Parity, dental caries and implications for maternal depletion syndrome in northern Nigerian Hausa women.

BACKGROUND: Female reproductive history, especially high parity, affects general health and may impact negatively on oral health. While parity has been positively linked to tooth loss, the specific association between parity and caries has not been adequately investigated. AIM: To determine the association between parity and caries in a population of higher parity women. Influences of likely confounders (age, socio-economic status, reproductive parameters, oral health practices and sugar consumption between meals) were considered. METHODS: This was a cross-sectional study involving 635 Hausa women of varying parity aged 13-80 years. Socio-demographic status, oral health practices and sugar consumption were obtained using a structured interviewer-administered questionnaire. All decayed, missing and filled teeth due to caries (excluding third molars) were noted, and tooth loss etiology was queried. Associations with caries were evaluated through correlation, ANOVA, post hoc analyses and Student's t tests. Effect sizes were considered for magnitude of differences. Multiple regression (binomial model) was used to investigate predictors of caries. RESULTS: Hausa women had a high prevalence of caries (41.4%) despite low sugar consumption; nonetheless the overall mean DMFT score was very low (1.23 ± 2.42). Older, higher parity women experienced more caries, as did those with longer reproductive spans. Additionally, poor oral hygiene, use of fluoride toothpaste and frequency of sugar consumption were significantly associated with caries. CONCLUSION: Higher parity (>6 children) was associated with higher DMFT scores. These results suggest that a form of maternal depletion, expressed as heightened caries susceptibility and subsequent tooth loss, occurs with higher parity.

Three-dimensional geometric morphometric studies of modern human occipital variation.

OBJECTIVES: To investigate three-dimensional morphological variation of the occipital bone between sexes and among populations, to determine how ancestry, sex and size account for occipital shape variation and to describe the exact forms by which the differences are expressed. METHODS: CT data for 214 modern crania of Asian, African and European ancestry were compared using 3D geometric morphometrics and multivariate statistics, including principal component analysis, Hotelling's T2 test, multivariate regression, ANOVA, and MANCOVA. RESULTS: Sex differences in average occipital morphology are only observed in Europeans, with males exhibiting a pronounced inion. Significant ancestral differences are observed among all samples and are shared by males and females. Asian and African crania have smaller biasterionic breadths and flatter clivus angles compared to Europeans. Asian and European crania are similar in their nuchal and occipital plane proportions, nuchal and occipital angles, and lower inion positions compared to Africans. Centroid size significantly differs between sexes and among populations. The overall allometry, while significant, explains little of the shape variation. Larger occipital bones were associated with a more curved occipital plane, a pronounced inion, a narrower biasterionic breadth, a more flexed clivus, and a lower and relatively smaller foramen magnum. CONCLUSIONS: Although significant shape differences were observed among populations, it is not recommended to use occipital morphology in sex or population estimation as both factors explained little of the observed variance. Other factors, relating to function and the environment, are suggested to be greater contributors to occipital variation. For the same reason, it is also not recommended to use the occiput in phylogenetic studies.

Association between parity and tooth loss among northern Nigerian Hausa women.

BACKGROUND: Female reproduction is associated with physiological, metabolic, and nutritional demands that can negatively affect health and are possibly cumulative when parity is high. While it is probable that maternal oral health is similarly affected, available evidence is based on fairly low parity populations and likely confounders affecting oral health status were not considered. AIM: To determine the relationship between parity and tooth loss in a population with many high parity women. Contributions of age, reproductive and socioeconomic parameters, and oral health practices were considered. MATERIALS AND METHODS: This was a cross-sectional study involving 612 Hausa women of all parity levels aged 13-65 years. Women with ≥5 children were considered high parity. Sociodemographic status and oral health practices were collected using a structured interviewer-administered questionnaire. All teeth present, (excluding third molars) and missing teeth were noted, with inquiries regarding tooth loss etiology. Associations with tooth loss were evaluated through correlations, ANOVA, post hoc analyses and Student's t tests. Effect sizes were used to interpret the magnitude of differences. Multiple regression (negative binomial model) was used to investigate predictors of tooth loss. RESULTS: Hausa women had a low prevalence of tooth loss, despite poor oral hygiene, and limited dental care. Older, middle SES, and higher parity women experienced significantly more tooth loss. Additionally, increased duration of reproductively active years was significantly related to fewer remaining teeth. CONCLUSION: Higher parity was related to greater tooth loss in Hausa women. Women with ≥5 children experienced more loss than lower parity age mates.

Does nutrition have an effect on the timing of tooth formation?

BACKGROUND: The effect of nutritional status on the timing of permanent tooth formation is not well understood, despite clear evidence that systemic stresses result in enamel defects during tooth formation. AIM: This study investigated the effect of nutritional status (measured as BMI, height, weight, mid-upper arm circumference, and head circumference) on permanent tooth formation. METHOD: This was a prospective cross-sectional study involving 642 (270 males, 372 females) healthy Black South African participants aged 5-20 years. The height and BMI were converted to z-scores using WHO z-score for age tables. The participants were grouped into underweight/short for age (<-2), normal (≥ - 2 to 2.0) and overweight/obese/tall for age (>2). Panoramic radiographs of the children were assessed using Demirjian's eight stages of permanent tooth formation and age was estimated using Demirjian's method. Probit regression analysis was used to calculate the mean age of attainment of the developmental stages for the left mandibular teeth (I2-M2). RESULTS: There was significant advancement in the age of attainment of the final (H) stage for the majority of permanent teeth in the overweight (mean male BMI 22.9; female 27.94) group compared to the underweight (p < .05). Negative binomial regression indicated that age, height, and BMI were significant predictors of the dental maturity score for males (p < .05), while age, height, weight, BMI and HC were significant predictors for females (p < .05). CONCLUSION: Nutritional status had a significant effect on the timing of tooth formation in males and females in the study population. The effect was mainly noticeable for children in the extremes of the spectrum of BMI z-scores.

Is parity a cause of tooth loss? Perceptions of northern Nigerian Hausa women.

BACKGROUND: Reproduction affects the general health of women, especially when parity is high. The relationship between parity and oral health is not as clear, although it is a widespread customary belief that pregnancy results in tooth loss. Parity has been associated with tooth loss in some populations, but not in others. It is important to understand the perceptions of women regarding the association between parity and tooth loss as these beliefs may influence health behaviors during the reproductive years. AIM: To explore the views of Hausa women regarding the link between parity and tooth loss. METHODS: Qualitative data were collected through a grounded theory approach with focus group discussions (FGDs) of high and low parity Hausa women (n = 33) in northern Nigeria. Responses were elicited on the causes of tooth loss, effects of tooth loss on women's quality of life, issues of parity and tooth loss, and cultural beliefs about parity and tooth loss. The data were analyzed thematically using ATLAS-ti. RESULTS: Respondents associated tooth loss with vomiting during labor, a condition termed 'payar baka'. Poor oral hygiene, excessive consumption of refined carbohydrates, tooth worm, cancer and ageing were also believed to cause tooth loss. The greatest impacts of tooth loss on the lives of the respondents were esthetic and masticatory changes. CONCLUSION: Respondents perceived that parity is indirectly linked to tooth loss, as reflected in their views on the association between vomiting during labor and tooth loss.

First systematic assessment of dental growth and development in an archaic hominin (genus, Homo) from East Asia.

Several human dental traits typical of modern humans appear to be associated with the prolonged period of development that is a key human attribute. Understanding when, and in which early hominins, these dental traits first appeared is thus of strong interest. Using x-ray multiresolution synchrotron phase-contrast microtomography, we quantify dental growth and development in an archaic Homo juvenile from the Xujiayao site in northern China dating to 161,000-224,000 years or 104,000-125,000 years before present. Despite the archaic morphology of Xujiayao hominins, most aspects of dental development of this juvenile fall within modern human ranges (e.g., prolonged crown formation time and delayed first molar eruption). For its estimated age-at-death (6.5 years), its state of dental development is comparable to that of equivalently aged modern children. These findings suggest that several facets of modern human dental growth and development evolved in East Asia before the appearance of fully modern human morphology.

The timing of permanent tooth development in a Black Southern African population using the Demirjian method.

BACKGROUND: Many aspects of growth have been documented for Black Southern African children, yet their dental development has not been comprehensively investigated. AIM: The present study was designed to provide information on age of attainment of dental development stages in Southern African children and to compare the findings with other populations. METHOD: This was a community-based cross-sectional study of 642 children (270 males and 372 females). Panoramic radiographs of children aged 5 to 20 years were assessed using Demirjian's eight stages of permanent tooth formation and age was estimated using Demirjian's method. Resulting dental ages were compared to the chronological ages. Probit regression analysis was employed to calculate the mean age of attainment of the developmental stages for the seven left mandibular teeth. Maturity scores and age of attainment were compared by sex and with published data on other populations. RESULTS: Females show significantly advanced dental maturity and dental ages, as well as earlier attainment of all stages of mineralization, compared to males (p < 0.05). The Demirjian method overestimated dental age in both males (0.8 ± 1.02 years) and females (1.0 ± 0.98 years). Cross-population comparisons illustrate that Black Southern African children are generally advanced in dental maturity compared to children of European and Asian ancestry. CONCLUSION: The Demirjian method significantly overestimated the chronological ages of Black Southern African males and females. Southern Africans attain dental maturity earlier than South Korean, Canadian, and Belgian children. These differences in dental maturity clearly illustrate the need for population-specific, rather than global, dental maturity standards.

Permanent tooth emergence: Timing and sequence in a sample of Black Southern African children.

OBJECTIVES: This study investigates mean age, sequence, and temporal trends of permanent tooth emergence in Black Southern African children and compares the findings with other population samples. MATERIALS AND METHODS: This community-based cross-sectional study involved 639 Black Southern African children between 5 and 20 years of age. Probit analysis was used to derive the mean age at emergence of the permanent teeth. Sex and cross-population comparisons were undertaken to determine similarities and differences in emergence timing and sequence. RESULTS: Females emerged all teeth earlier except for M3s (p < .05). Black Southern Africans have earlier mean ages of emergence compared to population samples from the USA, Europe, Australia, and Asia. Sexual dimorphism was detected in the mandibular I1/M1 emergence sequence (females, M1 I1 ; males, I1 M1 ). The sequence in males is similar in both jaws to males from other sub-Saharan African, USA, and European samples. Females show a similar sequence pattern in the maxilla with other sub-Saharan African, and also Australian and US females of European ancestry. There is a high frequency of polymorphism in the P1P2C1 emergence sequence, with significantly more P2P1C1 maxillary sequences seen among males. Polymorphic variation was common for the I1 M1 sequence in both males and females. DISCUSSION: Mean age of tooth emergence among Black Southern African children is similar to children from most other sub-Saharan African populations. No temporal change was seen in the mean age of emergence. Earlier permanent tooth emergence in Black Southern Africans is part of a general sub-Saharan pattern that is distinct from European and Asian populations.

Accuracy of the Demirjian and Willems methods of age estimation in a Black Southern African population.

The accuracies of the original Demirjian, modified Demirjian and Willems dental age estimation methods were compared for a Black Southern African population to determine their usefulness for forensic and anthropological purposes. Data were collected using a community-based prospective study design. Panoramic radiographs of seven left mandibular teeth from 540 children aged 5-15.99 years were scored using the three methods. Obtained estimates were compared to the chronological ages and mean absolute errors were calculated. The original Demirjian method significantly overestimated ages (males 0.85 years, female 1.0 years; mean absolute errors of 1.1 years for both sexes), as did the modified Demirjian method (males 0.90 years, females 1.21 years; mean absolute errors of males 1.1 years, females 1.4 years). The Willems method was the most accurate for Black Southern Africans, with the lowest significant mean difference (males 0.2 years, females 0.3 years) between dental and chronological age, with the least mean absolute errors (males 0.70 years, females 0.68 years).

The WITS Atlas: A Black Southern African dental atlas for permanent tooth formation and emergence.

Current dental maturity charts, such as the widely applied London atlas, do not take into consideration advanced tooth emergence and formation patterns observed in children of African ancestry. The result is inaccurate age estimation in Southern Africa, a region where there is great forensic and anthropological need for reliable age estimation. OBJECTIVES: To develop a population-specific atlas of permanent tooth emergence and formation for age estimation of Black Southern Africans. MATERIALS AND METHODS: Using data from a cross-sectional study of 642 school children aged 5-20 years, panoramic radiographs taken during routine dental examination in a mobile treatment van were analyzed using the Demirjian method of eight (A-H) tooth formation stages. Tables of the stages of tooth development for each tooth, including the third molars, were generated separately for age cohorts and by sex. The most frequently occurring (modal) stage of tooth formation was considered the signature developmental stage for the age. The relationship of the third molar occlusal surfaces with occlusal tables on the radiographs were checked and compared with the findings recorded during intra oral examination. RESULTS: Comparison with the London atlas shows that at age 9.5 years, the canine and premolar emergence are at least one year ahead and the third molar formation completes four years earlier in the WITS Atlas. DISCUSSION: Similarities in advancement in tooth formation and emergence across sub-Saharan Africa suggest that the WITS Atlas can be used for those populations as well.

The Demirjian versus the Willems method for dental age estimation in different populations: A meta-analysis of published studies.

BACKGROUND: The accuracy of radiographic methods for dental age estimation is important for biological growth research and forensic applications. Accuracy of the two most commonly used systems (Demirjian and Willems) has been evaluated with conflicting results. This study investigates the accuracies of these methods for dental age estimation in different populations. METHODS: A search of PubMed, Scopus, Ovid, Database of Open Access Journals and Google Scholar was undertaken. Eligible studies published before December 28, 2016 were reviewed and analyzed. Meta-analysis was performed on 28 published articles using the Demirjian and/or Willems methods to estimate chronological age in 14,109 children (6,581 males, 7,528 females) age 3-18 years in studies using Demirjian's method and 10,832 children (5,176 males, 5,656 females) age 4-18 years in studies using Willems' method. The weighted mean difference at 95% confidence interval was used to assess accuracies of the two methods in predicting the chronological age. RESULTS: The Demirjian method significantly overestimated chronological age (p<0.05) in males age 3-15 and females age 4-16 when studies were pooled by age cohorts and sex. The majority of studies using Willems' method did not report significant overestimation of ages in either sex. Overall, Demirjian's method significantly overestimated chronological age compared to the Willems method (p<0.05). The weighted mean difference for the Demirjian method was 0.62 for males and 0.72 for females, while that of the Willems method was 0.26 for males and 0.29 for females. CONCLUSION: The Willems method provides more accurate estimation of chronological age in different populations, while Demirjian's method has a broad application in terms of determining maturity scores. However, accuracy of Demirjian age estimations is confounded by population variation when converting maturity scores to dental ages. For highest accuracy of age estimation, population-specific standards, rather than a universal standard or methods developed on other populations, need to be employed.

Third molar impaction and agenesis: influence on anterior crowding.

Background Third molar influence on anterior crowding is controversial, but they are assumed to play a major role in compromising dental arch space. Aim To evaluate the relationship among impaction, agenesis and crowding in black South African males. Subjects and method Mandibles and maxillae of 535 black South African males in the Raymond A. Dart Collection of Human Skeletons, University of the Witwatersrand were examined for anterior crowding and third molar agenesis and impaction. Dental crowding was determined using Little's irregularity index. Results Individuals with impaction showed more moderate-to-extreme crowding than those with agenesis. Bilateral third molar presence was more frequently associated with ideal-to-minimal crowding. Weak positive but significant correlations between crowding and impaction were found (mandible, ρ = 0.154, p = 0.000; maxilla ρ = 0.130, p = 0.000). The direction was the opposite for bilateral presence of molars (mandible, ρ = -0.135, p = 0.02; maxilla, ρ = -0.111, p = 0.010). Odds of mandibular crowding were greatest in individuals with impaction (OR = 3.22, CI = 1.716-6.05, p < 0.001). Maxillary results were similar. Conclusion Third molar impaction plays a role in anterior crowding. Third molar presence was not associated with anterior crowding, while agenesis did not explain absence of crowding.

Evidence for long-term migration on the Balkan Peninsula using dental and cranial nonmetric data: Early interaction between corinth (Greece) and its colony at Apollonia (Albania).

This article seeks to identify "Greeks" and "non-Greeks" in "mixed" mortuary contexts in a Greek colony. Specifically, we test the hypothesis that Illyrian and Greek individuals lived and were buried together at the Corinthian colony of Apollonia, Albania (established ca. 600 BC). The pattern of human biological interaction at Apollonia is tested by identifying variation in genetic relatedness using biodistance analysis of dental and cranial nonmetric traits for three sites: Apollonia (n = 116), its founder-city Corinth (n = 69), and Lofkënd (n = 108), an inland site near Apollonia pre-dating colonization. Logistic regression analysis estimates that individuals from colonial Apollonia are most closely related to prehistoric Illyrian populations (from Lofkënd and prehistoric Apollonia), rather than Greeks (from Corinth). The phenotypic similarity between colonial Apollonia and prehistoric Illyria suggests that there was a large Illyrian contribution to the gene pool at the colony of Apollonia. However, some trait combinations show low biological distances among all groups, suggesting homogeneity among Illyrian and Greek populations (assessed through pseudo-Mahalanobis' D(2) ). The degree of phenotypic similarity suggests shared ancestry and long-term migration throughout these regions. The impacts of missing data and small sample sizes are also considered.

Late Middle Pleistocene hominin teeth from Panxian Dadong, South China.

The hominin teeth and evidence of hominin activities recovered from 1991 to 2005 at the Panxian Dadong site in South China are dated to the late Middle Pleistocene (MIS 8-6 or ca. 130-300 ka), a period for which very little is known about the morphology of Asian populations. The present study provides the first detailed morphometric description and comparisons of four hominin teeth (I(1), C1, P(3) and P3) from this site. Our study shows that the Panxian Dadong teeth combine archaic and derived features that align them with Middle and Upper Pleistocene fossils from East and West Asia and Europe. These teeth do not display any typical Neanderthal features and they are generally more derived than other contemporaneous populations from Asia and Africa. However, the derived traits are not diagnostic enough to specifically link the Panxian Dadong teeth to Homo sapiens, a common problem when analyzing the Middle Pleistocene dental record from Africa and Asia. These findings are contextualized in the discussion of the evolutionary course of Asian Middle Pleistocene hominins, and they highlight the necessity of incorporating the Asian fossil record in the still open debate about the origin of H. sapiens.

Antemortem trauma and survival in the late Middle Pleistocene human cranium from Maba, South China.

Paleopathological assessment of the late Middle Pleistocene archaic human cranium from Maba, South China, has documented a right frontal squamous exocranially concave and ridged lesion with endocranial protrusion. Differential diagnosis indicates that it resulted from localized blunt force trauma, due to an accident or, more probably, interhuman aggression. As such it joins a small sample of pre-last glacial maximum Pleistocene human remains with probable evidence of humanly induced trauma. Its remodeled condition also indicates survival of a serious pathological condition, a circumstance that is increasingly documented for archaic and modern Homo through the Pleistocene.

A new brain endocast of Homo erectus from Hulu Cave, Nanjing, China.

A new brain endocast of Homo erectus from Hulu Cave, Tangshan, Nanjing is described and compared with a broad sample of endocasts of H. erectus, Neanderthals, and recent modern humans. The Nanjing 1 endocast is reconstructed based on two portions of endocranial casts taken from the original fossil fragments. The fossil was discovered in 1993, near Nanjing, South China and is dated to ∼ 0.58-0.62 Ma. The cranial capacity is ∼ 876 cc, as determined by endocast water displacement. There are some common features of Nanjing 1 and other H. erectus endocasts that differentiate them from the Neanderthals and modern humans in our sample. These include small cranial capacity, low height dimensions, simple middle meningeal vessel patterns, a high degree of cerebral-over-cerebellar lobe overhang, elongated and quite separated cerebellar lobes, and a narrow, low, short and flat frontal region. Some features are found to vary among H. erectus, Neanderthals and modern humans, such as the lateral Sylvian fissure position and the venous sinus and petalial patterns. The Nanjing 1 endocast has unique, large, superior frontal convolutions, and strongly protruding Broca's caps. In contrast to other Chinese H. erectus from Hexian and Zhoukoudian, Nanjing 1 lacks strong posterior projection of the occipital lobes. Bivariate and principal component analyses indicate that the small volume and shape of Nanjing 1 is most similar to KNM-WT 15000, KNM-ER 3883, Sangiran 2 and Hexian, illustrating the combination of narrow, low, and short frontal lobes with wide posterior lobes.

A new Homo erectus (Zhoukoudian V) brain endocast from China.

A new Homo erectus endocast, Zhoukoudian (ZKD) V, is assessed by comparing it with ZKD II, ZKD III, ZKD X, ZKD XI, ZKD XII, Hexian, Trinil II, Sambungmacan (Sm) 3, Sangiran 2, Sangiran 17, KNM-ER 3733, KNM-WT 15 000, Kabwe, Liujiang and 31 modern Chinese. The endocast of ZKD V has an estimated endocranial volume of 1140 ml. As the geological age of ZKD V is younger than the other ZKD H. erectus, evolutionary changes in brain morphology are evaluated. The brain size of the ZKD specimens increases slightly over time. Compared with the other ZKD endocasts, ZKD V shows important differences, including broader frontal and occipital lobes, some indication of fuller parietal lobes, and relatively large brain size that reflect significant trends documented in later hominin brain evolution. Bivariate and principal component analyses indicate that geographical variation does not characterize the ZKD, African and other Asian specimens. The ZKD endocasts share some common morphological and morphometric features with other H. erectus endocasts that distinguish them from Homo sapiens.

Endocranial cast of Hexian Homo erectus from South China.

In this paper, we present data on the morphological features and linear measurements for the Hexian Homo erectus and other comparative endocasts, in order to highlight variation during human brain evolution. The endocast of Hexian was reconstructed in 1982, and an endocranial volume of 1,025 ml was estimated. The geological age is about 412 ka, or roughly contemporaneous with the Zhoukoudian (ZKD) specimens. There are some differences between Hexian and the modern Chinese male endocasts in our sample, including low position of the greatest breadth, low maximum height, a well-marked and prominent frontal keel, the flat surface of the frontal lobes, prominent sagittal keel along the center frontal and parietal lobes, depressed Sylvian areas and parietal lobes superiorly, strong posterior projection of the occipital lobes, anterior position of the cerebellar lobes relative to the occipital lobes, and the relative simplicity of the meningeal vessels. Compared with the ZKD, Indonesian, and African Homo erectus specimens, Hexian has more morphological features in common with ZKD. Principal component analyses indicate that Hexian is closest to the ZKD Homo erectus compared with the modern Chinese and other Homo erectus, but its great breadth distinguishes it. Metric analyses show that the brain height, frontal breadth, cerebral height, frontal height, and parietal chord from Homo erectus to modern humans increased, while the length, breadth, frontal chord, and occipital breadth did not change substantially.