly sculpted upper incisors in which labial curvature, lingual shoveling, and tuberculum dentale exhibit low grades of expression and low-moderate frequencies. First molars have full-sized hypocones with slight reduction in M2 and M3. Accessory cusps are infrequent and small. Mandibular teeth are morphologically simple and retain conservative attributes. Incisors and canines exhibit weak shoveling. Molar accessory cusps are infrequent, though C-6 attains moderate grades in M3. The molar series (M1:M2:M3) has an Y:X:X groove pattern and 5:4:4 cusp number. Upper M3 agenesis (5%) is less common than lower M3 agenesis (10.0%). Smith's Mean Measure of Divergence (MMD) and Ward's minimum variance cluster methods are used to assess inter-group bio-distance in global and regional South Asian settings. In the global comparison, multi-dimensionally scaled MMD values reveal three groups: African, Asian, and a third group composed of MLC, prehistoric South Asians, and European samples. Within South Asia, MMD and cluster analysis find MLC's closest affinities to the Chenchu, a living tribal group of Andhra Pradesh. This result contradicts earlier assertions based on osteological assessment that descendants of Mesolithic foragers of North India (MLC) cannot be identified in the Indian subcontinent. The next closest affinity is with Chalcolithic and Neolithic groups of Pakistan and with a late Chalcolithic group (INM) of west central India. As knowledge of the dental morphology of living and prehistoric South Asians increases, the population history of the subcontinent and its role in understanding world-wide patterns of migration will be clarified.

Asunto(s)

RESUMEN

This review highlights what is known regarding differences in tooth loss by sex/gender, and describes: gender-related tooth ablation (the deliberate removal of anterior teeth during life) found in skulls from history and prehistory; potential mediators of the relationship between sex/gender and tooth loss; the current epidemiology of gender differences in tooth loss (limited to North America); and risk factors for tooth loss in the general population and in women.

Asunto(s)

RESUMEN

OBJECTS: This study was designed to examine the magnitude and etiology of gender differences in oral health. South Asia was selected for study because sex differences in caries rates exist in prehistory here, great cultural diversity provides context, and clinical reports document caries by gender. METHODS: A literature survey yielded extensive data on caries rates in India, Nepal, Bangladesh, and Sri Lanka. The percentage of individuals with caries (prevalence) and the mean number of decayed, missing, and filled teeth (experience) comprise the data. Statistical tests for gender differences come from published sources or were independently computed. RESULTS: Higher caries rates were found more often among females than males. The data show that: (a) in male children caries rates are greater than, or equal to, female rates, (b) the gender bias reverses (F > M caries rates) from adolescence through the reproductive years, (c) mature adults typically exhibit significant differences, with higher caries rates in females, (d) a male gender bias in adults is rare, and (e) though some studies find no significant gender difference in caries, a female bias dominates. Tooth loss is also greater in women than men and often results from caries (vs. periodontal disease). CONCLUSIONS: The gender gap in oral health exists in South Asia and results from genetic, hormonal, and cultural influences. Three cultural factors contribute to this gender gap South Asia: (a) the relative value of sons and daughters, (b) frequent fasting among Hindu women, and (c) the belief that dietary restrictions result in easier childbirth.

Asunto(s)

RESUMEN

A sex difference in oral health has been widely documented through time and across cultures. Women's oral health declines more rapidly than men's with the onset of agriculture and the associated rise in fertility. The magnitude of this disparity in oral health by sex increases during ontogeny: from childhood, to adolescence, and through the reproductive years. Representative studies of sex differences in caries, tooth loss, and periodontal disease are critically reviewed. Surveys conducted in Hungary, India, and in an isolated traditional Brazilian sample provide additional support for a significant sex bias in dental caries, especially in mature adults. Compounding hormonal and reproductive factors, the sex difference in oral health in India appears to involve social and religious causes such as son preference, ritual fasting, and dietary restrictions during pregnancy. Like the sex difference in caries, tooth loss in women is greater than in men and has been linked to caries and parity. Results of genome wide association studies have found caries susceptible and caries protective loci that influence variation in taste, saliva, and enamel proteins, affecting the oral environment and the micro-structure of enamel. Genetic variation, some of which is X-linked, may partly explain how sex differences in oral health originate. A primary, but neglected, factor in explaining the sex differential in oral health is the complex and synergistic changes associated with female sex hormones, pregnancy, and women's reproductive life history. Caries etiology is complex and impacts understanding of the sex difference in oral health. Both biological (genetics, hormones, and reproductive history) and anthropological (behavioral) factors such culture-based division of labor and gender-based dietary preferences play a role.

Asunto(s)

Asunto(s)

RESUMEN

A reduction in enamel thickness due to disrupted amelogenesis is referred to as enamel hypoplasia (EH). Linear EH in permanent teeth is a widely accepted marker of systemic physiological stress. An enigmatic, nonlinear form of EH commonly manifest in great ape and human deciduous canines (dc) is known as localized hypoplasia of primary canines (LHPC). The etiology of LHPC and what it signifies-localized traumatic or systemic physiological stress-remains unclear. This report presents frequency data on LHPC, hypostotic cranial traits, and tooth size in a sample of juvenile bonobos, then tests hypotheses of intertrait association that improve knowledge of the etiology and meaning of LHPC. The fenestration hypothesis is tested using hypostotic cranial traits as a proxy for membrane bone ossification, and the relationship between tooth size, LHPC, and hypostosis is investigated. Macroscopic observations of EH, hypostotic traits, and measurements of buccolingual tooth size were conducted according to established standards. LHPC was found in 51.2% of bonobos (n = 86) and in 26% of dc teeth (n = 269). Hypostotic traits were observed in 55.2% of bonobos (n = 96). A test of the association between LHPC and hypostosis yielded nonsignificant results (chi(2) = 2.935; P = 0.0867). Primary canines were larger in specimens with LHPC than in unaffected specimens (paired samples t test; udc, P = 0.011; ldc, P = 0.018), a result consistent with the fenestration hypothesis of LHPC pathogenesis. Hypostosis was not associated with differences in tooth size (P > 0.05). LHPC may be an indirect indicator of physiological stress, resulting from large, buccally displaced primary canines.

Asunto(s)

RESUMEN

When dental caries rates are reported by sex, females are typically found to exhibit higher prevalence rates than males. This finding is generally true for diverse cultures with different subsistence systems and for a wide range of chronological periods. Exceptions exist, but are not common. In this paper, we present new data for sex differences in dental caries rates among the Guanches (Tenerife, Canary Islands), summarize results of meta-analyses of dental caries prevalence, and emphasize new research that stresses the critical role of female hormones and life-history events in the etiology of dental caries. Among the Guanches, corrected tooth-count caries rates for females (8.8%, 158/1,790) are approximately twice the frequency of caries among males (4.5%, 68/1,498). Higher caries prevalence among females is often explained by one of three factors: 1) earlier eruption of teeth in girls, hence longer exposure of girls' teeth to the cariogenic oral environment, 2) easier access to food supplies by women and frequent snacking during food preparation, and 3) pregnancy. Anthropologists tend to favor explanations involving behavior, including sexual division of labor and women's domestic role in food production. By contrast, the causal pathways through which pregnancy contributes to poorer oral health and higher caries rates are deemphasized or discounted. This paper presents recent research on physiological changes associated with fluctuating hormone levels during individual life histories, and the impact these changes have on the oral health of women. The biochemical composition of saliva and overall saliva flow rate are modified in several important ways by hormonal fluctuations during events such as puberty, menstruation, and pregnancy, making the oral environment significantly more cariogenic for women than for men. These results suggest that hormonal fluctuations can have a dramatic effect on the oral health of women, and constitute an important causal factor in explaining sex differences in caries rates.

Asunto(s)

RESUMEN

This study reports the prevalence, distribution, and expression of enamel defects in a sample of primary teeth (n = 225) from a prehistoric site in western India (1400-700 BC). Five enamel surfaces of individual, isolated primary teeth were observed for surface defects using a binocular stereomicroscope with variable power of magnification (8-20x). Standards for evaluating dental enamel defects (DDE) recommended by the Fédération Dentaire International (FDI) were employed. Details of defect expression were also recorded, including size, shape, and surface of tooth crown affected. Hypoplastic enamel defects were observed in 28% of teeth, but the distribution and expression of defects was not random. More than 50% of canine teeth had hypoplastic defects (HD); incisors and molar teeth exhibited far fewer HD. The buccal surface of canines was the most commonly affected crown surface. Areas of missing enamel were also common on the mesial and distal surfaces of canines and incisors and on the mesial surface of molar teeth. The high frequency of enamel defects found on interproximal crown surfaces warrants a label, and the name interproximal contact hypoplasia (IPCH) is proposed. Linear enamel hypoplasia (LEH) was absent from this primary dental sample. IPCH is more frequent in mandibular than in maxillary teeth, but no side preference was detected. In canine teeth, buccal hypoplasias (localized hypoplasia of primary canines; LHPC) were not positively correlated with interproximal hypoplastic defects. The etiology of IPCH may involve mesial compaction of developing teeth due to slow longitudinal growth of the jaws. Episodic bone remodeling results in ephemeral fenestrae in the mesial and distal walls of the dental crypt permitting tooth-tooth contact and disruption of amelogenesis. IPCH prevalence decreases across the subsistence transition from sedentary Early Jorwe agriculturalists to seminomadic Late Jorwe hunters and foragers, but the difference is not statistically significant. This may be due to underrepresentation of mandibular teeth in the sample. Am. J. Hum. Biol. 11:718-734, 1999. Copyright 1999 Wiley-Liss, Inc.