Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR)

The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five‐grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian‐derived populations exhibited the highest MxPAR frequencies while Indo‐European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Brief communication: The Granada osteological collection of identified infants and young children

The objective of this study is to present the characteristics of a collection of identified infants and young children housed in the Laboratory of Anthropology of the University of Granada, Spain. The sample, which is still being enlarged, is currently composed of 230 complete skeletons aged from 5 months of gestation to 8 years, with a majority below 1 year. It mainly dates from the mid‐20th century. The state of preservation is very good, and antemortem information is available from burial and death certificates, among other documents. Our sample makes an important contribution to the relatively few collections available in the world for investigating the osteological development of the skeletons of infants and young children from a physical anthropological perspective. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.     

Brief communication: First evidence of LSAMAT in non-native Americans: Historic Senegalese from West Africa

To date, the distinctive dental wear pattern known as LSAMAT, or “lingual surface attrition of the maxillary anterior teeth,” has been documented in prehistoric samples from Brazil, Panama, and Puerto Rico only. However, new data from a historic Senegalese sample reveals the first example of this wear pattern outside the Americas. The Senegal LSAMAT is present in 45% of 22 adult crania, and is associated with a caries rate of 40% in 38 adults (6.7% of 534 permanent teeth). A correlation between LSAMAT and caries was also observed in the Latin American samples. In these cases, it was hypothesized that LSAMAT was caused by the specialized consumption of an abrasive, high carbohydrate food, such as manioc. Manioc is a common cultigen in Senegal; thus, it may have also caused the African LSAMAT. The chewing of sugar cane could have been an additional, contributing factor. Am J Phys Anthropol 102:141–146, 1997. © 1997 Wiley-Liss, Inc.     

Brief communication: The Uto-Aztecan premolar in early hunter-gatherers from South-Central North America

The Uto‐Aztecan premolar is a discrete dental trait found in low frequency (<2%) among world populations. The highest frequencies of the trait have been found among the indigenous populations of North America and, to a lesser extent, South America. Because of the trait's relatively higher frequency in the Western Hemisphere, the antiquity and distribution of the feather is important for reconstructing the biocultural interactions of prehistoric populations. While early research concluded that the Uto‐Aztecan premolar originated in the American Southwest around 4,000 years Before Present (BP), more recent studies have discovered the trait across the Americas and in parts of Europe and Asia. For this study, over 300 dentitions representing foragers and farmers in south‐central North America were examined. The trait was found in relatively high frequency (over 11%) in Archaic hunter‐gatherer populations from Central Texas, with high frequencies also found in the adjacent western Gulf Coastal Plain. The presence of this trait in Early Archaic populations suggests that the trait was present by 8,000 BP and persisted at a high frequency into the Late Archaic period. Am J Phys Anthropol 149:318–322, 2012. © 2012 Wiley Periodicals, Inc.     

Brief communication: Variation in the frequency and form of the lower permanent molar middle trigonid crest

The frequency and form of the middle trigonid crest (MTC) in lower permanent molars is reported for 1,131 dental casts of Bushman (San), Bantu, Solomons, Hawaiians, Pima, Eskimo, Navajo, Chinese, and American whites. The MTC occurs most often on the first molar. We found very little intra-trait variation, so observations were scored on a present-absent basis. The MTC is most frequent in the African samples and rare in those of the other populations. Two reference plaques can be obtained to add to the existing series in the ASU dental anthropology system. © 1993 Wiley-Liss, Inc.     

Secular trend of dental development in Dutch children

Many studies have established dental age standards for different populations; however, very few studies have investigated whether dental development is stable over time on a population level. Therefore, the aim of this study was to analyze changes in dental maturity in Dutch children born between 1961 and 2004. We used 2,655 dental panoramic radiographs of 2‐ to 16‐year‐old Dutch children from studies performed in three major cities in the Netherlands. Based on a trend in children born between 1961 and 1994, we predicted that a child of a certain age and gender born in 1963 achieved the same dental maturity on average, 1.5 years later than a child of the same age born 40 years later. After adjusting for the birth year of a child in the analysis, the regression coefficient of the city variable was reduced by 56.6% and it remained statistically significant. The observed trend from 1961 to 1994 was extrapolated to 9‐ to 10‐year‐old children born in 2002–2004, and validation with the other samples of children with the same characteristics showed that 95.9%–96.8% of the children had dental maturity within the 95% of the predicted range. Dental maturity score was significantly and positively associated with the year of birth, gender, and age in Dutch children, indicating a trend in earlier dental development during the observation period, 1961–2004. These findings highlight the necessity of taking the year of birth into account when assessing dental development within a population with a wider time span. Am J Phys Anthropol 155:91–98, 2014. © 2014 Wiley Periodicals, Inc.     

Brief communication: Additional cases of maxillary canine‐first premolar transposition in several prehistoric skeletal assemblages from the Santa Barbara Channel Islands of California

This article identifies and discusses seven new cases of complete maxillary canine‐premolar transposition in ancient populations from the Santa Barbara Channel region of California. A high frequency of this tooth transposition has been previously documented within a single prehistoric cemetery on one of the Channel Islands. A total of 966 crania representing 30 local sites and about 7,000 years of human occupation were examined, revealing an abnormally high prevalence of this transposition trait among islanders during the Early period of southern California prehistory (～5500–600 B.C.). One of the affected crania is from a cemetery more than 7,000‐years‐old and constitutes the earliest case of tooth transposition in humans so far reported. The results are consistent with findings by other studies that have indicated inbreeding among the early Channel Islands groups. Together with the normal transposition rates among mainland populations, the decreasing prevalence of maxillary canine‐first premolar transposition among island populations across the Holocene suggests that inbreeding on the northern Channel Islands had all but ceased by the end of the first millennium B.C., most likely as a result of increased cross‐channel migration and interaction. Am J Phys Anthropol 143:155–160, 2010. © 2010 Wiley‐Liss, Inc.     

Brief communication: Study of noncarious cervical tooth lesions in samples of prehistoric,historic, and modern populations from the South of France

Noncarious tooth lesions (NCTL) are frequent findings in contemporary dental practices. Unlike other dental and periodontal diseases, NCTL have not been studied in an anthropological context. The purpose of the present study was to compare the prevalence of NCTL in three archaeological samples from the Copper Age and Middle Ages and in subjects examined in three dental practices. Both archaeological samples and dental-practice subjects were from southern France. In the archaeological sample group, no NCTL were detected in 3,927 teeth from 259 individuals. In the dental-practice group, prevalence rates were in agreement with current epidemiological data. Our data also suggest that prevalence of NCTL increases with age and is higher in females. Premolars were the most affected tooth type. Occurrence of NCTL has long been attributed to toothbrushing and to erosion by intrinsic and extrinsic acids. More recently, occlusal stress associated with tooth flexure has been implicated. The reasons underlying the total absence of NCTL in archaeological samples are discussed. The most likely explanations involve differences in lifestyle, diet, and dental condition.     

Technical Note: Cervical dimensions for in situ and loose teeth: A critique of the Hillson et al. (2005) method

In 2005, Hillson and colleagues developed a method for obtaining cervicometrics on a collection of loose teeth. However, I identified problems with the method when trying to apply it to material from archaeological collections with a mixture of in situ and loose teeth. The correct placement of the caliper tips at the suggested mesiodistal landmarks proved impossible for many in situ teeth. Their recommendation to rotate teeth to access the suggested landmarks resulted in large errors because not all teeth could be rotated. Other problems were identified with the suggested buccolingual dimensions of molars, which produced measurements that are not homologous across tooth class because of differential reduction in the distal cusps. Am J Phys Anthropol 154:159–164, 2014. © 2014 Wiley Periodicals, Inc.     

Brief communication: correcting overestimation when determining two-dimensional occlusal area in human molars

The robustness index (RI) is determined by multiplying dental mesiodistal and buccolingual diameters, and is used to estimate occlusal area. However, because teeth are not rectangular its calculation consistently causes overestimations. Moreover, teeth, in particular molars, are not identically shaped so overestimations vary. The current study seeks to determine the extent to which overestimations are affected by tooth shape and to improve RI's efficacy. Initially, 120 molars were sorted into six shape groups, which were determined by hypocone/hypoconulid expression. Three maxillary and three mandibular shape groups were set using the Arizona State University Dental Anthropology System. ANOVA results determined that RI overestimations, which averaged around 20%, were not the same for each shape category. Maxillary molars with large hypocones and mandibular molars with no hypoconulids were overestimated significantly less than the other molar groups. Regression-based correction formulae were generated and applied to the original sample. These formulae far more precisely estimated tooth area than RI and there were no differences in estimation based upon tooth shape. A subsequent validation study of 24 additional molars was undertaken to test the formulae on teeth not from the original sample. Overestimation/underestimation averaged 0.5% and was about the same for each of the tooth shape groups. Finally, six new correction formulae were generated using all 144 molars. The correction formulae provide, what is termed here, an adjusted robustness index (ARI), and it is recommended that ARI is used in future studies of molar occlusal area.     

Brief communication: Early hominin variability in first molar dental trait frequencies

This report documents greater variability in early hominin first molar dental trait frequencies than previous research indicated. Specifically, frequencies of several M1 dental traits that previously appeared to uniquely characterize Paranthropus are shown here to resemble those of the A. afarensis sample from Hadar. Like Paranthropus, A. afarensis from Hadar has a high frequency of cusp 6 and a low frequency of the protostylid. Paranthropus and A. afarensis are also not statistically significantly different in their frequencies of LM1 cusp 7, although this cusp is actually absent in the latter. Both groups differ significantly from A. africanus in their frequencies of these traits. Based on the developmental biology of molar cusp patterns, we suggest that the morphological similarities between Paranthropus and the Hadar sample may be homoplasies.     

Brief communication: The distribution of perikymata on Qafzeh anterior teeth

Recent studies have suggested that Neandertals and modern humans differ in the distribution of perikymata (enamel growth increments) over their permanent anterior tooth crowns. In modern humans, perikymata become increasingly more compact toward the cervix than they do in Neandertals. Previous studies have suggested that a more homogeneous distribution of perikymata, like that of Neandertals, characterizes the anterior teeth of Homo heidelbergensis and Homo erectus as well. Here, we investigated whether Qafzeh anterior teeth (N = 14) differ from those of modern southern Africans, northern Europeans, and Alaskans (N = 47–74 depending on tooth type) in the percentage of perikymata present in their cervical halves. Using the normally distributed modern human values for each tooth type, we calculated Z‐scores for the 14 Qafzeh teeth. All but two of the 14 Qafzeh teeth had negative Z‐scores, meaning that values equal to these would be found in the bottom 50% of the modern human samples. Seven of the 14 would be found in the lowest 5% of the modern human distribution. Qafzeh teeth therefore appear to differ from those of modern humans in the same direction that Neandertals do: with generally lower percentages of perikymata in their cervical regions. The similarity between them appears to represent the retention of a perikymata distribution pattern present in earlier members of the genus Homo, but not generally characteristic of modern humans from diverse regions of the world. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Basics in paleodemography: a comparison of age indicators applied to the early medieval skeletal sample of Lauchheim

Recent advances in the methods of skeletal age estimation have rekindled interest in their applicability to paleodemography. The current study contributes to the discussion by applying several long established as well as recently developed or refined aging methods to a subsample of 121 adult skeletons from the early medieval cemetery of Lauchheim. The skeletal remains were analyzed by 13 independent observers using a variety of aging techniques (complex method and other multimethod approaches, Transition Analysis, cranial suture closure, auricular surface method, osteon density method, tooth root translucency measurement, and tooth cementum annulation counting). The age ranges and mean age estimations were compared and results indicate that all methods showed smaller age ranges for the younger individuals, but broader age ranges for the older age groups.     

Brief communication: Short- and long-term in vivo human buccal-dental microwear turnover

Buccal-dental microwear depends on the abrasive content of chewed foodstuffs and can reveal long-term dietary trends in human populations. However, in vivo experimental analyses of buccal microwear formation processes are scarce. Here, we report the effects of an abrasive diet on microwear rates in two adult volunteers at intervals of 8 days over a period of 1 month and document long-term turnover over 5 consecutive years in the same subjects under an ad libitum Mediterranean diet. Buccal microwear was analyzed on mandibular first molars using high-resolution replicas and scanning electron microscopy. Microwear turnover was assessed by recording the scratches lost and gained at each time point. Our results indicate that scratch formation on enamel surfaces increased with a highly abrasive diet compared to both pre-test and post-test ad libitum dietary controls. In the long-term analysis, scratch turnover was higher than expected, but no significant long-term trends in microwear density or length were observed, because microwear formation was compensated by scratch disappearance. Our results confirm that buccal microwear patterns on mandibular molars show a dynamic formation process directly related to the chewing of abrasive particles along with ingested food. In addition, the observed long-term stability of buccal microwear patterns makes them a reliable indicator of overall dietary habits.     

Emergence of deciduous teeth in Punjabi children, north India.

Data on deciduous tooth emergence of 312 children aged 4 to 31 months of Punjabi parentage are presented. Probit analysis was used to derive the median age of tooth emergence. Female children are found to be advanced with respect to tooth emergence than their male counterparts. While comparing the present data with those from other populations it is found that, in general, the mean number of emerged teeth in Punjabi children is more at most ages, with lower median age of eruption for most teeth. Magnitude of interage variability in the eruption times is noticed to be maximum in the 16-17 and 20-21 months age groups. The findings of the study suggest that number of teeth can be used as a parameter for the estimation of age.     

Brief communication: The use of alternative dental measurements on deciduous teeth

The present study investigates the utility of cervical measurements in deciduous teeth and how they correlate with traditional measurements of the crown. First, this study establishes definitions by which these measurements could reliably be taken. Next, deciduous cervical and traditional crown diameters were taken on three distinct skeletal samples: a Neolithic assemblage from Central Anatolia (Çatalhöyük, n = 85), a precontact sample from Northern California (CA‐ALA‐329, n = 34), and a group of intrusive burials interred at Çatalhöyük that date between AD 60 and 1650 (n = 38). Across the dentition there are positive correlations between crown and cervical measurements, which tend to be higher in anterior teeth than in posterior teeth. Both measurements show low correlations with age; however, cervical measurements show fewer negative correlations with age. An intraobserver error study found low levels of error for both types of measurements. On a subset of the Çatalhöyük sample (n = 9), a principal components and biological distance analysis were conducted comparing the two types of measurements. Also, all three samples were subject to a canonical discriminant function analysis and the results from cervical and crown measurements were compared. All analyses produced slightly different results for each type of data suggesting that crown and cervical measurements capture different aspects of tooth shape. While cervical and crown measurements provide different statistical results, cervical measurements can provide information relevant to anthropological studies and may allow for larger datasets to be used by allowing the inclusion of teeth with modified crowns. Am J Phys Anthropol 149:299–306, 2012. © 2012 Wiley Periodicals, Inc.