The depth of the lingual fossa in permanent maxillary incisors of Norwegian Lapps

The depth of the lingual fossa in permanent maxillary incisors of three groups of Norwegian Lapps was measured. No statistically significant sex differences or group differences were found. The assembled weighted estimates for lingual fossa depth of three groups of Norwegian Lapps were for I₁ sup: 0.44 mm and I₂ sup: 0.30 mm. Mean lingual fossae depths in Norwegian Lapps clearly fall within the Caucasoid range.     

Family studies of tooth size factors in the permanent dentition.

Correlations between dimensions of the permanent teeth in Australian Aboriginals were studied by factor analysis to disclose the main sources of shared variability. Findings indicated that in both males and females most of the common variability in the tooth dimensions could be accounted for by factors representing mesiodistal size of anterior teeth, buccolingual size of anterior teeth, generalized size of the premolars and generalized size of the molars. Factor scores derived from the analysis were used to calculate intraclass correlations among brothers and among sisters. These correlations tended to be higher for the factors contributing most to the common variability indicating that the factors might represent fields under direct genetic control. There was no trend for intraclass correlations among siblings derived from multivariate scores to be consistently higher than those based on observed tooth dimensions. The main advantage to the user of factor analysis is the ability to interpret associations between interrelated variables more objectively than is possible by conventional correlation methods.     

An analysis of cercopithecoid odontometrics. I. The scaling of the maxillary dentition.

The relations between two tooth indices, post-canine area and incisor width in the upper jaw, and three variables, diet, body weight and body weight dimorphism, were examined separately for the males and females of 29 cercopithecoid species. Each species was assigned to one of three diet classes (folivore, frugivore, omnivore). Data on the other variable consisted of species means (log-transformed) obtained from published sources. The analytic techniques used were bivariate and multiple regression, the tooth indices being the dependent variables. All tooth indices scaled isometrically within diet classes, and all except female incisor width scaled with positive allometry across diet classes. In both sexes, the body weight adjusted mean incisor width of folivores was significantly smaller than that of either frugivores or omnivores. In the females, the body weight adjusted mean post-canine areas did not differ significantly across diet classes, while in the males the omnivores had a larger body weight adjusted mean post-canine area than either the folivores or frugivores. Female post-canine area was the only tooth index for which body weight dimorphism was a significant predictor. Extrapolations of these findings to other extant and to fossil primate species are discussed.     

Crown variations in the permanent teeth of modern man

In an attempt to synthesize the very numerous studies of crown variations, we have established global averages of certain dental traits for different human populations. We have classified seven of the most discriminant characteristics: mesiodistal and buccolingual crown diameters, shovel-shape form in the upper incisors, the number of upper and lower molar cusps, Carabelli's cusp, and the occlusal surface patterns.     

An analysis of cercopithecoid odontometrics. II. Relations between dental dimorphism, body size dimorphism and diet.

Odontometric, dietary, and body weight data were collected for a sample of 29 cercopithecoid species. Each species was assigned to one of three diet classes (frugivore, folivore, and omnivore) , and indices were constructed to estimate the extent of sexual dimorphism in body weight, postcanine area and incisor width in each of the species. Analysis proceeded by means of the analysis of covariance with the dental dimorphism indices as the dependent variables. Body weight dimorphism was not significantly related to either measure of dental dimorphism across the sample, and an analysis by diet alone revealed that omnivores show significantly higher dental dimorphism than do either of the other two diet classes. The relationship between this result and theories of sexual subniche differentiation is discussed.     

The size and morphology of the Nasioi dentition

Dental impressions were obtained on 240 Nasioi, a Melanesian population living on the island of Bougainville. Odontometric data are presented for both the permanent and deciduous teeth, and the former teeth are also examined morphologically. The results show that the Nasioi have large permanent teeth like other Australoid populations whereas the deciduous teeth are only of moderate size. The coefficients of variation are large in the permanent teeth compared to other populations but the sexual dimorphism in tooth size and variability is not remarkable. Morphologically, the permanent teeth of the Nasioi are characterized by a cusp number pattern, a high frequency of the Dryopithecus + pattern on the first mandibular molar, few individuals with a Cusp of Carabelli, and a moderate expression of shovelled-shaped anterior teeth.     

Secular changes in the angle of divergence of the first two metatarsals in the Japanese

This investigation concerns secular changes of the intermetatarsal M1-M2 angle in the foot of Japanese, from the prehistoric Jomon period to early modern times. The divergence of the first metatarsal from the second in both sexes in the reconstructed tarsometatarsal bones gradually decreased during this period. In addition, the difference between sexes or sides in each period is small and statistically insignificant. With time, the first metatarsocuneiform angles, in both sexes, also decreased in parallel with the reduction of the intermetatarsal M1-M2 angle, while the second metatarsocuneiform angles in both sexes increased. Both may play a role in decrease of the intermetatarsal M1-M2 angle. A conspicuous angular divergence of the first metatarsal from the second one occurred in comparatively recent times. This change would be accelerated by modification in life-style, together with the effects of footwear.     

Developmental abnormalities of the permanent dentition in prehistoric Ohio Valley Amerindians

The frequencies of developmental abnormalities in size, shape, number of teeth, and enamel formation are presented for a sample of 389 prehistoric Ohio Valley Amerindians from the following cultural complexes: Glacial Kame, Adena, Ohio Hopewell, Cole, Fort Ancient, and Erie (Whittlesey Focus). In addition, the magnitude of fluctuating asymmetry is determined for each tooth and for individuals of these groups. Tests of association indicate complexes with Late Diffuse economic adaptations (Glacial Kame, Adena, Hopewell) exhibit significantly higher frequencies of numerical abnormalities of M₃ and M³ enamel pearls, while Late Focal complexes (Cole, Fort Ancient, Erie) exhibit a higher frequency of severe, general linear enamel hypoplasia. The magnitude of fluctuating asymmetry is, however, generally the same in the Late Diffuse and Late Focal groups. The occurrence of two rare abnormalities with large genetic components, essentially limited to one Hopewell and one Adena mound, raises the possibility that the individuals interred in these mounds are biologically related. Since it is widely held that mound burials represent a status class of the population, it is likely that the Late Diffuse sample is biased in favor of a number of highly select population segments each of which contains biologically related individuals. Accordingly, the lower frequency of severe, general linear enamel hypoplasia in Late Diffuse groups is hypothesized as the result of the more advantageous circumstances expected for high status individuals, and the higher frequencies of numerical abnormalities of M₃ and M³ enamel pearls are hypothesized primarily as the result of mitigated selection on masticatory complex integration, and/or a biased sample. Comparisons with the deciduous dentition show the permanent teeth exhibit higher frequencies of developmental abnormalities. This result is explicable in terms of the more favorable developmental environment of the primary teeth, or a stronger developmental canalization.     

Interrelation between fusions in the primary dentition and agenesis in the succedaneous permanent dentition seen from an embryological point of view

The purpose of the present study was to elucidate the relationship between fusions in the primary dentition and the occurrence of agenesis in the succedaneous permanent dentition in a Danish child population and to elucidate this relationship from the recently described normal embryological development of the anterior parts of the human maxilla and mandible. The material included radiographs, either as intraoral film or as orthopantomograms from a total of 19 primary dentitions with a total of 21 fusions. Radiographs of the permanent dentition in the fusion regions were available for all 19 dentitions. Of 21 fusions, a total of 20 were in the mandible and one in the maxilla. In 15 cases, the fusions were between primary incisors and in six cases between lateral incisors and canines. Agenesis of a permanent lateral incisor always occurred when there had been fusion of a primary lateral incisor and a canine in the primary dentition. When fusion had been between primary incisors, there was only agenesis of an incisor in the permanent dentition in a few cases. The degree of fusion between the involved teeth was not related to the occurrence of agenesis. It is suggested that the intra-jaw differences are related to the recently reported prenatal developmental patterns of the alveoli of the incisors and canines. Moreover, it is suggested that neural crest developmental field differences between the developing maxilla and mandible may explain the inter-jaw differences in phenotypic abnormalities.     

Size and morphology of the permanent dentition in prehistoric Ohio Valley Amerindians.

Metric and morphological characterizations of the permanent teeth from a total of 155 prehistoric Amerindians are presented. The individuals represent samples from three Ohio Valley burial complexes (considered together as the Late Diffuse group): Glacial Kame, Adena and Ohio Hopewell. Metric data include common measures of central tendency and dispersion. From these measures estimates and analyses of the magnitude of sexual dimorphism and relative variability are presented as well as analyses of the patterns of these estimates. Forty morphological characters are also tabulated. The results indicate a number of provisional hypotheses: the generally larger tooth size of the Late Archaic Indian Knoll when compared to the Late Diffuse groups is consistent with the hypothesis of mitigated selective pressures in more technologically advanced groups; although tooth size is smaller in the Late Diffuse groups, dental morphology is as complex, or more so when compared to the Indian Knoll group. Since morphology and size do not covary exactly the biocultural forces resulting in smaller tooth size do not seem to act as strongly on dental morphology; odontological differences within the Late Diffuse arise primarily between the Glacial Kame-Adena and the Ohio Hopewell. These differences correspond to major biocultural changes in this area; although provisional hypotheses concerning odontological variability are erected, hypotheses concerning evolutionary trends must await the discovery of evolving lineages within these groups; similarities are noted among all compared groups including the pattern and magnitude of sexual dimorphism and relative variability. These parameters may be similar for all eastern Amerindians during this period; finally, the morphology of the deciduous dentition, which generally predicts that of the permanent teeth, is found to be less complex than the permanent teeth. This may be the result of a selective disadvantage for the individuals in the deciduous dentition sample which is reflected in the dentition.     

Comparative odontometry of the permanent post-canine dentition of American Whites and Negroes

The permanent post-canine teeth of American Whites and American Negroes of the New York City area were studied odontometrically. The mesio-distal and bucco-lingual dimensions of the crowns were measured, as was the total tooth height and crown height. The individual root lengths of these teeth were also measured, in several ways, as was root width. The mean total root volumes of these teeth was measured by a unique mercury displacement method. In another aspect of this study the mean angular divergence of the roots from a mid-coronal vertical plane was determined, while the robustness of these roots was described as a ratio between root width and length. Finally, an extensive comparison was made between our data and those in the literature on a number of African Negro populations. American Negro tooth crown and root dimensions and volumes were significantly different from those of American Whites only sporadically, although the Negro teeth usually tended to be larger. Our comparative data gave some indication that the size of both the maxillary and mandibular American negro teeth, as well as the shape of the mandibular (but not the maxillary) American Negro teeth are roughly intermediate between those of American Whites and South African Negroes. This suggestion that a “hybrid” population may possess intermediate values of crown index and of crown module is supported by our analysis of Hottentot-South African Negro hybrids with their presumptive parental stocks.     

Patterns of tooth size variability in the dentition of primates

Published data on tooth size in 48 species of non-human primates have been analyzed to determine patterns of variability in the primate dentition. Average coefficients of variation calculated for all species, with males and females combined, are greatest for teeth in the canine region. Incisors tend to be somewhat less variable, and cheek teeth are the least variable. Removing the effect of sexual dimorphism, by pooling coefficients of variation calculated for males and females separately, reduces canine variability but does not alter the basic pattern. Ontogenetic development and position in functional fields have been advanced to explain patterns of variability in the dentition, but neither of these appears to correlate well with patterns documented here. We tentatively suggest another explanation. Variability is inversely proportional to occlusal complexity of the teeth. This suggests that occlusal complexity places an important constraint on relative variability within the dentition. Even when the intensity of natural selection is equal at all tooth positions, teeth with complex occlusal patterns must still be less variable than those with simple occlusion in order to function equally well. Hence variability itself cannot be used to estimate the relative intensity of selection. Low variability of the central cheek teeth ( \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm M}\frac{1}{1} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm M}\frac{2}{2} $\end{document}) makes them uniquely important for estimating body size in small samples, and for distinguishing closely related species in the fossil record.     

Ethnic and secular influences on the size and maturity of seven year old children living in Guatemala City

Three groups of children, those of European parentage, those of Guatemalan parentage, and those of mixed European-Guatemalan parentage were measured for height, weight, and skeletal maturity. The children were born between 1945 and 1965, they were all of high socioeconomic status, and they all attended the same private school in Guatemala City. At 7 years, the boys of the European group were significantly taller than boys of the Guatemalan group. European and mixed European-Guatemalan girls were significantly taller than Guatemalan girls. These results are maturity independent. The influence of skeletal age was removed statistically by analysis of covariance. Girls of the mixed group were significantly heavier than girls of European and Guatemalan groups. Mixed group girls also had more significantly advanced skeletal ages than European girls. When the patterns of size and maturity status are analyzed by sex, there is evidence for a relatively greater environmental influence on the boys and a relatively greater genetic influence on the girls. Dividing the data into two birth year cohorts, 1945 to 1955, and 1956 to 1965, does not provide evidence for secular trends in growth or maturation. These results are similar to those from studies in developed nations that report an end to the secular trend for the “well off” population of those countries.     

Comparison of the increase in body size between 1899 and 1970 in a specially selected group with that in the general population

Height and weight data for varsity football players from 1899 to 1970 were analyzed for evidence of a secular trend in such a specialized sample. Recent football teams ('61–'70) are, on the average, 2.6 inches (6.6 cm) taller and 35.3 pounds (16.05 kg) heavier than the teams at the turn of the century (1899–1910). The estimated trend over the 70 year span was 0.37 inches (0.94 cm) per decade for stature and 5.04 pounds (2.29 kg) per decade for weight. Unfortunately, it is not possible to partition these trends and obtain separate estimates for the “secular” effects and for those effects that might be attributed to “recruiting practices.” The observed trend for stature in football players corresponds with the upper limit of the estimated range for adult secular trend data for stature from Western European countries, and is greater than that reported for American young adult males both in college and in the general population.     

Development of the orangutan permanent dentition: Assessing patterns and variation in tooth development

This study examines dental formation and alveolar emergence in a large cross-sectional sample composed primarily of wild-reared orangutans (N = 89) in order to provide information on the development of the permanent dentition in this hominoid and to address questions of variation in individual tooth formation, between teeth and between individuals. All specimens have been radiographed in lateral aspect and stages of crown and root formation recorded for all teeth. The ranges of crown and root formation of I¹₁, C¹₁, P⁴₄, and M³₃ have been calculated relative to the stage of M₁¹ development within a specific tooth quadrant. Then, for each specimen, BMDP scatterplot and nonparametric statistics have been used to graph changes in stages of these teeth relative to M¹₁ stages and to examine relationships between pairs of upper and lower dental counterparts and between teeth of each jaw. Results indicate 1) high correlations between upper and lower tooth pairs and between many of the permanent teeth within individuals, 2) a relatively large range of variability in individual tooth development (multistage ranges relative to M¹₁), 3) greater variation in root development at emergence than earlier reports, and 4) evidence of variability within the sequence emergence pattern of the orangutan. © 1996 Wiley-Liss, Inc.     

Factors affecting the distribution of enamel hypoplasias within the human permanent dentition

Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0-2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0-6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable "polar" teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length and direction, may influence the development and expression of enamel surface defects.     

Aspects of dental development in the orangutan prior to eruption of the permanent dentition

In spite of a resurgence of interest in the interpretation of the sequences of dental development and eruption in various Plio-Pleistocene hominoids as being either “modern human” or “ape-like,” the body of comparative material on the extant hominoids remains deficient in critical areas. In concert with recent attempts to rectify this situation, we present the results of our studies on dental morphogenesis in the orangutan. We have focused on the growth and eruption of the deciduous dentition as well as early stages of permanent tooth formation and have found that 1) many permanent teeth develop earlier than was thought, 2) differences exist between development in the upper and in the lower jaw, and 3) states of tooth formation can vary significantly among individuals of similar chronological age or tooth eruption status.     

Size and shape in similarity coefficients based on metric characters

A variety of quantitative measures of distance and similarity have been used in physical anthropology, often without sufficient prior testing of their usefulness and understanding of their meaning. A variety of such coefficients were compared by applying them to an odontometric sample. It was found that Penrose's size-shape dichotomy extends not only to his coefficients but to all other similarity measures as well, such as the coefficient of racial likeness, generalized distance, canonical variates, and Q-mode correlation. Only size differences were detected by the C.R.L., Penrose's size distance, D², and canonical variates, and as a result these methods failed to produce an accurate classification. Penrose's shape distance and Q-mode correlation coefficients produced better results due to their determination of similarity on the basis of more important shape and morphological differences. The D² and canonical variates methods were converted to shape measures through Q-mode standardization of the raw data, whereupon they also produced more meaningful results.