Variation in Dental Crown Morphology in Malaysian Populations

Dental crown variation was studied inthe four main population groups living in Malaysiausing dental casts (upper and lower) obtained from 790individuals. The aims of the study were to characterizevariation in 13 dental crown traits, within groups as wellas between groups, and to assess affinities between thegroups based on frequencies of occurrence of dentalfeatures. Using chi-square analysis and Fisher’s exacttest, the majority of dental traits were found to bebilaterally symmetrical and to demonstrate low sexualdimorphism. Comparisons of trait frequencies betweengroups revealed similarities between Malays, Jahai(Negritos) and Chinese who conformed to MongoloidSinodont-Sundadont dental patterns, whereas theIndians conformed to an Indo-European pattern.Phenetic distance analysis, using the mean measureof divergence, showed that Indians were markedlyseparated from the other three groups, while Malayswere closer to Jahai than to Chinese. These findingsbased on dental traits are consistent with historicalexplanations of affinities between modern Malaysianpopulations.

Frequency and Variability of Five Non-Metric Dental Crown Traits in the Primary and Permanent Dentitions of a Racially Mixed Population from Cali, Colombia

The purpose of this study was to determinethe prevalence and variability of five non-metric dentalcrown traits (Carabelli cusp, protostylid, groove pattern,and cusps 6 and 7) in the deciduous (Um2 and Lm2)and permanent (UM1 and LM1) teeth in children inthe mixed-dentition, and to compare these frequencieswith the literature. A descriptive study was conductedto characterize the dental morphology of young subjectsin mixed dentition stages. The Arizona State UniversityDental Anthropology System (ASUDAS) and Grine,Sciulli, and Hanihara methods were used as referenceto compare the prevalence of dental traits in dentalcasts from 100 subjects from a Colombian racially mixedpopulation. The high prevalence of furrows and pits ofthe Carabelli cusp, minor expressions of the protostylid(foramen cecum), and the low frequencies of cusps 5 and6, plus the behavior of the expression of groove patterncollectively suggest that this group reflects influences byboth the Mongoloid and Caucasoid dental complexes.Correspondence of trait expression in both the primaryand permanent dentition was also demonstrated (P< 0.05). Some of the non-metric trait frequencies alsoexhibited sexual dimorphism.

Wheat shovelomics II: Revealing relationships between root crown traits and crop growth

Optimization of root system architecture represents an important goal in wheat breeding. Adopting new field methods for root phenotyping is key to delivering this goal. A novel ‘shovelomics’ method was applied for phenotyping root crown traits to characterize the Savannah x Rialto doubled-haploid (DH) population in two field experiments under irrigated and rain-fed conditions. Trait validation was carried out through soil coring on a subset of 14 DH lines and the two parents. We observed that drought reduced grain yield per plant by 21.0%. Under rain-fed conditions, nodal root angle and roots shoot-1 were positively associated with root length density (RLD) at 40-60 cm depth; RLD was also positively correlated with grain yield. Nodal root angle and roots shoot-1 were also positively associated with canopy stay green and grain yield under rain-fed conditions. We conclude that shovelomics is a valuable technique for quantifying genetic variation in nodal root traits in wheat, revealing nodal root angle and root number per shoot provide useful selection criteria in breeding programs aimed at improving drought tolerance in wheat.HighlightNodal root angle and number shoot-1 measured using ‘shovelomics’ were positively associated with root density at depth and yield under drought in a Savanah x Rialto wheat DH population.

Mixed dentition Morphology characteristics: a correlation between 3 non-metric dental traits in temporal and permanent dentition in scholars from Cali - Colombia

Summary: Objectives: Determine the correlation of the frequency and variability of three Non-metricdental crown traits (Carabelli cusp, protostylid and molar pattern cusp) between deciduous (um2/lm2)and permanent (UM1/LM1) teeth in mixed-dentition subjects. Materials and methods: A descriptivestudy was conducted to determine the dental morphology in mixed dentition stage of young subjects.The Arizona State University Dental Anthropology System ASUDAS and Grind and Sciulli Methods wereused as reference to compare frequency of dental traits in dental casts of 100 young individualsracially mixed. Results: A high expression of furrows and pits of the Carabelli cusp, a highfrequency of protostylid in degree 1 (foramen secum) and a expression of molar pattern cusp,revealed that the studied population received influences of the Mongoloid and Caucasoid dentalcomplexes. Correspondence on the traits expression among temporal and permanent dentition was alsoconfirmed. Bilateral symmetry and sexual dimorphism in the analyzed non-metric dental crown traitswere found. Key words: Dental anthropology. Dental morphology. Non-metric dental crown traits. Mixeddentition.

Paramolar tubercle on second upper left premolar - a case report

Summary: This paper is a casereport description of the paramolar tubercle presence on the buccal surface of left upper secondpremolar (25 tooth). The description was done under the dental anthropology point of view and thistooth mark may be useful to classify and identify human populations. Key words: Dental anthropology.Dental morphology. Non-metric dental crown traits. Paramolar tubercle.

Frequency and variability of dental morphology in deciduous and permanent dentition of a Nasa indigenous group in the municipality of Morales, Cauca, Colombia

Objectives: To determine the frequency, variability, sexual dimorphism and bilateral symmetry of fourteen dental crown traits in the deciduous and permanent dentition of 60 dental models (35 women and 25 men) obtained from a native, indigenous group of Nasa school children of the Musse Ukue group in the municipality of Morales, Department of Cauca, Colombia. Material and methods: This is a quantitative descriptive, cross-sectional study that characterizes dental morphology by means of the systems for temporary dentition from Dahlberg (winging), and ASUDAS (crowding, reduction of hypocone, metaconule and cusp 6), Hanihara (central and lateral incisors in shovel-shape and cusp 7), Sciulli (double bit, layered fold protostylid, cusp pattern and cusp number) and Grine (Carabelli trait); and in permanent dentition from ASUDAS (Winging, crowding, central and lateral incisors in shovel-shape and double shovel-shape, Carabelli trait, hypocone reduction, metaconule, cusp pattern, cusp number, layered fold protostylid, cusp 6 and cusp 7). Results: The most frequent dental crown features were the shovel-shaped form, grooved and fossa forms of the Carabelli trait, metaconule, cusp pattern Y6, layered fold, protostylid (point P) and cusp 6. Sexual dimorphism was not observed and there was bilateral symmetry in the expression of these features. Conclusions: The sample studied presented a great affinity with ethnic groups belonging to the Mongoloid Dental Complex due to the frequency (expression) and variability (gradation) of the tooth crown traits, upper incisors, the Carabelli trait, the protostylid, cusp 6 and cusp 7. The influence of the Caucasoide Dental Complex associated with ethno-historical processes cannot be ruled out.