A preliminary description of the dental morphology of the Peruvian Indian

A geometric morphometric approach to the study of variation of shovel-shaped incisors

OBJECTIVES

The scoring and analysis of dental nonmetric traits are predominantly accomplished by using the Arizona State University Dental Anthropology System (ASUDAS), a standard protocol based on strict definitions and three-dimensional dental plaques. However, visual scoring, even when controlled by strict definitions of features, visual reference, and the experience of the observer, includes an unavoidable part of subjectivity. In this methodological contribution, we propose a new quantitative geometric morphometric approach to quickly and efficiently assess the variation of shoveling in modern human maxillary central incisors (UI1).

MATERIALS AND METHODS

We analyzed 87 modern human UI1s by means of virtual imaging and the ASU-UI1 dental plaque grades using geometric morphometrics by placing semilandmarks on the labial crown aspect. The modern human sample was composed of individuals from Europe, Africa, and Asia and included representatives of all seven grades defined by the ASUDAS method.

RESULTS

Our results highlighted some limitations in the use of the current UI1 ASUDAS plaque, indicating that it did not necessarily represent an objective gradient of expression of a nonmetric tooth feature. Rating of shoveling tended to be more prone to intra- and interobserver bias for the highest grades. In addition, our analyses suggest that the observers were strongly influenced by the depth of the lingual crown aspect when assessing the shoveling.

DISCUSSION

In this context, our results provide a reliable and reproducible framework reinforced by statistical results supporting the fact that open scale numerical measurements can complement the ASUDAS method.

Expression of Carabelli trait in children from Southern India - A cross sectional study

BACKGROUND

The distribution of the Carabelli trait is highly variable in different regions and races of the world.

OBJECTIVE

To determine the prevalence of Carabelli trait in a group of children from Nellore.

MATERIALS AND METHODS

Children who attended the department between October 2011 to March 2012 were selected and examined for the expression of Carabelli trait in the maxillary primary second molar, permanent first and permanent second molars on the basis of the classification developed by Kraus and standards developed by Dahlberg.

STATISTICAL METHODS

Descriptive statistics was performed and the relative frequency of expression in each category, according to Kraus's and Dahlberg's classification was calculated. Sexual dimorphism was statistically analyzed using Mann-Whitney U-test.

RESULTS

A total of 89.8% of primary second molars, 63.7% of permanent first molars, and 8% of permanent second molars showed some form of expression of Carabelli trait in the target population.

CONCLUSION

Though there was a high frequency of intermediate expressions of this trait, occurrence of a definite cusp of Carabelli on the primary maxillary second molar and permanent maxillary first molar was relatively infrequent. A high percentage of the permanent maxillary second molars showed complete absence of Carabelli trait and there was no sexual dimorphism. Bilateralism with varying degrees of asymmetry was noted and there was tendency for concordance between the two sides but not within individual sides.

Dental relatedness corresponding to mortuary patterning at Huaca Loro, Peru

Within and between tombs at the 1,000-year-old site of Huaca Loro on north coastal Peru, interment characteristics vary to an intriguing degree. Following and elaborating upon prior intracemetery studies, biological relatedness among associated burial groupings was assessed using 23 dental characters (assuming familial allele segregation) for 29 individuals. Biological patterning was based on multivariate distance between individuals using all traits, rather than the previously widespread reliance upon univariate comparison of each trait separately within samples. This multivariate approach did seem more informative. Statistically significant variation of biological similarities and dissimilarities corresponded to spatial groupings and also to various specific archaeological indications of the cohesiveness, or lack thereof, of interment pattern. The partition of biological distances among tombs at Huaca Loro supports the archaeological evidence that the tombs represent a planned elite cemetery.

Morphologic characteristics of the Alaskan Eskimo dentition: IV. Cusp number and groove patterns of mandibular molars

Data on the permanent dentition of 63 coastal and 33 inland Alaskan Eskimos are presented. The number of cusps and groove pattern of the mandibular molars were recorded. Agenesis of the mandibular third molars was classified and the mesiodistal and buccolingual crown diameter was measured on the first and the second mandibular molars. The predominant pattern of the lower first molars was Y5, while for the second molar the dominating patterns were +5 and +4. In the lower third molar, +5 was found in the majority of cases. For M1 and M2, men showed a stronger tendency toward a conservative pattern than did women. In the case of M2, the inland population exhibited a more conservative trait than did the coastal population. No connection was seen between the groove pattern and agenesis of M3, however, a reduction in the mesiodistal crown diameter for the second molars was seen when the number of cusps is reduced from 5 to 4.

Variability of a dental morphological trait

A study of morphologic variability was made for maxillary incisor lingual fossa depth. The problem of variability is discussed, and new methods for the statistical treatment of variability are presented. Possibly, the best procedure to express biologic variability is to present SDs, CVs, Xs, ranges, RCs, and the logarithmic graphic method of the relationship between CV and X. No sex differences in variability could be demonstrated. Maxillary centrals and laterals in the Eskimo were found to have relatively equal variability. This is seen in connection with the great functional demand on Eskimo incisors, giving less reduction of the laterals, a possible simultaneous commencement of calcification for I1sup and I2sup, and possible genetic drift. Comparison of variability for six populations shows no racial differences in variability. Variability is not found to increase with inbreeding. Population comparisons do not confirm little reduction in the Eskimo to be associated with high variability. Genetic drift might be the explanation of the homogeneity of maxillary incisor lingual fossa depth in East Greenland Eskimos.

The depth of the lingual fossa in permanent maxillary incisors of East Greenland Eskimos. II. Side asymmetry, sex differences, comparison of centrals and laterals and anthropologic aspects

Maxillary incisor lingual fossa depth was measured on casts of East Greenland Eskimo dentitions. No directional side asymmetry was found. The present study is the only which shows mean lingual fossa depth to be significantly deeper in the female than in the male. Larger incisor strength in the females is functional as the females are known to use their incisors as tools. The present investigation shows that on the question of sex differences conclusions should be drawn for the examined population only, and that generalization to other populations should be avoided. Mean lingual fossa depths were significantly different for centrals and laterals, but the laterals demonstrate special lack of reduction in this population. Lack of reduction of incisors together with frequent agenesis of third molars demonstrate that the posterior dentition may reduce independently of the anterior dentition. Mean lingual fossa depth, and relative fossa depth, in East Greenland Eskimos clearly show Mongoloid values.

Tooth size of Ticuna Indians, Colombia, with phenetic comparisons to other Amerindians

This study reports an odontometric analyses of unadmixed, adult Ticuna Indians, Colombia, South America. This group is characterized by crown diameters intermediate in size relative to the known Amerindian range and, in turn, to the range in modern man. Sex dimorphism is absent in Ticuna tooth size; there is a strong retention of the MI > M2 size sequence. The Ticuna are compared multivariately to other Indian groups reported in the literature, using the size and shape coefficients of L.S. Penrose. Tooth size clusters the groups into small, medium, and large-toothed classes, but does not yield a pattern attributable to known genetic or historical affinities. Shape coefficients distinguish Indians from non-Indians (Caucasian, Negroid, and Australian samples), primarily on the basis of 11-12 proportionalities. Neither size nor shape discriminates between North and South American groups.

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 fossa depths in Norwegian Lapps clearly fall within the Caucasoid range.

Dental condition of two tribes of Taiwan aborigines--Ami and Atayal

This is a study of dental and oral conditions of Taiwan aborigines from the epidemiological and anthropological points of view. A total of 166 Ami and 128 Atayal adolescents were included from their original living area, the Hwa-Lien Hsin and Wa-Lai District, Taiwan, Republic of China. Oral examination was done carefully and caries incidence, periodontal index, and Angle's Classification combined with OFI were included. After that, hydrocolloid impressions were taken, and dental casts were immediately made. The mesiodistal and buccloingual crown diameters and also the arch depth and width were measured using a sliding caliper. Dental morphological traits, such as shovel-shaped incisors, Carabelli's cusp, protostylid, and upper and lower molar groove patterns were observed and classified, and the results are given with statistical analysis. The aborigines have a quite low incidence of dental caries and periodontal disease which may be related to their dietary habits, good oral hygiene, and good dental occlusion. With regard to the differences between the Ami and Atayal, most of the date show no statistical significance except in the dental occlusion. The Atayal's occlusion is better than that of the differences of genetics or other factors. There are no sex differences in all the date in the dental survey, but there are sex differences in both the misiodistal and buccolingual crown diameters of both the Ami and Atayal tribes (the tooth crown of the male subjects is invariably broader and larger than that of females). In the dental arch dimensions, most of the data show no sex diffreence, except in the breadth of the upper and lower dental arch of the Atayal. Anthropologically, there are no statistical differences, in mesiodistal and buccolingual crown diameters and most of the data of dental arch dimesions, but there is a difference in arch depth in Ami and Atayal adolescents. The Atayal have a deeper dental arch than do the Ami. As for dental morphologi, the Taiwan aborigines have a high frequency of shovel-shaped incisors and Carabelli's trait but a relatively low frequency of protostylid. There are no definite differences between races in the occlusal pattern of maxillary first molars, but there are differences in the maxillary second molars. The usual pattern is 4-- for the upper first and second molars of the Taiwan aborigines as well as for thedibular occlusal pattern, the first molar tends to follow the primitive "dryopithecus" pattern of 5 cusps and Y configuration, but in the second molar there are varying degrees of departure from Y5 to the more advanced +4 pattern with +5 and Y4 as intermediates.

A comparative study on the dental health status of five precolumbian Peruvian cultures

In a survey of dental health status of ancient Southern Peru, 101 skeletal remains were studied from five cultures: Paracas, Nazca, Tiahuanaco, Ica, and Inca. The Paracas and Ica cultures exhibited more missing antemortem teeth per mandible than the other cultures. Frequency of missing one or more third molars was less than expected and not as high as reported in peoples of Mongoloid heritage. The Paracas, Ica and Nazca, "coastal" cultures had a higher caries incidence than the "inland" cultures. Whether this relates to some difference in diet or water supply remains unresolved and warrants further investigation. Moderate attrition was noted in all the Precolumbian cultures but pulpal involvement was not observed. Osteitis, noted in all the cultures, was more pronounced in the Nazca, Paracas and Ica cultures. There appeared to be a direct relationship between caries involvement and the number of missing antemortem teeth to osteitis. Calculus was heavier in the Paracas and Ica cultures. In addition, the Paracas culture exhibited a dark brown stain on the teeth which may imply some difference between the cultures in either the food, water or social habits.

Some observations on the dentition of an isolated group in northeast Poland

Clinical examination of the teeth and the mouth was carried out on a group of 133 "Old Believers," 54 males and 79 females, and a control group of 138 Poles living in the same area of Augostova in northeast Poland, 63 males and 75 females. Studying the frequency of Carabelli's cusp, shovel-shaped incisors, missing teeth, microdonita, supernumerary teeth, and torus palatinus in both groups, it was found that Carabelli's cusp and torus palatinus are more frequent among Poles. Such differences could be attributed to differences in ethnic origin of the two groups.

Genetic structure of a tribal population, the Yanomama Indians. XIII. Dental microdifferentiation

Data are presented on the frequency of the following eight dental traits in 635 Yanomama and 65 Makiritare Indians: upper central incisor rotation or winging, shoveling of maxillary incisors, maxillary molar hypocone reduction, Carabelli's trait, mandibular molar cusp number, mandibular molar cusp pattern rotation of second lower premolar, and pattern of second lower premolar cusps. Yanomama dentition is unusual in the high frequency of six cusps on the mandibular molars. There is marked dental microdifferentiation between villages; significant agreement was observed between a matrix of pairwise "dental distances" based on six morphological traits and corresponding matrices based on 11 genetic systems and on geographic location.

Dental abnormalities in the deciduous and permanent dentitions of individuals with cleft lip and palate

ANORMALITATES DENTAL IN LE DENTITION PRIMARI E PERMANENTE DE INDIVIDUOS CON FiSSURA DE LABIOS E/o DE PALATO.—Le dentitiones primari e permanente de 39 subjectos con fissura del labios e/o del palato esseva studiate a base de material in le collection de modulos serial del Centro pro le Studio de Palatos Fisse al Universitate Illinois. Le objectivo esseva determinar le natura, le frequentia, e le distribution de anormalitates morphologic del coronas. Plus anormalitates dental occurreva in fissuras palata que in altere typos. Ex un gruppo total de 1716 unitates dental, 189 esseva anormal (11 pro cento). In casos de fissura palatal, le dentes mandibular esseva afficite non minus frequentemente que le dentes maxillar.