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

International audienc

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

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.Facultad de Ciencias Naturales y MuseoConsejo Nacional de Investigaciones Científicas y Técnica

Exposition environnementale au bruit et à la pollution de l'air au cours de la grossesse avec comorbidités associées: Un sur risque d'accouchement prématuré ? Résultats de l’étude PrémaBquA

International audienceL’objectif était d’analyser le lien entre l’exposition environnementale au bruit et à la pollution de l’air en milieu urbain et la prématurité chez les femmes dont le risque d’accouchement prématuré était augmenté par la présence d’une ou plusieurs comorbidités. Méthode. Une étude cas-témoins a été conduite sur les grossesses uniques accompagnées d’au moins une comorbidité. Les accouchements ont eu au CHU de Besançon ou de Dijon entre 2005 et 2009. Le niveau sonore de nuit (Lnight en façade du bâtiment d’habitation) et la concentration en dioxyde d’azote (NO2) dans les 50 m autour de l’habitation ont été modélisés à l’adresse déclarée au moment de l’accouchement. Une régression logistique conditionnelle a été conduite. Résultats Au total, 507 cas et 1 996 témoins ont été inclus. Les expositions résidentielles moyennes au bruit (Lnight) et au NO2 étaient respectivement de 52,3 dB(A) et de 25,0 µg.m-3. Le nombre moyen de comorbidités par femme était de 1,7 (étendue=1-6) ; L’odds ratio associé à la prématurité était, pour 2 comorbités, de 1,17 (IC95%:1,34-2,18) et, pour 5 à 6, de 12,57 (IC95%: 4,29-36,80). Les odds ratios associés à la prématurité étaient de 1,23 (IC95%:0.97-1.56) pour une valeur de Lnight ≥ 55 dB(A) et de 0,83 (IC95 %: 0,61-1,13) pour une concentration environnementale en NO2 ≥ 40 µg.m-3. Discussion. Les résultats sont en faveur d’une relation de type dose-réponse entre le nombre de comorbidités et le risque de prématurité. Chez les femmes enceintes dont le risque de base est augmenté du fait de la présence d’une ou plusieurs comorbidités, le risque d’accouchement prématuré ne semble pas être augmenté par une exposition à de faible concentration de NO2. En revanche, les résultats sont compatibles avec un effet modéré de l’exposition environnementale au bruit sur le risque de prématurité

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.Supplementary material: Table S1 Supporting Information Table 1. Visual scoring performed by two independent observers (intra‐ and interobserver tests). SSc: Statistical Scoring; VS1T1: Visual scoring Observer 1 Test 1; VS1T2: Visual scoring Observer 1 Test 2; VS2: Visual scoring Observer 2. In some cases, the observers gave an intermediate rating (0_1 meaning a category between ASUDAS references 0 & 1). Table S2: Supporting Information Table 2. Definition of UI1 shoveling grades (Scott et al., 2018; Scott & Irish, 2017; Turner et al., 1991). Table S3: Supporting Information Table 3. Correlations between various measurements obtained from the coordinates of the 7 ASUDAS reference casts. The ASUDAS category values were also compared against these metrics. Table S4: Supporting Information Table 4. Correlations between various measurements obtained from the coordinates of all French samples (both contemporary and medieval). Maximum depth and hollow area are the directly measured metrics based on the non‐Procrustes alignment method. Principal components were obtained from both Procrustes and non‐Procrustes methods. Only PC1 is presented here for simplicity. Shades of color represent the degree of correlation, with darker green corresponding to the highest degrees and white to the lowest degree. Table S5: Supporting Information Table 5. Correlations of rater‐assigned ASUDAS categories with various measurements obtained from the coordinates of all French samples. Figure S1 Supporting Information Figure 1. Principal Component loadings represented as PC shape changes. Results are shown here for non‐Procrustes PCs; the plots for Procrustes PCs are very similar. The axes are same as in Figure 2. The black line, showing the shape for ASUDAS reference cast category 3, indicates the baseline in all figures. The thick colored curve in each figure represents a + 1 unit shift toward the direction of the PC from the baseline. Thin dotted lines join the coordinate of each of the 100 points before and after the shift, thus representing the amount and direction of shift for each point.Toulouse Dental Faculty (PLTRO); Midi‐ Pyrenées Region; Université Toulouse III–Paul Sabatier; CHU de Toulouse; Université de Toulouse; French CNRS; Arizona State Universityhttps://wileyonlinelibrary.com/journal/ajpahj2020Anatom